Igor

MixBuzz500 build/support tHread
« 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.
« Last Edit: June 06, 2010, 06:46:51 AM by Igor »
http://www.ij-audio.com
(new site hopefully will be up in July)


Igor

Re: MixBuzz500 build/support tHread
« Reply #1 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...




« Last Edit: June 05, 2010, 08:00:05 PM by Igor »
http://www.ij-audio.com
(new site hopefully will be up in July)

Igor

Re: MixBuzz500 build/support tHread
« Reply #2 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).

« Last Edit: July 27, 2010, 03:39:11 PM by Igor »
http://www.ij-audio.com
(new site hopefully will be up in July)

AudioGimmer

Re: MixBuzz500 build/support tHread
« Reply #3 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.


stereokillah

Re: MixBuzz500 build/support tHread
« Reply #4 on: June 07, 2010, 05:50:13 PM »
the sifam meter is 1262061 and bezel B is 1262079, everithing is good.
« Last Edit: June 07, 2010, 07:52:40 PM by stereokillah »
if your neighbour is hunger .. don't give him fish, teach him how fishing ...

AudioGimmer

Re: MixBuzz500 build/support tHread
« Reply #5 on: June 07, 2010, 06:19:46 PM »
Ah, my mistake. Sorry. Thanks for clearing that up.



Igor

Re: MixBuzz500 build/support tHread
« Reply #6 on: June 12, 2010, 08:31:48 PM »
Regarding the meter, Ptownkid's should fit fine (according to datasheet).
http://www.ij-audio.com
(new site hopefully will be up in July)

stereokillah

Re: MixBuzz500 build/support tHread
« Reply #7 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?
if your neighbour is hunger .. don't give him fish, teach him how fishing ...

Igor

Re: MixBuzz500 build/support tHread
« Reply #8 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.
http://www.ij-audio.com
(new site hopefully will be up in July)

stereokillah

Re: MixBuzz500 build/support tHread
« Reply #9 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
if your neighbour is hunger .. don't give him fish, teach him how fishing ...


JamesW

Re: MixBuzz500 build/support tHread
« Reply #10 on: July 02, 2010, 10:53:24 PM »
Igor thanks for this project what is the current draw for the unit
Subject to change with out notice

Igor

Re: MixBuzz500 build/support tHread
« Reply #11 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.
http://www.ij-audio.com
(new site hopefully will be up in July)

stereokillah

Re: MixBuzz500 build/support tHread
« Reply #12 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


 
if your neighbour is hunger .. don't give him fish, teach him how fishing ...

Igor

Re: MixBuzz500 build/support tHread
« Reply #13 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.
http://www.ij-audio.com
(new site hopefully will be up in July)

stereokillah

Re: MixBuzz500 build/support tHread
« Reply #14 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
if your neighbour is hunger .. don't give him fish, teach him how fishing ...

stereokillah

Re: MixBuzz500 build/support tHread
« Reply #15 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
« Last Edit: July 05, 2010, 07:13:47 PM by stereokillah »
if your neighbour is hunger .. don't give him fish, teach him how fishing ...

Igor

Re: MixBuzz500 build/support tHread
« Reply #16 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.
http://www.ij-audio.com
(new site hopefully will be up in July)

Igor

Re: MixBuzz500 build/support tHread
« Reply #17 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:
http://www.ij-audio.com
(new site hopefully will be up in July)

stereokillah

Re: MixBuzz500 build/support tHread
« Reply #18 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.
if your neighbour is hunger .. don't give him fish, teach him how fishing ...

Igor

Re: MixBuzz500 build/support tHread
« Reply #19 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?
:)
« Last Edit: July 05, 2010, 09:51:58 PM by Igor »
http://www.ij-audio.com
(new site hopefully will be up in July)