[BUILD] 1176 Rev A - Back to the beginning...

[Janzoulou]

Did more searching on the boards.

Issue: Tracking wont let me adjust the meter in a propper way.

Voltages on Q11,12,13 are looking all good. Switch is also working good. Solder-points are also checked.

The meter I also checked. It is exaclty working like the other one. (DUAL)

But tracking-adj  lets me only adjust -3dB, where the other board I can go up to -10dB (what I need)

Anybody got some hints for me where I am doing something wrong?  ???  ???

And what is about the Toroidal, is that normal that they got a little buzz when connected to AC?

Thanks.

PS: and yes, the trim is working and the GR is working 

 

[Janzoulou]

Tried to do the tracking adjustment with instruction Mic Daddy recomended in Reply #1072. I cant get the meter reading somewhat right. - 3dB is the most it is showing, then i reach the end of the trim. (it is doing 4,8K in that position, so its working...)

Any suggestions??? Please, I am scratching my head now the second day.  :'(

 

[sage]

Tried on BASS AND WORKS GREAT !!!!!
STRANGE THING: with no audio passing thru when the releasse is at its max (7 fully CW) the VU meter indicates 0 - when we move the relase knob to CCW the VU meter grows a whole db and  a half ....

is that normal?

Hey I am little puzzled by this behavior of the realease knob/VU meter interaction... is that normal? Any opinion?

 

[Janzoulou]

Sage, in my opinion that seems normal. My working unit has the same behavior. 

Cheers, Fredi

 

[sage]

Ah good ! I feel released !

This unit, as far as I could tell from the little test I did here just with the bass, sounds really amazing - I wanted to make sure this behavior was normal or a indication of something wrong -

I really wanna take a moment to thank this forum and Mike at Hairball, David at Cinemag, Gary at Henson and everyone who helped with their knowledge and their willingness to share it -

sage

 

[Janzoulou]

Still not solved my issue.... cant get the tracking adjust on one of my dual to work. Tried to calibrate several times. Compression is fine, sound is fine (ok fantastic!  ;D ) but the tracking adjust wont work. The voltages on the meter are the same as on the working one. The meter from the faulty one works good on the other side.. hmmm. I am stuck.

@ Sage: Do you have also a little buzz-sound on the toroidal? Mine makes a little buzz - sound like there is moving something inside when it gets AC.

 

[abechap024]

Still not solved my issue.... cant get the tracking adjust on one of my dual to work. Tried to calibrate several times. Compression is fine, sound is fine (ok fantastic!  ;D ) but the tracking adjust wont work. The voltages on the meter are the same as on the working one. The meter from the faulty one works good on the other side.. hmmm. I am stuck.

@ Sage: Do you have also a little buzz-sound on the toroidal? Mine makes a little buzz - sound like there is moving something inside when it gets AC.

Check your wiring, double check the solder connections (with a multimeter) to and from the trim pot. Its there, its always something.

 

[Janzoulou]

Thanks a lot for the quick reply!!

I did already check 3 times. Can it be the trimm - pot is not working, although when i de-solder i can measure between B and C the variable resistance? (0 - 4,8K)?

Will recheck everything again tomorrow, when I got time. BTW: the Voltages at Q 11,12,13 are fine...

Cheers, Fredi

 

[Janzoulou]

Alright.. still no succsess... rechecked all solders, Ratio - board and wiring. Al resistor - values are like in the BOM and voltages are fine.

Replaced R44 and checked all connections surrounding it.

Calibrated a few times, still no success, the highest amount i get with R44 is somewhat around -3dB GR-tracking. (for -10dB real GR measured outside. With DMM and inside a DAW)

The baby works fine, compression is like the other one and levels are almost exactly the same on both units.

Then i tried to put the tracking on the working one in the same range like the one where i got the problem. (thought, alright, seems like i should live with that?)
Then the strange thing happened: the tracking was quite different on both units on different Ratio - settings.

The wiring is exactly the same...

Can it be that Q12 + 13 are to much way out of being matched and i should match them for good and similar tracking - behavior? Can it be that the 5K trim - pot is not enough range? On the left channel i can push the needle with the tracking from 0 - +3 dB.

Shall i replace these transistors? And if yes, which ones I could possibly use?

