MixBuzz1 Build/Support thread

[Igor]

To be continued.... This year, of course.

@ mata_haze:

I was overconfused with too many information.
Actually, the things are more simple than it looks at first glance.

I have checked the Threshold pot is wired properly
(I get a swing of + and - 12V at the wiper)

The swing at wiper of THRESHOLD pot should be about +...-7V, if 10k pot used, and R76, R68 are 3k3

and the Ratio and attack-release pots are ok.

I have carried out the following measurements:
on IC3 on both PIN 8 and PIN 14 I have the following: (DC)

RATIO          Voltage Swing
1.5                                3 - 17 mV
2                               203 - 216 mV
4                           no swing 156 mV (fixed)
6                               361 - 362 mV              
8                               380 - 381 mV
10                             391 - 392 mV

on the same Chip (Ic3) I have a swing of 5 to 150 mV on PIN 1 and 7. (DC)

Don't mind IC3 for now, maybe, it is in GSSL mode.

I am trying to figure out were my mistake lies I can see that the DC voltage runs all the way from the wiper of the threshold pot to PIN 1 and PIN 7 of IC3 and then it gets "messy" on PIN 8 and 14, also no DC after the diodes D6L and D6R.
also the makeup works fine so IC5B it's ok.
I am using IGOR's mod to implement a continuos pot for attack and release, so I am not using the stepped lorlin.

The prob is not here as well. For now, all this does not means, because the prob is before this stage:

After further investigations I have found out that the sidechain signal stops before hitting the detector.
I can trace the a sinewave (1V RMS) up until the left side (looking at schematics) of R14L and R14R and then it disappears.

by checking TP1 and TP2 I found out there is no sinewave there either.

!!! We should see some sinus (amplitude depends on THRESHOLD setting) at TP1,2!!!!

I am assuming the VCA works in a "current fashion" rather than voltage and then IC1A and IC5A
then convert the current into voltage again hence the TP1 and TP2 afterwards.

OK...THAT2181 VCA's are used, right? In case of whatever, 2151 are different and can't be used here w/o change.
In any case, all these VCA's are working in current mod.

I am not sure what the " - CONTROL " and " + CONTROL" means on pins 5 and 7 of the VCA,
are they not just supply +-15 VDC? or should I expect some signal there too?

+contr and -contr are +/-15V supply voltages for sidechain (power supply decoupled to 5 sections).

EDIT: I have +15 VDC on pin 7

RIGHT

and -15VDC on the 5k1 resistor attached to pin5. there is -2.85 Vcc on pin 5 of the VCA.

I never measured the voltage at pin5, but this seems OK.
EDIT: right from datasheet:

Voltage at V- No Signal -2.85 V

The VCA's are connected right....seems, the prob is somewhere at opamp after VCA, maybe, ferrite beads are not installed....etc

OK than... Put THRESHOLD pot at center position, there should be 0V at its output.

For next, I mean sidechain VCA's, IC5L, IC5R.

Check the voltage at pin3 of VCA's; should be 0v.
Check the voltage at pins 1,8,4, should be 0V.
Check ALL parts across, and probably, you'll find a part with wrong value;
maybe, VCA's are reversed in sockets (pin 1 instead of 8
EDIT: 99.9%, the VCA's are OK, because -2.85V is absolutely fine at PIN5 of VCA);

check if ferrite beads or 0R jumpers are installed at place of R39 L/R.

measure the voltages at TP1, TP2, should be 0.00V DC as well.

And, of course, let us know the result.

More coming soon.

 

[benlindell]

Does anyone have an idea of a mouser part number for the headers that connect the little boards behind the release switch and the meter board to the main board, I've never used these before so I'm not even sure what to search for.

 

[tekno808]

Igor,

I'm a little confused about the GSSL/Turbo switch , when switch is open it's Turbo mode , when it's closed it's GSSL mode but then the led lights up ,should it be the opposite ?

Danny.

 

[mata_haze]

For next, I mean sidechain VCA's, IC5L, IC5R.

