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Project Specific Discussions => Dynamic Processors => Topic started by: Igor on June 03, 2010, 08:44:20 PM

Title: MixBuzz500 build/support tHread
Post by: Igor on June 03, 2010, 08:44:20 PM
Hi to all!

Here is the build/support thread for MixBuzz500,
full-featured GSSL...well, this is actually 4000' deck on-board compressor
with provision for GSSL link and cool sidechain features.

Started here:
http://www.groupdiy.com/index.php?topic=24404.0

Than,
http://www.groupdiy.com/index.php?topic=38730

Let's keep this tHread clear and elegant as possible.
Only questions related to troubleshooting, assembly and part sourcing.

We already have funny half-spammed ordering tHread...
than, feel free to post all other MixBuzz500-related questions here:
http://www.groupdiy.com/index.php?topic=38730

I will post tomorrow assembly guide with pictures....

For now, please download docs and BOM!!!!

http://twin-x.com/groupdiy/thumbnails.php?album=405

(docs_v1_4.zip contains last updated information, some errors in BOM's were fixed)

Farnell p/Nr's looks like #1123700 in Bom's.
Paste them into Farnell search field (without "#" )
For sure, there are other alternatives. All this is welcome,
maybe, somebody will help us with Mouser or Digikey order codes.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on June 05, 2010, 07:52:19 PM
And here are the pictures of build progress.
Descriptions will be added later as well as VCA notes, adjustment procedure, etc.

Here's the album with photos:
http://s251.photobucket.com/albums/gg291/diy33609/mixbuzz500/

And...

(http://i251.photobucket.com/albums/gg291/diy33609/mixbuzz500/P1040866.jpg)


(http://i251.photobucket.com/albums/gg291/diy33609/mixbuzz500/P1040870.jpg)
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on June 06, 2010, 06:33:46 AM
Note about VCA.

I tested this compressor with DBX202X, replacement board with 4xTHA2181( A and C),
and replacement board with 1xTHAT2181C. For other VCA's, R100, R3, R4 on audio board can be different.

DBX202X has internal resistors on inputs 8x10K, than, input resistance should be skewed
by 1k25. Control port impedance is 832 Ohm. I.e. R6=3k74, R3=4k99, R100=909R.

On VCA replacement board supplied with kit, there are 4x2181 VCA's, input resistors are 4x20k,
and control port impedance is same as 202x 832 Ohm).
I.e. R6=jumper (0R), R3=4k99, R100=909R.

For "more sound" use only one THAT2181C, bit misadjusted for more harmonics.
In this case, install only one VCA and according resistors on input board,
no change in control port circuit (NE5534, 100R, 732R).
In this case, R3=20k, R6=0R (jumper), R100=909R.
It is possible to lower C1 down to 22pF.

/BOM values are right.

For other VCA's, refer to datasheet for input, control port and output resistors.
DBX VCA datasheets can be found in useful_stuff1.zip

Sidechain VCA's.
Simplest and cheaper solution is THAT2180C, don't install SC_SYM trimpot and R33.
There's no need for A version VCA in sidechain.

Trimpot adjustment.
Adjust for minimum distortion with analyzer (audio) and 0mV dc offset (sidechain).
Don't have analyzer?
Sidechain: adjust for 0.0 mV DC at IC11a, NE5532, pin1
Audio: adjust for 0.0 mV DC at IC11b, NE5532, pin7
{fixed}

Sidechain trimpot (RV1) on audio PCB: changes threshold point... install 5k1 and forget.
Threshold trim (TR_TRM): changes threshold zero. Omit (install nothing) and forget!!!
(Or use side screw, 50k, 10(25) turns trimpot to change 0db threshold point @ratio=4).

Added at July 11th.
Some words about testing the unit.
IMHO, easy way to do this is connect power supply to all boards
via 3-pin Molex connectors and use pair of same cable assembly's for audio.
I.e. take 5 of Molex 3-pin/2.54 pitch connectors,
MOLEX - 22-27-2031 #9731156
MOLEX - 22-01-2035 #1697895
MOLEX - 08-50-0032 #9773789

SOLDER 20-25cm wires to "crimp" pins;
Than, connect 3 of wire assembly's in parallel-this is for power supply.
Feed audio in/out via 2 wire assembly's left.  If somebody need picture,
tell me to post.
--------------
Other way is testing inside the 51X (500) rack.
Take other modules from rack (if your 51X rack is full of them :)
Solder 3x25 cm wires from front panel PCB power supply
connector to one of audio PCB's, and use longer (20-25cm) ribbons.

Check CTL and SC ribbons goes to according boards, say, CTL1/SC1 to left etc.
Put audio PCB's inside the rack, to slots...say 3 and 7.
This way, we have some space inside the rack to put scope probe or multimeter.
Check unit is passing audio with unity gain (make-up at 0) and measure DC offsets.
If audio PCB's soldered without mistakes, it should power up fine from first take.
The rest is just test the ratios and maybe change R60.
------------------------
Update July 12th.
Ratio calibration.
There's lot of info about this, search forum. Just want to add some
info gathered from building some MixBuzzeZZZZ
and real life experience with nice 4000G lady.
Actually, this is feedback compressor which is built across sidechain VCA.
After all, the control signal for sidechain VCA mixed with MAKEUP control voltage,
/sorry my english :) / than controls AUDIO VCA.
The ratio of "sidechain compressor" is a bit higher than actual audio ratio.
Mind, there's no log converter and linear rectified signal controls log VCA's ports.
There's kinda slope limiter after 1.3v threshold at ratio "1:2", but,
this is not logging, again.
To be at perfectionist's side, it is possible to measure the sidechain's ratio first
by measuring signal at IC11A, pin1, applying first signal 2db down threshold
(not to be misunderstood, 2db gain reduction), than
applying 10 or 20db more and measuring output again at IC11A, pin1.
If 1% resistors used, I think, it is useless procedure, but...just to be at safe side.
My sidechain ratios were constant for all builds, about 2.1:1, 4.3:1 and 10.5:1.
Than, we go to audio, input signal is to let meter show 1-2 db GR, measuring output,
input signal 10 or 20 db more, measuring output.
Less R60 higher the ratio, more R60 lower the ratio.
I needed to change it to 33R only with DBX202X VCA.
/Yours 202x can differ/
However, there can be slight differences inside same batch of VCA's,
some adjustment may be needed.
I got to exactly 2,4,10 in 3 of MixBuzz500.

Added July 27th.

Use regular, 5 or 5.08mm pitch, 50...63V film capacitors for sidechain filters.

Important parts quality-wise are in audio path.
C1, C2, C3, C4, C5, C6, C7, R3, R4, R5, R6, R100, IC11 are critical parts.

The rest of parts should be within the specs, like in BOM.

Use 1% metal film for precision, except R96, 98, 87, 89-these resistors goes to LED's, relays, etc.
They can be 10% carbon resistors.
R87/R98: 1/4W, 10%, closer value to calculated (see BOM).

12V relays. Coil resistance should be more than 250 Ohm. 90% of relays are within this spec.
Each slot consumption according to Lunchbox specs should be less than 80mA.
It is better to spent these milliamperes to OPA2604 and quad/eight (DBX202X) VCA.
I recommend to use relays with more than 500 Ohm coil resistance.
This data easy to get from datasheet.
My MixBuzz500 has 960 Ohm coil relays.
It doesn't adding the cost (I paid approx. $2.5 per relay).

Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on June 06, 2010, 04:11:27 PM
Hey Igor looks fantastic, looking forward to my kit arriving.
Just going thru the BOM, and wanted to check re. the Sifam meter, [cos they're not cheap!]. Your Farnel code brings up what I think is the back of panel mounting version? I thought we needed the 'B' version, for front of panel mounting with the full bezel.
Just wanted to be sure.

Thanks for all the hard work you've put into this project.

Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on June 07, 2010, 05:50:13 PM
the sifam meter is 1262061 and bezel B is 1262079, everithing is good.
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on June 07, 2010, 06:19:46 PM
Ah, my mistake. Sorry. Thanks for clearing that up.


Title: Re: MixBuzz500 build/support tHread
Post by: Igor on June 12, 2010, 08:31:48 PM
Regarding the meter, Ptownkid's should fit fine (according to datasheet).
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on June 12, 2010, 09:51:10 PM
HI,
with my poor english i'm not sure to be in the good way for R87, R98
To deteminate it

Quote
DEPENDS ON RELAY'S COIL RESISTANCE; THE MATH IS SIMPLE:
RELAY'S PAIRS ON AUDIO BOARDS CONNECTED IN SERIES, I.E. 12+12=24V;
POWER SUPPLY IS +/-16V (32V RAIL-TO-RAIL);
VOLTAGE DROP ON R87+R98 IS 8V; THAN:
R87=R98=(RREL/6) (ONE SIXTH'S OF RELAY COIL RESISTANCE)

that mean it's a 2X2.2 A around 6A
so  8/6= 1,33k for relay 12V

Right?
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on June 12, 2010, 09:58:12 PM
A-ha! Simply, measure relay's coil resistance with multimeter, or get it from datasheet.
My 12V relays has 980 Ohm coil. 980/6=167 Ohm; closer value is 160 or 180 OHM,
1/2W or 1W resistors will be fine there.
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on June 13, 2010, 08:27:19 AM
thank Igor, it's a sign it's your ppost number 1176, your futures 500 series project talk
Title: Re: MixBuzz500 build/support tHread
Post by: JamesW on July 02, 2010, 10:53:24 PM
Igor thanks for this project what is the current draw for the unit
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 03, 2010, 06:07:28 PM
Depending on op-amps/VCA's/relay's/VU illumination LED's etc used, 70...200mA.
Useful link:
http://il.farnell.com/molex/92321-1010/cable-assembly-ribbon-10way-10cm/dp/1012202

Test proc/assembly guide coming soon.
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 03, 2010, 09:47:39 PM
HI ,
just one questions about the 5mm led, the + is on the plate of round, first up second down ...
?



perhaps a newbie question

Thank you


 
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 04, 2010, 05:44:09 PM
OOPS!
Usually, anode is round, cathode is flatten.
My miss, I forgot to print +/- for 5mm led's on PCB.
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 05, 2010, 02:58:14 PM
OOPS!
Usually, anode is round, cathode is flatten.
My miss, I forgot to print +/- for 5mm led's on PCB.
no it's just a new reason to lurn something, for me.

Bests
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 05, 2010, 07:03:44 PM
new questions ,
 does the crimp power on the 12v relay need to be linked with the power crimp of one audio pcb please?
that what i seen on your picture.

do i have to joined ( stuffed ) the SJ point?

and CAPACITOR CBP should be 100nf what does it change please?



thanks
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 05, 2010, 07:35:32 PM
Power-3 pin connector on small pcb located at the back of front panel
should be connected to one of boards.
Crimp or not to crimp: up to you. I used to solder these pins.
Another solution is:
http://il.farnell.com/jsp/level5/module.jsp?moduleId=en/230246.xml
http://il.farnell.com/phoenix-contact/1725669/terminal-block-pcb-2-54mm-3way/dp/3041360
You need only one side at connector, second side of cable can be soldered to PCB.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 05, 2010, 07:39:36 PM
BTW. I cut crimp pins after soldering. This way it goes really easy.
Mogami thin microphone cable is my favorite for in/out shielded connections.
This is the way how it looks finished:
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 05, 2010, 08:11:17 PM
thank you i have some pin connector at home, and soory i would to says pin connector not crimp.

Quote
Mogami thin microphone cable is my favorite for in/out shielded connections.
This is the way how it looks finished:
but this are just for the calibration, right?

and what about the other question please


Quote
do i have to join ( stuff ) the SJ point?

and CAPACITOR CBP should be 100nf what does it change please?
cause one is almost finish avtualy my wife is in hospital, when i'm not with her, visiting, i stuff or i sleep.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 05, 2010, 09:50:17 PM
Yes, this is just for calibration.
It is easy to calibrate the unit (if audio boards stuffed correct :) just with use of 51x rack, four 20cm length 10-pin ribbons, and 20cm wires going to 3-pin Molex (for front PCB power).
This is what I did with first unit.
As we doing thing in 500-format, and have to calibrate it, there's some mess,
but Mixbuzz500 done with mind to minimize it.

Other option to calibrate the unit is 4x3-pin Molex connectors (2xpower, IN and OUT).
Power should be connected for both L and R sides when adjusting.
I have only one channel of analyzer (sorry, I don't trust to PC soundcard based analyzers....
or maybe my hardly modyfied Boonton 1120 lies, hmmmmm.....as when laptop's
onboard soundcard shows 107 db s/n in RMAA, I want to kill the man who invited RMAA :)

SJ points. Mixbuzz done with thought it should be modular, and SJ points reserved for
C&B option. If there's no C&B, these points should be connected, like picture shows.
http://i251.photobucket.com/albums/gg291/diy33609/mixbuzz500/P1040223.jpg
http://i251.photobucket.com/albums/gg291/diy33609/mixbuzz500/P1040224.jpg

To all builders:
Please check this thread:
http://www.groupdiy.com/index.php?topic=39897.0
When you put Mixbuzz500 in 51x rack, please do it carefully /not to short power supply.
PUT TABS at pin16!!!!!
All my new 51X/500 projects will be done with the SLUT at pin 16 ;)
BTW. I thought a bit about 500 API etc racks and got to mind it was bad possible
format for keeping the audio till 51X racks came! Shame!!!! only 800 milliamperes for
11 modules at +/-16 volts!!!! No way. My 51x rack's power supply was tested at 1.5A each +/-16 and +/-24V, all loaded at same time, and noise (without weighting filters, hate'em more than Mondeal), was -89 db ref 1V AC at worst case at -16V....
Maybe RMAA was showing -130db :)
IMHO this is OK for audio. How people was able to live before 51x format appeared?
:)
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 06, 2010, 03:37:16 PM
Got a good question by e-mail and like to share it:
Quote
Will a dbx 202xt work fine in the unit? I can get a pair of them. Would the input resistance be different from the 202x?
According to 202XT datasheet, voltage control constant is -20db/volt, same as 202x.
Input impedance is 1k25/same again. Control port impedance is 810...832R, by datasheet, it is same as 202x....
DBX202XT has different control schematic than 202X, it use both inverting and non-inverting ports of VCA's.
IMHO, bit useless...anyway, so they did :)
Try R6=3k74, R3=4k99, R100=909R. IMHO this will work fine.
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 06, 2010, 03:41:00 PM
same value as 202X
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 06, 2010, 04:52:14 PM
I never tried 202XT, but 99.9% yes.
X and XT using different schematics for control port,
in XT version, control voltage goes to both + and - control ports of VCA's
(inverted to EC- and non-inverted to EC+).
Title: Re: MixBuzz500 build/support tHread
Post by: jensenmann on July 07, 2010, 04:46:39 AM
Gentlemen, what´s up with our twin-x galery? Igors link to his zip files doesn´t work anymore. Igor, any chance to host it somewhere else?
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on July 07, 2010, 05:36:07 AM
Hi.
Please excuse some noob questions. I'm in the UK and I'm having trouble sourcing some parts. Farnell's site always wants to direct me to their US supply for lots of the parts, and don't seem to have some parts in the right size. e.g. control PCB C30/31 220UF in 2.5mm pitch.
UK people, who do you look to first for components?

I was going for Panasonic for the general electrolytics, is there a particular series I should be looking for? and how about for the audio grade electrolytics? Panasonic again, or Nichicon or?

Jensenmann, do you mean the docs for Mixbuzz? I saw them still up there earlier? I can email them to you if you pm me.

Thanks and apologies...
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 07, 2010, 05:48:39 AM
C30/C31 can be 3.5mm pitch, 8 mm diameter as well. Will fit fine.

I like these caps (again, personal taste, your choice can be different:
http://il.farnell.com/jsp/level5/module.jsp?moduleId=en/388706.xml
http://il.farnell.com/jsp/level5/module.jsp?moduleId=en/438036.xml
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 07, 2010, 05:50:46 AM
@jensenmann: strange...it works now!
In case you need docs to be sent to your mail, feel free to email/pm.
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on July 07, 2010, 11:47:29 AM
Hi,
What are the specs of the Elma knobs you used in this build?  I'm looking to order some. Thanks!
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on July 07, 2010, 12:20:33 PM
Quote
Hi,
What are the specs of the Elma knobs you used in this build?  I'm looking to order some. Thanks!

No Elma here, Lorlin and Bourns, documents (BOM etc...) can be found on first page.
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on July 07, 2010, 12:50:10 PM
C30/C31 can be 3.5mm pitch, 8 mm diameter as well. Will fit fine.

I like these caps (again, personal taste, your choice can be different:
http://il.farnell.com/jsp/level5/module.jsp?moduleId=en/388706.xml
http://il.farnell.com/jsp/level5/module.jsp?moduleId=en/438036.xml


Thanks Igor I'll get back to filling the order form....

Farnell's site is sloooooow

AG
Title: Re: MixBuzz500 build/support tHread
Post by: desol on July 07, 2010, 12:50:51 PM
Received the MixBuzz today...this sunny day. Like clockwork...as usual Igor. :)
Title: Re: MixBuzz500 build/support tHread
Post by: JamesW on July 07, 2010, 01:18:17 PM
C30/C31 can be 3.5mm pitch, 8 mm diameter as well. Will fit fine.

I like these caps (again, personal taste, your choice can be different:
http://il.farnell.com/jsp/level5/module.jsp?moduleId=en/388706.xml
http://il.farnell.com/jsp/level5/module.jsp?moduleId=en/438036.xml


Thanks Igor I'll get back to filling the order form....

Farnell's site is sloooooow

AG
Digikey list these Panasonic caps under "M" series
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 07, 2010, 04:18:14 PM
hi,soon i 'll have to calibrate the unit

i did it like that

Quote
DBX202X has internal resistors on inputs 8x10K, than, .
Control port impedance is 832 Ohm. I.e. R4=3k74, R3=4k99, R100=909R.

THAT2180C, don't install SC_SYM trimpot and R33.
There's no need for A version VCA in sidechain.

Sidechain trimpot (RV1) on audio PCB: changes threshold point... install 5k1 and forget.
Threshold trim (TR_TRM): changes threshold zero. Omit (install nothing) and forget!!!

well just need:Audio: adjust for 0.0 mV DC at IC11b, NE5532, pin1 it's trimmer SYM right?

could i calibrated it one board audio by one without controle board if not one by one with controle board?

cause i'll used the card edge connector linked to 51X prototyping PCBs
(http://www.silentarts.de/DIY/GDIY51X/IMG_5902.jpg)

thanks




Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on July 07, 2010, 04:27:16 PM
Quote
Hi,
What are the specs of the Elma knobs you used in this build?  I'm looking to order some. Thanks!

No Elma here, Lorlin and Bourns, documents (BOM etc...) can be found on first page.

I believe Igor used Elma knobs (not switches) for his build.  I am a noob, I wanted to know where to source those knobs.
Thx.
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 07, 2010, 04:28:56 PM
yes i think you right it's elma knobs perhaps you could find it on farnells
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on July 07, 2010, 04:43:08 PM
Quote
I believe Igor used Elma knobs (not switches) for his build.  I am a noob, I wanted to know where to source those knobs.
Thx.

Oh excuse my french, i mismatch knobs with pots  ::), yes elma knobs, well Farnell has black ones and some in grey, you have to choose the cap color and with or without line, or arrow on the bottom, just put Elma in the search field, and i found a swiss distributor that has most of them, but never dealed with them yet, www.distrelec.ch, you need to choose your county tough, price changed according to that, better to live in EU.
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on July 07, 2010, 05:57:17 PM
Quote
I believe Igor used Elma knobs (not switches) for his build.  I am a noob, I wanted to know where to source those knobs.
Thx.

Oh excuse my french, i mismatch knobs with pots  ::), yes elma knobs, well Farnell has black ones and some in grey, you have to choose the cap color and with or without line, or arrow on the bottom, just put Elma in the search field, and i found a swiss distributor that has most of them, but never dealed with them yet, www.distrelec.ch, you need to choose your county tough, price changed according to that, better to live in EU.

C'est pas grave!  :)  I'm finding it very difficult to find a lot of audio electronic parts here in Ontario.  I'm sure some of you Ontarians on this forum could chime in with info, it would be greatly appreciated.  The best around here is Sayal, but their selection is limited.  I'm sure there's some hidden Gems in Toronto.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 08, 2010, 04:24:50 AM
Quote
well just need:Audio: adjust for 0.0 mV DC at IC11b, NE5532, pin1 it's trimmer SYM right?
If everything assembled ok, yes :)

Quote
could i calibrated it one board audio by one without controle board if not one by one with controle board?
Yes, to check if the audio path is OK it is enough.
To check the compressor, everything-both audio boards
and control board - should be powered!


Quote
cause i'll used the card edge connector linked to 51X prototyping PCBs
Of course.

Quote
I'm finding it very difficult to find a lot of audio electronic parts here in Ontario.

I didn't used any exotic parts. Most of stuff available from Mouser/Farnell/Digikey.
THAT chips, meter and ELMA knobs, are all available from Farnell/Newark.
Please let us know what parts are hard to source for you.
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on July 08, 2010, 04:47:49 AM

cause i'll used the card edge connector linked to 51X prototyping PCBs
(http://www.silentarts.de/DIY/GDIY51X/IMG_5902.jpg)

thanks

Hey Stereokillah.

Do you have many spare edge connectors like in the picture? I'm building my mixbuzz for a 6 slot lunchbox and it's tight in there. They'd be handy for making a testing setup.

AG
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 08, 2010, 05:11:47 AM
Please PM me, I did some test PCB's like on the picture.
Can send a pair on request for free, just pay shipping cost.

Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on July 08, 2010, 08:32:34 PM
Thanks for the info Igor.
Farnell, Digikey and Mouser don't have a shop in Canada.  It's the duties/taxes that I'd like to avoid if possible.  UPS/Fedex are brutal for that.  Last thing I bought from the US was a microphone capsule for $125 and the tax/duty came out to $57!! I can buy alot of parts here, but stuff like meters, THAT VCAs, and things that are more "audio related" seem to be much harder to source.  Thanks again for your input.  Can't wait to put your kit together!
Title: Re: MixBuzz500 build/support tHread
Post by: mikefatom on July 08, 2010, 08:56:38 PM
dbeeson,

I buy pretty much ALL of my parts from Digikey.ca/Mouser Canada and never have an issue with duties/brokerage. They are paid for by Digikey and Mouser themselves. The good thing about Digikey is that they only charge $8 (duties/brokerage paid for) for shipping and it usually arrives the next business day (depends on when you place the order).
Mouser on the other hand charges $20 with the same terms.

Both will ship for free for order over $200CAD.

I almost always have a pending order from them :).

Farnell also has a Canadian webstore.

Hope that helps,

Cheers

Mike

Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 08, 2010, 10:38:30 PM
ok after reading the schema, i found some infos, thz jumper JP1 need to be conected only if we want to bypass the Sidechain filter
and i think there is a typo here
Quote
Sidechain: adjust for 0.0 mV DC at IC11a, NE5532, pin7
Audio: adjust for 0.0 mV DC at IC11b, NE5532, pin1


in fact with the schema should be

Sidechain = RV1= IC11a = pin1

Audio = SYM = IC11b = pin7

this would explain why when I use the trimmer SYM does not change the voltage on pin1

o my dog i'm gone be ingenier  :o ;D ;D ;D ;D joke



Title: Re: MixBuzz500 build/support tHread
Post by: diyfanatic on July 09, 2010, 04:35:12 AM
Quote
o my dog

 ;D ;D ;D
Title: Re: MixBuzz500 build/support tHread
Post by: RedNoise on July 09, 2010, 06:43:24 AM
o my dog i'm gone be ingenier  :o ;D ;D ;D ;D joke

Ahahahahaa!!! ;D ;D ;D ;D
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 09, 2010, 11:57:24 AM
it's alive  ALIVE!!!!!

(http://i296.photobucket.com/albums/mm171/renbis/CIMG0017.jpg)

all mode work just one thing , the ratio  on 4000 mode compress even ifthere is no sound , the meter give more than 8 of db rection like on my picture , perhaps i cause i've not put the TR TRimmer or pehaps one error.

and don't forget to link the 3 point on the side of switch on off on if not the relay could not work and the unit stay in bypass

Title: Re: MixBuzz500 build/support tHread
Post by: RedNoise on July 09, 2010, 12:19:48 PM
thumb up my friend!!! ;)
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on July 09, 2010, 12:20:20 PM
Does any one know what chip to use to give me the biggest tonal difference from a Roll Music Super Stereo?  I have one of those and love it and would like to have a mixbuzz that is different tonally and such.  Thanks.  Another great project by Igor.
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on July 09, 2010, 12:35:52 PM
First out of the gate Stereokillah, and looking sweet.