Thanks a lot folks... think without this forum i already went nuts... ;-)

Fredi

when i do

 

[Echo North]

Alright.. still no succsess... rechecked all solders, Ratio - board and wiring. Al resistor - values are like in the BOM and voltages are fine.

Replaced R44 and checked all connections surrounding it.

Calibrated a few times, still no success, the highest amount i get with R44 is somewhat around -3dB GR-tracking. (for -10dB real GR measured outside. With DMM and inside a DAW)

The baby works fine, compression is like the other one and levels are almost exactly the same on both units.

Then i tried to put the tracking on the working one in the same range like the one where i got the problem. (thought, alright, seems like i should live with that?)
Then the strange thing happened: the tracking was quite different on both units on different Ratio - settings.

The wiring is exactly the same...

Can it be that Q12 + 13 are to much way out of being matched and i should match them for good and similar tracking - behavior? Can it be that the 5K trim - pot is not enough range? On the left channel i can push the needle with the tracking from 0 - +3 dB.

Shall i replace these transistors? And if yes, which ones I could possibly use?

Thanks a lot folks... think without this forum i already went nuts... ;-)

Fredi

when i do

You could increase the trimmer but that is usually putting a bandaid on a larger problem.  Does the VU work in +4 mode?  It's possible new FETs might resolve the issue but I'm dubious.  What is your DCV at the gate of Q11?  When you put R44 back into circuit to do the tracking, confirm with a continuity tester it's actually in circuit.

 

[Janzoulou]

Hello Mike! Thanks a lot for replying!

Gate at Q11 is 1,009V DC

Vu works in +4 and R44 is in circuit. Checked all points around it and whole GR-Meter Section. Whole calibration works like a charm up to point of tracking adjust.

The meters are not the ones you sell in your shop, I use these ones http://elcodis.com/parts/2464254/SQ10.html.

I did a rectifier with germanium diodes and put a cap to make the movement somewhat usable.

On one channel it works well, can calibrate (do it with DMM and DAW) and at the end i do the tracking adjust for somehow readable assign. (these Meters are not perfect but ok.. should have purchased yours at the end... so next time I know.)

When i swap the meters the problem stays, so it is not the meters, I guess.

EDIT:
I guess it was the Meters.  + 
After I disconnected both, I did bias - set with DMM and DAW/ Motu Traveler. (Like you, Mike, described in  Reply #1518 on: 27 November 2012) Then I removed the Caps on the VU - Meter and did Null - adjust and then the tracking-adj. Without the Caps on the meters I could sett them at least both to the same reading. But I had to trim them total different. ?? Then I installed different Caps like there have been prior.(was a bit of try and error) so the reading is somehow usable. I went with some 4,7uf. I should have taken better meters, thats for sure! Thought this Meters where not that bad as they are used in some trident desks.. :-\
guess there they got good alligned buffer - amps. 

BTW: would it be possible to set some buffer amps for metering or would the tracking and null set not work anymore? You can hit me if that was a dumb question.

Hey thanks again for helping me out.. I am really excited about getting this compressor to work inside my studio! And believe me this wont be the last one... 8)
After doing a Jensamp - Dual with some W295 in 2HE, racking some NTP 179-400 into Stereo - Unit and building a Summing Amp with 475-2c 48 into 2 and now getting to finish the dual -REV A, I would call myself already addicted to DIY...

 

[uffetuff]

I waited a while for my components to be shipped from Mouser. Now i got a mail that one component is discontinued. They gave me an alternative, but since i'm not very tallented in how the components work i need some help to say if it will work allright.

This is the one that should have been:
http://se.mouser.com/Search/m_ProductDetail.aspx?Kemet/C315C100J2G5CA/&qs=/ha2pyFadujdy7Ynj6fRAVPJO/nqjLZdg/fKUnmJxGbwoOg/oswFBQ==

The one they recomend as replacement:
http://se.mouser.com/Search/m_ProductDetail.aspx?R=80-C315C100J2G


Will this work?
I'm sorry if you lack info from me. I'm on tour atm and don't have the BOM to say wich part it is. Writing on the phone. If someone can tell me it would be great, otherwise i will add more info about this when i get home.

Thanks!

