All things G1176 - the new "repost" thread.

[JRE Productions]

Jacob,

Thanks for the help......um...and the persistance to investigate things on my own. I did learn valueable lessons on checking and rechecking solder joints (or lack of), componenent values ect. I completed two units at the same time. Both had the same components wrong (4.2K instead of 4R2). Once I found the first one, the other was a no brainer. I also had a wire inverted on one (15/17), and two resistors that only one leg was solder on. Funny how you check and double check when installing the components, and then later find wrong ones anyway.

I will try a new FET for the metering. Thanks,

Joe

 

[JRE Productions]

Jacob or anyone...

one last question. I used early API #7 VU meters for my compressors. These are true VU meters. I did not give this any thought until last night. Do I still need to add the 3K6 or 3k9 resistor in series with the meter? Or does the circuit board compensate for this resistance as part of the design?

The meters seem to function fine with out any added resistors between the PCB and the meter. But if needed I can open them back up and add it in.


Oops maybe two questions...

For meter lights I found a 28 vdc bulb like the #47 style. I came off the circuit board and used a 500 ohm 3 watt resistor to drop the voltage to about 21 volts under load of the light. This seems to be a pleasant brightness for the meters. Not to bright, but not dark either. With the 25-0-25 volt toriod, am I overloading it at all? I think I got the 30va toriod.

All is working and nothing seems to get to hot.

Thanks again

Joe

 

[enthalpystudios]

just wondering, has anyone used alternate input transformers on this one? i have oep's for the outs, but I was thinking of using some stancor wf30's (same as utc a-20's) for the input. I read somewhere in separate thread (talking about the o12) that someone had used an a20 on the input, but i'm not sure if he meant the g1176 or a real 1176.... anyway, i'm just wondering if I can wire it to the pads for the lundahl and terminate it the same way or if i'll have to do things differently.

getting a t-attenuator, unfortunately, is just not in the budget

billy

 

[Esset]

okey, here we go again! One channel up and working and loving it! One is still making me sleepless at night.

Checked the whole board (i think) capacitor oriantation, resistor value (compared to the working unit), solder blobs, shorts, unsoldered cables.

found the following, had switch places on the 180ohm and 1Mohm resistors. Here was the big screw up on my voltages, and the signal dropping out around Q2.
Switched them and the unit started passing audio!!!

Meter wasn't working so I switched the TL071 and the BF245A, and it started moving a bit in VU-mode. But not nearly as much as on my other fully working unit.

Its not compressing at all, and the meter doesn't work in GR-mode (probably due to the Gr not working :? )

Really need your help now, running out of places to look!!!

Voltages as they look now.
E-B-C
Q2 0,54-0,87-177
Q3 1,15-1,77-11,96
Q4 11,6-12,4-30
Q5 4,4-4,4-28,6
Q6 28,8-28,8-14,3
Q7 29,4-28,8-14,3
Q8 13,7-14,1-30
Q9 13,6-13-0,003
Q12 4-4,2-14,8
Q13 14,4-14,8-30
Q14 2,4-3,4-16,3
Q15 16,3-16,3-30

Some look good others not so good. Are the changes so big that the no-compression problem should be due to them, or is it in some other area.

On page 40 or something soundguy seemed to have a similar problem but there was no reply from with were the problem were, or if he fixed it (kinda taking for granted that he fixed it)

 

[Esset]

never mind my last post, came home today powered the unit up andit just started working, must have been to tired yesterday or the unit just might needed a night to rest :shock:

 

[enthalpystudios]

Well, I've figured out how to wire my stancor wf-30's for 600:600, and see where to solder to the input transformer section of the board....

question is, will I need those 2 10k resistors as specified for the lundahls? Or possibly something else?

I've left them out for now, everything else is stuffed, I was going to go ahead and begin wiring.

Billy

 

[Aryuserius?]

searched, but couldn't find a similar problem.