What are people using for sockets for the 2181 chips?



AG
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on July 09, 2010, 01:56:20 PM
Stereokillah, well done! 
Mike, thanks for the info.  I didn't know those companies had Canadian distribution. 
I'm wondering if this meter from hairball is a direct replacement for the AL19 used in this build:
http://hairballaudio.com/shop/product_info.php?cPath=25&products_id=61

Anybody know?
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 09, 2010, 02:38:06 PM
Thank you every body.
Quote
"dbeeson" I'm wondering if this meter from hairball is a direct replacement for the AL19 used in this build:
  yes this model have the exact size and fsp  like AL19 it's the substitute

Quote
What are people using for sockets for the 2181 chips?
you could use the half of Tl074 socket, i used socket line 40 pin that should be cut by 8 pin i found it on ebay but don't rembember where.
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 09, 2010, 06:25:43 PM
after some test i found other problem but not the error, the output signal is like limiteur, with the makeup or with source the sound can't be more than -14db peak on my protools.

 
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 10, 2010, 08:13:46 PM
Stereokillah: you FAST!!!!!! Congrats, and let's see how we fix it together.

Quote
in fact with the schema should be

Sidechain = RV1= IC11a = pin1

Audio = SYM = IC11b = pin7

Thanx for pointing to this. My mistake. Fixed.

I updated third post of this thread.

Now, little by little.
I thought pictures shows it clear that unit should be tested outside the rack.

Quote
all mode work just one thing , the ratio on 4000 mode compress even ifthere is no sound ,
the meter give more than 8 of db rection like on my picture ,
perhaps i cause i've not put the TR TRimmer or pehaps one error.
I think there's an error here.
Let's do next. Take the unit outside the rack and connect it with Molex connectors,
in/out and power supply. Power supply should be connected to both audio and control pcb's.

Or, disassemble it and put audio pcb's into slots and use longer wires to front panel.

First thing we do, is check audio passing at unity gain when makeup at zero.
Than, the rest.

Check CTL1 and SC1 goes to left, CTL2 and SC2 goes to right.
Check if there's no mess with power connection to front PCB.

Quote
and don't forget to link the 3 point on the side of switch on off on if not the relay could not work and the unit stay in bypass
That's right :)
This jumper is for people who will use the unit in GSSL or Gyraf mode only,
but... just put a solder joint here to have both options.

Quote
after some test i found other problem but not the error, the output signal is like limiteur, with the makeup or with source the sound can't be more than -14db peak on my protools.
Something is wrong. Let's check audio for unity gain first.
What VCA's are used? Maybe, wrong resistor somewhere?
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 10, 2010, 09:17:19 PM
hi igor,

thanks for congrats without my wife in house i have so much time to do what i want.

Quote
Quote
all mode work just one thing , the ratio on 4000 mode compress even ifthere is no sound ,
the meter give more than 8 of db rection like on my picture ,
perhaps i cause i've not put the TR TRimmer or pehaps one error.
I think there's an error here.
Let's do next. Take the unit outside the rack and connect it with Molex connectors,
in/out and power supply. Power supply should be connected to both audio and control pcb's.



Or, disassemble it and put audio pcb's into slots and use longer wires to front panel.

First thing we do, is check audio passing at unity gain when makeup at zero.
Than, the rest.

Check CTL1 and SC1 goes to left, CTL2 and SC2 goes to right.
Check if there's no mess with power connection to front PCB.

yes i found the error this morning it was one diode on controle board in a bad sens "RESOLVED"

before pput it in the box i've calibrated it but now is disassambled and i test it with 15pins edge connector and prototyping PCBs

this is what i did exactly

-CBP 100nf AVX

- relay coil resistance is 360ohm well tbd is 60ohm 1/2

- VCA dbx 202X R4=3k74, R3=4k99, R100=909R + timmer  ( 5532 pin7 is at 0.0mV )

- dip tl074 5532 1646 1246 tl072

- VCA sidechain THAT2180C without trimmer

- trimmer sidechain filter changed to 5k1 pin 1 and 3
 
- no trimmer on TR TRM

during this message i found one thing perhpas should help us : on the bom you said R6 3k74 but on the thread you said R4 perhaps and i put 3k74 on R6 and R4 but R4 need to be 0R right?


once again an aclamation for Inspector COLOMBO. ;D ;D ;D ;D ;D ;D ;D ;D ;D
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 10, 2010, 09:49:58 PM
I understand you. Hope the things will be better.

Quote
yes i found the error this morning it was one diode on controle board in a bad sens "RESOLVED"

Tell us which one. Does the unit works now?

Quote
-CBP 100nf AVX
Or X7R, etc. 47nf...0.22uF will do the job.

Quote
- relay coil resistance is 360ohm well tbd is 60ohm 1/2
I used relay's with coil resistance about 1k. Less current, less load for power supply.
Your math is right.

Quote
- VCA dbx 202X R4=3k74, R3=4k99, R100=909R + timmer  ( 5532 pin7 is at 0.0mV )

R6=3k74, R3=4k99, R100=909R.
R4 is ferrite bead or jumper.
Killah, many thanx for pointing on this!
I had 2 schematic versions, corrected 3rd post of this thread.

Quote
- dip tl074 5532 1646 1246 tl072

- VCA sidechain THAT2180C without trimmer

- trimmer sidechain filter changed to 5k1 pin 1 and 3
 
- no trimmer on TR TRM
Right

Quote
during this message i found one thing perhpas should help us :
on the bom you said R6 3k74 but on the thread you said
R4 perhaps and i put 3k74 on R6 and R4 but R4 need to be 0R right?

R6=3k74, R3=4k99, R100=909R.
R4 is ferrite bead or jumper..


Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 10, 2010, 10:02:27 PM
it's 4 am oclock in france i will try the unit this afternoon,

Quote
Tell us which one. Does the unit works now?
for the ratio 2 in 4000 mode the error was D8 i I put in the wrong direction, it work fine just still have limiting
Quote
Or X7R, etc. 47nf...0.22uF will do the job.
yes it's 100nf X7R not avx

i put ferrite instead of 3k74 on R4 now i think it's fine,

Well need i calibrated it a new time for audio trimmer?
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 10, 2010, 10:15:33 PM
Great :) Let's see how we can fix this limiting.
No need to re-calibrate audio trimpots.
Check little by little front pcb, maybe an error here.
Can you explain how does the unit limiting?
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 10, 2010, 10:20:30 PM
i think it was caused by the 3K74 in R4 i'll try the unit this afternoon to see.

is limited at -14db peak without or with make up same if i give some gain in the input, the sound can't go up - 14db. and give some saturation
Title: Re: MixBuzz500 build/support tHread
Post by: RedNoise on July 11, 2010, 02:34:45 AM
 :o Killah'mazing :o
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 11, 2010, 06:03:35 PM
ok, the R4 3k74 was the cause of limiting now the unit work nice

related problems:

- on ratio 2 the point of vu meter come to 8, cause of the diode D8 (for 4000 mode) D7 ( for gsll mode)in bad direction
- R34 & R40 burn the TL074 IC7 is in bad direction, change the resistor and the TL074
- SWITCH 3pdt on off on seems don't work, jsut link the three points ratings of the switch

Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 11, 2010, 06:15:17 PM
Quote
ok, the R4 3k74 was the cause of limiting now the unit work nice
MAN.... My congrats!!! You're fast!!!!

related problems:

Quote
- on ratio 2 the point of vu meter come to 8, cause of the diode D8 (for 4000 mode) D7 ( for gsll mode)in bad direction
- R34 & R40 burn the TL074 IC7 is in bad direction, change the resistor and the TL074
- SWITCH 3pdt on off on seems don't work, jsut link the three points ratings of the switch

In other words:

Check carefully if there's no components placed wrong. Check all resistor values.
Thanx again to Stereokillah, why not Sherlock Holmes?
:)
I corrected 3rd post of this thread, BOM is right;
Put solder joint to pads near the 3pdt switch;
Thanx to 10R resistors, they acts as fuses if op-amp placed in wrong direction :)

Another thing. Regarding this thread:
http://www.groupdiy.com/index.php?topic=39897
Be careful when placing the unit inside 51x rack not to short power supply rails.
It is really hard to do: I tested MixBuzz500 in both 51X and Lunchbox racks),
but...who knows, everything possible.
For future, I will do all my 500/51x stuff with "slotted" connector.


Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 12, 2010, 04:56:11 PM


thank you for this great projetc

Sherlock Holmes ???
why because he had a pipe  ;D

i prefer Colombo because Appearances are deceptive, and he have always a  cigar  :D
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 12, 2010, 07:27:48 PM
:)

Thank you! Really, I very impressed.
Are you cigar smoker?
BTW, did you checked the ratios? And, please let us know about sound.
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 12, 2010, 08:04:30 PM
 i did'nt  realy have time to check the performance, i've added trimpot for threshold , very interisting and i think to calibrate it, it's just as your feelµ.
 i need to move all my material during this week, i'll check all after in good condition.

Quote
Are you cigar smoker?
no some times cigario
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 13, 2010, 04:36:37 AM
Cool! Looking forward.
Title: Re: MixBuzz500 build/support tHread
Post by: oceres on July 13, 2010, 08:16:39 AM
 ;D can't wait to start building this baby! I'm so excited

I'm sourcing parts at the moment and I've no idea which leds to buy... there's too many of them lol

lamp size 5mm / T-1 3/4 ? forward current? Is it ok to use flat-top for the 3mm led?
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 13, 2010, 09:21:30 AM
;D can't wait to start building this baby! I'm so excited

I'm sourcing parts at the moment and I've no idea which leds to buy... there's too many of them lol

lamp size 5mm / T-1 3/4 ? forward current? Is it ok to use flat-top for the 3mm led?
Yes, it is OK for 3mm flat top led. Will look neat.
Regarding the VU illumination LED's. Easy way is to check at your local
electronics store for brignt LED's.
Or, search supplier for filters: led, 5mm, 1500-5000 mcd brightness, pcb mounting, 10...30 deg, etc, like here:
http://il.farnell.com/jsp/search/browse.jsp?N=500004+1004334+543666+373739+463779+373740+373741+5116075+356266+567790+578218+578818+578805+578802+578796+578790+578772+578766+578755+578748+5075942+578728+578724+578363+578373+578383+578392+578416+578423+578431+578436+578461+578475+578487+578493+578514+578523+578556+578572+578603+578646+578655+578675+578709+578720+5368163+5368166+5368176+5368172+5368179+5368183+5368140&Ns=PRICE_PLS_017_PRICE1|0&Ntk=gensearch_001&Ntt=led+5mm&Ntx=mode+matchallpartial&locale=en_IL&appliedparametrics=true&getResults=true&originalQueryURL=/jsp/search/browse.jsp%3FN%3D500004%2B1004334%26Ntk%3Dgensearch_001%26Ntt%3Dled%2B5mm%26Ntx%3Dmode%2Bmatchallpartial%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_IL%26catalogId%3D%26prevNValues%3D500004%2B1004334
Title: Re: MixBuzz500 build/support tHread
Post by: RedNoise on July 14, 2010, 01:16:13 PM
Hi there here's a pic of my work in progress...
(http://a.imageshack.us/img257/3985/dscn3231.jpg) (http://img257.imageshack.us/i/dscn3231.jpg/)
 :P
Title: Re: MixBuzz500 build/support tHread
Post by: Ryake on July 14, 2010, 05:47:44 PM
Can't wait to get mine in the mail and get started. This will help me get my mind off the world cup being over  ;D
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 14, 2010, 06:32:12 PM
@Rednoise: superfast French DIY team!!!!! Cool. Very accurate.

OHHH!!!!! Don't remind me world cup. PLEASE!!!
It was impossible to drink beer at any pub there. Those football people!!!!
Those huge screens with running football robots!!!! GOOOL!!!!!!
Hell is other people, (c) Jean-Paul Sartre, I agree, but real hell is Word Cup. No way.
I was sooo happy it finished!  ;D :P : :D
Title: Re: MixBuzz500 build/support tHread
Post by: RedNoise on July 15, 2010, 12:22:51 AM

Hell is other people, (c) Jean-Paul Sartre, I agree, but real hell is Word Cup. No way.


Especialy when you were french supporter for this one WC... :-\ ...Worst : my second blood is Italian... :-X
Title: Re: MixBuzz500 build/support tHread
Post by: Ryake on July 15, 2010, 08:45:10 AM
The US was first in their group but France and Italy didn't even get out of their group. Very strange haha
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on July 15, 2010, 01:14:55 PM
Back to the mixbuzz questions....

1. What about pins for the VCA replacement boards to connect to the audio boards. Igor, did you just use resistor legs soldered to the VCA boards and then to the audio boards?

2. Sockets for the Thats VCA chips? Are there any off the shelf sockets for 8pin SIL?
Rednoise, what did you use? I see you have already got some soldered in there... [ and very neat work it looks too]

AG
Title: Re: MixBuzz500 build/support tHread
Post by: RedNoise on July 15, 2010, 02:27:01 PM
Hi AudioGimmer!
Regarding That VCA sockets , I used SIL 32 cut @ 8 points...It worked fine in my GSSL so...ie :
http://cgi.ebay.fr/32-way-SIL-Socket-Header-Turned-Pin-Grooved-2-pack-/180530615923?cmd=ViewItem&pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item2a08769673
I intend to use 202X , not the VCA replacement boards , but : 1N4007 cut legs are a good and cheap pins
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on July 15, 2010, 05:10:23 PM
Hey RedNoise, those look perfect, merci beaucoup.

Soldering starts next week, I have some free time.....

AG
Title: Re: MixBuzz500 build/support tHread
Post by: RedNoise on July 15, 2010, 05:13:14 PM
This build is a real pleasure to solder!!!I hope you'll enjoy it as I do !
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 15, 2010, 07:44:31 PM
hello guys, i would give you a small trick with ribbon.

cut 4 parts about 20cm put your connector on it and after calibration just cut in the middle two of this to have 4 ribbon for assembled the unit .
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 16, 2010, 08:53:45 AM
Already answered, almost nothing to add...
Diode legs etc are perfect for VCA replacement boards.
Replacement board with 4x2181B sounds really nice, worthy to try.
4x A grade VCA's IMHO overkill, I did not heard the difference between A and B grades.


hello guys, i would give you a small trick with ribbon.

cut 4 parts about 20cm put your connector on it and after calibration just cut in the middle two of this to have 4 ribbon for assembled the unit .


Excellent idea about ribbons!!!
Title: Re: MixBuzz500 build/support tHread
Post by: Brizco on July 20, 2010, 01:04:33 PM
finished the mixbuzz today and tried to test it... but: R16 is burning on both audio boards! (R16 is 10R 1/2W)

now i have to look for the reason... every hint is welcome!

Title: Re: MixBuzz500 build/support tHread
Post by: Brizco on July 20, 2010, 03:17:56 PM
finished the mixbuzz today and tried to test it... but: R16 is burning on both audio boards! (R16 is 10R 1/2W)

now i have to look for the reason... every hint is welcome!



found the mistake: both ina134 are defective!
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 20, 2010, 03:31:46 PM
Strange. Did you used new ones? BTW. Don't use INA134 or other 0db line receivers.
INA134 etc will be +6 db overall gain versus bypass.

In any case, THAT1246, INA137 or SSM2143 (-6db line receiver) is the right choice.
Check everything twice before installing on PCB! Op-amps, resistors, diodes,
cap's polarity, etc.

Checked with BOM, in case of whatever:
1   THAT1246 /INA137P           IC1   
1   THAT1646 /DRV134P           IC8   
Title: Re: MixBuzz500 build/support tHread
Post by: Brizco on July 20, 2010, 04:32:38 PM
i used new ones... really strange! never happened before: on both audio boards at the same time!

i will try ina137, but have to buy them first :)

Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 20, 2010, 07:37:00 PM
Check the key position, both at the socket and PCB.
All these 8-pin line receivers have same pinout. Difference is gain,
speed, maximum output swing and distortion.
Sonically and measurement-wise, THAT1246 and INA137 more or less same.
Maybe, THAT bit cleaner.
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on July 20, 2010, 07:52:38 PM
Has anyone used Ptowns meter yet?  I'm starting to source parts and was wondering about it. 

Also, if I want to use the Crush and Blend option.  Is that something that can be built into the 2 space case or is that an external hook up of some sort?  Not sure how that works.  Sorry if its a stupid question. 
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 20, 2010, 08:06:23 PM
hi,
don't have digikey or mouser bom, i've ordered almost parts on farnell cause there is farnell code on the igor Bom 
http://twin-x.com/groupdiy/thumbnails.php?album=405 (http://twin-x.com/groupdiy/thumbnails.php?album=405)and sifam meter but you could use hairball one now http://hairballaudio.com/shop/product_info.php?cPath=25&products_id=61 (http://hairballaudio.com/shop/product_info.php?cPath=25&products_id=61)
for the dip, i've ordered all in that here  http://www.profusionplc.com/pro/gex/pcatdtl0  (http://www.profusionplc.com/pro/gex/pcatdtl0) and http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=THAT1646P08-U (http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=THAT1646P08-U)cheaper than farnell and other , same for the vca 2180LB http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=THAT2180CL08-U (http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=THAT2180CL08-U)

Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 20, 2010, 08:08:09 PM
Dan, I started to draw another 500 module for C&B option, it is almost there.
But, got the mind to make 1176 on 500/51x format, and stopped on 500C&B for this time.
If there are people interested to add C&B to MixBuzz500, as 3rd slot, it is easy.
BTW, stay tuned for MixBuzz1 (1RU with more options/flexibility).
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 20, 2010, 08:09:12 PM
Stereokillah: thanx!
I ordered some meters from Hairball, will post test results here.
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on July 20, 2010, 08:15:35 PM
Igor I would be interesting in both the CnB and the Meters from Hairball.

Also, you have to stop making all these sweet projects.  I can't keep up money or time wise! :)


Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 20, 2010, 08:22:05 PM
Hm. Dan, really thanx! I do these projects for my fun first.
Than, some of projects shared here, I hope another people will have same fun!
If there's an interest in C&B addition to MixBuzz500, 1 slot, 500 format, post here.
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on July 20, 2010, 08:24:29 PM
would the CnB be something that could be used with other projects as well or just the mixbuzz?  Either way is cool but would be great if it could be used with any Stereo Comp or whatever.  Is that even possible?
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 20, 2010, 08:29:06 PM
It requires some wiring to MixBuzz500. 6 shielded cables in total.
Yes, it should be possible to hook it to other stereo comp...But what is the reason,
if there are other C&B boards which doesn't require 500' edge connector :)
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on July 20, 2010, 10:29:48 PM
i feel pretty dumb but what is the deal with VCA replacement boards?  Is there a thread somewhere I'm missing?  I think I'm the only guy who hasn't built a GSSL on the forum yet so I'm in the dark about half of this stuff.

It seems to me that I can either use the DBX or build a VCA replacement board.  How do I know what the sonic difference is and is it possible to build the VCA replacement boards and swap them in and out to see what I like the most?

Another question.  Is there any reason to use a better Quad Op-AMp then a standard TL074.  If so are there any simple solutions for that?  I see there is a TLO74/AD713 on the photos (my boards are not here yet).  Is the AD713 a direct upgrade?  Also which one do I want?  I see a huge price difference between them (link below). Also, sonically what can one expect from the upgrade.  If its a direct plug I can just test them out once built easy enough.

(http://il.farnell.com/jsp/search/browse.jsp?N=500004+1004392&Ntk=gensearch_001&Ntt=AD713&Ntx=mode+matchallpartial)


Thanks
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on July 21, 2010, 06:00:10 PM
Quote
How do I know what the sonic difference is and is it possible to build the VCA replacement boards and swap them in and out to see what I like the most?

you can used the pin socket for DOA like this you can put and leave your vca board as your choice
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 21, 2010, 07:37:22 PM
Quote
..but what is the deal with VCA replacement boards?  Is there a thread somewhere I'm missing?

Original 4000' deck compressor used DBX202 VCA. There are many mods of 202, please download docs
(link at first page of this thread) and read. This is "homework" :)
After homework, soldering will go easier, have a fun!

Quote
It seems to me that I can either use the DBX or build a VCA replacement board.  How do I know what the sonic difference is and is it possible to build the VCA replacement boards and swap them in and out to see what I like the most?

DBX202C should have its own character. I believe it should. But, never tried :)

The rest of 202's is pretty same : pre-THAT era VCA's with almost same pinout llike 2181/2151,
paralleled in eights or quartets. More or less distortion, more or less CV breakthrough,
this or that values for input/feedback resistors, sometimes, different control port impedances.

Maybe there are other discrete versions. AFAIK, 200 wasn't used in 4000 series compressors.
I don't pretend to be last instance for this info in any case :)
If somebody have more info to share, wellcome!!!

Replacement board: more or less DBX202R, IIRC.
Using 8 of THAT2181A VCA's is true overkill; have no any benefit IMHO
neither distortion nor headroom-wise.
However, quartet sounds really good. Very clean, but adds tiny bit of second harmonic if bit
misadjusted. For all guys who love "more sound", one 2181C is the option.
Explained some posts ago.
Quote
Another question.  Is there any reason to use a better Quad Op-AMp then a standard TL074.  If so are there any simple solutions for that?  I see there is a TLO74/AD713 on the photos (my boards are not here yet).  Is the AD713 a direct upgrade?  Also which one do I want?  I see a huge price difference between them (link below). Also, sonically what can one expect from the upgrade.  If its a direct plug I can just test them out once built easy enough.

No, really, 074 is not in audio. It doesn't matter at all.
Why I used AD713, because I have some tens left, bought about 100 from surplus store for $2.
It is really cheaper for me than buy TL074 at electronics store for $1.25 :)
But, AD713 opamp is fast and have very good DC characteristics (low offset).
If you can get them for cheap, use in every possible compressor's etc control circuit.

Audio op-amp is IC11. NE5532, OPA2604 is good choice.
OPA275 will not be the best here as it has relatively high offset and should work with low impedances
to reach its performance curves.

My last opamp affair was LME49710. Really, cool.
In MixBuzz500 we need dual op-amp.
Maybe, worthy to try LM4562.
One thing. OPA2604 has excellent DC performance (low offset) and very fast.
IMHO, this is excellent choice.
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on July 21, 2010, 09:58:28 PM
Igor and killah, thanks.  This info has been helpful.  I have read everything I think I can except the 200 page thread about the GSSL comp.  Just trying to make sure I have things straight.

Thanks again and Igor let us know what you find about the Hairball meter. 


If any one else has and comments on sonics of different VCA's and what not i would love to know your thoughts as best as audio can be described.

A side note:

A friend of mine say "talking about audio is like dancing about art"  It makes no sense.  So, I understand it may be hard to describe the sonics of the vca's.

Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on July 22, 2010, 10:11:27 AM
Igor, I'm stoked to hear you're building the 1176 in 500 format.  I was about to spring for an Action, but I think I'll wait for this.  I got the hairball meter a couple of days ago.  Looks cool!  The range on the meter is not quite as wide as the Sifam, but I have no problems with that at less than half the cost.
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on July 23, 2010, 02:08:14 PM
Quote
Audio op-amp is IC11. NE5532, OPA2604 is good choice.
OPA275 will not be the best here as it has relatively high offset and should work with low impedances
to reach its performance curves.



Is OPA2604 a good upgrade for IC9 on the VCA Replacement board as well?
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 23, 2010, 03:40:22 PM
OPA2604 is dual op-amp. Single op-amp needed for VCA replacement board.
To drive the control port of VCA, requirements are: low noise and low output impedance,
as well as good DC performance. I think OPA604 will work fine at "homebrewed 202",
i.e. VCA replacement board. In original 202* VCA's, NE5534/NE5532 were used
to drive control ports of 8-pin IC VCA's.
I used NE5534, it worked fine.

/BTW.

Quote
A friend of mine say "talking about audio is like dancing about art"  It makes no sense.  So, I understand it may be hard to describe the sonics of the vca's.