Check the voltage at pin3 of VCA's; should be 0v.
Check the voltage at pins 1,8,4, should be 0V.
Check ALL parts across, and probably, you'll find a part with wrong value;
maybe, VCA's are reversed in sockets (pin 1 instead of 8
EDIT: 99.9%, the VCA's are OK, because -2.85V is absolutely fine at PIN5 of VCA);

check if ferrite beads or 0R jumpers are installed at place of R39 L/R.

measure the voltages at TP1, TP2, should be 0.00V DC as well.

And, of course, let us know the result.

More coming soon.

threshold pot in the middle I get -7 on one side of the pot, -0.7 at the wiper amd + 7 on the other side of the pot

Check the voltage at pin3 of VCA's; should be 0v.  YES = 0V
Check the voltage at pins 1,8,4, should be 0V.  YES = 0V ( I assume of the VCA)
ck if ferrite beads or 0R jumpers are installed at place of R39 L/R  yes ferrite Beds installed instead of resistors.
R76 and R68 are definitely 3K3
measure the voltages at TP1, TP2, should be 0.00V DC as well  YES =0V

what else should I check?

Best,
Mattia.

 

[funball2]

hi all ,

finished and working!!!

mistake i made was stupid simple , you have to connect or jump the soft / tight connection if you use the stepped lorin switch , otherwise distortion of the not so nice kind !!! ;D

c&b mixpot works , i use a lin pot but got a lot more when mixpot is in middle position any workaround ???

sounds great !!!!!! 8)

cheers

funball

 

[piano]

OK, so if you want to use the DUAL or the SOFT/TIGHT switch you can not use the stepped Lorin switches that come with kits - you have to use pots you purchase outside of the kit.

 

[mata_haze]

HEllo Igor,
I have checked the sidechain VCAs section once more and I can confirm all the resistors and capacitors are exaclty the value thay have to be EXCEPT:
all the  47K are instead 47.5K
all the 5K1 are 5K11
R74 (360K) it's 357K
R49 (470K) it's 475K
R59 (330K) it's 332K
(values are nominal from the colour code)

C29L and C29R have 334 written on them.
I bought the components from your kit so I suppose the values are in within specs.
there is an LF347 instead of a TL074 on IC3 and a DG403DJ instead of a DG403 on  IC2

I am attaching a couple of high resolution pics..perhaps someone will spot a silly mistake..
there are 2 resistors which I have lifted from the board just to measure their value (you can see them in the pic) they are R37L and R48
diodes are all the right way around and so are the VCAs.

Please Igor, I am reaching "desperation zone"

 

[chefducuisine]

Hi Guys,


I've been on a business trip and just checked back again.
I have added a few files to my picture gallery because of requests / PMs:

HiRes Picture of the full version mainboard:
http://twin-x.com/groupdiy/displayimage.php?pid=4381&fullsize=1

Picture of the Backside of my LED Meter & Switch Board:
http://twin-x.com/groupdiy/displayimage.php?pid=4380&fullsize=1

LED Meter & Switch board Layout
http://twin-x.com/groupdiy/displayimage.php?pid=4378&fullsize=1

LED Meter & Switch board checkplot
http://twin-x.com/groupdiy/displayimage.php?pid=4379&fullsize=1

Please pay attention when you want to built this type of LED Meter & Switch board - this is not DIY friendly because of its tiny track size it is difficult to etch and solder.
LEDs and switches have to be soldered to the front, the connector has to be soldered to the backside although it is a single sided PCB.
A few posts ago is the information which switches and LEDs I used for the built.
The LED Meter itself is based on Igors supplied one - one can still use his driver.
I changed the switch arrangement completely - please be aware! The switches are below the meter. Each one is connected via wires to the different terminals. See pictures to get the idea.

... hope the above files help.


@Piano:

Almost all your questions are answered within the documentation Igor posted in the first place:
Please have a look here:
http://twin-x.com/groupdiy/thumbnails.php?album=416
Download Zip File 'DOCS_v2.4'

You can install the soft / tight switch weather you are using pots or Lorlin switches. In fact you should at least install a jumper on JP4 between Pins 2 & 3 to get normal SSL mode, otherwise the unit will distort terribly.
If you look at the file 'SCHEMATIC_ALL.PNG' out of 'DOCS_v2.4' it will be clear what the soft / tight switch (JP4) does and why it doesn't matter if pots or Lorlin switches are used.
The pot just allows a more flexible adjustment of the time constants compared to the original thing.


