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

muffy1975 said:

Hi message for Mike at Hairball,

got the new Avel but the secondary wiring side diagram on the actual transformer is not matching up ( I think ).

Usually on the secondary I wire the black and yellow together for the centre and take red and orange to the sides.

Is this still correct?

The primary side for 240v I wire the violet and grey together and take blue and brown to neutral and live respectively

Thanks in advance Mike.

Click to expand...

There was a report that some of the Avel transformers in my last batch may have had incorrect labels on them (not sure if this is your issue).  

If in doubt refer to the data sheet:
http://avellindberg.com/pdf/avel_y23_range.pdf

and compare to:
http://www.diyfactory.com/data/transformer_connections.gif

For the primary I think you want grey/violet together, brown to live and blue to neutral (looking at the data sheet).

For the secondary I think you want red and orange together and connected to the 0V (ct) pad. Black and yellow go separately to each of the 25V pads.

Mike

ciao
curiosity ...
can add  the LN circuit  to rev A  ?
thank

ilfungo said:

ciao
curiosity ...
can add  the LN circuit  to rev A  ?
thank

Click to expand...

the rev A is the first and last revision that didn't incorporate the low noise circuitry. it is the main reason it sounds the way it does. the low noise circuitry completely changed the way the 1176 sounded.

Hey guys, Both of my units are working great. Installed them at a studio and used them on a vocal session the other day.

They sound awesome but they are acting a little weird. After compressing they seem to oscillate a bit and its length and intensity directly correlate to the amount of compression. It's so slow that it's inaudible but it makes editing things a bitch.

Any Ideas what this could be/how I can fix it? I know I can filter it out easily but I'd like to get the unit working perfectly.

I don't have any noise issues on my unit. I don't think adding the LN circuit is necessary. I think the older components used to make the originals may have been an issue for noise. Especially when stacked together. (Caps, Resistors etc.)

I also never had any editing problems due to an oscillating waveform. But will look closer next time I use mine. Or maybe I will recall a recording to see. Let you know.

I also didn't do any mods to mine. It is strictly to the schematic.

John

Edit: I checked and DO Not have any sine wave artifact like that on mine. Wish I could help but something must be wrong. Hopefully someone here can help. That hit is really clipped. You sure it is not due to the source?

Mouser is out of 33pf caps for C6 & I'm ordering parts for my present Rev D build & future A build.

Can I swap in a 47pf at C6??
Or can I just leave C6 out & up the R16 to 100k like they do in the second Rev A schematic?
I'm not sure how this position affects the circuit.

Cheers
Sean

I have some 33 pf Wimas left over. I would be happy to send you a couple. Just email me with your address. I would think the correct part would be best. Mouser part number FKP233/1000/5. That the one you need?

John

Ringwraith said:

Mouser is out of 33pf caps for C6 & I'm ordering parts for my present Rev D build & future A build.

Can I swap in a 47pf at C6??
Or can I just leave C6 out & up the R16 to 100k like they do in the second Rev A schematic?
I'm not sure how this position affects the circuit.

Cheers
Sean

Click to expand...

Best to stick with the 33pf value, this cap is in the Feedback path IIRC. A film cap is not a necessity either, you could easily swap in a ceramic which is probably closer to the original design.

Mouser part # 80-C320C330J2G5CA

http://ca.mouser.com/Search/ProductDetail.aspx?R=C320C330J2G5CAvirtualkey64600000virtualkey80-C320C330J2G5CA

Would be a good choice.

Mark

Yeah the JBL schematics are hand drawn. Hard to read some stuff. But I think the Mnats build is damn close. I was very surprised at how warm the rev A sounded. Even though the parts were so different. I always thought the rev D was warm and crisp and fast. The rev A is similar. Both sound great.

John

Mouser is out of J309 but has J309_D26Z
Can I use them, are they basically the same thing??

Thanks
Sean

hello
it is normal that the compressors have a lot 'of noise (shhhhhh)?
the problem may be that I connected to a tac scorpion  inserts unbalanced?
sorry for my english....

They are more noisy than other varieties of 1176.

ilfungo said:

hello
it is normal that the compressors have a lot 'of noise (shhhhhh)?
the problem may be that I connected to a tac scorpion  inserts unbalanced?
sorry for my english....

Click to expand...

hello and thanks Rob
I still have a doubt about the calibration of the Q bias ...
0775 measured input I put on XLR pin 2 and pin 1?
Pin 3 must be connected to pin 1?
If I measure the output of the sound card I get 0775
connected to the compressor (maybe for the T-pad) Measure 0336
correct?

the unbalanced connection can be a problem?

connect the output of the soundcard to 2 & 3 on the blue stripe. The input is through a transformer.  it is not necessary to connect pin 1 to 3

ilfungo said:

hello and thanks Rob
I still have a doubt about the calibration of the Q bias ...
0775 measured input I put on XLR pin 2 and pin 1?
Pin 3 must be connected to pin 1?
If I measure the output of the sound card I get 0775
connected to the compressor (maybe for the T-pad) Measure 0336
correct?

the unbalanced connection can be a problem?

Click to expand...

Thanks Rob
but I must measure 0,775 between pin 2 and pin 1 ?
or between pin 2 and pin 3?
Thanks

For the adjustment of the Q-Bias it doesn't really mather. But for example, to set 0db on the VU-meter you must measure (+4dB = 1,22v) between pin 2 and 3 (on the output). So as a rule I always measure between 2 and 3.

I agree with these fellas opinions.  I did my calibration with success by hooking up my signal gen with positive lead to pin 2 and the ground lead to pin 3.  I was able to get through the entire cal procedure with no trouble.

ciao
about a year ago I bought on ebay a output transformer  for 1176
No. 11148 apparently old (who sold it to me told me that he was an original Urei processor) without any other written ...
I think it is the processor used in the Rev F
Can you tell me something?
Thanks

ilfungo said:

ciao
about a year ago I bought on ebay a output transformer  for 1176
No. 11148 apparently old (who sold it to me told me that he was an original Urei processor) without any other written ...
I think it is the processor used in the Rev F
Can you tell me something?
Thanks

Click to expand...

That is the number for the output transformer on the rev F in the manual.  If you were thinking of using it for the Blue Stripe it's not the right one.  The 11148 is for the later class A/B output, like the silver face units have.  The rev F is a kind of inbetween the true class A black face & the op amp input silver faces.    It has the output of the silver face with the input of a black face !

Thanks Rob
I can use it in new Mnats rev F ?
thanks