Absolutely agree. In bad Hebrew-to-English translation, local proverb says:
These words from your mouth to God's ear :)
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 23, 2010, 09:34:28 PM
In case of whatever, link for power supply bypass capacitors (220uF):
http://il.farnell.com/panasonic/eca1ehg221/capacitor-220uf-25v/dp/9692835
http://il.farnell.com/panasonic/eeufc1e221/capacitor-220uf-25v/dp/9692142
http://il.farnell.com/panasonic/eca1ehg221/capacitor-220uf-25v/dp/9692835
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on July 26, 2010, 01:05:50 PM
The soldering is coming on slowly [not enough free time and a few missing/wrong items delivered from my parts orders ???]

Couple of questions
1. Power for the small board with time constants/ratio etc. Does this come from the 3 points at the top of either audio PCB just above the sym trim pot?
2. My relays have coil resistance of 360 ohm each. So the resistors R98 and R87 should be 60 Ohm right?
I couldn't get any .5watt 60R so I ordered some 60R4 0.6 watt. Now this is going to sound dumb, but they look physically small, like the rest of the 1/4 watt resistors. I guess as their resistance is low they aren't are physically big as say the .5watt 2K resistor in R89.
Does that sound reasonable or are these not right?

BTW, thanks Igor, the PCBs are excellent to work with.


AG
Title: Re: MixBuzz500 build/support tHread
Post by: dmp on July 26, 2010, 01:47:22 PM
About higher wattage resistors being small, I've noticed this also. My guess is that they are making resistors that have a higher rated max temperature.
From what I remember, higher wattage resistors used to be larger only to increase the surface area for heat transfer. The resistor's power dissipation is transferred to ambient as heat, where the larger the surface area the lower the required resistor temperature for a given power dissipation.
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on July 27, 2010, 11:56:22 AM
Well, coming along now.
Control boards all done, VCA boards done, just need to finish the Audio boards.
I had ordered all WIMA caps for the polys, and I could only get 100v rated ones, which it turns out are physically too big to fit in the sidechain filter part of the PCBs Doh!
If the suppliers are still out of stock, any other recommended brands/types to look out for?
(http://farm5.static.flickr.com/4110/4834146029_9334e53e0a.jpg)
(http://farm5.static.flickr.com/4110/4834754242_51f257f1fa.jpg)


AG
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 27, 2010, 02:21:38 PM
Photos: impressive! Looks very accurate.

Couple of questions

Quote
1. Power for the small board with time constants/ratio etc. Does this come from the 3 points at the top of either audio PCB just above the sym trim pot?

Yes, take the power for small PCB from one of audio boards. 3 wires can be soldered directly,
or with use of Phoenix 2.54mm pitch screw terminals, or with use of 3-pin 2.54mm pitch Molex connector.
Don't crimp, solder! :)
Quote
2. My relays have coil resistance of 360 ohm each. So the resistors R98 and R87 should be 60 Ohm right?
I couldn't get any .5watt 60R so I ordered some 60R4 0.6 watt. Now this is going to sound dumb, but they look physically small, like the rest of the 1/4 watt resistors. I guess as their resistance is low they aren't are physically big as say the .5watt 2K resistor in R89.
Does that sound reasonable or are these not right?

I used relays with approx. 1kOhm coil. Less power consumption, etc. 12V relays cost is almost same for
different coil resistance, BUT why spent additional milliamperes, especially in case of Lunchbox?
It comes up as 15-20 ma per slot difference. I'd like to spent them to OPA2604's
and quad (eight in case of 202X etc) VCA's.


However, 360 Ohm is OK, within the specs for power supply consumption.

Use regular, carbon, cheap, 1/2W, 10% 62, 68, or even 75 Ohm resistors, it is fine.
99% of relays have working range within 30% of specified coil voltage at least.

1/2W resistors will be about +30 deg C at home temp +25 C.
I think yours 60R4 will work fine as well.

Quote
BTW, thanks Igor, the PCBs are excellent to work with.
Thanx :) I love those little beasts too :)

Quote
I had ordered all WIMA caps for the polys, and I could only get 100v rated ones, which it turns out are physically too big to fit in the sidechain filter part of the PCBs Doh!

No need for cool audiofoolish capacitors in sidechain filters!
5mm pitch, 50-63V film capacitors.
Farnell have all values for up to $0.7/cap.
Mouser/Digikey should have the caps too.
Parametric search, pick nice looking ones in normal price range. Like:

http://il.farnell.com/jsp/search/browse.jsp?N=500004+1000229+5087885+5087887+5087944+5087945+565143+565129&Ntk=gensearch_001&Ntt=capacitor&Ntx=mode+matchallpartial&No=0&getResults=true&appliedparametrics=true&locale=en_IL&catalogId=&prevNValues=500004+1000229&filtersHidden=false&appliedHidden=false&originalQueryURL=%2Fjsp%2Fsearch%2Fbrowse.jsp%3FN%3D500004%2B1000229%26Ntk%3Dgensearch_001%26Ntt%3Dcapacitor%26Ntx%3Dmode%2Bmatchallpartial%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_IL%26catalogId%3D%26prevNValues%3D500004%2B1000229
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on July 27, 2010, 02:33:24 PM
Thanks igor.
Re. relays, I just picked those as they were on your BOM, I didn't consider the power consumption. Now you point that out it makes sense: However, don't think I'll desolder these just to swop over...

I'll order some more caps tomorrow....


... and I'll have some of the others leftover for your 500series 1176....!!

AG
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 27, 2010, 02:56:56 PM
:)
Cool. Regarding the power consumption, the unit will be within the specs with 360 Ohm relays.
With OPA2604, DBX202X, 360Ohm relays, we get about 65...80 ma per slot... fine.
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on August 02, 2010, 01:43:44 PM
Almost there, still need to check some things, but with all these beer talking in the Brewery, i need a break  ;) ;D

(http://img833.imageshack.us/img833/954/mixbuzzzzz.jpg)
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 02, 2010, 07:21:29 PM
OOOOOO!!!!!!! Good job!

Really, guys. I am happy. This thing in right hands!!!!

I need some beers too, but later :)

To all guys, in case of whatever:
Don't forget to put stoppers on switches at right positions :)
(just had a mail about this)

I am bit busy till Aug 7th, but in case of whatever feel free to mail.
Title: Re: MixBuzz500 build/support tHread
Post by: Brizco on August 06, 2010, 12:12:14 PM
Finished!
after i used the ina137 everything just worked, calibration was easy. the whole kit is just awesome, everything fits like it should!

thank you igor!

(http://img831.imageshack.us/img831/8928/dsc00582g.jpg)
(http://img28.imageshack.us/img28/4136/dsc00579hh.jpg)

...69eq arrived this week, but still missing the pcb's, i emailed you :)
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on August 06, 2010, 12:40:34 PM
Nice work Brizco. Genuine DBX VCAs?

I'm all done apart from calibration and final assembly. No time at the minute  :(

How did you calibrate yours? inside a rack or externally with long power/audio leads


AG
Title: Re: MixBuzz500 build/support tHread
Post by: Brizco on August 06, 2010, 01:25:33 PM
i have an a-design 500hr with opened top for testing and calibrating my 500projects. for the mixbuzz i used longer ribbon-cables, about 30cm.

yes, original dbx 202's.
Title: Re: MixBuzz500 build/support tHread
Post by: ultra-alex on August 06, 2010, 03:06:35 PM
nice build, briz...
where did you get those dbx202?
cheers, alex
Title: Re: MixBuzz500 build/support tHread
Post by: Brizco on August 07, 2010, 05:26:43 AM
nice build, briz...
where did you get those dbx202?
cheers, alex

got them from the black-market.. but dont know anymore from which member.
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on August 07, 2010, 12:50:33 PM
Well, finally finished up the Mixbuzz.
Adjusted for zero DC on IC 11a&b for audio and sidechain outside of lunchbox, and then stuck the audio cards in to take a listen.

(http://farm5.static.flickr.com/4074/4868644975_ddf814df2c.jpg)
(http://farm5.static.flickr.com/4100/4868644373_2a74b8bdeb.jpg)

On program material it sounds great, very pleased. I do have 2 issues though.
1. The ratio switch seems reversed: for a given threshold for onset of compression 2:1 gives more GR than 4:1 which gives more than 10:1 .....Hmmmm

2. I need to adjust where threshold for zero is [i.e. for onset of compression feeding 0VU into the unit]. Having never built a GSSL design before, I don't know the procedure. Can anyone run me through it. I did install trimmers at RV1 on audio boards, and I preset them to 5k1 before soldering 'em in.

Great project Igor, thankyou.

AG
Title: Re: MixBuzz500 build/support tHread
Post by: pacemaker on August 07, 2010, 05:52:59 PM
Hi Guys,
i am now finishing my mixbuzz too,
will post some pics later,
i am using THAT 2181LB VCAs,
so i guess some resistances values need to be adjusted
Sorry for being such a noob,
i've tried to fi nd the solution by myself,
but couldn't suceed,
Any help would be really appreciated,
and Igor , amazing job !!!
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on August 07, 2010, 07:27:46 PM
AudioGimmer,

for your ratio check your resistor on the controle board

R65,72,73,77,78,79,80,82,85,86,90,91,92,93 if you've got the good value

on my pictures you could see one line with 620k  diode 68k 270k and 510k and the second 620k diod 68k 510k and 270k

perhaps you did a error here.


pacemaker

how many VCa on your DBX202X REPLACEMENT BOARD ?
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on August 08, 2010, 03:47:08 AM
Hey, Stereokillah. You're up early!

I'll get a chance to check tomorrow. Thanks.

AG
Title: Re: MixBuzz500 build/support tHread
Post by: pacemaker on August 08, 2010, 04:48:02 AM
Hi Stereokillah,
only one VCA per boards,
thanks for your help mate!
francois
Title: Re: MixBuzz500 build/support tHread
Post by: pacemaker on August 08, 2010, 07:00:14 AM
And my mistake,
i'm using 2180LB , not 2181LB
thanks for your help,
Francois
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on August 08, 2010, 07:01:02 AM
Quote
For "more sound" use only one THAT2181C, bit misadjusted for more harmonics.
In this case, install only one VCA and according resistors on input board,
no change in control port circuit (NE5534, 100R, 732R).
In this case, R3=20k, R6=0R (jumper), R100=909R.
It is possible to lower C1 down to 22pF.

it's same for THAT2181LB, i think the only difference is the  harmonics

Quote
Trimpot adjustment.
Adjust for minimum distortion with analyzer (audio) and 0mV dc offset (sidechain).
Don't have analyzer?
Sidechain: adjust for 0.0 mV DC at IC11a, NE5532, pin1
Audio: adjust for 0.0 mV DC at IC11b, NE5532, pin7
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on August 08, 2010, 07:05:22 AM
ok if it's 2180lb
Quote
Sidechain VCA's.
Simplest and cheaper solution is THAT2180C, don't install SC_SYM trimpot and R33.
There's no need for A version VCA in sidechain.
Title: Re: MixBuzz500 build/support tHread
Post by: pacemaker on August 08, 2010, 07:23:01 AM
ok so no change on the VCA board,
and R33 and 50k trimpot shouldn't be installed,
thanks for your answer stereokillah !
Regards,
francois
Title: Re: MixBuzz500 build/support tHread
Post by: Biasrocks on August 08, 2010, 11:01:01 PM
(http://img831.imageshack.us/img831/8928/dsc00582g.jpg)
(http://img28.imageshack.us/img28/4136/dsc00579hh.jpg)

Looks great Brizco, may I ask where did you source the control knobs?

Mark
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on August 09, 2010, 12:04:39 AM
Hi Mark,
I've bought these at Sayal electronics... www.sayal.com.  I was there the other day and they have them.  Funny, because I bought the aluminum ones for this build and the black ones for the 169 eq. They are the same as Brizco's.  Too bad you weren't a little closer to the Toronto area.  Closest store to you is Cambridge.  I'm heading there this week and I'll get a part number for you.
Title: Re: MixBuzz500 build/support tHread
Post by: Brizco on August 09, 2010, 02:40:44 AM
Quote

Looks great Brizco, may I ask where did you source the control knobs?

Mark

Bought them at www.musikding.de:
http://www.musikding.de/product_info.php/info/p2546_Knebelknopf-Alu-schwarz.html

Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on August 09, 2010, 06:17:44 AM
AudioGimmer,

for your ratio check your resistor on the controle board

R65,72,73,77,78,79,80,82,85,86,90,91,92,93 if you've got the good value

on my pictures you could see one line with 620k  diode 68k 270k and 510k and the second 620k diod 68k 510k and 270k

perhaps you did a error here.

Stereokillah, all resistors OK, and I checked the diodes, they are good too. Gotta do some work now, but will test again later today.
Thanks.

AG
Title: Re: MixBuzz500 build/support tHread
Post by: Biasrocks on August 09, 2010, 09:29:49 AM
 Closest store to you is Cambridge.  I'm heading there this week and I'll get a part number for you.

That'd be great.

Mark
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on August 09, 2010, 01:51:35 PM

ok
try to changed the Tl074 by another one to see if something change and perhaps it's your lorlin, you need to put it in first position before making the "stop position"(sorry i' don't know how to translate it); if not you could have some problem

Quote
Stereokillah, all resistors OK, and I checked the diodes, they are good too. Gotta do some work now, but will test again later today.
Thanks.

AG
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on August 09, 2010, 05:22:28 PM
OK.
Changed the TL074, checked the stop on the Lorlin switch.
I adjusted the trim on the control board so the onset of compression requires more input and then re-calibrated the sidechain sym.

With a steady test tone input producing say 6-8dB or GR on the 2:1 ratio and selecting different ratios[ and not adjusting the threshold pot] the 2:1 setting still shows more GR than 4:1 which still shows more GR than 10:1

HOWEVER I then decided to measure the actual gain reduction that each ratio setting is actually producing [by setting up a steady GR of 4dB and then measuring the required increase in input level to give 3-4 dB output gain. The results:

2:1  = 2.4:1
4:1  = 3.7:1
10:1 = 6.5:1

So the compressor and the ratio switch seem to be working OK, just that increasing the ratio doesn't automatically increase the amount of gain reduction. [ which is what I was expecting ] The 2:1 and 4:1 ratios are pretty close, the 10:1 is a little gentle

In terms of the rest of the calibration, I get unity gain in/out, the GR meter is pretty accurate [using tones and some good VUs whilst testing the ratios] and the unit sounds gooooood!

Thats enough for tonight, thanks Stereokillah, for your help and useful suggestions.


AG
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on August 09, 2010, 07:08:50 PM
right,
in the gssl and mixbuzz, if i've good remenber the trhesold is not at same point for the difeerents ratio cause of the knee, anybody may confirm?

Don't have my material since 3 week can't try myself
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on August 09, 2010, 07:33:51 PM
My GSSL works the same...
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 09, 2010, 08:01:46 PM
Wow!!! Was busy some days, opened this thread, you cool, guys! Nice progress!

Some words about ratio.
I copypasted ratio switch exactly as it was on 4000' deck. This is the way it works,
like gain reduction on 33609 goes "more-right".

Quote
With a steady test tone input producing say 6-8dB or GR on the 2:1 ratio and selecting different ratios[ and not adjusting the threshold pot] the 2:1 setting still shows more GR than 4:1 which still shows more GR than 10:1
Yes, it done by way to keep same amount of compression at different ratios.
For me it seems....strange at least, BUT that's the way it goes in original comp.

Quote
HOWEVER I then decided to measure the actual gain reduction that each ratio setting is actually producing [by setting up a steady GR of 4dB and then measuring the required increase in input level to give 3-4 dB output gain. The results:

2:1  = 2.4:1
4:1  = 3.7:1
10:1 = 6.5:1
Quote
So the compressor and the ratio switch seem to be working OK, just that increasing the ratio doesn't automatically increase the amount of gain reduction. [ which is what I was expecting ] The 2:1 and 4:1 ratios are pretty close, the 10:1 is a little gentle

Pretty close. Try to measure with more gain reduction, or, maybe, check resistors
at ratio switch for Deutch precision :)

Quote
In terms of the rest of the calibration, I get unity gain in/out, the GR meter is pretty accurate [using tones and some good VUs whilst testing the ratios] and the unit sounds gooooood!

This is the best news :)

Quote
Thats enough for tonight, thanks Stereokillah, for your help and useful suggestions.

I want to thank Stereokillah for support too!
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on August 10, 2010, 02:56:59 AM

Quote
So the compressor and the ratio switch seem to be working OK, just that increasing the ratio doesn't automatically increase the amount of gain reduction. [ which is what I was expecting ] The 2:1 and 4:1 ratios are pretty close, the 10:1 is a little gentle

Pretty close. Try to measure with more gain reduction, or, maybe, check resistors
at ratio switch for Deutch precision :)

Hey Igor.
I checked all components going in [and good thing too, there were some mislabelled caps and resistors in my order from Farnells...] so I think resistors are OK. I double checked them when trouble shooting too. I'm not too concerned and actually I'm just going to enjoy using it for a little bit! Strange that the 2 low ratios are a touch high, but that 10:1 is low. If I adjusted R60 I might bring the two lower ratios nearer to spec I suppose.

I might consider swopping the 3352s for OPA 604s on the audio pcbs if they are just drop in replacements.

One last question about RV1 on audio PCBs. I set both my trimmers to 5K1 before I put them in. Is it necessary to adjust them in circuit with tones so that both sidechains are producing exactly the same control signal? What would be the best way to do that?

Great project, Igor

AG
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 10, 2010, 04:29:12 AM
Hi AG!
IMHO, everything is fine with your compressor.
To be 100% up-to-specs, try to measure again at 1:10 ratio and maybe change
(decrease) R60 for 10-15%. Simply put something like 470Ohm...3k in parallel to R60.

Here is a lot of info:
http://www.groupdiy.com/index.php?topic=944.0

Do search over the forum, I saw similar question about ratios/threshold.

Quote
I might consider swopping the 3352s for OPA 604s on the audio pcbs if they are just drop in replacements.
OOPS. You mean 5532, right? OPA2604 will be fine there.

Quote
One last question about RV1 on audio PCBs. I set both my trimmers to 5K1 before I put them in. Is it necessary to adjust them in circuit with tones so that both sidechains are producing exactly the same control signal? What would be the best way to do that?

If resistors are 1% and caps are from same batch, no need to care about this,
the tracking should be very close. Just fit 5k1 instead of trimmer and forget.
To be at more than safe point, feed 1Khz, get 10db of compression,
check both channels with and without filters, than,
check with 50Hz and 10kHz for same GR tracking with SC filters.

Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on August 10, 2010, 05:11:28 AM

Quote
I might consider swopping the 3352s for OPA 604s on the audio pcbs if they are just drop in replacements.
OOPS. You mean 5532, right? OPA2604 will be fine there.

Yes of course, 5532! I'm a terrible typist ???

I'll check the sidechains as you suggest, just for thoroughness, but really I'm just going to start using the Mixbuzz. Maybe next time I put an order in with Farnell I'll get some OPAs to try out. [I suspect that could be soon, seeing that your 51x 1176I is progressing nicely  ;) ]

I had read the thread on ratios, I'll have another read through.

Cheers

AG
Title: Re: MixBuzz500 build/support tHread
Post by: ultra-alex on August 13, 2010, 06:12:22 AM
igor, do you have a frontpanel file to share? corel, fpd, whatever...
i want to customize mine. cheers, alex
Title: Re: MixBuzz500 build/support tHread
Post by: Biasrocks on August 14, 2010, 10:29:11 PM
I'm using an original black can dbx 202 vca in my build.

Gain Control Constant: -6mv/db
Gain Control Input R: 197R +/- 2%

In the THAT corp application note for this VCA

http://www.thatcorp.com/datashts/dn127.pdf (pg 2)

they are showing 100K RIN and 100K ROUT values.

Should I set R6/R3 to 100K and R100 to 197R?

The RSYM resistor appears to be 1M as well.

Any guidance would be appreciated.

Mark
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on August 15, 2010, 07:39:46 AM
oh! will be a few concurency
(http://ep.yimg.com/ca/I/mercenary-audio_2117_7664035)

check the spec
http://www.mercenary.com/dramobsid500.html (http://www.mercenary.com/dramobsid500.html)

sorry to disturb your question Biasrocks
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 15, 2010, 07:59:51 AM
Front panel.cdr: mailing within some minutes

/hehe. saw the post about competitors, was posted at same time;
IIRC Ob*dian 500 comp exists about a year, TXIO...OK, nice!
/back to VCA's

Quote
I'm using an original black can dbx 202 vca in my build.

Gain Control Constant: -6mv/db
Gain Control Input R: 197R +/- 2%

Oh.... OK :)
JFET opamp should be used, like OPA2604.
/100k Rin/Rout arevery high impedances, to avoid dc offsets/thumps.
R2, R6, R4, R3, C1, SYM trimpot: see drawing C.

Here is the math how to recalculate VCA resistors.
If there's mistake in my calculations, I don't pretend to be final instance:)

According to drawing A, 50mV/db on 832 OHM for "original" as well 202x VCA.
So, 50/832=0.06 - current in microampreres to cause 1db drop; the current is same on
series connected resistors; than, we take whole chain resistance
and divide it to current to find "total" voltage:
(100+909+832)*0.06=110.46 mv
this is the voltage causing 1db of gain reduction at pin7 of IC7B
(actual sidechain control voltage to cause 1db of gain reduction).

Was really surprized btw why this question wasn't answered before :)

See drawing B.
We represent VCA control port with 197 Ohm resistor (in case of 202 black) going to ground.
r60 still 100 Ohm, R100 is our X, the rest is school math.
(197/6)=((100+X+197)/110.46)
Please don't ask if this about 3k31 and is this correct. I did not tried :)
But, should work.
Title: Re: MixBuzz500 build/support tHread
Post by: ultra-alex on August 15, 2010, 08:34:01 AM
okay, once again. if using a 202 black can, THEN...
R6 100k, R3 100k, R2 1M = R100 3k33, use OPA2604 instead of NE5532, change C1 to 10p and the SYM trim to 100k!
did i interpret your last post and attached drawings right?  ;D
thanks, alex
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 15, 2010, 08:42:44 AM
Seems right, but why do you going to use black 202? :)
Title: Re: MixBuzz500 build/support tHread
Post by: Harpo on August 15, 2010, 10:38:51 AM
they are showing 100K RIN and 100K ROUT values.
Should I set R6/R3 to 100K?
R6 and R3 could be decreased a little IMHO.
With THAT1246 in front, giving -6dB signal gain, voltage swing in front of the VCA can not be higher than Vsupply/2. For the max.allowed signal current of 500uA for (Iin+Iout), this is 250uA max.for Iin in bypass condition. 18V/250uA=min.value 72K for Rin. Pick next avail.standard value 75K. Same value for feedback resistor for unity gain, because the THAT1646 makes up the -6dB loss from the line receiver. Decrease 33pF compensation cap to 12-15pF.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 15, 2010, 11:27:42 AM
Thanx Harpo! Great point. Yes, this will work better. IMHO 68K1 will be fine instead of 100k as well.
Title: Re: MixBuzz500 build/support tHread
Post by: Biasrocks on August 15, 2010, 11:33:29 AM
Thanks for your help guys, much to digest.

Mark
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on August 15, 2010, 01:30:16 PM
Done Deal, tested, calibrated, Thanks to Igor for the Project, and to StereoKillah for his PPM scales and clarifications.

(http://img62.imageshack.us/img62/6792/mixxbuzz.jpg)
Title: Re: MixBuzz500 build/support tHread
Post by: ultra-alex on August 15, 2010, 01:44:57 PM
nice knobs. where did you get those?
cheers, alex
Title: Re: MixBuzz500 build/support tHread
Post by: RedNoise on August 15, 2010, 01:54:59 PM
HI Zayance , have you got the "inverted" ratios??
(2:1=10 , 4:1=4 , 10:1=2)
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on August 15, 2010, 03:01:58 PM
@Ultra Alex: These are Kilo international knobs, you can find them at Digikey, just type Kilo in the search field, these are 15.88cm knobs IIRC, anyway you'll find out.

@Rednoise: No when testing on the lab, Ratio were ok, a little high for the 2:1 the rest was ok.