@ Mattia:
The HiRes Picture you requested is in my Gallery - please see link above. Sorry for the delay.
From your pictures I saw that you did not install a jumper or switch on JP4 - please check, otherwise the unit will distort terribly.
Are your solderjoints OK? A few joints on the resistors still look golden as far as I can see it on the pictures.


@ SKJGProject:
All details to my LED Meter & Switch board are in the gallery - see links above. But again, be warned: It is difficult to built because of its tiny size.


Regards,

Chris

 

[funball2]

great Chris!!,

well my friends and i , (well i am building 5 units) are mainly using the mixbuzz1 for live concerts .
so the only problem is the so great mix c&B funktion is not so smooth , center is +3db .
for studiowork that is minor problem.

hope someone finds a solution, i use linear pots maybe some log but where and what?

thanks for the help

cheers

jan funball

 

[chefducuisine]

Jan,


Igor wrote on page 3:
' I used dual 10k lin DUAL pot. In ideal, the best case is quad 2x log / 2x revlog 10k pot, but I cannot find them anywhere. Dual 10k lin alternative works best for me.'

Just an idea: You can use a four deck rotary switch and solder your own resistors to mimic the 2x log / 2x revlog.

Check this:
http://uraltone.com/kauppa/product_info.php?info=p1078_Rotary-switch--4x24.html&XTCsid=j9gm9k71i9h1pcgmon1ac7kcd4

24-pos should be enough for mixing wet/dry in a live situation.

I have used the blue Alps pot for Mix: 1,8 dB in the middle position. However there are tolerances.
Best way would be using the switch with appropiate resistors I suggested above.

Cheers,

Chris

 

[mata_haze]

Hi Guys,


I've been on a business trip and just checked back again.
I have added a few files to my picture gallery because of requests / PMs:

HiRes Picture of the full version mainboard:
http://twin-x.com/groupdiy/displayimage.php?pid=4381&fullsize=1

Picture of the Backside of my LED Meter & Switch Board:
http://twin-x.com/groupdiy/displayimage.php?pid=4380&fullsize=1

LED Meter & Switch board Layout
http://twin-x.com/groupdiy/displayimage.php?pid=4378&fullsize=1

LED Meter & Switch board checkplot
http://twin-x.com/groupdiy/displayimage.php?pid=4379&fullsize=1

Please pay attention when you want to built this type of LED Meter & Switch board - this is not DIY friendly because of its tiny track size it is difficult to etch and solder.
LEDs and switches have to be soldered to the front, the connector has to be soldered to the backside although it is a single sided PCB.
A few posts ago is the information which switches and LEDs I used for the built.
The LED Meter itself is based on Igors supplied one - one can still use his driver.
I changed the switch arrangement completely - please be aware! The switches are below the meter. Each one is connected via wires to the different terminals. See pictures to get the idea.

... hope the above files help.


@Piano:

Almost all your questions are answered within the documentation Igor posted in the first place:
Please have a look here:
http://twin-x.com/groupdiy/thumbnails.php?album=416
Download Zip File 'DOCS_v2.4'

You can install the soft / tight switch weather you are using pots or Lorlin switches. In fact you should at least install a jumper on JP4 between Pins 2 & 3 to get normal SSL mode, otherwise the unit will distort terribly.
If you look at the file 'SCHEMATIC_ALL.PNG' out of 'DOCS_v2.4' it will be clear what the soft / tight switch (JP4) does and why it doesn't matter if pots or Lorlin switches are used.
The pot just allows a more flexible adjustment of the time constants compared to the original thing.


@ Mattia:
The HiRes Picture you requested is in my Gallery - please see link above. Sorry for the delay.
From your pictures I saw that you did not install a jumper or switch on JP4 - please check, otherwise the unit will distort terribly.
Are your solderjoints OK? A few joints on the resistors still look golden as far as I can see it on the pictures.