No 30v at output of 7824 regulator. -10v ok. VU meter went to zero @ power up then came back to -10. when unplugged and plugged back in, meter just goes to -10 now. 4003 diodes ok. replaced voltage regulator, again-started ok then within 2 seconds meter went back to -10. Any ideas? POssible dead short in the output line of the voltage regulator? Any help is appreciated.

-Mike

 

[gyraf]

POssible dead short in the output line of the voltage regulator?

If you have input voltage to the regulator, but no output voltage at all, then yes.

Check - as always - for shorts between traces. Check for correct type and orientation of transistors (specially the output devices)

Jakob E.

 

[enthalpystudios]

well, I have both of my units passing audio. I think on one I have an obvious joint or wiring issue, as a 'wiggle' seemed to cause quite a stir. I'm going to take a closer look at it.

The other, I can't quite get..... it passes audio, but distorted. -10dbFS with input and output all the way up.

It's passes the same audio in bypass/gr/vu modes, but although the output is quite low, the VU (in VU mode) reads very hot, the needle smacking the right side back and forth.

Bypass mode is the same, but with no meter activity.

GR mode sounds the same, although the needle simply sticks to the right constantly, no movement whatsoever regardless of audio.

I'ts 630 am, so I'm going to sleep, but I just can't figure that one. All the wiring and joints do appear to be alright. The other unit only seems to have a bad joint on one interconnecting wire.

Well, tomorrow's another day.

Oh, almost forgot to ask.... I just realized that I didn't stuff C*1 and C*2 (100uf lytic and a .1 poly). I'm using mnats revH board, and I didn't see those listed on the BOM. Are they:

a Needed all the time? or
b. Needed if using an input transformer???
or c. Not needed at all?

thanks, and good morning EST GMT-5

billy

 

[enthalpystudios]

Also, I left C* (1000uf lytic) and C16 (33pf) unstuffed.... C* was unlisted on the mnats BOM and C16 looked like it was left out. SHould I try using these?

thanks,

billy

 

[enthalpystudios]

So, it appears that during those tests I had the tl071s backwards. Something confused me and I got it backwards....

I'm going to assume they aren't good, and I can either run out and pick some up, or can i use an OPA134 in its place?

Also, I double checked for cold joints and shorts, and the one thing I found, aside from double soldering some suspect looking joints, was an unsoldered leg of CR1, the joint closest to Q6

Hopefully that was the source of some of my troubles.

I think I may go pick up some extra bc107's and bc560's and some tl071s, although If they work in this cct I do have some opa134's. Luckily I bought 25 bf245a's, so I have plenty of spares there.

Then when I get back I can start dbl-checking voltages and R values.

billy

 

[enthalpystudios]

god, i'm the worst, i'm sorry to post so many crap comments just to get to the next step on my own....

anyway, i began checking resistors by color code, and voila, R71, 7.68k, was a 221k...... futurlec sent me a bag of 20 221k R's labeled 7.68k, so, lesson learned... Double check before stuffing man!!!!

<----idiot (impatient probably)

i see now how many problems and how much time that saves

so, hopefully that was the source of many of my issues, although i'm going to keep double checking.

I was going to ask if a 7.5k would be ok, but I've got a 10k and a 33k in parallel at 7.66k and 7.78k, which is within 1% tolerance, so....

thanks guys, even if it's just so I might vent and think 'out loud'

billy

 

[enthalpystudios]

well, i think i may have answered my own questions with dumb luck and guesswork (only a slight amount of logical deduction)

anyway, 1st channel is working beautifully. I mean really beautfiul! incredible.

of course i have *nothing* to compare it to.

I've never owned a hardware compressor, and i've never owned anything with transformers, guitar amps aside. So I can't compare, or say anything like that, but after coming up on tascam cassette 4 track mic pres, and soundblaster live + behringer, to a mackie 24/8 with a 20 bit Layla, I must say that md421->green pre->G1176 sounds extremely pleasing.

stancor wf-30 on the input and oep on the output, mostly pretty good components.

mci VU meters, and some how I fit two units in this one box.

