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

[snooty]

Does anyone know what resistor would make the rev A a tad brighter? 

I remember reading somewhere that there's a resistor acting as a high shelf around 15k or so...but its lowering the the high frequencies by a db or so.  But I can't find this info...  In my Rev A with Sozo caps in the signal path the unit has more depth than the spragues but its also darker.  If it was a bit brighter I'd have something special.

 

[evilcat]

I don't know what transistor you use but the 5088 are significantly brighter than the 3708. As for the resistors, I don't know ??? !

Best,
Ben

 

[Bonke]

So, I have finished a 1176 rev A.
It passes audio but it sounds thin with no bottom at all. (low volume as well)
The compressor doesn´t seem to compress either.
I have callibrated it exept for the gain reduction meter adjustment where I couldn´t get the meter up to zero.
30V and -10V are fine. (within .1 V)
When I send 0,775VAC to input xlr (measured between pin 1 and 2) I cant seem to get anyting like that on the output xlr. When i connect my DMM to the output xlr and increase the outputknob I get a peak almost fully cw. Goes from 0.2V and 1,7V with a pop and a big increase in noice. But without the DMM no pop or noice so maybe no problem.
I have tried to find out what the problem is for two days now. Getting tired and cranky.

(It is the hairballkit with BOM from mouser)

Anyone who could lead an ole cranky sweede in the right direction?  

Henrik

 

[MicDaddy]

follow the audio, an oscope would be great.

Measure the input verify ~.775VAC etc..and just follow it along until something goes wacky.

Take some good macro photos of the input stage of your compressor guts, as well as the pcb somebody might 'see' something.

 

[Bonke]

Thank you for the answer!
Actually I just switched from my mixers unbalanced send and return to my soundcards balanced ins and outs and IT WORKS!!!!!!! ;D
Now I get a a nice round compressing unit.
Let´s recallibrate!

A not so cranky anymore sweede!

 

[MicDaddy]

Don't you just love it when it's something simple  ;D

The smallest things can get overlooked sometimes, like most anything taking a step away for awhile usually helps me.

 

[Bonke]

Indeed!!! I love it!
If only life were as simple as DIY, but wait, it is!!

So any idea why it sounds shit when connecting to my unbalanced send and return on the mixer? Phase issue?

Henrik

 

[Bonke]

Also, when in all button in mode the vu is up on +3 all the time. Is this normal behavior?

Fantastic compressor!° Running some drums through it now. My, my, this is what I´ve been hearing and wanting!!!!

Henke

 

[Biasrocks]

Also, when in all button in mode the vu is up on +3 all the time. Is this normal behavior?
Henke

Well the ALL BUTTON MODE is anything but normal.  8)

Yes the meter will usually peg all the way to the right.

Mark

 

[Bonke]

Cool!
I´m gonna tidy up the inside tomorrow and then on to my rev D build.
Maybe some more testing/enjoying first.

As everyone who has finished this project I would like to thank Mako and Mike at Hairballs for this amazing project. The PCB´s are top notch and so are the kits. Also the documentation on both mnats and hairballs webpages are great.

Thanks guys!!!!!!!!!!

henrik

 

[tmuikku]

...
So any idea why it sounds Sh*t when connecting to my unbalanced send and return on the mixer? Phase issue?
...

Just use appropriate cable! 1176 has transformers so XLR pins 2 and 3 ( tip and ring if TRS ) need to be connected. Look from Rane notes http://www.rane.com/note110.html

 

[bieckmusic]

I'm loving how the 1176 sounds, but I can't get the gain reduction meter to work. When I adjust the q-bias pot there is no needle movement. When the meter is set to GR mode, the meter stays at zero. The meter works fine in +4 or +8 mode. The q-bias pot turns infinitely in both directions without any needle movement. 
???
any ideas?

 

[Echo North]

Turn it enough and it will break.

Pull the trim pot and test it with an ohm meter to confirm it's working.

 

[AudioguyII]

Hi everyone.

First off!
Thanks to everyone here!

I love my 2 new 1176 Rev A's

I'm having a problem when trying to calibrate.
Step 1: Q bias adjust seems simple enough.... DOne

But when I do Step 2, calibrating discrete meter.
I cant get the voltage at resistor R74 to change.... always stays at 0.5 volts .
the trimmers work well, I played around and adjusted them roughly by ear, and levels, the meter changes, output changes...so trimmers are working.

Any ideas?

thx again!!!!!

 

[Bonke]

You should measure between testpoints on rev A not R74. TP 10 & TP 11 that is. Try that and your callibration will go much better!

Henrik

 

[AudioguyII]

Hi Henrik,

Thx for the reply.....
sorry for my lack of experience... where / what are the testpoints?

Sincerely,
Michael

 

[Bonke]

Uppdated my answer. TP 10 & 11.

Henrik

 

[AudioguyII]

Ha.... I was searching just now... found them as well..

thx.. trying to calibrate them now.

THX!!!!!!!!!

 

[Bonke]

Glad I could help!

Henrik

 

[bieckmusic]

Hi, thanks for the idea.  I checked out and pulled the q-bias pot and it seems to be working.  It measured 2.17 on my ohm meter set to 20kohm mode, then as i turned it, each half turn pulled it down about .10 ohm.  Is that proper operation.  So I still can't figure out why the GR meter mode stays put at 0  ???

I'm including a picture of my board, just to make sure I orientated it the right direction ...  I appreciate all the help and feedback!!!     
greg