Bad news for me  :'( :'(, everything was working nice in the Lab, so i inserted in the box, putting tabs for helping the PCB getting to the right pins, conclusion smoke  :'( :'( :'(, so turn off, and check the pins of the rack, and what the f..k, some crazy voltage 62v :o :o :o >:(, at pin -16v, where is this voltage coming from...S..t, totally forgot to check that before inserting, and even when my box was finished IIRC, seem to be good on the PCB molex tough that i remember, i don't get it, anyway, some hours of troobleshooting, and well who knows maybe everything is smoked, visually all res were ok, only one 1646 seem to have burned, all the rest well don't know, BAD DAY FOR ME  :(
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 15, 2010, 03:40:21 PM
Nice knobs, very nice meter, now, relax.
10R resistors acts like a fuses. Check them at first.
THAT1646 probably shorted power supply rails and maybe nothing else did not blew out.
Take all chips out from sockets and check for power supply consumption.
Then, start to insert them one-by-one, continue checking if no smoke.
Than feed sound, repeat test pro, that's it. Please let us know.
I am very curious what really blew out.
Title: Re: MixBuzz500 build/support tHread
Post by: Harpo on August 16, 2010, 08:21:44 AM
IMHO 68K1 will be fine instead of 100k as well.
Sure. Looking closer, a THAT124x doesn't swing rail to rail but typ.+/-2V off its supply rails. Supply voltage from psu probably is +/-16.5V (ignoring voltage drop in 10R fusing resistors) or a little lower, not +/-18V. Schematic differs from GSSL, where signal is always running thru the VCA. Your design is coming with hardwire bypass, so no VCA-bypassing and min.compression ratio is at least 2:1, allowing a 2/3 Iin to 1/3 Iout current sharing within the DBX202 VCA. Rin and Rfb might decrease further to (((+16.5V-2V)-(-16.5V+2V))/2) / (500uA*2/3) = min.43K5.
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on August 19, 2010, 10:57:24 AM
hmmm, i Absolutely don't get it, i just connected the boards alone in the rack, one board with chips out, all had good voltages on right pins, and tried with the other one that had the components all in, and everything is fine, no crazy voltages on the pins or whatsoever, DBX getting correct voltages all Socket pins getting correct voltages and no Smoke  ??? ??? ??? ??? ??? ??? ??? at least on one of the boards and Controller board not connected, didn't check sound passing still but very Weird issue, maybe a pin got shorted when inserting the card  ???, Now i need to check all the configuration in the box and not out of it, just to have a better look of that.

EDIT: 51x Rack not API
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on August 19, 2010, 11:11:09 AM
Are you fitting the mix buzz in a Lunchbox or 51x rack?

Its a pretty tight fit in a 6 slot lunchbox, making sure both cards sit properly in the backplane.
I had a problem the first time I assembled all the PCBs etc in the metalwork. One of the ribbon cables had got damaged and the sidechain was going nuts. I disassembled and rechecked everything outside the rack, and then very carefully put it all back together and it worked fine.

I'm sure you'll get it fixed.....

The gimmer
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on August 19, 2010, 02:36:30 PM
Hi,

any suggestions on the silver mica caps?

All I can find is way to big. Is it correct that the schematic and the PCB component numbers don't correspond or is there an upgrade of the schematic?

No input and output caps, Is there a risk to put accidently 48V on it? Should we put clamping diodes?

BTW I love assambling this project.
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on August 19, 2010, 05:14:42 PM
The only micas I could find were physically large, and the lead spacing too big.

I very carefully bent the legs in an S shape to make them fit the board, and used some thin silicon sleeving to prevent any shorts.

I'd post a picture, but the mixbuzz is in my lunchbox hard at work at the moment...

The Gimmer
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on August 23, 2010, 06:49:57 PM
some protection against 48V and RFI is suggested in the date sheet. I would strongly recommand this modification for reliability:
look at page 9 of:  http://www.thatcorp.com/datashts/THAT_1606-1646_Datasheet.pdf
Title: Re: MixBuzz500 build/support tHread
Post by: canidoit on August 23, 2010, 11:10:36 PM
Done Deal, tested, calibrated, Thanks to Igor for the Project, and to StereoKillah for his PPM scales and clarifications.

(http://img62.imageshack.us/img62/6792/mixxbuzz.jpg)
Zayance, how does it sound? Have you compared it with other compressors?
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on August 24, 2010, 07:43:23 AM
@Canidoid: Well sounded Smokey  :D, still didn't repaired, so will let you know....
Title: Re: MixBuzz500 build/support tHread
Post by: oceres on August 24, 2010, 12:17:41 PM
I'm trying to figure out what kind of ferrite bead is suitable for R4 and R39? Are there different ones?
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on August 24, 2010, 01:31:08 PM
just use resistor leg for each.
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on August 24, 2010, 03:35:12 PM

R4, R39 is ferrite bead or jumper: It's a great thing Igor implemented this use it when you are going to use a fast opamp with high GBW. You don't want RFI.
RS stocknumber 226-8191   Panasonic   EXCELDR35C  or RS stocknumber 226-8185  Panasonic EXCELSA35
Title: Re: MixBuzz500 build/support tHread
Post by: oceres on August 25, 2010, 07:02:46 AM
Thanks!

I found excelsa35 from DigiKey and it's 3.5mm x 5mm so it should fit just fine.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 28, 2010, 09:13:02 PM
Hi to all, I had crazy busy week than nice but short vacation.
Back to our Mixbuzz500 stuff.....

Quote
but i definitely can see some smoke residue on the sides of the 1246 on each boards
(Rectification of the last post, it's the 1246 not the 1646!)....

OK....I think +48V somehow passed to input. Bad to hear about this.
Again!!!!, tabs for 51X rack, and never power on the rack before the module sits perfect inside the slot!
Quote
Well i think one of the DBX is dead  
Cry, without the chips but DBX in i'm reading 27v on the V+ pin,
i really don't get what happened, everything is fine in the box....
and the unit was working properly in the lab...

Something wrong happens inside your 51X rack, or maybe the module inserted wrong way.

+48V is far from input/output connectors. Strange.....

Quote
PS: I think there is a way to check the DBX, like its resistance?

Yes. Take it out from PCB (desolder). There are I_IN and I_OUT pins of VCA.
Put in-between "fake unity gain resistor" with value=R3-R6. I.e. if R3=47K, and R6=jumper,
use 47K (DBX202C version); if 202X used, and r3=5k, r6=3k74, use 1k25 resistor.

Put audio board inside the rack, check if all sits fine, connect control board,
only after checking everything is right, power on.

Audio board's gain should be 0db (audio and control boards should be connected!).

Than, check the voltage at VCA's control signal pin, without makeup/compression.
It should be 0V. Power off, take "fake unity gain resistor" out, put VCA. It should work.
If not works, VCA probably (99%) is dead.


Quote
hmmm, i Absolutely don't get it, i just connected the boards alone in the rack,
one board with chips out, all had good voltages on right pins,
and tried with the other one that had the components all in, and everything is fine,
no crazy voltages on the pins or whatsoever,
DBX getting correct voltages all Socket pins getting correct voltages and no Smoke  
Huh Huh Huh Huh Huh Huh Huh  

Good news. Use crocodile for -(common) probe of multimeter (in case of whatever);
maybe previous measures were wrong?

Quote
at least on one of the boards and Controller board not connected,
didn't check sound passing still but very Weird issue,
maybe a pin got shorted when inserting the card  
Huh, Now i need to check all the configuration in the box and not out of it,
just to have a better look of that.

No, 48V is far from input/output pins. Very strange. Maybe.....
In case rack was powered, module got first (somehow????) +48V than the rest of voltages....
Kill me here, impossible, if all voltages reading OK at the card edge.
If module was reversed (pin 1 goes to pin 15)...but same, impossible!!!!!
Tony, I thought about this issue, one more hour and I will smoke-up like your THAT1246!!

BTW. The audio board's relays are in BYPASS in default state.
This means, to check the audio board, you have to connect control
(front panel) board. For ROUGH check, enough one audio and control board.
For normal test, BOTH audio and control boards should be connected!

/in case of whatever:
CTL1, SC1 goes to CTL and SC left, CTL2, SC2 goes to CTL and SC right.
Or vice verse, but don't mess say CTL1 with CTL2. This way compressor will work wrong.
See first posts of this thread.


Quote
One of the ribbon cables had got damaged and the sidechain was going nuts.

Guys! What happens! Somebody PUT A SPELL on those freaky ribbons!!!!
2 ribbons FUBARu'ed for one week!!!!!!
C'mon, easy with'em :)


Quote
any suggestions on the silver mica caps?
Will try to answer in Zen weird way :)
OK....The story is next. (a bit OT!) Me and my friend from Bardo Mastering
tested Sontec kit stuffed with different kinds of caps some years ago.
Relay based A/B box (my mastering console) and ATC monitors.
Monster/Kimber/etc super-duper BS wiring in case of whatever,
but I don't trust any hi-end cables except military silver-plated teflon isolated,
which never were rated as hi-end audio cables.
We found immediately that EQ stuffed with SilverMica "anti-oscillation",
or "feedback" caps, sounded better than other with NPO's, 63V.
I can hear it as more definite highs. More details. Less fog.
Again, I hate sound talks like punchy-crispy.
So, I ALWAYS use micas at important places.
Second reason, I have about 2 kg of low value SilverMica's from surplus
and (or thus) may be wrong :)
Silver micas mostly have 7...10mm spacing for 47...82pf (C1); they fit fine on PCB,
maybe, bend leads a bit.
Quote
some protection against 48V and RFI is suggested in the date sheet.
I would strongly recommand this modification for reliability:
look at page 9 of:  http://www.thatcorp.com/datashts/THAT_1606-1646_Datasheet.pdf

line recievers/drivers:
 THAT1246  IC1: some additional  RFI protection look at page 4 and page 5 fig 4 of :
 http://thatcorp.com/datashts/THAT_1240-Series_Datasheet.pdf  .
 As suggested do this directly on the connector.
 The IC is protected against +48V on the input pins, so no worry there.


Up to you. I personally hate "useless" or "additional" components.
Audiopath should be short and simple as possible. Diodes can be installed on pcb,
there's a plenty of space. THAT1646 doesn't needs capacitors at it's out.
THAT1246's out bypassed with capacitor and it has -6db gain, so, no need for input capacitors as well
even in case of little DC offset at out of device connected to Mixbuzz500 input.
"Fool protection": install diodes. I prefer to check everything before putting module
in the rack and sleep good with mind of lack of additional components in my pure soundpath Mixbuzz :)

Quote
I also suggest to lower R7 to 1K for better S/N ratio.

Nope. IC8 (THAT1646) see at it's input: R7 in parallel to impedance of C3/C5, plus R5=68R,
plus output impedance of IC11B. It is less than 100R in 20-20Khz.
Lowering R7 to 1K: will give audible phase shift at low freq's and little (some db) drop at 20Hz.
Those who good with math can calculate/simulate. No noise floor improvement.

The noise floor actually caused by VCA's impedance...
I.e. using 4 paralleled 2181's and R3=5k IMHO not too bad solution :)

Quote
Somebody tried to leave out (bypass) the coupling caps in front of the linedriver?
Need some clarification, but, if you mean C3/C5, there will always be some tens of millivolts
of dc offset at IC11b out,even in case VCA perfectly calibrated. VCA gain changes, offset changes a bit as well. Little DC offset appears especially when VCA gives positive gain.
IMHO, MixBuzz500 using necessary minimum of parts,
mods and tweaks are at your own rescue and taste, but....feel free to tell if there some ideas :)
In any case, this is build support thread;
for "mod" people:  first build and make it working 100%, than mod at your rescue :)

Title: Re: MixBuzz500 build/support tHread
Post by: zayance on August 29, 2010, 05:50:12 AM
Quote
Tony, I thought about this issue, one more hour and I will smoke-up like your THAT1246!!
:D :) Sorry about this, i found it super weird too, since everything was working good on the bench, and the rack inserted i believe well? Still pretty tight to see tough, but full way at the back and the front panel sitting nicely, i've measured the entraxe of the cards before fitting in....
I'm waiting for some 1246 to exchange, and retry on the bench with and without DBX's and your tip, and carefully will try boards out of metal chassis, in the rack afterwards and we will see.
Thanks a lot Igor.
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on August 29, 2010, 02:16:08 PM
Hi Igor, thanx for popping in, I was waiting for some decent explanation.

Quote
Quote
some protection against 48V and RFI is suggested in the date sheet.
I would strongly recommand this modification for reliability:
look at page 9 of:  http://www.thatcorp.com/datashts/THAT_1606-1646_Datasheet.pdf

line recievers/drivers:
 THAT1246  IC1: some additional  RFI protection look at page 4 and page 5 fig 4 of :
 http://thatcorp.com/datashts/THAT_1240-Series_Datasheet.pdf  .
 As suggested do this directly on the connector.
 The IC is protected against +48V on the input pins, so no worry there.


Up to you. I personally hate "useless" or "additional" components.
Audiopath should be short and simple as possible. Diodes can be installed on pcb,
there's plenty of space. THAT1646 doesn't need capacitors at its out.
THAT1246's out bypassed with capacitor and it has -6db gain, so, no need for input capacitors as well
even in case of little DC offset at out of device connected to Mixbuzz500 input.
"Fool protection": install diodes. I prefer to check everything before putting module
in the rack and sleep good with mind of lack of additional components in my pure soundpath Mixbuzz Smiley
I agree with you but in real life, it is imaginable to patch preamps inputs with phantom power on, on outs and ins of other outboard. I have repaired more than one outboard piece ruined in this way. So like you said; "Fool protection": install diodes
Quote
Quote
I also suggest to lower R7 to 1K for better S/N ratio.

Nope. IC8 (THAT1646) see at it's input: R7 in parallel to impedance of C3/C5, plus R5=68R,
plus output impedance of IC11B. It is less than 100R in 20-20Khz.
Lowering R7 to 1K: will give audible phase shift at low freq's and little (some db) drop at 20Hz.
Those who good with math can calculate/simulate. No noise floor improvement. The noise floor actually caused by VCA's impedance...
I.e. using 4 paralleled 2181's and R3=5k IMHO not too bad solution Smiley

You are right again. I'm just sceptic if I see resistors with high values.

Quote
Quote
Somebody tried to leave out (bypass) the coupling caps in front of the linedriver?
Need some clarification, but, if you mean C3/C5, there will always be some tens of millivolts
of dc offset at IC11b out,even in case VCA perfectly calibrated. VCA gain changes, offset changes a bit as well. Little DC offset appears especially when VCA gives positive gain.
IMHO, MixBuzz500 using necessary minimum of parts,
mods and tweaks are at your own rescue and taste, but....feel free to tell if there some ideas Smiley
In any case, this is build support thread;
for "mod" people:  first build and make it working 100%, than mod at your rescue Smiley

You see, again it is good that I asked it before. Your explanation makes sense so I don't have to lose time and try to mod it.
Damn it's a good design. There is no room for improvement!!!
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 30, 2010, 07:15:32 PM
Ops. Never pretended:)
Always there is room for improvement. But please, build unit first than modify :)

High value resistors (in continue to R7 discussion):
it used to pull line driver's input (that1646) to ground after decoupling capacitor.
I fully agree, sometimes high value resistors causing us think about noise :)
In any case, "worse" impedance-wise point in this compressor is VCA.
The rest of places in Mixbuzz500 kept on low as possible impedances.
IMHO, the total noise of MixBuzz500 is way lower as GSSL, but
this is different story.

BTW. How many people have their units up and running?
Tell us! :)
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on August 31, 2010, 08:27:41 AM
Quote
But please, build unit first than modify Smiley

I agree completely. But we want to learn something. And while building, some questions come to mind. This forum, in this case again you Igor, is a nice help to succeed in this. That's the beauty of DIY & a good forum. Something that was impossible in the past!!
Thanx technology, thanx Igor.
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on September 03, 2010, 07:16:05 PM
I just had a friend give me a sifam meter.  It looks like it is the correct one for this build but I'm not sure.  It is the presentor shape, in the bottom left lower corner of the meter it says 19.  In the right bottom corner it says 2.5.  The scale is 0-100 currently.  On the top of the housing of the motor it says 12V / 20mA.

Anyone know if this sounds like the correct meter.  If so I just need a different bezel.

Thanks
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on September 04, 2010, 07:55:14 PM
Hmmm... Not enough info :)
Dan, please send photo by mail, will try to help.

Tony: crossed the fingers, waiting for "Yes, it works!" from you.
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on September 04, 2010, 08:34:03 PM
email sent.

Thanks Igor
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on September 06, 2010, 10:30:49 AM
I spent my long weekend building this work of art and I'm nearly completed.  I have a couple of noob questions that I hope to have cleared up.  Thanks again Igor for such an awesome project.  The PCBs are great to work with!

Diode:
Am I ok to fit an IN4003 for D1?  I only have IN4001 and IN4003.

JP1:
I'm assuming this is a simple jumper?  I stuck a resistor leg there.

Hairball meter:
This meter has led's already inside the meter, and has 2 tabs on the back for power.  I know I need to take a feed from led 2,3,4 network, but where? 

THAT 2180c for sidechain:
These don't fit in the sockets too well, do you guys clip a bit off the legs to fit them in?  I'm worried they'll just fall out if the unit gets knocked. 

What do you guys use to cut the shafts off the lorlin switches?  A rotary tool?

Those are all my noob questions.  I want to be sure of everything before I do the final assembly/calibration.  I can't wait to start smashing drums with this thing!
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on September 06, 2010, 11:26:18 AM
Hope I can help with some of your questions [only the simple ones! ]

1. Yup, JP = jumper: resistor leg is good
2. THAT 2180C and sockets:
Well, I used the 2181 and they are tight to get into the socket. They do pretty much go all the way in though. If it feels like it could fall out, its not in properly. What did you use for sockets?
3. To cut the Lorlins I used a hacksaw, just a small cheap one.

Re. diodes and meter, I'm not sure, but hopefully someone will answer those for you.

The Gimmer.

ps. Igor, I used my Mixbuzz over the weekend on a session and it ROCKED!!

Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on September 06, 2010, 12:40:04 PM
dbeeson, 1n4003 is ok  in the bom the posibilty begin with 4002 so you could put all that is more than it 4003 4004 but not 4001.

for the led vu, i propose you  to forget the inside led at time and put big led on the board, like taht will be easyer to change if one blow
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on September 06, 2010, 03:10:59 PM
Thanks guys! I managed to get the 2180s in the sockets...just wasn't pushing hard enough I guess.  Nice and tight now. 
On the audio boards, am I supposed to ignore CNB and G pads?
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on September 07, 2010, 04:25:04 AM
look at the datasheet all these diodes are the same except voltage rating

page1:
http://www.elfak.ni.ac.rs/phptest/new/html/Studije/predavanja-literatura/osnove/pdffiles/1N4001-D.pdf

They all work. I take 1N4004 or higher. I never take lower numbers in stock, don't see the point of them still existing
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on September 07, 2010, 10:58:06 PM
Quote
On the audio boards, am I supposed to ignore CNB and G pads?
C&B pads provided for connection to external C&B.
If you don't use C&B (it is not issued yet, so probably... answer Yep :)
the bottom layer SMD pads should be shorted...that's it.

Sorry, was crazy busy these days, it is almost morning here and I found some time for forum;
big thanx to all you, guys, for support!

C&B with M/S: coming....soon! Around November, if all goes OK, first proto' will work.


The Gimmer.

ps. Igor, I used my Mixbuzz over the weekend on a session and it ROCKED!!



This did me the day! Really, like a good pipe filled with Latakia smoked at my balcony!!!!
Or, even more.
/a view from here:
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on September 08, 2010, 09:00:02 AM
Thanks Igor.  Not sure which SMD pads you're referring to but I'll have a look today.  I finished the build last night, fired it up. No errors, looks great!  I will take pictures today, I just need to fit some knobs.  Then I'll start putting it through it's paces. 

A quick tip for calibrating with the 500 series lunchbox.  Use long molex cables as stated by Igor.  Remove IC11 and cut a small lead (4/5cm), strip and insert into socket 7. Install IC. You can now attach your probe to the tip of the lead. This is much easier than trying to probe Pin 7 if you want to calibrate it in the rack.  I calibrated both boards in 15 min with this trick. 

Once again Igor, Awesome project.  It was even simple enough for a complete noob like me to put it together correctly.  You are gifted man!
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on September 08, 2010, 02:50:45 PM



Quote
Not sure which SMD pads you're referring to but I'll have a look today.
Quote
Crush and Blend option
Quote
SJ points. Mixbuzz done with thought it should be modular, and SJ points reserved for
C&B option. If there's no C&B, these points should be connected, like picture shows.
http://i251.photobucket.com/albums/gg291/diy33609/mixbuzz500/P1040223.jpg
http://i251.photobucket.com/albums/gg291/diy33609/mixbuzz500/P1040224.jpg
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on September 08, 2010, 05:45:31 PM
Hey guys, noob questions here.  I am still slowly sourcing parts for a US build.  Seems a lot cheaper to use parts from mouser to do this.

1. Any reason not to use these epco caps in the sidechain?  I just want to make sure they are quality enough for this build.  This would be the cap for c27 for instance.
http://www.mouser.com/Search/ProductDetail.aspx?R=B32529C223K189virtualkey59250000virtualkey871-B32529C223K189

2. Also, I have a number of higher value uf caps and voltage that will probably fit in the PS bypass section.  I can use those correct just not lower value or voltages is my understanding.

Thanks guys
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on September 09, 2010, 08:49:44 AM
Quote
Any reason not to use these epco caps in the sidechain?

No reason

Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on September 09, 2010, 11:38:17 PM
Thanks, I can't believe how much cheaper those caps are then the other brands.   

Also, while at it is an AD713 a good chip for IC3 or no reason to use anything special here?

How are these sounding?  I can't wait to try it on some drums and subgroups. 
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on September 10, 2010, 03:15:48 AM
Some confusion when installing the VCA boards and looking at Igor's prototype:
http://www.groupdiy.com/index.php?topic=39459.msg487509#msg487509
just to make shure expencive VCA's are not blown away.
In the new kits/PCB's the VCA boards should not be mounted up side down like in Igor's picture but they should be mounted like in my picture, correct?
At least that is what I measure
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on September 17, 2010, 09:34:04 AM
Everything working good and sounding great, My bad eyes couldn't even see the the power cord i made for powering up the Time constant board was not good! :-[ :-[ ::) ::)
Its R40 that had burned, nothing to do with the rest everything was fine, thanks to your 10R resistors acting as fuses, and i had some minor contact in one of the ribbon cables...

I really need to go see the doc for visual check....
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on September 17, 2010, 02:03:14 PM
Ok, I'm really close to powering this up!  Just a few small questions. I think I'm gonna try the 2181C mis adjusted for harmonics. Any tips on how far to mis adjust?

Also, C1. I read it can be lowered to 22pf. Any reason to want to lower it?  I have a few 330PG3 (33pf) silver mica's laying around I was hoping I could use those there. Any reason I can't use those?

Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on September 17, 2010, 10:01:25 PM
Well, looks like I have a little problem.  The unit powers up fine but I only get one channel working.  I've checked over both cards and they are identical, I couldn't find any solder bridges.  I switched the ctl and SC cables around to make sure it wasn't a cable issue.  When I run audio through the non-working channel there's no sound at all, but the vu meter is working, the needle is jumping with the transients.  I'm wondering if there's a concentrated area (s) I should be looking at to solve this.  I'm assuming that the VCA is working if the VU is showing compression.  Any help would be greatly appreciated. 
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on September 17, 2010, 11:00:28 PM
[quote author=dbeeson link=topic=39459.msg506461#msg506461 date=1283950802
A quick tip for calibrating with the 500 series lunchbox.  Use long molex cables as stated by Igor.  Remove IC11 and cut a small lead (4/5cm), strip and insert into socket 7. Install IC. You can now attach your probe to the tip of the lead. This is much easier than trying to probe Pin 7 if you want to calibrate it in the rack.  I calibrated both boards in 15 min with this trick. 

Once again Igor, Awesome project.
[/quote]
Thanx! Will be happy when it works and makes a records!

A little correction, IC11 can have small dc offset (in case of tl074 for xample), so than please calibrate
with op-amp :) Not sure there will be difference more than 1-2 mv...anyway, let's be at safe side :)


Quote
Any reason not to use these epco caps in the sidechain?

No reason



Sidechain caps: just use regular poly'...nothing freaky, they don't affect the sound quality.
Of course, ceramic no good here, but poly, or film, 50-63V, enough.... :)

Thanks, I can't believe how much cheaper those caps are then the other brands.    

Also, while at it is an AD713 a good chip for IC3 or no reason to use anything special here?

How are these sounding?  I can't wait to try it on some drums and subgroups.  