I'll post some pics tomorrow after the first session with these puppies (provided I can get the 2nd guy going ;]

thanks so much everyone for putting this together....

I honestly can't express my gratitude enough for this place.... It showed me that I could record with professional tools on a medium-low budget, and it seems like ages since I sold my mackie and started buying parts (headache). Really paying off over here.

This first band since my 'revamp' or whatever is a metal band, a genre i've never recorded before, but i'll post some all diy samples in the brewery soon enough.

thanks again everyone!

billy

 

[enthalpystudios]

well, kind of spoke too soon.... seems i've searched and searched and found a few others who have had the problem, but can't find anything more than that.

my one channel is still excellent, and the other channel sounds and compresses just fine, although its not been calibrated yet. I set the q bias, and dist trim, although i'm using a free computer distortion meter, i got it as low as that program said it would go.

anyway, when I go to set the tracking and the GR meter, I can't get the meter to move whatsoever. I noticed the trimpot for gr zero was opposite the other unit, so i switched it around, but its still not budging.

seems i've turned this thing forever both ways, not a hair of movement.

meter reads fine in VU. passes audio wonderfully, and is def. compressing, maybe not quite right yet, but def. compressing.

thanks for any thoughts anybody might have

billy

 

[JRE Productions]

It seems to me Jacob said the TL074 was used for the meter. (I think...someone may need to correct me.) But if you had some earlier problems with power, you might want to change that one. If you used sockets, just pop one out and switch it to the other. But ....just so you know, I am not much more knowledgable than you at this...

Joe

 

[Gachet]

Hi everybody,

I've just finished stuffing and wiring my first board and it's passing audio,the vu meter works?but it's not compressing at all and the vumeter is not working in GR mode.
All voltage looks fine.I tried different FETs but the problem is still there.

What are the voltage needed around Q2?
What should I do now?This problem looks recurant;is there any procedure in that case?I didn't find anything(to many posts)?

Thanks

 

[imo]

If you go to Gyraf's site, www.gyraf.dk, he has a pretty accurate schematic of the 1176. There are voltages listed for each of the transistors, and it will give you a good idea if you are in the ballpark
Imo

 

[Gachet]

Hi

I already have this schematic and checked voltage with it.But nothing is specified around Q1.
The input stage as well as the output seem to work fine.Just a very little less gain when bypassing the unit.
Enough gain ,no hum.The voltages seem to be correct too.No shorts beetween traces.
But no compression and the GR mode doesn't work.The q bias and tracking pots don't make anything
My voltages are:

E B C

Q2 : 0,5 0,9 1,6
Q3 : 1 1,6 11,8
Q4 : 11,2 11,8 28,6
Q5 : 4,1 4,6 26,9
Q6 : 27,5 26,9 13,6
Q7 : 28,1 27,5 13,6
Q8 : 13,1 13,7 28,6
Q9 : 13 12,4 0

Q12: 3,6 4,2 14,8
Q13: 13,6 14,7 28,6
Q14: 2,7 3,3 15,8
Q15: 15,3 15,8 28,6


Q1: D0 S0 G0 => Is that normal?
Q1017,8 S0,4 G0

Voila;Help is needed THANKS

 

[Gachet]

hooooooo

Nobody has an idea?!!

Please?

 

[fucanay]

I just finished the front panel for my first G1176 and I plugged it in and it sounds great even without having done the calibration. I've never calibrated anything and I'm not entirely sure my DMM is right for it. I'm supposed to be reading mV but I think I can only do down to a tenth of a volt AC. Anything less show 0.0 . So I think I have some problems on that front. Anyone care to point me at a decent DMM for this?

But I got my front panel mostly finished.

Picture

Unless I can find some rub on lettering, it'll be getting the Sharpie labeling treatment. I love the big meter I got from Jollyted. I don't think I'll even bother backlighting it.

Matt