[BUILD] 1176 Rev F/G - new board, new transformer!

[regularjohn]

Ah, gotcha.  Thanks for the info!

 

[regularjohn]

Got another one for ya...

R59 is 3.9K on the pcb but 3.6K on the schematic and BOM.

Anyone know which one it really is, or are they close enough that you can use either one?

 

[beaversaber]

Just finished wiring up my 1176,
It passes signal, but seems to be oscillating a pulse at 20hz that increases in volume/speed as i turn the attack knob to the left towards the off position.  Has anyone else had this problem?

Also,
The couple NTE resistors I used don't show anything when I test them with a multimeter.  Is this normal?

And finally, the VU meter is pegging in GR mode.  It's the hairball one, and I can't seem to find anything wrong in the GR meter driver section of the board.  I already checked this section in the meta and couldn't find anything

 

[regularjohn]

And finally, the VU meter is pegging in GR mode.  It's the hairball one, and I can't seem to find anything wrong in the GR meter driver section of the board.  I already checked this section in the meta and couldn't find anything

Did you perform the proper calibrations?
If not, check out this page: http://www.axtsystems.com/index.php?option=com_content&view=article&id=56:1176lncalibration&catid=34:1176ln&Itemid=62

 

[bdubya]

Hey beaversaber, I ran into this, too.  In my case I was trying to measure a resistor greater than 2MegaOhms on a cheap DMM that won't read greater than 2MegaOhms, and consequently reads like the resistor is open.  Could that be it?

ben

 

[beaversaber]

It's actually not reading that the resistor is open (ie doesnt go up to zero), the needle just doesn't budge.  I am also using a cheap analog multimeter.  Works fine for all the other resistors except the NTE ones

 

[beaversaber]

And yes, I tried calibrating.  it pegs no mater what I do

 

[beaversaber]

Silly me, the battery on my multimeter was dying.  Replaced it and they read fine.  Still having oscillation/meter issues though

 

[regularjohn]

Yes, the B11148 is the transformer for the mnats rev f and rev g builds.

 

[mac]

Illfungo,

http://www.waltzingbear.com/Schematics/Urei/Urei_1176LN_series_F_page_3.htm here is schematic to see for yourself the wiring too!

Eds 11148's sound awesome!

Mac

 

[ilfungo]

Thanks for your help
my trasformer is 11148 and not B11148
can be is an original old trasformer?
Thanks

 

[SaMpLeGoD]

Hello all, I finished my Rev. F with opamp on the input and the B11148 at the output. It's already regulated and working fine, but I just want to know, what's the function of the R2 trimmer at the input's section? I thought it should be something like input's gain... but I just turn it and nothing happens. Anyways, is there any way to rise the input's gain? the comp just start compressing with the input about 3 o'clock... with a fixed threshold, I thing rising the input gain, sole the problem and let the 1176 more like the stock unit.

Cheers,

Eddie

 

[loopermc5]

Hey all trying to  do the q bias on a rev f and it's not doing anything. Then I realized I didnt test any of the 2n3707 for hfe would this effect it if their under 250 should I pull them? everything else has been check 20 times what am I missing? also wont go to zero in gr.......ugh!

 

[SaMpLeGoD]

I'm trying to rise the input gain of my 1176 Rev F, shoud I rise the R1A and R1C? or can I get more gain rising only R5 (input's pot)
Thanks a lot!!

Eddie

 

[mnats]

...what's the function of the R2 trimmer at the input's section?

The trim pot's function is what is printed above it on the screen overlay and on the original schematic (not my redrawing) - Common Mode Rejection ADJustment.

I'm trying to rise the input gain of my 1176 Rev F, shoud I rise the R1A and R1C? or can I get more gain rising only R5 (input's pot)

Not sure why you would need to do this - the Rev F and previous units actually step the input down through the input transformer while the Rev G IC input option has a gain of 1. Check your wiring to make sure it is correct first. If you really need to increase the gain of the input stage, increase the value of R1A. Increasing the value of R5 won't change the gain of the previous stage while R1C will only affect the + signal.