@ SKJGProject:
All details to my LED Meter & Switch board are in the gallery - see links above. But again, be warned: It is difficult to built because of its tiny size.


Regards,

Chris

Hello Chris,
thank you for the super pictures!
yes JP4 it's wired to a switch, it was not installed because I was taking the picture.
Joints are all good , the holes are plate through so even though there is a bit of unsoldered pad on the top the connection should be good.I have re-done them all JUST IN CASE, but no result.
the interesting thing is that I am building 2 units and BOTH behave in exactly the very same way..so I have been consistent in my mistake: I have managed to repeat it twice. where is it? I don't know.
I have checked my boards against yours twice..I cannot spot any reverse diode or cap or anything like that. I must be overseeing something.

I have noticed you have not installed JP1L, JP1R and JP2L, JP2R, is there a specific reason? I thought we were meant to install them if the board is fully populated...

Thank you very much for your help and pictures, it's VERY MUCH appreciated!
Mattia.

 

[funball2]

mattia,

install all ic and unjump everything exept jp4 or switch it ,

what is happening then?

cheers

jan on duvel beer

 

[funball2]

Chris,

i can live with 1.8 db on center with the alps blue but linear ???

now i measure 4.8 db , bit to much on big line array stuff

thanks

jan on duvel beer

 

[mata_haze]

mattia,

install all ic and unjump everything exept jp4 or switch it ,

what is happening then?

cheers

jan on duvel beer

It WORKS!!!!
I am running off my laptop I will verify it 100% tomorrow in the workshop!!! but I can almost say it's fine.
I knew it was something SILLY!

THANK YOUUUUUU!
I can't wait to use it in the next session!!!!!!!

 

[funball2]

cheers man !!!

duvel is great studio beer !!

 

[chefducuisine]

Gongrats Mattia,

glad you sorted it out.
Now show us some pictures!!! ;D

From the questions I received, more people are struggling with the jumper settings of this built.
I am referencing to the file 'JUMPERS.png' out of Igor's doc package:
- JP1L & JP 1R shorts out the sidechain filters - only needed if no SC Filter installed.
- JP2R & JP 2R shorts out the mix functionality - only needed if no Mix / Blend option installed.

..hope this helps others who are uncertain with jumper settings!


Regards,

Chris

 

[mata_haze]

Hello everybody,
half good news: the good news is that I can hear : the unit compresses
bad news I  cannot do the line up as I cannot get it into compression by following the procedure.
the unit seems to be compressing with input signals above 16dB...

If I disconnnect the RATIO board the compression seems to happend at any level, I can change the threshold level and the unit compresses. I am not able to determine the ratio, but I can definitely see it compresses.

I am going to take pics of the RAtio boards and post them..pehaps someone might be able to spot IF there is a mistake there

back to square one.

IGOR?

M.

 

[SKJGProject]

will compare it to my build asap...

@küchenchef thx for the pics and pcb layout, i accidentally ****** up the led orientation
on igors meter board and destroyed 2 pins on both led bars while desoldering and the board
is messy so i better use yours.
unfortunately i'm more or less a noob in diy audio land and
have never etched by myself but maybe someone in germany plans to do one board and makes another one for me too  ;D

i'm almost done with the pcb work, cp11 for the PS and the 20k resistors for the vca boards were missing in my kit,
and i still need a case and power trafo...any suggestions for a good one in germany?

i'm also planning to use pots on attack and release and want to know what difference is between the expensive
ALPS ones you've posted and the ones igor supplied with his kit (only the case for MIX)?

 

[briomusic]

I get all my components (including power transformers, and occasionally cases) from banzaimusic in berlin.
Conrad might be quicker for you in Duesseldorf, they do decent torroids (for required rating values see earlier in the thread). Then of course there is Buerklin, rs, farnell if you have a larger order.
For the case you could also check the whitemarket, quite a few GSSL/mixbuzz cases and frontpanels on offer.

 

[SKJGProject]

is this one good? i have -70db humming problems with my tube pultec and want to use a shielded one if it's necessary...
http://de.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2238550