AD713 not "sounding" here. They are in sidechain. AD713 is fast, perfect dc-vise opamp.
To make very precision tracking, best imho. But hey, I used them by reason I bought
some hundreds for few bucks at surplus. Sidechain quad opamps; use LF347, enough!

Some confusion when installing the VCA boards and looking at Igor's prototype:
http://www.groupdiy.com/index.php?topic=39459.msg487509#msg487509
just to make shure expencive VCA's are not blown away.
In the new kits/PCB's the VCA boards should not be mounted up side down like in Igor's picture but they should be mounted like in my picture, correct?
At least that is what I measure


For THAT2181's, "1" is printed at pcb silkscreen.
You correct.
VCA "replacement" board can fit only one way.

Quote
Everything working good and sounding great, My bad eyes couldn't even see the the power cord i made for powering up the Time constant board was not good! Embarrassed Embarrassed Roll Eyes Roll Eyes
Its R40 that had burned, nothing to do with the rest everything was fine, thanks to your 10R resistors acting as fuses, and i had some minor contact in one of the ribbon cables...

Tony, happy about healthy baby, wish to make many platina's and good sound!!!!!

Ok, I'm really close to powering this up!  Just a few small questions. I think I'm gonna try the 2181C mis adjusted for harmonics. Any tips on how far to mis adjust?

Also, C1. I read it can be lowered to 22pf. Any reason to want to lower it?  I have a few 330PG3 (33pf) silver mica's laying around I was hoping I could use those there. Any reason I can't use those?



33pf is fine. Lowering...maybe, possible to hear the effect on ultraclean ribbon-twitter monitors...what VCA's do you use?

Harmonics. First, adjust for 0V DC. With op-amp in socket (it matters).
Than, listen after ratios check, when adjusted.
Than, use good soundcard and kinda RMAA. Or: one turn of 24-turn pot will do the job.
Listen again after mis-trimming. Up to your taste, more compression "dirt"
but more "size" cab be better or worse :)
In general, I prefer analyzer for distortion calibration.
Difference between 0.02% and 0.07%THD calibrated at 0dbV, unity gain,
can be heard with Adam S3a, Lynx2, my CRM as level control setup.
(mind, I don't have acoustic treatment at workshop :)

Quote
Well, looks like I have a little problem.  The unit powers up fine but I only get one channel working.  I've checked over both cards and they are identical, I couldn't find any solder bridges.  I switched the ctl and SC cables around to make sure it wasn't a cable issue.  When I run audio through the non-working channel there's no sound at all, but the vu meter is working, the needle is jumping with the transients.  I'm wondering if there's a concentrated area (s) I should be looking at to solve this.  I'm assuming that the VCA is working if the VU is showing compression.  Any help would be greatly appreciated.  

That's strange. Does unit passing audio in bypass? I.e. when only audio pcb is inside the slot,
it should pass audio because bypas relays connecting in and out.
If bypass is OK, switch comp IN by connecting the ribbons, front panel pcb,
its power supply and control pcb; it can be good idea to trace the signal with scope....
For now, please let know about bypass. Visual check can help as well.
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on September 17, 2010, 11:39:48 PM
Thanks for the quick reply Igor.  The audio pcb is passing audio in bypass but not when the compressor is engaged.  But the meter does show compression.  I'm only running audio through one side at a time.  When the compressor is engaged, there is no hiss or a sound of any kind.  The signal is not getting to the output.  I've been meaning to take some pictures but my camera is having issues. All ribbons are where they should be.   Thanks again for the help. 

For the IC11 calibrating trick, I do leave IC11 in place, I just stick a small lead in the hole of pin 7 before I replace the IC. The IC wedges the lead in the socket nice and tight. 
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on September 18, 2010, 10:26:36 AM

AD713 not "sounding" here. They are in sidechain. AD713 is fast, perfect dc-vise opamp.
To make very precision tracking, best imho. But hey, I used them by reason I bought
some hundreds for few bucks at surplus. Sidechain quad opamps; use LF347, enough!


33pf is fine. Lowering...maybe, possible to hear the effect on ultraclean ribbon-twitter monitors...what VCA's do you use?

Harmonics. First, adjust for 0V DC. With op-amp in socket (it matters).
Than, listen after ratios check, when adjusted.
Than, use good soundcard and kinda RMAA. Or: one turn of 24-turn pot will do the job.
Listen again after mis-trimming. Up to your taste, more compression "dirt"
but more "size" cab be better or worse :)
In general, I prefer analyzer for distortion calibration.
Difference between 0.02% and 0.07%THD calibrated at 0dbV, unity gain,
can be heard with Adam S3a, Lynx2, my CRM as level control setup.
(mind, I don't have acoustic treatment at workshop :)


Igor Thanks

So C1 probably effects the highend clarity a little.  If I am right the lower the cap value the more the high end may roll of a little?

Thanks for tips on mis adjusting for Harmonics!

 
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on September 19, 2010, 11:24:50 PM
I used the old patch cord (w/ .1uf on the tip) into an amp to probe the audio path and it seems that the dbx 202xt is faulty  :-[  I get a signal at I_in but nothing at I_out.  I measured +17.3 at +E and -17.3 at -E with the meter.  Could there be anything else to check?  If I desolder and remove the vca from the circuit and install the 1k25 resistor between I_in and I_out, should there be signal at the output if I switch in the circuit?  So close...
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on September 20, 2010, 03:44:50 AM
Quote
Could there be anything else to check?  If I desolder and remove the vca from the circuit and install the 1k25 resistor between I_in and I_out, should there be signal at the output if I switch in the circuit?  So close...

What do you measure on the vca control port? Does it change if you change the make-up gain pot?
Did you put a drop of solder on SJ1?
Title: Re: MixBuzz500 build/support tHread
Post by: oceres on September 20, 2010, 04:51:32 AM
first I've to say this project has been pure joy to assemble! two thumbs up

so the thing is I have all of the pcb's stuffed and ready to go but found out that I was missing TL072 (IC10)

Can it be replaced with something else without any mods atleast until I get some TL072's? I have OPA2604 and NE5532

...It's almost finished and I'm anxious to fire it up  ;D
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on September 20, 2010, 09:22:31 PM
Quote
So C1 probably effects the highend clarity a little.  
If I am right the lower the cap value the more the high end may roll of a little?
Don't think the audio effect will be hearable...anyway.

Quote
I used the old patch cord (w/ .1uf on the tip) into an amp
to probe the audio path and it seems that the dbx 202xt is faulty  
Embarrassed  I get a signal at I_in but nothing at I_out.  

Inverting input of opamp in inverting connection is virtually 0 ohm to ground, nothing supposed to
be here till it starts to clip (this is the trick of op-amp, nothing at inverting input but yes,
there's an output :)
In other words, opamp tries to maintain same signal at - input as it see at + input. + input is grounded.
Try at op-amp's out, IC11B, pin7. Another opt: like Reanimator wrote, check what happens at control port-
maybe somehow VCA cuts the signal.

Quote
I measured +17.3 at +E and -17.3 at -E with the meter.  
Could there be anything else to check?  
If I desolder and remove the vca from the circuit and install the
1k25 resistor between I_in and I_out,
should there be signal at the output if I switch in the circuit?
If 1k25 installedbetween I_in and I_out, yes, signal supposed to be at the OP-AMP OUTPUT,
but don't de-solder VCA yet....
Seems, solder jumper is not installled or something simple.

Quote
Can it be replaced with something else without any mods atleast until I get some TL072's?
I have OPA2604 and NE5532
5532 not very precision dc-vise, and not like high impedances; ratios can be slightly fubarooed; try opa2604, it is jfet opamp; than replace it with tl072 or another jfet opamp,
dc precision and speed (at least 10v/usec) this is what means here.
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on September 20, 2010, 10:21:05 PM
Hey guys,  these are my relays.

http://www.citrelay.com/Relay%20Products.htm

I can't figure out what resistance they are because I don't know what watts it will be running at?  Seems to me running at 12vdc and .15w they have a coil resistance of 960r.  But I'm not sure if .15w is the correct value? 

If so then 960 divide by 6 = 160r.  So both R98 and R87 should be 160r .5w resistors. 

Thanks for any help clarifying in advance.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on September 20, 2010, 10:37:40 PM
Hey guys,  these are my relays.

http://www.citrelay.com/Relay%20Products.htm

I can't figure out what resistance they are because I don't know what watts it will be running at?  Seems to me running at 12vdc and .15w they have a coil resistance of 960r.  But I'm not sure if .15w is the correct value? 

If so then 960 divide by 6 = 160r.  So both R98 and R87 should be 160r .5w resistors. 

Thanks for any help clarifying in advance.

Dan, easy way: just measure the coil resistance with multimeter. 160r can be 150r, carbon cracked, 1/2w, 20%.
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on September 21, 2010, 06:48:39 PM
Got it!

One more question then I am ready to test I think. 

Quote
and don't forget to link the 3 point on the side of switch on off on if not the relay could not work and the unit stay in bypass
That's right Smiley
This jumper is for people who will use the unit in GSSL or Gyraf mode only,
but... just put a solder joint here to have both options.


Do I just need to do a solder bridge over all these points as well?  Like SJ1 and SJ2?

Thanks
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on September 21, 2010, 06:57:30 PM
Quote
Do I just need to do a solder bridge over all these points as well?  Like SJ1 and SJ2?

Yep
Title: Re: MixBuzz500 build/support tHread
Post by: oceres on September 22, 2010, 06:30:29 AM
5532 not very precision dc-vise, and not like high impedances; ratios can be slightly fubarooed; try opa2604, it is jfet opamp; than replace it with tl072 or another jfet opamp,
dc precision and speed (at least 10v/usec) this is what means here.

thanks Igor! I tried it with opa2604 in IC10 and it worked yay! Calibration was a breeze and the unit sounds absolutely wonderful. It's my first buss compressor so I'm blown away how good it sounds. I have 4x that2181A with LME49710 and compression is so clean and smooth it's like hitting transients with white pillows... if that makes any sense ;D

ps. Do I need to re-calibrate SYM 50k if I swap out IC11 (ne5532) for opa2604 too?

Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on September 22, 2010, 11:03:57 PM
Thanks for the help Igor.  I switched all dips on each board and found the faulty board to be working when I did so.  So I narrowed it down to the DRV134.  Just ordered a new one.  Thanks again.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on September 23, 2010, 07:15:58 PM
Quote
thanks Igor! I tried it with opa2604 in IC10 and it worked yay!

HURRAY!!!!!!!!!!!!!!!!!!

Quote
Calibration was a breeze and the unit sounds absolutely wonderful. It's my first buss compressor so I'm blown away how good it sounds. I have 4x that2181A with LME49710 and compression is so clean and smooth it's like hitting transients with white pillows... if that makes any sense.

I feel happy :) Now, do a great track with MB500!!!

Yes, 2181A+LME49710 combo should work great.
My personal opinion, 2181A don't worth additiional $3 per VCA, soundwise.
Neither it is tooooo sterile, no, it still has some VCA sound if you listen it
in hi-res monitoring setup, and the diffrence between perfectly adjusted
for minimum distortion A or B grade is almost negligible.
For me, quartet of 2181B after trimming sounds more "alive".
Anyway, it is just my opinion...
Paralleling VCA's does not lowers minimum possible distortion;
but, it increases the dynamic range, what is important IMHO.

Smooth transient response is matter of timing capacitor and PCB layout, as well.
I did not used tantalums here by this reason; one 0.47uf poly cap used for
all release settings except A, with a little rearranging the release switch if
you guys noticed. Time constants remains same, anyway.

Quote
ps. Do I need to re-calibrate SYM 50k if I swap out IC11 (ne5532) for opa2604 too?
Maybe. 5532 is not best dc precision opamp.

Quote
I switched all dips on each board and found the faulty board to be working when I did so.  So I narrowed it down to the DRV134.  Just ordered a new one.  Thanks again.
Yes, DRV134 is good chip.
In general, if we got to "balancers", line receivers/drivers, here is what I think.
Using even best opamps for "re' and 'balancing" the line not worth this
neither cost nor quality-wise.
It never will sound better or cleaner than TI or THAT chips, without
talking about harmonic content.
I avoided capacitors in soundpath at every possible places, to get
minimum unwanted sonic artefacts, thanx to these chips.
And, another thing. Try to feed 1khz 5V P-P squarewave into GSSL's output balancer,
sum the + and - output with pair of 2k resistors and 100R trimpot and adjust for less possible signal;
than, see on scope what you get here.
As well, GSSL output balancer does not likes when - is connected to ground.

These are the reasons why I used "balancing" chips.
INA137, DRV134, THAT1646, THAT1246, can be used in MixBuzz500.
Beware of SSM2142, it is not best line driver. However, SSM2143 can be used at the input.
Title: Re: MixBuzz500 build/support tHread
Post by: kibadachi on September 24, 2010, 04:39:44 AM
Can someone who already built the mixbuzz500 recommend part numbers for

CAPACITOR-CERAMIC/NPO/COG 2.5MM PITCH  22P      and for

CAPACITOR-NPO/COG/SILVER MICA  33P      C2,5-3   
                                                 56P      C5/2.5   C1

Preferable Mouser, or Farnell.
   
Thanks

Title: Re: MixBuzz500 build/support tHread
Post by: zayance on September 24, 2010, 05:05:46 AM
Can someone who already built the mixbuzz500 recommend part numbers for

CAPACITOR-CERAMIC/NPO/COG 2.5MM PITCH  22P      and for

CAPACITOR-NPO/COG/SILVER MICA  33P      C2,5-3  
                                                 56P      C5/2.5   C1

Preferable Mouser, or Farnell.
  
Thanks


22P
http://fr.mouser.com/Murata/Passive-Components/Capacitors/Ceramic-Capacitors/Multilayer-Ceramic-Capacitors-MLCC-Leaded/_/N-4gzxjZ1z0zlft?P=1z0x4jpZ1z0y7ye
33P
http://fr.mouser.com/Murata/Passive-Components/Capacitors/Ceramic-Capacitors/Multilayer-Ceramic-Capacitors-MLCC-Leaded/_/N-4gzxjZ1z0zlft?P=1z0x6f9Z1z0y7ye
56P
http://fr.mouser.com/Murata/Passive-Components/Capacitors/Ceramic-Capacitors/Multilayer-Ceramic-Capacitors-MLCC-Leaded/_/N-4gzxjZ1z0zlft?P=1z0x638Z1z0y7ye

Pick your choice  :)
Title: Re: MixBuzz500 build/support tHread
Post by: kibadachi on September 24, 2010, 06:04:26 AM
Thanks.

You guys respond faster than i can ask ;D
Title: Re: MixBuzz500 build/support tHread
Post by: ultra-alex on September 24, 2010, 12:45:41 PM
man, this bloody beast turns into a real challenge!  ;D
i just burned my fingers on a f***ing hot 2181. need some cold beers first before i start crying for help.  ::)
cheers, alex
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on October 19, 2010, 07:47:40 PM
I was wondering if any of you folks could point me in the right direction.  After solving the problem with the 2nd channel line driver, everything now works except for the makeup gain.  I turn the knob and there is no change in level after compression.  I've tested the pot and it works.  Not sure where I should be poking around. Any ideas?
Title: Re: MixBuzz500 build/support tHread
Post by: stereokillah on October 20, 2010, 04:08:30 PM
check your tl074 ic7
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on October 20, 2010, 06:22:03 PM
Thanks Stereokillah.  I think I will order another one.  Is there a way to test it?  I know pins 5,6,7 are the op amp for the makeup, I just don't know what to look for.  Thanks again.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on October 24, 2010, 05:17:09 PM
Check the voltage on wiper of makeup pot changes from 0 to about 8V; check R53, R59;
of course, at pin 6 IC7 there's 0V, it is inverting ground-referenced amp;
if compressor works, i.e. you get compression when changing threshold, the problem is not IC7B.
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on October 25, 2010, 09:04:00 AM
It was indeed the TL074.  I replaced it and the compressor works beautifully.  TL and TM are still doing funny things, but I'll do some investigation when I have more time.  Thanks guys!
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on October 25, 2010, 10:43:49 AM
If the compressor was working with bad TL074, but has no makeup....
Gain reduction signal, or control voltage, comes to IC7B, thru R54.
Makeup voltage comes to IC7B thru R59. Op-amp which passing gain reduction signal
but not passing makeup voltage... Same electrons :) Strange selectivity!
 ::)  ::)  ???  ???
Anyway, I am happy it works, check the ratios etc, if you already did it,
let us know about sound!
Title: Re: MixBuzz500 build/support tHread
Post by: dbeeson on October 25, 2010, 02:11:11 PM
I thought it was wierd myself.  The ratios are correct. I did a drum bus test last night and this thing is fantastic.  It's really handy to have both 4k and GSSL in the same unit.  I'm finding the GSSL to be more aggressive, and it worked well for the raunchy style of beat I laid down.  I could see myself using it in 4k mode most of the time though.  It seems I forgot to put the stop on the release switch and if I go beyond auto, it distorts...but actually sounded really cool with the dirty beat.  I will post some clips when I get the time. 
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on October 25, 2010, 05:22:47 PM
Great news! Regarding the release switch, you easy can have 6th position, just install
R||C, between A6 or C6 point of release switch to gnd...Try 220K and 0.1uf,
for very fast aggressive setting, or you can mix two RC for another auto mode.
Yes, 4k is my default mode too :)
Clips-welcome!
Title: Re: MixBuzz500 build/support tHread
Post by: Brolik on December 25, 2010, 04:32:40 PM
Just to be clear, as I have found some conflicting or confusing wording in this thread:

JP1 on the audio board DOES NOT need to be jumped?

and

The three pads on the back of the control board by the bypass switch DO need to be jumped?

Thank you in advance for clarifying.

Merry Christmas!
Title: Re: MixBuzz500 build/support tHread
Post by: Infernal_Death on January 08, 2011, 02:46:26 PM
Received some of the last parts for this project today and finished it nearly (only meter is missing). 1 channel worked from the beginning, the other had a very distorted signal. Could trace it to the output of the Audio VCA. At the end it was a defective 5532 (IC11B). Now everything works. Just need to put it together (install boards in the metalwork, put knobs on), then ordering a meter and of course finishing my GDIY 511 Rack PSU.

Igor, nice project as always and a breeze to put together.

Flo
Title: Re: MixBuzz500 build/support tHread
Post by: Infernal_Death on January 08, 2011, 03:30:53 PM
Just to be clear, as I have found some conflicting or confusing wording in this thread:

JP1 on the audio board DOES NOT need to be jumped?

and

The three pads on the back of the control board by the bypass switch DO need to be jumped?

Thank you in advance for clarifying.

Merry Christmas!


Brolik, it really should be clear when looking at the schematics.
JP1 only needs to be jumpered if you don't populate the sidechain filter.
Yes all the three pads on the back of the control board need to get joint together, so you can switch between GSSL and Turbo mode and the relays still get switched.
Title: Re: MixBuzz500 build/support tHread
Post by: Brolik on January 10, 2011, 01:07:05 PM
Thanks for the help! I'm almost done as well. I have to admit that schematics of this complexity still fluster me a bit. I'm getting there, but still working on small psu's and gain stages and such. Great build though! Can't wait to get my 51x up and running so I can try it out!
Title: Re: MixBuzz500 build/support tHread
Post by: johnny dance on January 21, 2011, 11:52:54 AM
I know its lazy, but does anyone have a farnel or mouser cart made u for this? I am about 40% putting one together but thought I would ask
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on January 21, 2011, 05:06:08 PM
Cool. Seems this built goes OK.
Curoius: how many people have tested and working MixBuzz500?
Title: Re: MixBuzz500 build/support tHread
Post by: AudioGimmer on January 21, 2011, 06:18:31 PM
Cool. Seems this built goes OK.
Curoius: how many people have tested and working MixBuzz500?

Me, for 1...

The Gimmer
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on January 21, 2011, 07:28:59 PM
14 MixBuzz500 are working for sure, as I know, including 6 I built myself... Not bad!
If you have working MixBuzz500, why not write here?
;)
Title: Re: MixBuzz500 build/support tHread
Post by: waner on January 22, 2011, 09:32:15 AM
I have two that`s working great!!

One "Hifi" with four VCA on the VCA board and the other with only one VCA.

Thanks alot for this mixglueing project!!

Mattias
Title: Re: MixBuzz500 build/support tHread
Post by: JamesW on January 22, 2011, 10:24:26 AM
14 working units this is good to hear.  This project is rising to the top of my pile and I hoped the reason for no posts was that no one had any problems. 
Title: Re: MixBuzz500 build/support tHread
Post by: kibadachi on January 22, 2011, 10:33:44 AM
I am testing the unit outside the rack.
Audio passes through in standby.
Audio passes in 4000 and gssl mode.
I can use make up to increase level but no compression. I hear the relays when switching from bypass to 4k and gssl.
Meter is not moving.
Can someone give me a starting point for troubleshooting?
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on January 22, 2011, 12:26:57 PM
First, let's check the voltage beween gnd and wiper of threshold pot,
it should change from approx. +6.5 to -6.5 Volt when rotating the THRESHOLD pot.

Then, let's check if audio passing thru sidechain: feed about 1V RMS sinus 1Khz to input, set 4000 mode,
sidechain filter OFF, check with scope at IC3d (14), IC3A (1), there should be sinus 0.5V RMS;
than, check if there's a signal on CTL pin 5 (10 pin IDC connector);
than, check the signal on IC11A (1), sinus, it's amplitude changes with position of threshold pot;
than, check if rectifier works-on IC10A, (1) should be rectified full-wave signal when threshold set to low (CCW);
than, check if there's a voltage CTL-10, should be saw-looking signal which changes depending on amount of compression and time constants;
than, check the voltage on IC7D (14), this is the control voltage (should be meter deflection), etc.....

Before all this,
Check jumpers;
Check if CTL and SC cables going to their channels respectively,
i.e., CTL1, SC1 to left and CTL2, SC2 to right channel;
Check all connections etc...

Of course, there is a little mistake, wrong connection or wrong component somewhere :)
Cool let's find it....me a way curious :)
Title: Re: MixBuzz500 build/support tHread
Post by: kibadachi on January 23, 2011, 10:08:16 AM
When i checked the voltage between gnd and and wiper i found some "forgotten" solderings on the control board. fixed and working!
Thanks Igor for the starting point.
Now that the interns are working i have to find some knobs to match the sonical with the aesthetical.

Any recommendations for the F' rite Red lookalike knobs or some anodized aluminium colored knobs with skirts?
I also like the knobs that Skylar rendered. ( http://www.groupdiy.com/index.php?topic=37604.msg463588#msg463588 ) Any of these knobs available in real life?
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on January 23, 2011, 02:28:11 PM
That's good!!!! Have a fun doing music with your Mixbuzz500!!

I am not best source for knobs advice.... ELMA is my personal taste;
another funny option:
http://www.smallbearelec.com/Detail.bok?no=782
Many others are available, check Banzai, Smallbearelec etc for knobs....
Title: Re: MixBuzz500 build/support tHread
Post by: culteousness1 on February 22, 2011, 04:02:18 PM
Hey all,

I just tested my finished unit. First without ics everything was alright.
Then I put in the ics and tested again.

Unfortunately two resistors (R47, R44) on one board went up in smoke and started glowing  :o.

Other board seems to be working.

Thanks in advance!

Greetz from Cologne,
Carsten

Title: Re: MixBuzz500 build/support tHread
Post by: Igor on February 23, 2011, 08:14:36 AM
Check the direction of IC's and if there's no shorts...
Title: Re: MixBuzz500 build/support tHread
Post by: culteousness1 on February 23, 2011, 11:10:13 AM
Thanks for your reply Igor!

Good news! Your diagnosis was right. I inserted IC10 in the wrong direction  >:(.

Now I have to replace those resistors and proceed checking.