 

[sage]

for the 10pF i have got this part from Mouser:

140-100N2-100J-RC

If my notes are right this is C 11 - not in audio path - so not sure it will make a difference as long as the value is right.

Your link comes up in Swedish so it's harder to follow but if you look for the part number that I listed above you will be fine as my Rev A sounds amazing!

sage

 

[uffetuff]

Thanks alot!

Sorry about the swedish links. Hungover and confused in the van.

 

[lukidewa]

Update in my case. VU meter still does not respond with 0dB signal directly.
Is VU meter broken?

Sounds like it.  Is it a Hairball meter?

If so email me:  info at hairballaudio dot com

Mike

Sorry for late respond in this forum. I was sent email to you about VU meter, many thanks to hairball audio for fast respond.

Back to my problem. While waiting new VU meter, I borrow VU meter from my friend (buy from hairball too).  I get 0dB in the VU meter from directly input signal. But I still can't do Q bias. Meter not reaction when input potentio turn CW.

 

[acoustix]

Tried on BASS AND WORKS GREAT !!!!!
STRANGE THING: with no audio passing thru when the releasse is at its max (7 fully CW) the VU meter indicates 0 - when we move the relase knob to CCW the VU meter grows a whole db and  a half ....

is that normal?

Hey I am little puzzled by this behavior of the realease knob/VU meter interaction... is that normal? Any opinion?

I have the same thing on my old revA.
Try to put your "16" terminal block in PCB (the output pot ground) to the ground point case 

For me this fix the problem

 

[mikerl]

My 1176 Rev A has been working, and in use for a while now.  but im wondering about the calibration i did. 

When i use the compressor as a hardwear insert in pro tools, my input and output have to be fairly low for the compressor to not clip the input of pro tools.. it got me thinking about how i did the calibration...

being that the only tone generator that i have IS pro tools, i sent the compressor a 1k tone, line level, from the output of my 002 interaface.. and this is how i calibrated the meter and the gain reduction.  Can anyone tell me if this is ok, and if so, what level i should be sending the compressor from pro tools, in order to get proper calibration?  I just want to ensure that its working properly, and that the GR shown on the meter is accurate...  i have been hesitant to use this compressor much (altho it sounds good) for fear that im getting much higher levels of gain reduction than the meter is showing.

Mike

 

[Echo North]

My 1176 Rev A has been working, and in use for a while now.  but im wondering about the calibration i did. 

When i use the compressor as a hardwear insert in pro tools, my input and output have to be fairly low for the compressor to not clip the input of pro tools.. it got me thinking about how i did the calibration...

being that the only tone generator that i have IS pro tools, i sent the compressor a 1k tone, line level, from the output of my 002 interaface.. and this is how i calibrated the meter and the gain reduction.  Can anyone tell me if this is ok, and if so, what level i should be sending the compressor from pro tools, in order to get proper calibration?  I just want to ensure that its working properly, and that the GR shown on the meter is accurate...  i have been hesitant to use this compressor much (altho it sounds good) for fear that im getting much higher levels of gain reduction than the meter is showing.

Mike

I like using a good DMM (that can handle 1K AC) rather than the meter.

Send a 1K tone and check the level at the input (across pin 2 and 3).  You may find you'll have to send closer to +8dbu or something from protools to get 0dbu at the input due to impedance loss.  Once you know you're getting 0dbu at the input (0.775VAC across 2 and 3), move the DMM to the out put and run your qbias and tracking adjustments.  You'll know 100% it's working correctly if you do it right.

Mike

 

[mikerl]

Thanks so much for the reply, i'll do this asap and get compressing!

 

[sage]

Tried on BASS AND WORKS GREAT !!!!!
STRANGE THING: with no audio passing thru when the releasse is at its max (7 fully CW) the VU meter indicates 0 - when we move the relase knob to CCW the VU meter grows a whole db and  a half ....

is that normal?

Hey I am little puzzled by this behavior of the realease knob/VU meter interaction... is that normal? Any opinion?

I have the same thing on my old revA.
Try to put your "16" terminal block in PCB (the output pot ground) to the ground point case 

For me this fix the problem

unfortunately it did not fix for me! shoot i got excited but it did not change anything.....

sage