Hey all trying to  do the q bias on a rev f and it's not doing anything. Then I realized I didnt test any of the 2n3707 for hfe would this effect it if their under 250 should I pull them? everything else has been check 20 times what am I missing? also wont go to zero in gr.......ugh!

The gain of the transistors should not affect the q bias adjustment itself. If you missed the note about hFE on the BOM before stuffing them then it is possible you missed other things as well, so just look at the basics. Compare voltages with Jakob's schematic and where they aren't similar check for incorrect or faulty components, solder bridges and wiring mistakes. Your report that neither the q bias nor the meter zero works correctly suggests there are at least two faults as these are separate functions of the overall circuit.

 

[SaMpLeGoD]

Not sure why you would need to do this - the Rev F and previous units actually step the input down through the input transformer while the Rev G IC input option has a gain of 1. Check your wiring to make sure it is correct first. If you really need to increase the gain of the input stage, increase the value of R1A. Increasing the value of R5 won't change the gain of the previous stage while R1C will only affect the + signal.

Well, It's my 7th 1176 builded, 3xRev J, 2x Rev D, 1x Rev A and 1x Rev F... I even just can wire another 1176 with my eyes closed kidding... the problem is that it compress and work perfectly, but just start compressing about at 3 o'clock, when in the normal behaviour is that it start compressing like 11 to 12 o´clock... so I'm reaching the threshold point to late... I thought the cause could be the input's gain... I saw the schematic and it acts like a buffer at the input, the gain is 1 with the 10k resistors across the opqmps... what do you think it could be?

Thanks a lot!
Cheers,

Eddie

 

[mnats]

Well, It's my 7th 1176 builded, 3xRev J, 2x Rev D, 1x Rev A and 1x Rev F... I even just can wire another 1176 with my eyes closed kidding... the problem is that it compress and work perfectly, but just start compressing about at 3 o'clock, when in the normal behaviour is that it start compressing like 11 to 12 o´clock... so I'm reaching the threshold point to late... I thought the cause could be the input's gain... I saw the schematic and it acts like a buffer at the input, the gain is 1 with the 10k resistors across the opqmps... what do you think it could be?

I've already given you one suggestion but clearly you don't think that it is worth checking. So just measure the gain of the IC stage. As you correctly pointed out earlier, the 1176 has a fixed threshold so if everything is working perfectly it should be as though you were driving it with a 1:1 transformer at the input.

 

[SaMpLeGoD]

Well, It's my 7th 1176 builded, 3xRev J, 2x Rev D, 1x Rev A and 1x Rev F... I even just can wire another 1176 with my eyes closed kidding... the problem is that it compress and work perfectly, but just start compressing about at 3 o'clock, when in the normal behaviour is that it start compressing like 11 to 12 o´clock... so I'm reaching the threshold point to late... I thought the cause could be the input's gain... I saw the schematic and it acts like a buffer at the input, the gain is 1 with the 10k resistors across the opqmps... what do you think it could be?

I've already given you one suggestion but clearly you don't think that it is worth checking. So just measure the gain of the IC stage. As you correctly pointed out earlier, the 1176 has a fixed threshold so if everything is working perfectly it should be as though you were driving it with a 1:1 transformer at the input.

I was just kidding Mako, sorry for that, sure I will check it out thanks anyways

Eddie

 

[loopermc5]

ok I was wrong  I can do the q bias but I still cant get my meter to zero out I checked all my voltages gone through the schematic checked wiring for the millionth time what else should I look at need suggestions please.  :-\

 

[mnats]

ok I was wrong   I can do the q bias but I still cant get my meter to zero out I checked all my voltages gone through the schematic checked wiring for the millionth time what else should I look at need suggestions please.  :-\

What happens when you turn the tracking adjust trimmer?