Greetz,
Carsten
Title: Re: MixBuzz500 build/support tHread
Post by: johnny dance on February 27, 2011, 03:14:41 PM
I know its lazy, but does anyone have a farnel or mouser cart made u for this? I am about 40% putting one together but thought I would ask

OK so i sort of pulled the digit out and put together a close to complete cart...
-I have a 65quid resistor kit in there (easier for me, but not nessecary)
-Missing a few of the caps, the wiring, and the DBX replacement pin connectors I think

-Is there anything else missing, over/underspec'd (it looks $$$y)

Line No.   Order Code   Qty   Description   Mftr. & Part No.   RoHS   Line Price
                  
1   3322592   30   CAPACITOR CERAMIC 0.22UF, 50V, Y5V, RADIAL   VISHAY BC COMPONENTS - K224Z15Y5VF5TL2   Y-EX    1.53
2   1141760   10   CAPACITOR, 22PF, 50V, NP0, RADIAL   VISHAY - K220J15C0GF53L2   YES    1.36
                  
3   1311572   2   CAPACITOR SILVER MICA 33PF, 500V, RADIAL   CORNELL DUBILIER - CD15ED330JO3F   YES    1.96
4   1311557   4   CAPACITOR SILVER MICA 33PF, 500V, RADIAL   CORNELL DUBILIER - CD10ED330JO3F   YES    6.2
                  
5   1311576   4   CAPACITOR SILVER MICA 56PF, 500V, RADIAL   CORNELL DUBILIER - CD15ED560JO3F   YES    4.08
6   1669202   10   CAPACITOR, 15NF, 50V, 5%   PANASONIC - ECQV1H153JL   YES    0.81
                  
7   1669204   10   CAPACITOR, 22NF, 50V, 5%   PANASONIC - ECQV1H223JL   YES    0.9
8   1744826   10   CAPACITOR, FILM, 50V, 47NF   PANASONIC - ECQV1H473JL   YES    0.66
                  
9   1744827   10   CAPACITOR, FILM, 50V, 68NF   PANASONIC - ECQV1H683JL   YES    0.61
10   1744829   10   CAPACITOR, FILM, 50V, 0.22UF   PANASONIC - ECQV1H224JL   YES    0.91
                  
11   1712374   8   CAPACITOR POLYESTER 0.15UF, 63V, RADIAL   EPCOS - B32529C154J   YES    0.69
12   1744833   10   CAPACITOR, FILM, 50V, 1UF   PANASONIC - ECQV1H105JL   YES    2.6
13   1702698   8   ALUMINUM ELECTRO. CAPACITOR   VISHAY BC COMPONENTS - MAL214066221E3   YES    5.84
14   8767408   20   CAPACITOR, 47UF, 50V   PANASONIC - ECA1HAM470X   YES    2.74
15   8766940   4   CAPACITOR, 10UF, 35V   PANASONIC - ECA1VAD100X   YES    0.68
                  
16   9341234   100   RESISTOR, 0.25W 1% 12K   MULTICOMP - MF25 12K   YES    2.3
17   9342362   1   RESISTOR, KIT, 0.25W 1% E6   MULTICOMP - MF0W4FFE006KIL   YES    65.66
                  
18   1354171   12   AMP, VOLT CONTROLLED, TRIMMABLE, 2181   THAT CORPORATION - THAT2181AL08-U   YES    65.52
19   1426379   2   OP AMP, DUAL LOW NOISE, SMD, SOIC8   ON SEMICONDUCTOR - NE5532AD8G   YES    2.76
                  
20   1354147   4   LINE RECEIVER, BALANCED, 1246, DIP8   THAT CORPORATION - THAT1246P08-U   YES    11.56
21   1354158   8   LINE DRIVER, BALANCED, 1646, DIP8   THAT CORPORATION - THAT1646P08-U   YES    28.32
                  
22   1354168   2   AMP, VOLT CONTROLLED, PRETRIM, 2180   THAT CORPORATION - THAT2180CL08-U   YES    7.58
23   1103005   4   IC, OP AMP, DUAL JFET, DIP8   TEXAS INSTRUMENTS - TL072ACP   YES    4.36
                  
24   1105902   4   IC, OP AMP, QUAD JFET, DIP14   TEXAS INSTRUMENTS - TL074ACN   YES    2.92
25   1384133   20   SWITCHING DIODE, 100V, 150mA, DO-35   NTE ELECTRONICS - 1N914   YES    0.84
                  
26   1467514   4   DIODE, STANDARD, 1A, 1000V, DO-41   FAIRCHILD SEMICONDUCTOR - 1N4007   YES    0.32
27   9526820   20   INDUCTOR, AXIAL   MURATA - BL01RN1A1D2B   YES    4.2
28   9265252   20   INDUCTOR, FERRITE BEAD, 105Z   MULTICOMP - MCAB 035090-33   YES    1.56
29   9353011   4   TRIMMER, SMD, 12 TURN 50K   BOURNS - 3269W-1-503LF   YES    17.88
30   9480218   4   RELAY, PCB, DPCO, 12VDC   MULTICOMP - HRS2H-S DC12V   YES    6.24

Line No.   Order Code   Qty   Description   Mftr. & Part No.   RoHS   Line Price   Line note
31   636332   12   HEADER, STRAIGHT, 10WAY   AVX INTERCONNECT - 008380010000010   YES    16.2
32   636034   12   SOCKET, IDC, 10WAY   AVX INTERCONNECT - 008290010000011   YES    17.52
                  
33   1106784   8   HEADER, STRAIGHT, 10WAY   HARTING - 09 19 510 7324   YES    8.32
34   1818129   20   PLUG & SOCKET CONN, HEADER, 3POS, 6.35MM   MOLEX - 10-84-4030   TBA    7.28
                  
35   1847277   12   PLUG & SOCKET CONNECTOR, HEADER 3POS 3MM   MOLEX - 43650-0324   YES    19.51
36   1426380   2   IC, OP AMP, DUAL LOW NOISE, PDIP8   ON SEMICONDUCTOR - NE5532ANG   YES    2.42
                  
37   9843817   10   DIODE, SMALL SIGNAL, DO-35   FAIRCHILD SEMICONDUCTOR - 1N914   YES    0.53
38   1780709   2   LED, 3MM, RED, 200MCD   BIVAR - 3SURC   YES    0.37
                  
39   1384846   6   LED, 5MM, YELLOW, 6.3MCD, 585NM   CHICAGO MINIATURE LIGHTING - 4304H7   YES    0.92
40   9490272   2   IC, V REG +12V, 78L12, TO-92-3   NATIONAL SEMICONDUCTOR - LM78L12ACZ   YES    0.82
                  
41   9490396   2   IC, V REG -12V, 79L12, TO-92-3   NATIONAL SEMICONDUCTOR - LM79L12ACZ   YES    1.08
42   1123700   4   SWITCH, 2POLE, 6 POS   LORLIN - CK1060   YES    5.68
                  
43   1123703   1   SWITCH, 4POLE, 3 POS   LORLIN - CK1062   YES    1.42
44   1123699   1   SWITCH, 1POLE, 12 POS   LORLIN - CK1059   YES    1.42
45   1550189   1   SWITCH, SOLDER TAG, 3PDT, ON-OFF-ON   MULTICOMP - 1M33T1B5M1QE   YES    2.14
46   7991967   1   SOCKET, PCB, 0.1    20WAY"   HARWIN - M20-7822046   In Stock
47   1022262   10   HEADER, 1ROW, 20WAY   HARWIN - M20-9992046   YES    7.5
48   9358323   2   POTENTIOMETER, 10K   BOURNS - PCW1J-B24-KCB103L   YES    12.26
49   9608648   1   TRIMMER, 24 TURN 50K   VISHAY SPECTROL - M64W503KB40   Y-EX    1.35
                  
50   1262061   1   METER, 19W, 0-1MA   SIFAM - 19W0-1MA0-100   YES    41.89
51   1262079   1   BEZEL, FRONT, 19W   SIFAM - 19W, BEZELB   YES    1.71
                  
52   1141778   10   CAPACITOR, 0.22UF, 50V   VISHAY - K224K20X7RF53L2   YES    3.3
53   9750878   10   CAPACITOR, 0.1UF, 63V   EPCOS - B32529C104K   YES    2.8
                  
54   9750908   5   CAPACITOR, 0.33UF, 63V   EPCOS - B32529C334K   YES    1.8
55   9750916   5   CAPACITOR, 0.47UF, 63V   EPCOS - B32529C474K   YES    3.15
                  
56   9691936   5   CAPACITOR, 220UF, 10V   PANASONIC - EEUFC1A221   YES    0.92
57   1765147   2   RESISTOR, METAL FILM, 2KOHM, 500mW, 1%   VISHAY DALE - CMF552K0000FHEB   YES    0.46
                  
58   1106093   2   IC, OP AMP, LOW NOISE, 5534, DIP8   TEXAS INSTRUMENTS - NE5534AP   YES    1.72



Title: Re: MixBuzz500 build/support tHread
Post by: culteousness1 on February 27, 2011, 03:29:58 PM
One more working unit here after some minor errors!

Now I can start the F76 build. Any news on the F76 support thread, Igor?

Thank you for this project, Igor!

Greetz from Germany,
Carsten
Title: Re: MixBuzz500 build/support tHread
Post by: Marcocet on February 27, 2011, 05:37:13 PM
I know its lazy, but does anyone have a farnel or mouser cart made u for this? I am about 40% putting one together but thought I would ask

OK so i sort of pulled the digit out and put together a close to complete cart...
-I have a 65quid resistor kit in there (easier for me, but not nessecary)
-Missing a few of the caps, the wiring, and the DBX replacement pin connectors I think

-Is there anything else missing, over/underspec'd (it looks $$$y)

https://uk.farnell.com/jsp/profile/viewSavedCart.jsp?orderId=o1540218006




Link's not working.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on February 27, 2011, 07:05:41 PM
Hey Carsten, that's great news!
Enjoy your MixBuzz, and tell us about sound!
Yes, I starting F76 build/support thread within few minutes...
Kits will be sent this week (I hope.. :) Sorry for delay, guys.

@johnny dance: I cannot login with this link. Please pass thru BOM little-by-little.
For all important parts there are Farnell p/n's.
BOM doesn't has p/n's for resistors etc as there is a lot of choice.


Title: Re: MixBuzz500 build/support tHread
Post by: johnny dance on February 28, 2011, 09:13:42 AM
Just put my most recent cart above... most of it is there I believe... any major errors?
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on February 28, 2011, 09:40:40 AM
Just put my most recent cart above... most of it is there I believe... any major errors?

Well you're asking Igor to do your job, the best way to be sure of the order is to have board in front of you, and BOM, while you're searching around check the board and dimensions, never know some parts can be big, and just cross mark each components, everybody here bothers doing that, and it's part of the deal and fun of DIY  ;) :)
And if you don't have the board still, well wait for it then....
Title: Re: MixBuzz500 build/support tHread
Post by: johnny dance on February 28, 2011, 09:53:16 AM
Just put my most recent cart above... most of it is there I believe... any major errors?

Well you're asking Igor to do your job, the best way to be sure of the order is to have board in front of you, and BOM, while you're searching around check the board and dimensions, never know some parts can be big, and just cross mark each components, everybody here bothers doing that, and it's part of the deal and fun of DIY  ;) :)
And if you don't have the board still, well wait for it then....

Hey Happy to do my own job, not a problem. actually was just sharing to help anyone else in my boat trying to order most of the parts for this, might make it easier for someone else that's all... I mean I've already put the BOM together.. .all I need to do is click 'buy'...  8)

And as far as the benefit to me it was more... 'hey i didn't use that i used this and it sounds great/is cheaper'.... etc... might make life easier for everyone else.  :o
Title: Re: MixBuzz500 build/support tHread
Post by: zayance on February 28, 2011, 10:08:01 AM
Just put my most recent cart above... most of it is there I believe... any major errors?

Well you're asking Igor to do your job, the best way to be sure of the order is to have board in front of you, and BOM, while you're searching around check the board and dimensions, never know some parts can be big, and just cross mark each components, everybody here bothers doing that, and it's part of the deal and fun of DIY  ;) :)
And if you don't have the board still, well wait for it then....

Hey Happy to do my own job, not a problem. actually was just sharing to help anyone else in my boat trying to order most of the parts for this, might make it easier for someone else that's all... I mean I've already put the BOM together.. .all I need to do is click 'buy'...  8)

And as far as the benefit to me it was more... 'hey i didn't use that i used this and it sounds great/is cheaper'.... etc... might make life easier for everyone else.  :o

Ah Yes of course, thanks for the effort  :)
Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on March 13, 2011, 02:05:34 PM
Hey guys, I have been finally able to start testing and calibrating the Mixbuzz.  I have found a few problems but I have a few questions to help solve a few more things. 

1.  both channels track together but don't have the same output.  They are off by a few db and seem to act respond slightly different to compression at different thresholds.  Any idea where to look. (I used 1% resistors everywhere)

2.  my switch for the release time has been broken so I wonder if that could mess with the 2 channels.  So I pulled it out.  Is there a simple way to jumper the switch to a position so I can finish testing until the replacement shows up?

3.  For calibrating do I just need to set the threshold as high as possible (for no compression) and the gain to zero.  Then measure IC11 for DC offset?

4.  I have read the entire thread a few times looking for trouble shooting ideas and looked over the boards for mistakes a number of times.  I'm gonna go look again with fresh eyes but I thought I would post to see if anyone had any ideas.  Or do they just not track exactly the same left to right like one would think?

Thanks guys, I can't wait to finally have this one done and in use.


Title: Re: MixBuzz500 build/support tHread
Post by: dandeurloo on April 01, 2011, 11:17:06 PM
Update:

1. I replaced the broken switch.

2. I was able to trim the audio VCA to .062 THD

3. I added a 1k trim pot before the VCA in order to match the gain on the tow channels.  now both channels put in and out 0.000 db!



PROBLEM:
in both the 4000 and the GSSL modes I get nothing from the side chain.  The threshold and gain both don't change a thing, at all.  Both channels.  So I must have something pretty obvious over looked.  I've looked these boards and schematics over 100 times and still can't find it.  Any help would be appreciated.

I'm so close and with the added trim pots added before the VCA this thing should track very nice.  I can't wait to hear it!

Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on April 12, 2011, 01:56:57 PM
Where to get the edge connector for the little test-pcb's (the ones with the XLR's) in Europe?
Title: Re: MixBuzz500 build/support tHread
Post by: culteousness1 on April 12, 2011, 02:06:28 PM
I searched for them at Farnell without luck.

So I ordered mine from Volker at the WM.
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on April 23, 2011, 08:43:45 AM
Thanks culteousness1, Volker for the edge connector. One working Mixbuzz500 more.

I first installed 100k instead of 100 ohm for R60 on the control board. Result low output with a slight increase if I turned the Threshold down. Unit is sounding great now. Thanks again Igor!!

I tested my Mixbuzz 500 not assembled yet in the frame and with a DC power supply. You can limit the current (to 15mA) and save you from burning expencive IC's.
One disadvantage is that you can easily put the connectors for SC and CTL in the wrong position. I did it for a short moment. The current limiting on my power supply and the smart lay out saved me and nothing got damaged.
If you are testing one channel at a time, don't forget to connect the CTL-flatcable to the other channel too, otherwise the unit will stay in bypass (relais connected in series between both channels).

Now I have to finish my: How to build Mixbuzz500 step by step.
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on April 26, 2011, 01:40:12 PM
I need some help with the SYM trimmers. I have no distortion meter so I used the method Igor suggested 0 volts on the output pins of IC 11 (opa2604). The thing is that it is constant drifting. In the beginning much more and after 30 minutes some millivolts. The other thing is that the trimmers are at there end position and I'm using 4x 2181A's on the VCA boards and also 2181A in the sidechain. (It was cheaper to order 10 x 2181 of the same model)


Is there some freeware distortion meter?

Do I leave out R33 and SC_SYM and forget the DC on pin 1  of IC11?

Is there another way?
Title: Re: MixBuzz500 build/support tHread
Post by: mnats on May 08, 2011, 07:54:57 AM
(http://mnats.net/images/mixbuzz/MixBuzz-500_completed_front_crop.jpg)

Thanks Igor - Works great!

I've posted some notes here: http://mnats.net/mixbuzz_500_build.html
Title: Re: MixBuzz500 build/support tHread
Post by: reanimatorstudio on May 09, 2011, 08:00:26 AM
Congrats mnats!! Your notes are really great too. I'm going to put a link in my "How to build a Mixbuzz 500 step by step" if you don't mind :http://www.groupdiy.com/index.php?topic=40493.msg553174#msg553174



I need some help with the SYM trimmers. I have no distortion meter so I used the method Igor suggested 0 volts on the output pins of IC 11 (opa2604). The thing is that it is constant drifting. In the beginning much more and after 30 minutes some millivolts. The other thing is that the trimmers are at there end position and I'm using 4x 2181A's on the VCA boards and also 2181A in the sidechain. (It was cheaper to order 10 x 2181 of the same model)


Is there some freeware distortion meter?

Do I leave out R33 and SC_SYM and forget the DC on pin 1  of IC11?

Is there another way?
Title: Re: MixBuzz500 build/support tHread
Post by: noulou on May 10, 2011, 04:35:48 AM
(http://www.kiwistudio.gr/groupdiy/buzz500.jpg)


brilliant kit as usual, thanks Igor!
Title: Re: MixBuzz500 build/support tHread
Post by: wowi on May 14, 2011, 11:40:55 AM
One more 500 Mixbus ready here, but ... a little bug has survived:

The left channel has 3db more output than the right. This occurs, even if the threshold is turned up, so that there is no compression.
When i go on bypass, everything is ok. Both channels compress and sound as they should.

Any idea where to look ?

Wolfgang
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 18, 2011, 08:18:50 PM
Which VCA's used?
Wrong resistor in audio path, maybe... Wrong resistor at VCA PCB...
Or, 5534 at VCA PCB has too much offset....almost impossible.
Other-vice, IF the CV at one side was not correct... But the control voltages are tied together.
As usual, CHECK EVERY PART, and you'll find the mistake.

@Mnats: awesome!!!! I just reading
http://mnats.net/mixbuzz_500_build.html.
Man, I have to learn from you how to give REAL build support!!!!
I wish to have bit more time, as well))
Title: Re: MixBuzz500 build/support tHread
Post by: Marcocet on July 29, 2011, 06:16:36 PM
Okay, here's where I'm at

I finished putting the unit together. It powers up, and I can hear the relays clicking as I go in and out of bypass. The meter is showing gain reduction as I turn the threshold knob. However the audio doesn't seem to be effected at all, and the make up gain doesn't change the output either.

Any thoughts? I can't seem to track it down... Thanks
Title: Re: MixBuzz500 build/support tHread
Post by: culteousness1 on July 29, 2011, 06:40:43 PM
Is there some freeware distortion meter?

You may check RightMark Audio Analyzer:

http://audio.rightmark.org/index_new.shtml (http://audio.rightmark.org/index_new.shtml)

It's abled to measure the Total Harmonic Distortion and there is a free version.

Cheers,
Carsten
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on July 30, 2011, 01:40:52 PM
Strange... Did you connected the power supply of small (control) pcb?
Title: Re: MixBuzz500 build/support tHread
Post by: Marcocet on August 03, 2011, 10:37:36 AM
Yes. The bypass LED is functioning perfectly, and the meter appears to be showing gain reduction although the output is not being effected. I can hear the relays clicking when I flick the bypass so I assume that's not the issue. Any other thoughts?

I'll take some pictures when I get a chance to put my hands on it again. Thanks

Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 03, 2011, 04:16:28 PM
Great. Let's check:

When turning MAKEUP and THRESHOLD pots, at the pin 7 and 8 of IC7b the voltage should change within range of couple of volts,
(without getting deep into precision mathematic) :)

If yes, check resistors R60=100r, R75=49r next.
Than, go to audio board and check if there's voltage change when rotating the trimpots at CTL connector, pins 1 and 3
(or, check at R100, R45). Check R100=909R. Maybe, bad contact at pin 1 of CTL connector.
If this does not helps, check on VCA adaptor PCB: R101=732R, R102=100r, check if IC9 (NE5534) installed correct as well.
Title: Re: MixBuzz500 build/support tHread
Post by: Marcocet on August 08, 2011, 11:58:24 PM
Found it. I'd done the calculations for R100 right (using a 202C) but somehow put the wrong value in! The makeup not working was just a bad contact.

It's totally awesome. Thanks for all the help and for your hard work Igor.

Title: Re: MixBuzz500 build/support tHread
Post by: Igor on August 09, 2011, 02:41:34 AM
Cool, enjoy!
Title: Re: MixBuzz500 build/support tHread
Post by: timmygrimm on September 25, 2011, 08:27:49 PM
I'm trying to put together Mouser part numbers for everything.

https://www.mouser.com:443/ProjectManager/ProjectDetail.aspx?AccessID=d986302f5e

I think I got everything with the following exceptions:

- 6.8uf audio grade caps (C38) arent available through Mouser. Don't know if I can sub in a value or just find a different source.

- Mouser seems to have no 5mm LEDs...

- I'm not sure what to order for the PCB INTERCONNECT SOCKET/RAW CONNECTORS.

- Got the 10 pin male headers, but couldn't find any female sockets with horizontal wire mount like I see in people's photos. I put this http://www.mouser.com/Search/ProductDetail.aspx?R=M80-8881005virtualkey57420000virtualkey855-M80-8881005 in the project, but not sure if it will fit / work.

- I put these ferrite beads on the order but not sure if they will fit. http://www.mouser.com/Search/ProductDetail.aspx?R=4212-2virtualkey51820000virtualkey807-4212-2

- I ordered 2181A(s) as per BOM, but others say 2180A is best choice? Confused...

- Not sure which 10 connector wire to order (gauge, etc). Options here: http://www.mouser.com/Wire-Cable/Flat-Cable/_/N-5ggm?P=1z0vl9dZ1z0vt0b


If people wouldn't mind double checking my work... I spent quite a bit of time trying to get things right (cross-referencing Farnell parts), but I have have had some completely unusable parts show up on my doorstep before, so any help would be greatly appreciated and hopefully other US people can benefit from this. Tried to put Igors ref #s on things, but alas some are missing.

Best,

Tim
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on September 25, 2011, 11:21:53 PM
Hi, I am not very familiar with Mouser, BTW, scroll this thread, there was an alternative BOM with all p/nr's from Digikey or Mouser IIRC.
Will try to help...

Quote
- 6.8uf audio grade caps (C38)

Tantalum, 16-25V

Quote
- Mouser seems to have no 5mm LEDs...

No way :)

Quote
- I'm not sure what to order for the PCB INTERCONNECT SOCKET/RAW CONNECTORS.

Check Farnell 7991967 and  1022262 ; Mouser should have similar products.

Quote
- I ordered 2181A(s) as per BOM, but others say 2180A is best choice? Confused...

Others, aye! :)

2181A will work absolutely fine. 2180 is pre-trimmed, the only difference

Quote
10 pin male headers,

HEADER, STRAIGHT, 10WAY

http://il.farnell.com/avx-interconnect/008380010000010/header-straight-10way/dp/636332?Ntt=636332

- Not sure which 10 connector wire to order (gauge, etc).

Socket, IDC, 10 way

http://il.farnell.com/avx-interconnect/008290010000011/socket-idc-10way/dp/636034?Ntt=636034

Hope this helps.
Title: Re: MixBuzz500 build/support tHread
Post by: timmygrimm on September 26, 2011, 02:05:37 AM

Thanks Igor!

I scrolled through the whole thread again and didn't see an alternative BOM, but I looked through your suggestions and think I have everything covered.

https://www.mouser.com:443/ProjectManager/ProjectDetail.aspx?AccessID=d986302f5e

I'm wondering if cut dip-16 sockets will work for the 2181s since the spacing is pretty tight, but it seems like the only option.

Anyway, I'll order this and update the thread if there are issues.

Best,

Tim
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on October 01, 2011, 03:10:37 PM
Mouser: haven't passed one-by-one, but looks allrighty. The ferrite beads are bigger than I used, but will fit.
More inductance won't be worse here.
Quote
I'm wondering if cut dip-16 sockets will work for the 2181s since the spacing is pretty tight, but it seems like the only option.
This is exactly what I did too.

BTW. Helpful info from people who built MB500:

http://mnats.net/mixbuzz_500_build.html

http://www.groupdiy.com/index.php?topic=40493.0
Title: Re: MixBuzz500 build/support tHread
Post by: bkbirge on October 12, 2011, 12:02:42 AM
Man, that's a great timesaver, thanks for sharing. Just finished my 51x rack and gearing up to start this project finally after having the PCB's for over a year.


Thanks Igor!

I scrolled through the whole thread again and didn't see an alternative BOM, but I looked through your suggestions and think I have everything covered.

https://www.mouser.com:443/ProjectManager/ProjectDetail.aspx?AccessID=d986302f5e

I'm wondering if cut dip-16 sockets will work for the 2181s since the spacing is pretty tight, but it seems like the only option.

Anyway, I'll order this and update the thread if there are issues.

Best,

Tim
Title: Re: MixBuzz500 build/support tHread
Post by: bkbirge on October 16, 2011, 11:53:28 PM
Build in progress pic. Almost done, missing some parts from the BOM and some mismatches etc.
Title: Re: MixBuzz500 build/support tHread
Post by: bkbirge on October 17, 2011, 11:53:25 AM
Question about the bypass caps on the vca boards, the BOM says 220uf but that is different compared with the other boards' BOM, seems it should be 220pf ? Which is correct, thanks!

Also, any plans to finish up the crush & blend w/MS expansion?
Title: Re: MixBuzz500 build/support tHread
Post by: bkbirge on October 25, 2011, 06:10:36 PM
All built! Now I just need to calibrate. I've put 2180A's in the build, the pre-trimmed vca's, how does this change the calibration procedure, if at all? I do have all the trimmers installed, figured I'd do that in case I swapped out for 2181's at some point.
Title: Re: MixBuzz500 build/support tHread
Post by: bkbirge on October 26, 2011, 11:36:43 AM
Anyone able to help? The sidechain filters and ratio knobs don't seem to behave as expected, at least if they do it is a lot more subtle than I expected, to the point I can't really hear it. The other stuff works, audio passes nice and clean, compresses nicely, attack/release work well, metering seems to work, each side is reasonably balanced.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on November 07, 2011, 02:47:44 AM
Question about the bypass caps on the vca boards, the BOM says 220uf but that is different compared with the other boards' BOM, seems it should be 220pf ? Which is correct, thanks!

Also, any plans to finish up the crush & blend w/MS expansion?

Typo. The byp caps should be 47nF....0.22uF.

Ohho. It is drawn, layed out and waiting. One good day.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on November 07, 2011, 02:49:26 AM
All built! Now I just need to calibrate. I've put 2180A's in the build, the pre-trimmed vca's, how does this change the calibration procedure, if at all? I do have all the trimmers installed, figured I'd do that in case I swapped out for 2181's at some point.

In case of use 2180 instead of 2181, throw these 50k trimmers out.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on November 07, 2011, 02:58:12 AM
Anyone able to help? The sidechain filters and ratio knobs don't seem to behave as expected, at least if they do it is a lot more subtle than I expected, to the point I can't really hear it. The other stuff works, audio passes nice and clean, compresses nicely, attack/release work well, metering seems to work, each side is reasonably balanced.

Check for mistakes. I have same eyes, hands and mathematics as you, but have no your compressor at my workbench.
Feed 50 Hz, adj threshold for 20 db of compression w/o filters; GR should be less with filters.

Ratio:
http://www.groupdiy.com/index.php?action=post;msg=487554;topic=39459.0
(R60)

Test pro for MixBuzz1 can be applied to small bro predessor.
http://www.groupdiy.com/index.php?topic=41654.msg517391#msg517391
Title: Re: MixBuzz500 build/support tHread
Post by: bkbirge on November 07, 2011, 11:21:19 AM
Thanks Igor I'll check that out. At this point everything seems to be working but not calibrated very well. The ratio switch performs different for each board, one side slight gain reduction on increasing ratio, the other side the opposite so I know it's a calibration issue. I will dump the 50k trimmer and see if that helps. Using it in mono so far sounds really nice, tames my upright bass resonances much more musically than my other gear, far more transparent sounding than what I remember from using the official SSL boxes years ago. I did blow a bank of 2180's at first somehow during my initial calibration, annoying. Gotta work on the steady hands when power applied. Thanks for a great project, I will post pics and clips when it is truly running to spec.


Anyone able to help? The sidechain filters and ratio knobs don't seem to behave as expected, at least if they do it is a lot more subtle than I expected, to the point I can't really hear it. The other stuff works, audio passes nice and clean, compresses nicely, attack/release work well, metering seems to work, each side is reasonably balanced.

Check for mistakes. I have same eyes, hands and mathematics as you, but have no your compressor at my workbench.
Feed 50 Hz, adj threshold for 20 db of compression w/o filters; GR should be less with filters.

Ratio:
http://www.groupdiy.com/index.php?action=post;msg=487554;topic=39459.0
(R60)

Test pro for MixBuzz1 can be applied to small bro predessor.
http://www.groupdiy.com/index.php?topic=41654.msg517391#msg517391
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on November 08, 2011, 11:57:02 AM
OK, cool than, calm my curiosity what was the issue when fixed!
Title: Re: MixBuzz500 build/support tHread
Post by: bkbirge on November 20, 2011, 12:20:05 AM
Finally had some time away from the fam to work on this... took out the 50k trimmer since I'm using 2180's and set RV1 for 5.1k. Clumsy fingers effed something up, one channel is mega distorted now, and the 5532 on the vca gets too hot to touch, swapped it out for new and same thing. Other channel sounds wonderful. Looked for solder bridges, etc nothing found, so I'll start swapping ic's from the other channel.
Title: Re: MixBuzz500 build/support tHread
Post by: bkbirge on December 01, 2011, 12:11:35 PM
All works great, latest and last issue was the 5532 on the vca board is actually supposed to be a 5534, lol duh. As usual my brain and sensory organs are conspiring against me daily. Anyway, this was my first 51x module build and a huge thanks to those of you that built it and documented before me, as well as to Igor of course for developing the project.
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on December 06, 2011, 05:11:48 PM
Great! Have a fun.
Title: Re: MixBuzz500 build/support tHread
Post by: rascalseven on December 08, 2011, 11:51:54 AM
What is this resistor?  It's on the back of the front panel sub pcb.  Can't find a reference to it.

http://s251.photobucket.com/albums/gg291/diy33609/mixbuzz500/?action=view&current=P1040233.jpg

I'm about to assemble the populated pcb's now and check the thing out, and I'm not using a resistor here, so just making sure I'm not missing something.

Thanks!

JC
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on December 08, 2011, 10:35:27 PM
R60, ratios...
In this one, I got lower than should be ratios, and connected this resitor in parallel to R60 instead of replacing R60 to lower value.
Title: Re: MixBuzz500 build/support tHread
Post by: timmygrimm on January 01, 2012, 11:33:30 PM

Hey All,

I got the test boards with my Mixbuzz... Where do I get the edge connectors for these?

Thanks!

Tim
Title: Re: MixBuzz500 build/support tHread
Post by: culteousness1 on January 02, 2012, 02:27:43 AM
See reply #237.

Volker's WM-thread (http://www.groupdiy.com/index.php?topic=39570.msg488632#msg488632)

Cheers,
Carsten
Title: Re: MixBuzz500 build/support tHread
Post by: [silent:arts] on January 02, 2012, 08:11:20 AM
I got the test boards with my Mixbuzz... Where do I get the edge connectors for these?

http://classicapi.com/catalog/index.php?cPath=84_86
Title: Re: MixBuzz500 build/support tHread
Post by: culteousness1 on January 02, 2012, 09:13:23 AM
Yes. Of course.

Didn't see his location...
Title: Re: MixBuzz500 build/support tHread
Post by: fazeka on January 15, 2012, 03:23:16 PM
Hi Igor,

Have a problem with my MixBuzz500 build, similar to kibadachi:

http://www.groupdiy.com/index.php?topic=39459.msg532896#msg532896 (http://www.groupdiy.com/index.php?topic=39459.msg532896#msg532896)

On my build, audio passes through in standby and audio passes in 4000 and gssl mode. I think I can hear it compressing, but make up does not seem to increase level and other controls seemingly not working. Like kibadachi, I hear the relays when switching from bypass to 4k and gssl. Meter is not moving as well.

Then I looked at your post:

http://www.groupdiy.com/index.php?topic=39459.msg532916#msg532916 (http://www.groupdiy.com/index.php?topic=39459.msg532916#msg532916)

"First, let's check the voltage beween gnd and wiper of threshold pot, it should change from approx. +6.5 to -6.5 Volt when rotating the THRESHOLD pot."

But when I measure from outer lug of threshold pot to center lug 2 of same, I get ~-13.33 V to zero when rotating threshold. If I measure other outer lug to center lug, I get zero to ~+13.33 V while rotating.

Suspicious as ~13.33/2 = ~6.67, which is close to 6.5 as stated in post above (actually, range should be +/- 6.5 V).

Any ideas on troubleshooting?

Best,
Chris
Title: Re: MixBuzz500 build/support tHread
Post by: Harpo on January 15, 2012, 05:32:15 PM
'...beween gnd and wiper of threshold pot...'
the pins at the pots outer lugs are not at gnd/0V, but your measurements look OK.
Double check resistor values, especially R55, R59, R60, R70, R74 and R75.
Title: Re: MixBuzz500 build/support tHread
Post by: fazeka on January 15, 2012, 05:49:19 PM
'...beween gnd and wiper of threshold pot...'
the pins at the pots outer lugs are not at gnd/0V, but your measurements look OK.
Double check resistor values, especially R55, R59, R60, R70, R74 and R75.

Oops... :-[ ...feel stupid... Don't know why I thought that...

Let me check again.
Title: Re: MixBuzz500 build/support tHread
Post by: fazeka on January 16, 2012, 05:32:36 AM
Hmmm...

Double-checked everything. Resistors, etc.

Regarding specifics to my build: R60 = 100R, R75 = 49R9

Voltages while sweeping threshold pot are still strange:

-7.01 to -6.93 on one leg
+6.39 to 6.46 on the other leg

Threshold pot bad, maybe?
Title: Re: MixBuzz500 build/support tHread
Post by: Harpo on January 16, 2012, 07:17:00 AM
Voltages while sweeping threshold pot are still strange:
-7.01 to -6.93 on one leg
+6.39 to 6.46 on the other leg
Threshold pot bad, maybe?
No. Your pot seems close to perfect.
Your 50K law bending trimmer TR_TRM seems a little off center, loading down one side a little more or your 3K9 resistors R68+R76 are a little off their stated value.
Measuring threshold between wiper and 0V will give a +/-6.7415 VDC reading with all parts and +/-12 voltage rails being perfect (usually these come with tolerances).
Double check resistor values in the sidechain section again for the most likely reason of misbehaviour.
Title: Re: MixBuzz500 build/support tHread
Post by: fazeka on January 17, 2012, 07:06:06 PM
Hi,

I've not given up, but I've spent the last two days quadruple checking and everything looks right to me. I am stumped as to what else is causing this misbehavior and/or where else to look...

I will continue with it, I must be missing something despite my scrutiny. It's the proverbial needle in a haystack!

Thanks,
Chris
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on January 23, 2012, 06:11:08 PM
Just for test, pull out the VCA's or balanced line driver/receiver out of sockets and check if you get audio in both gssl and 4k modes.
There was an issue about a year ago, +/-15V was not connected to control board. However, all this is strange, I have to meditate on your MB500 issue ;)

Edit: sorry, sorry, this is not the issue. Check the ribbon cables, maybe, control voltage does not arrives from control board to vca's.
Or, maybe, short somewhere.
Tell if you found something, I have now more time for forum fun, we'll try to pass together with scope on all points.
Title: Re: MixBuzz500 build/support tHread
Post by: fazeka on January 23, 2012, 08:54:57 PM
Hi Igor,

This past week I took a break from the MixBuzz and worked on my NV73 "The Don" pair. Also got a new Tek scope to play with (2245A) very nice since my Tek 485 died...

I will revisit the MixBuzz in a day or two and will report back.

Thanks,
Chris
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on February 02, 2012, 11:43:51 PM
Hi Igor,

This past week I took a break from the MixBuzz and worked on my NV73 "The Don" pair. Also got a new Tek scope to play with (2245A) very nice since my Tek 485 died...

I will revisit the MixBuzz in a day or two and will report back.

Thanks,
Chris

TEKTRONIX 2245A!!! Yep, very nice thingy. I cannot live with digital scopes. Mean, it is great for tracing the signals, but
something is wrong here. I am big fan of 5000/7000 family, have working 5110, 7603 and D13 on workshop.
For now, bought crazy thingy - HP1980B, for $80 from surplus, it do everything I need except... well, ok, it isn't job for an oscilloscope :)

Cool than, post here, will try to help in free minute!
Title: Re: MixBuzz500 build/support tHread
Post by: timmygrimm on February 10, 2012, 01:41:15 AM


My unit is working! After a brief hiccup with a mis-wired power connector (was thinking wires should go straight across, when of course they should be mirror-image), and some confusion around SJ3 (I didn't know it was there... couldn't figure out why my relays weren't working!).

I had a Sifam meter from my first project (a failed GSSL) which doesn't work anymore apparently. It's really kind of fun using it without the meter though! I am just running an OH mic from some drums I recorded at Sound City (RIP) to test it. Sounds amazing... really cool at extreme settings (at least on this drum overhead, I would be more delicate on a mix for sure). I already want more of them!

An odd thing that happens - when I turn sidechain filter up to "T" area - I get blistering levels, which remain even after I turn the knob back the other way. If I switch the ATK around it goes away. Strange...

I put in RV1 before I read Igor's note about it. Is there a way to measure it in circuit to get the proper resistance?

Thank you Igor!

Tim
Title: Re: MixBuzz500 build/support tHread
Post by: timmygrimm on February 17, 2012, 10:37:23 AM

Got a nice working assembled compressor here. My only beef with it at the moment is that the meter action seems quite sloppy. It doesn't have that satisfying snap of the SSL compressor. Do folks think this is the meter itself (Hairball) or the circuit / calibration?

http://www.youtube.com/embed/H-rYyAg_Zxk
Title: Re: MixBuzz500 build/support tHread
Post by: desol on February 17, 2012, 01:41:16 PM
I think it's just the meter itself. They have a new offering in the presentor series...FR, for fast response.

http://www.sifam.com/meterCategory.asp?cat=Presentor%20-%20FR
Title: Re: MixBuzz500 build/support tHread
Post by: timmygrimm on February 18, 2012, 08:50:19 AM

The original Sifams seem to do fine in the G384... but mine isn't a Sifam, it's a Hairball. I didn't see anything about the meter calibration in the docs... did I miss something?

In other news I am using the Mixbuzz on a mix right now and it sounds great!

Tim
Title: Re: MixBuzz500 build/support tHread
Post by: timmygrimm on February 25, 2012, 09:07:11 AM


Sorry to bug y'all but I'm confused on this meter issue. I installed the trimpot by the meter but I can't find it's adjustment procedure mentioned anywhere by Igor or others. I can't believe that the meter is inherently so bad. It bounces every time it comes back from deflection. I'm all for using my ears but...
Title: Re: MixBuzz500 build/support tHread
Post by: Igor on February 27, 2012, 03:27:35 PM
Meter calibration: with 1ma FSD meter, no need.
R50 = 2k can be changed to get correct reading.

An odd thing that happens - when I turn sidechain filter up to "T" area - I get blistering levels,
which remain even after I turn the knob back the other way. If I switch the ATK around it goes away. Strange...

I put in RV1 before I read Igor's note about it. Is there a way to measure it in circuit to get the proper resistance?

Just desolder it and install 0.25W 1% 5k1 (IIRC, see BOM).

Maybe c24 is leaky, btw. Check all solderings, should be something wrong ;)
Title: Re: MixBuzz500 build/support tHread
Post by: toolboxmuziq on October 17, 2012, 02:03:29 PM
has anyone compared this to the serpent audio sb4001? also has/will anyone ever considered making a demo video to show the compability of this unit?
Title: Re: MixBuzz500 build/support tHread
Post by: saxmonster on December 29, 2012, 05:45:45 PM
So could I install one VCA on each replacement board or do I need to install all four?  Can I do a any combo as long as each card has the same amount as the other one.  Like 2x2 or 3x3 or 1x1?

Thanks
-Scott

Title: Re: MixBuzz500 build/support tHread
Post by: Junction on May 24, 2013, 10:37:39 AM
Can anyone tell me where to buy the 10K Lin pots for MakeUp gain and Threshold for Igors MixBuzz 500? The farnell part number for the bourns pots on Igor's BOM appears to have a different pinout than on the pcb.

Cheers
Title: Re: MixBuzz500 build/support tHread
Post by: ArnauTS on May 25, 2013, 07:32:47 AM
I've used that pots from bom and they work fine so i think that you might be confusing the pinout?
Anyway, get the pots from bom and you'll be safe.
Hope it helps
Title: Re: MixBuzz500 build/support tHread
Post by: Junction on May 25, 2013, 11:48:14 AM
I've used that pots from bom and they work fine so i think that you might be confusing the pinout?
Doh! .... thanks, you're absolutely right, i was looking at some pads on the circuit board under where the pot is mounted, thinking thats the pot connections, now i look again and I see the three pads along one side of the pot which is consistent with the bom pot.
Thank you thank you .... now back on track
:)
Title: Re: MixBuzz500 build/support tHread
Post by: juniorselector on June 23, 2013, 06:47:42 PM
Anyway to get the PCB's for this unit?

Or even better: a kit?
Title: Re: MixBuzz500 build/support tHread
Post by: ramshackles on June 24, 2013, 04:12:36 AM
I'll be supplying them in a few weeks.
Title: Re: MixBuzz500 build/support tHread
Post by: bkbirge on June 24, 2013, 05:32:04 PM
This is a great compressor, I use it all the time.
Title: Re: MixBuzz500 build/support tHread
Post by: juniorselector on June 26, 2013, 10:06:03 AM
@ramshakles

Great! Can you please drop me a PM when that happens?
Title: Re: MixBuzz500 build/support tHread
Post by: ramshackles on June 26, 2013, 10:50:32 AM
join the mailing list at
www.ramshacklerecording.com
Title: Re: MixBuzz500 build/support tHread
Post by: okgb on July 28, 2013, 08:44:08 AM
Bumping
Also can anyone give an approx cost to finish this project ?
Title: Re: MixBuzz500 build/support tHread
Post by: ramshackles on July 28, 2013, 10:18:10 AM
Assuming you have the PCB & metalwork kit:
Guesstimate from working through the BOM; ~£150-200, excl meter, knobs. Remember there are 2 audio boards 2 VCA boards and 1 control board per build (The BOMS detail parts for 1 board of each).
Maybe someone who built one recently can give a better estimate...
Title: Re: MixBuzz500 build/support tHread
Post by: saxmonster on July 28, 2013, 03:56:25 PM
Looks to be about $220 in parts from mouser,

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=B077476F23

I never got around to building mine as I was able to get an sb4001 kit.

You might have to go through my cart again.

-Scott
Title: Re: MixBuzz500 build/support tHread
Post by: buildafriend on August 21, 2013, 07:17:46 PM
I think I ended up spending around 500USD
Title: Re: MixBuzz500 build/support tHread
Post by: 100WChris on August 23, 2013, 06:46:15 AM
i was spending about 450€, but i used only the good stuff :-)
definitely worth every cent!
if igor would not paused his career, i would love to build a second unit.
Chris
Title: Re: MixBuzz500 build/support tHread
Post by: irfrench on November 20, 2013, 07:29:31 AM
Hi all. 

Can anyone confirm the spacer/stand-off dimensions Igor supplied?

I'm hoping to get some of the Ramshackle offerings but these are PCBs only.

Thanks,
Ian


 :)


EDIT!

Thinking about it logically - typically the boards are about 5mm off the normal 'L' bracket, and it is a stereo unit so audio boards will be 1.5 inches apart according to 500/51x mechs.  The remaining standoffs are only useful with Igors metal work.

Problem solved?  Please correct if I'm wrong!


 :) ;D ::)
Title: Re: MixBuzz500 build/support tHread
Post by: ramshackles on November 20, 2013, 08:53:37 AM
Yes there should be 1.5 inches between each connector on a 51x/500 backplane...
38.1 mm standoff's are not that common however; you might get away with a 38mm one
Title: Re: MixBuzz500 build/support tHread
Post by: Sammas on May 07, 2014, 01:37:17 AM


Has anyone used DBX 202c gold can VCA's in this project?
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on May 20, 2014, 12:01:54 PM


Has anyone used DBX 202c gold can VCA's in this project?

I missed this for some reason.  I am also planning too use gold cans.

There's no info on it in this thread, but Igor provides the correct resistor values in the 1RU Mixbuzz thread, so that is what I'm going to follow.

http://groupdiy.com/index.php?topic=41654.msg587347;topicseen#msg587347

Cheers
Title: Re: MixBuzz500 build/support tHread
Post by: Sammas on May 20, 2014, 07:46:46 PM


Has anyone used DBX 202c gold can VCA's in this project?

I missed this for some reason.  I am also planning too use gold cans.

There's no info on it in this thread, but Igor provides the correct resistor values in the 1RU Mixbuzz thread, so that is what I'm going to follow.

http://groupdiy.com/index.php?topic=41654.msg587347;topicseen#msg587347

Cheers

Thanks Rob!
Title: Re: MixBuzz500 build/support tHread
Post by: taliska on August 13, 2014, 05:04:38 PM
Hi all!

So I've had my mix buzz pcbs for a quite a while, and a couple months back I decided to tackle it. Building was straightforward for the most part, but at the time nobody was offering the metal work (Frank's site had a message saying he hadn't received the pcbs yet...). Anyway, undeterred I decided to hack something together myself using a couple of the sleds that Volker & Jeff sell (I had some left over due to deciding not to use them on my studer build ages ago). Anyway, I created an fpd file but was a bit hesitant sending it off as the everything's a bit fixed layout on the mix buzz, so it was either going to be right or a costly mistake! I was also a bit wary of screwing up the hpgl as I'd never done that before.

Anyway, long story short...I got bored of looking at my mix buzz in pieces, so I went ahead and sent off the fpd last week and the panel arrived today. Once I'd checked that it was correctly laid out, I used it to space the two pots that "live on stilts" and then soldered them down. After that, I traced the panel on to the sleds and drilled a lot, dremelled a lot, and q max punched a hole for the meter. After a bit of man-handling things seemed to fit and so now all I have to do is to go through the final stage of assembly and tests at some point, but I'm stoked to be almost done with it.

Anyway, without further ado, here's a pic. I'm posting the fpd file later as that's pretty much the only capacity I'm able to contribute in at the moment... ;)

Cheers,

Kaz
Title: Re: MixBuzz500 build/support tHread
Post by: taliska on August 13, 2014, 06:14:32 PM
Ok, as promised here's my fpd file.

Things to note:

- The holes are all good and in the correct location, so it's a good starting point even if you don't want to use my hpgl.
- There isn't a rectangular cut out for leds above the meter as they're not needed for the hairball meter.
- There are lots of 3mm holes for putting hex bolts in. That's because I wanted to make sure it was going to be sturdy given that my sled is actually two single width sleds combined. In the end I didn't end up using them all (specifically the ones in the middle between the attack and release labels), so you can remove the ones you don't want. It's also worth moving the two hex bolt holes at the bottom about 5mm higher, as they are almost off the edge of the sleds in my version.

Anyway, there you go. I hope this helps someone out, though as always, it's up to you to make sure that the fpd is correct for your use before you send it off for fabrication. Use at your own risk.

Cheers,

Kaz

P.S. Don't forget to rename file from .txt to .fpd before using.
Title: Re: MixBuzz500 build/support tHread
Post by: taliska on August 16, 2014, 01:00:03 PM
So finally plugged in, tested, and put my mix buzz in to my rack! A picture's attached for the sake of audio porn.

When I built this, I installed most of the trimmers, as I had them to hand rather than the fixed resistors. Unfortunately that means that there's a slight lack on info on how to calibrate them, but all in all, things seems to be working ok with a minimal calibration. Adjusted for 0 dc offset for side chain part of 5532 (pin1) using sym trimmer in the side chain section. Adjusted for 0 dc offset for audio part of 5532 (pin 7). Of course, Igor doesn't mention what level of signal to do that with and what to have the controls set to, so I freestyled it / half followed the debug stuff on page 12.

Anyway, seems to be working well when I put some drums through it. Only bit I'm not happy with is the long bundled up ribbon cables that will need shortening at some point, but were purposely kept long for testing.

Very straightforward build for the most part and can highly recommend it, though I made it harder for myself by lifting some traces accidentally when I built one of the audio boards, so had to do a few point to point connections to restore the circuit.

All's well that ends well! ;)

Kaz
Title: Re: MixBuzz500 build/support tHread
Post by: wilson.joshd on September 14, 2014, 03:12:14 PM
I know this is a fairly old thread but I'm really keen to do this build so hopefully someone can help me out. I've had a lot of trouble finding where I can order this from.

Thanks in advance for any help you can give!

Josh
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on September 14, 2014, 04:19:09 PM
The PCBs are available from ramshackle recording. The front panel someone posted an fpd file for a few posts ago. In terms of the cage, I think you're own your own I'm afraid
Title: Re: MixBuzz500 build/support tHread
Post by: culteousness1 on September 15, 2014, 03:59:49 AM
[email protected] offers panels and custom L brackets for the MixxBuzz500:

http://www.frontpanels.de/miscellaneous-frontpanels/igor-s-projects/ (http://www.frontpanels.de/miscellaneous-frontpanels/igor-s-projects/)

Best,
Carsten
Title: Re: MixBuzz500 build/support tHread
Post by: wilson.joshd on September 15, 2014, 02:12:26 PM
Thanks so much for the info guys! Can't wait to get everything ordered.

Josh
Title: Re: MixBuzz500 build/support tHread
Post by: Vac11 on October 14, 2014, 01:57:12 AM
Does anyone have current and complete BOM from farnell.com? From whom you buy parts?

Thank you for your help!
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on October 14, 2014, 06:31:50 AM
Does anyone have current and complete BOM from farnell.com? From whom you buy parts?

Thank you for your help!

Farnell has pretty much everything for this project.  I ordered the parts across several orders and some things like resistors I had already so I don't have a complete BOM.  Igor gives Farnell order codes for most items on the first page of this thread though so you should not have any problem with ordering the wrong parts.  Please post if you are unsure about anything and I will assist.

One item I know is now discontinued at Farnell is the meter.  I think you'll need an alternative source for this.
Title: Re: MixBuzz500 build/support tHread
Post by: Vac11 on October 14, 2014, 09:51:16 AM
Thanks for replay. I'm an absolute beginner....

1st page of this thread shows me:

"For now, please download docs and BOM!!!!

http://twin-x.com/groupdiy/thumbnails.php?album=405"

When I click on the link it reports me fatal error... :(
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on October 14, 2014, 10:10:04 AM
Thanks for replay. I'm an absolute beginner....

1st page of this thread shows me:

"For now, please download docs and BOM!!!!

http://twin-x.com/groupdiy/thumbnails.php?album=405"

When I click on the link it reports me fatal error... :(

Ah, my mistake.  I thought that the BOMs were actually posted on the font page in one of the early posts of the thread but they are not.

You can get the BOMs and some other useful info from Ramshackle Recording's website :

http://cdn.shopify.com/s/files/1/0256/3541/files/MixBuzz_Docs_V1_4.zip?340

Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on May 03, 2015, 10:50:48 AM
Did anyone get this project working with the DBX Gold Cans?  I am just trying to calibrate now and I'm seeing a 6 - 7dB drop when engaging the compressor with make up gain at 0.  Just wondering if the resistor values I used (which Igor posted in the Mixbuzz1 support thread) are correct or not.

Using DBX202C gold can VCA's in MixBuzz1:

DBX 202C GOLD CANS
RXX APPLY TO BOTH L AND R (R100L, R100R)
R6 40K2
R2 1MEG...1.5 MEG
R100 710R
R4 JUMPER/FERR BEAD
R3 40K2
C1 5PF


Also struggling to get the DC offsets to set correctly with OPA 2604 in IC 10 and IC11 positions, but I'm more concerned about the drop in level when the compressor is engaged at the moment...
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on May 04, 2015, 07:44:28 AM
OK, so maybe I was wrong to blame the resistors around the Gold Can for the drop in level when engaging the compression circuit.

I am injecting a 0.775V sine wave, and I am measuring round the circuit using my multimetter set to AC.  I am measuring using audio hot as my reference voltage.

If I measure at pin 2 or 3 of the THAT 1246 I see my .775V

If I measure at the output out the THAT 1246 I see .390V

If I measure on the left hand side of R6 (on the schematic) I see .390V

If I measure on the right side of R6 on the schematic, the same point as DBX I-IN, I see  .780V

If I measure at the output of the DBX (I_OUT) I see .780V

So it looks like the level is maintained through the Gold can, even with the compressor engaged.  Does this seem right?

If I then measure at pin & of the opamp, OPA2604, I see .580V.

So the audio level seems to be dropping inside the OPA2604.

Can anyone comment on this?  Any ideas what might be going on?

Thanks!
Title: Schematics
Post by: daveee on May 04, 2015, 08:01:38 AM
Hi,
Does anyone have the MixBuzz1 v2.5 schematics they could upload please? :)
All links I've found seem to be broken.
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on May 05, 2015, 05:23:34 PM
Audio circuit schematic now attached to my post two above.

A question - R3 and R6 were specified as 40K2 by Igor, but in the design note 127 from That Corp, they specifiy 50K in those positions (figure 3 here in this doc : www.thatcorp.com/datashts/dn127.pdf)

Why this difference?  Could this account for the fact I'm not seeing unity gain through the compressor circuit?

Thanks,

Rob
Title: Re: MixBuzz500 build/support tHread
Post by: Harpo on May 06, 2015, 08:32:54 AM
I am injecting a 0.775V sine wave,
between XLR-pins2/3 and this AC voltage measured between these XLR pins 2/3 with your sine generator connected.
Quote
and I am measuring round the circuit using my multimetter set to AC.
AC volts at a frequency your multimeter can handle, most often far below 1kHz.
Quote
I am measuring using audio hot as my reference voltage.
Dunno of any circuit where an audio hot reference (moving target) would be useful. Use the 0V reference voltage.
Quote
If I measure on the right side of R6 on the schematic, the same point as DBX I-IN, I see  .780V
If I measure at the output of the DBX (I_OUT) I see .780V
These VCAs are current-in/current-out devices, these pins are already called I-In and I-Out as a reminder. Current is measured in amperes (in this spot and in your case below 0.4mA), not in volt.

Quote
If I then measure at pin & of the opamp, OPA2604, I see .580V.
So the audio level seems to be dropping inside the OPA2604.
Assuming opamp-out pin 6, with same value resistors R3 and R6 in front of the VCA (40K2?) and feedback resistor between opamp pins2/6, AC level will be the same with control voltage 0.000V and compensation cap C1 increased to a useful value (maybe 22...47pF). Your 5pF wouldn't help the opamp from oscillating at a frequency outside the range of bats with capacitive component output of the VCA in front connected.
Quote
A question - R3 and R6 were specified as 40K2 by Igor, but in the design note 127 from That Corp, they specifiy 50K in those positions
With THAT1246 in front and +/-18VDC supply, the debalancer will not put out more than |18V-2V| peak. The VCA input will not see more than 16Vpk/40K2=0.000398A=0.4mA. Sounds safe enough, except for the +/-18VDC supply when the datasheet states the upper limit for the DBX202C to be +/-15VDC +/-10% +5%, giving +/-16.5VDC +/-15.75VDCabs.max.
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on May 06, 2015, 04:06:40 PM

Thank you for your reply Harpo.  I think I'm misunderstanding some stuff, so I have some follow up comments / questions.

Yes - I'm measuring the sine wave between pins 2 and 3.  The reason I was trying to measure around the circuit using pin 2 as a reference was because I don't see anything on my meter or scope when using ground as a reference.

My audio interface is not truly balanced; it's impedance balanced.  I wonder if this is making things harder to take a reading.

I see from what you've written that measuring voltage on each side of the VCA doesn't really mean anything, but this leaves me stuck about how to measure the level at different places in the circuit.

Also, when you say

Quote
Assuming opamp-out pin 6, with same value resistors R3 and R6 in front of the VCA (40K2?) and feedback resistor between opamp pins2/6

Do you mean pin 6?  Pin 7 is the output pin of NE5532 and OPA2604.

Am I correct in thinking that resistors R3 and R6 effectively control the unity gain value?

And am I right to judge from your answer that yes, with the resistor values I've used, I should get unity gain?

And does C1 have any effect on setting unity gain?  Or is its job just to cancel oscillation?

Thanks
Title: Re: MixBuzz500 build/support tHread
Post by: Harpo on May 08, 2015, 05:29:57 AM
Yes - I'm measuring the sine wave between pins 2 and 3.  The reason I was trying to measure around the circuit using pin 2 as a reference was because I don't see anything on my meter or scope when using ground as a reference.
The input of the balanced line receiver THAT1246 exclusively operates the differential between pins 2/3 without reference to and whatever you might call "ground" (at least misleading without qualifier like chassis-ground, safety-ground, psu-ground, ..., they are all different potential with different meaning). After debalancing, the Vac signal level can be measured in respect to 0V reference voltage.

Quote
My audio interface is not truly balanced; it's impedance balanced.  I wonder if this is making things harder to take a reading.
No difference for 99.9% of the usual suspects when not running loooong wires in rf-contaminated locations.

Quote
Also, when you say
Quote
Assuming opamp-out pin 6, with same value resistors R3 and R6 in front of the VCA (40K2?) and feedback resistor between opamp pins2/6
Do you mean pin 6?  Pin 7 is the output pin of NE5532 and OPA2604.
Was the obviously wrong assumption, your '...pin & of the opamp...' might be referencing a pin 6.

Quote
Am I correct in thinking that resistors R3 and R6 effectively control the unity gain value?
yes, as long as you don't miss the rest of the sentence 'with control voltage 0.000V' ...

Quote
And am I right to judge from your answer that yes, with the resistor values I've used, I should get unity gain?
yes, with no faulty parts. (you maybe operated -different from schematic DBX202X that allows a +/-18Vdc supply- a DBX202C VCA without circuit modification outside its supply limits. Unfortunately exceeding parts abs.max values most often is a single try experience. Maybe you got lucky and your VCA survived...)

Quote
And does C1 have any effect on setting unity gain?  Or is its job just to cancel oscillation?
Yes and yes, depending on frequency. The cap in conjunction with R3 set a LPF with its -3dB point in Hz set at 1/(2*PI()*R*C) with R in ohm and C in farad. (from some posts above your IMHO too low value C1 would be 5pF = 0.000000000005F = 5E-12F, setting a HPF at 792kHz)
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on May 09, 2015, 08:13:56 AM
Yes - I'm measuring the sine wave between pins 2 and 3.  The reason I was trying to measure around the circuit using pin 2 as a reference was because I don't see anything on my meter or scope when using ground as a reference.
The input of the balanced line receiver THAT1246 exclusively operates the differential between pins 2/3 without reference to and whatever you might call "ground" (at least misleading without qualifier like chassis-ground, safety-ground, psu-ground, ..., they are all different potential with different meaning). After debalancing, the Vac signal level can be measured in respect to 0V reference voltage.


OK, clear.  I get .338V when measuring at pin 5 / 6 of the THAT 1246 with respect to audio ground.  That looks OK to me (1/2 of .775V)

Quote
Quote
My audio interface is not truly balanced; it's impedance balanced.  I wonder if this is making things harder to take a reading.
No difference for 99.9% of the usual suspects when not running loooong wires in rf-contaminated locations.

Thanks for the confirmation

Quote
Quote
Also, when you say
Quote
Assuming opamp-out pin 6, with same value resistors R3 and R6 in front of the VCA (40K2?) and feedback resistor between opamp pins2/6
Do you mean pin 6?  Pin 7 is the output pin of NE5532 and OPA2604.
Was the obviously wrong assumption, your '...pin & of the opamp...' might be referencing a pin 6.

Apologies, I didn't see that I'd mis-typed the pin number in my initial post.  My fault.

Quote
Quote
Am I correct in thinking that resistors R3 and R6 effectively control the unity gain value?
yes, as long as you don't miss the rest of the sentence 'with control voltage 0.000V' ...

Is pin E_C on the DBX VCA the the place to measure this?  I get -0.001V there

Quote
Quote
And am I right to judge from your answer that yes, with the resistor values I've used, I should get unity gain?
yes, with no faulty parts. (you maybe operated -different from schematic DBX202X that allows a +/-18Vdc supply- a DBX202C VCA without circuit modification outside its supply limits. Unfortunately exceeding parts abs.max values most often is a single try experience. Maybe you got lucky and your VCA survived...)

I've only used the VCA in this circuit where the supply voltage is + / - 16V and I haven't messed around with resistor values, so there shouldn't be any issue with having damaged the VCA.

Quote
Quote
And does C1 have any effect on setting unity gain?  Or is its job just to cancel oscillation?
Yes and yes, depending on frequency. The cap in conjunction with R3 set a LPF with its -3dB point in Hz set at 1/(2*PI()*R*C) with R in ohm and C in farad. (from some posts above your IMHO too low value C1 would be 5pF = 0.000000000005F = 5E-12F, setting a HPF at 792kHz)

I'll put a 33p WIMA in there because I have some of those in stock.


One further observation.  I wasn't testing with the meter connected at first.  When I did connect the meter, with the compression circuit engaged the needle jumps to about 6.5dB of compression, so similar to the 7dB reduction I'm seeing on the meter in my DAW.

To me this would indicate that the problem is actually somewhere in the compression circuit, because with threshold and makeup gain both set to zero, I'd expect to see the meter read zero compression if the problem with the drop in level was due to something in the audio circuit...  Does that sound right or not?

Thanks once again for your help!
Title: Re: MixBuzz500 build/support tHread
Post by: Harpo on May 09, 2015, 01:43:51 PM
Is pin E_C on the DBX VCA the the place to measure this?  I get -0.001V there
Better use the output pin of the driving opamp for an easier rescaling, but it can be used. With your 50mV/dB or 20dB/V control law, your -0.001V at Ec will cause a current gain of 0.02dB with a working following current-to-voltage converter (a working IC11b would try its best to hold its virtual-ground pin5 at same potential as pin6, so VCA or opamp is either broken or oscillating). The 650R control port impedance of a DBX202C is different from a DBX202X, so your R100 or R60 or R55 parts value would need adaption for similar result.

Quote
I've only used the VCA in this circuit where the supply voltage is + / - 16V and I haven't messed around with resistor values, so there shouldn't be any issue with having damaged the VCA.
+/-16VDC is still more than the from datasheet allowed +/-15VDC +5%. Maybe easiest done with the -0.6 voltage drop thru a series diode to each DBX202C supply pin.

Quote
I'll put a 33p WIMA in there because I have some of those in stock.
Ok. LPF at 120kHz should help oscillation.

Quote
One further observation.  I wasn't testing with the meter connected at first.  When I did connect the meter, with the compression circuit engaged the needle jumps to about 6.5dB of compression, so similar to the 7dB reduction I'm seeing on the meter in my DAW.

To me this would indicate that the problem is actually somewhere in the compression circuit, because with threshold and makeup gain both set to zero, I'd expect to see the meter read zero compression if the problem with the drop in level was due to something in the audio circuit...  Does that sound right or not?
Probably coincidence. With 0.001V at Ec, your meter will not deflect to 6.5dB (whatever uA this might be on your scale). Get the audio signal unity gain correct first before focusing on the disco/eyecandy section. Meter response (yours is a 1mA fsd meter for sure?) can be corrected by tweaking (probably increasing) R50 in a later stage.
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on May 10, 2015, 04:24:10 PM
Is pin E_C on the DBX VCA the the place to measure this?  I get -0.001V there
Better use the output pin of the driving opamp for an easier rescaling, but it can be used. With your 50mV/dB or 20dB/V control law, your -0.001V at Ec will cause a current gain of 0.02dB with a working following current-to-voltage converter (a working IC11b would try its best to hold its virtual-ground pin5 at same potential as pin6, so VCA or opamp is either broken or oscillating). The 650R control port impedance of a DBX202C is different from a DBX202X, so your R100 or R60 or R55 parts value would need adaption for similar result.
I tried NE5532 for IC11 and the measurements were the same.  Seems IC11 is not the problem here.  R100 was adjusted as per this post: http://groupdiy.com/index.php?topic=41654.msg587347;topicseen#msg587347 but I did use a 715r resistor as I couldn't get 710r.  I have not examined whether R60 / R55 need to be changed because Igor did not mention these resistors when getting the gold cans working in Mixbuzz1.  Happy to hear any opinion or advice on these though.

Quote
Quote
I've only used the VCA in this circuit where the supply voltage is + / - 16V and I haven't messed around with resistor values, so there shouldn't be any issue with having damaged the VCA.
+/-16VDC is still more than the from datasheet allowed +/-15VDC +5%. Maybe easiest done with the -0.6 voltage drop thru a series diode to each DBX202C supply pin.
OK, I'll look into this.  In fact my 51X PSU is running slightly low at 15.75V / -15.8V so pretty close to the 15V + / - 5% value quoted on the datasheet, but I'd rather get the VCAs running as close to the correct voltage as possible.


Quote
Quote
I'll put a 33p WIMA in there because I have some of those in stock.
Ok. LPF at 120kHz should help oscillation.
I tried 33pf on one channel and sadly it didn't make any difference to the unity gain issue when compression is engaged.  I'll swap the other channel in due course to minimise the possible oscillation problem though.

Quote
Quote
One further observation.  I wasn't testing with the meter connected at first.  When I did connect the meter, with the compression circuit engaged the needle jumps to about 6.5dB of compression, so similar to the 7dB reduction I'm seeing on the meter in my DAW.

To me this would indicate that the problem is actually somewhere in the compression circuit, because with threshold and makeup gain both set to zero, I'd expect to see the meter read zero compression if the problem with the drop in level was due to something in the audio circuit...  Does that sound right or not?
Probably coincidence. With 0.001V at Ec, your meter will not deflect to 6.5dB (whatever uA this might be on your scale). Get the audio signal unity gain correct first before focusing on the disco/eyecandy section. Meter response (yours is a 1mA fsd meter for sure?) can be corrected by tweaking (probably increasing) R50 in a later stage.

Yes, it's a Sifam 19W 0 - 1mA meter.  But yes, I'll ignore this for now.
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on May 21, 2015, 12:53:34 PM
Hi Harpo

Did you see my last post? Can you advise on anything else to check? I'm really stuck here and don't want to start changing things randomly in case I break a different part of the circuit
Title: Re: MixBuzz500 build/support tHread
Post by: Harpo on May 22, 2015, 11:10:39 PM
Pull out the audio VCA and jumper VCA-In to VCA-Out (pins at center of the smaller VCA module sides) with a piece of wire (diameter and length of a paper clip might come handy if you have the VCA pins in sockets). If you now have undistorted audio with unity gain level, you know the culprit ...
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on October 02, 2015, 04:12:09 AM
Pull out the audio VCA and jumper VCA-In to VCA-Out (pins at center of the smaller VCA module sides) with a piece of wire (diameter and length of a paper clip might come handy if you have the VCA pins in sockets). If you now have undistorted audio with unity gain level, you know the culprit ...

Hi Harpo,

This went off the boil for a bit but I want to get back on it now.  I will do perform the test you suggest this weekend. 

Do I need to remove both VCAs or can I just test one channel and leave the Gold Can in the other channel?

Thanks,

Rob
Title: Re: MixBuzz500 build/support tHread
Post by: Harpo on October 03, 2015, 01:03:15 AM
Pull out the audio VCA and jumper VCA-In to VCA-Out (pins at center of the smaller VCA module sides) with a piece of wire (diameter and length of a paper clip might come handy if you have the VCA pins in sockets). If you now have undistorted audio with unity gain level, you know the culprit ...

Hi Harpo,

This went off the boil for a bit but I want to get back on it now.  I will do perform the test you suggest this weekend. 

Do I need to remove both VCAs or can I just test one channel and leave the Gold Can in the other channel?

Thanks,

Rob
Doesn't matter. Your measure for unity gain (complete unit, XLR voltage in=XLR voltage out) at the jumpered/audio-VCA removed channel. If you have more than one multimeter and a spare jumper, you could measure both channels simultaneously for whatever reason ...
Title: Re: MixBuzz500 build/support tHread
Post by: Enchilada on December 02, 2015, 05:58:19 AM
Hey guys. Does anyone know where I can pick up the PCB kits from it if they're still being made. Been checking this site for a while now and it's been out of stock for ages

http://ramshacklerecording.com/products/mixbuzz-pcb-set

Thanks,

Kris
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on December 02, 2015, 06:45:31 AM
Put a wanted ad in the Black Market?
Title: Re: MixBuzz500 build/support tHread
Post by: jasonallenh on December 02, 2015, 01:12:41 PM
Unfortunately, Igor has disappeared, so I don't know if James at Ramshackle has the permission to make more... I wish we had some sort of rule/agreement in place that would allow for such projects to continue.

=jh=
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on December 02, 2015, 02:01:04 PM
All true, but my suggestion was to put a wanted ad in the Black Market so someone with PCBs could sell you theirs.  That is how I got mine long after Igor had disappeared and Ramshackle had sold out.
Title: Re: MixBuzz500 build/support tHread
Post by: jasonallenh on December 04, 2015, 08:50:52 PM
Understood  :D
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on December 08, 2015, 05:13:09 PM
Pull out the audio VCA and jumper VCA-In to VCA-Out (pins at center of the smaller VCA module sides) with a piece of wire (diameter and length of a paper clip might come handy if you have the VCA pins in sockets). If you now have undistorted audio with unity gain level, you know the culprit ...

Hi Harpo,

This went off the boil for a bit but I want to get back on it now.  I will do perform the test you suggest this weekend. 

Do I need to remove both VCAs or can I just test one channel and leave the Gold Can in the other channel?

Thanks,

Rob
Doesn't matter. Your measure for unity gain (complete unit, XLR voltage in=XLR voltage out) at the jumpered/audio-VCA removed channel. If you have more than one multimeter and a spare jumper, you could measure both channels simultaneously for whatever reason.

I've finally got this on the bench and started to test, aaaaaand

Now the unit doesn't pass audio on either channel when it is in normal or GSSL mode. In bypass audio passes cleanly. Turning any of the controls has no effect on this.

Currently I have the left hand side with VCA in jumpered to VCA out and the right hand side still has the gold can in place.

I'll start going through the circuit to see where the signal gtes lost tomorrow. Strange that both sides have the same behaviour. That points to the control board being the culprit in would guess...
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on December 12, 2015, 05:07:09 AM
Hmm, very odd indeed.

As soon as I engage the compressor in either GSSL or 4000 mode mode, I lose signal at the input on both L & R channels

So that indicates that when I switch in the compressor, something is shorting the audio signal to ground, correct?
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on December 19, 2015, 06:00:11 AM
Edit...  Stupid patchbay wiring error
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on December 22, 2015, 06:45:09 AM
OK, so finally back on track from your advice from a few months ago Harpo.

I've connected VCA in to VCA out on the right hand channel, and I get unity gain.  Left hand side with Gold Can still installed remains the same.

So, the problem is with the VCAs, or the choice of components around them.

Any recommendation on which component values to start tweaking to get this working properly?

Thanks,

Rob
Title: Re: MixBuzz500 build/support tHread
Post by: rob_gould on December 22, 2015, 09:56:27 AM
Pull out the audio VCA and jumper VCA-In to VCA-Out (pins at center of the smaller VCA module sides) with a piece of wire (diameter and length of a paper clip might come handy if you have the VCA pins in sockets). If you now have undistorted audio with unity gain level, you know the culprit ...

Hi Harpo,

This went off the boil for a bit but I want to get back on it now.  I will do perform the test you suggest this weekend. 

Do I need to remove both VCAs or can I just test one channel and leave the Gold Can in the other channel?

Thanks,

Rob
Doesn't matter. Your measure for unity gain (complete unit, XLR voltage in=XLR voltage out) at the jumpered/audio-VCA removed channel. If you have more than one multimeter and a spare jumper, you could measure both channels simultaneously for whatever reason.

I've finally got this on the bench and started to test, aaaaaand

Now the unit doesn't pass audio on either channel when it is in normal or GSSL mode. In bypass audio passes cleanly. Turning any of the controls has no effect on this.

Currently I have the left hand side with VCA in jumpered to VCA out and the right hand side still has the gold can in place.

I'll start going through the circuit to see where the signal gtes lost tomorrow. Strange that both sides have the same behaviour. That points to the control board being the culprit in would guess...

Title: Re: MixBuzz500 build/support tHread
Post by: Estudis Ground on April 04, 2017, 02:52:47 AM
Hi,
I'm going to build a mix buzz comp and I was wondering if there's somebody sharing a trustable and tested BOM from Mouser's


thanks in advance
Title: Re: MixBuzz500 build/support tHread
Post by: mrdarwin on May 07, 2017, 04:17:46 AM
Hi there!
Just bought a fully built but never used Mixbuzz 500.
Calibrated sym, 5k1 to RV1, unit works fine... but threshold is too low: when I apply a +4dBu sine, ratio 2, fast attack and release and threshold to +15, the unit compress to 8dB!
I removed the 50k trim behind the meter, and no change... any idea? is it normal? same settings on my SB4000 and not same result... it appears the threshold is too "low"...
thanks