All things G1176 - the new "repost" thread.

[jrmintz]

[quote author="al_p"]yep. there's a lot of stuff that eats up panel space quickly if you are doing a dual. i'm using giant meters from an MCI tape machine. 3.5" wide, counting the mounting hardware, and just about 3.25" high with the illumination kit. also be aware of lips and flanges that connect your chassis to your panel. i haven't even started the guts yet, just doing metal work and mocking it up to make sure it's all good.[/quote]

Also the chassis is sometimes not the full height of the face plate - in particular that's true of Par-Metal enclosures - so you can get a nasty surprise if you cut it too close. Par-Metal 1u enclosures are actually 1.32" high, or something like that. The covers also have flanges on the front edge, which you can cut away but it's a real pain. I built an SSL with a 1.5" meter and the box wouldn't close. I had to buy another box and rip it all out of the Par-Metal box. You really have to read the specs - of course I saw later that it gave the actual height on the web site.

:thumb:

 

[bluebird]

I built two 1176's a while ago and have been using them for some stereo stuff.

I noticed the other day that when in "all buttons in" mode and letting some drums really breathe I noticed the release times of the two 1176's where significantly different.. With the drums panned center going through both units.

With both release knobs fully CCW I had to turn one almost to 12:00 for the "breathing" to match.

Although I haven't looked I'm assuming the release pots are the same. So I started thinking and remembered I had used two different brands of diodes (FD 333) in the sidechain circuits. A different brand in each 1176 that is.

would this cause the release times to differ?

 

[Michael Krusch]

I always print out my frontpanel design before I send it to Schaeffer and put everything on the paper to check it out. Has safed my much money.

 

[bluebird]

Bump

anyone have any ideas about my previous post?

 

[jrmintz]

Bluebird,

Did you match the Fets?


I used mine tonight for the first time, worked like a charm and sounded great. It's unbelievably rewarding. Thanks again Jakob and everyone who helped.

:guinness: :sam:

 

[bluebird]

No I did not match my fet's. so different fets will have different release times? gosh I would not think they would be so different.

interesting....

 

[jrmintz]

[quote author="bluebird"] so different fets will have different release times? [/quote]

I can't say that for sure, but if parts placement and values are the same in both units it's a place to start. Somewhere in this thread is PRR's fet matching jig. It's very simple and works great.

Good luck!

 

[bluebird]

Thanks jrmintz,

with a little searching I found PRR saying it would be very hard to have two 1176's tracking the same anyways....

 

[orson whitfield]

Today my G76' made her debut at a real studio and it was a disappointment :roll: The signal was very low. It was barely there even with the in and out cranked all the way up. It worked for me at home. Could something have broke on the way there? They were routing a vocal track from the SSL to it.

 

[orson whitfield]

[edit]

 

[yan_b]

ok i pluged my unit and nothing burned (i hope), and the vu reacts to input signal, and in and out knob's.
i have built mnat's version pcb and as i understand it ,because the output tx is wierd 2:1 i shoul'd multiply by 2 the measures sujested by jacob in the output during the q bias calibrating , am i right?

 

[yan_b]

ok after some more tests i discoverd that since i used 2n5457 wich have different leg order, i mounted them in the wrong way.
i turned them to the correct order.
now i have checked the transistors voltage, q2 to q9 seems fine, and the input and out put gain changes with the in/out pot's, and the voltage of the output seem's to be in order for 50mv input, about 6.9v
how ever q12 colector is pulsating so does q13 b&e q14 c b &e and q15 b&e, the output also start to pulsate(in fast attack time)
also the meter does not respond in gr mode (except for a slight movment when i turn tracking pot)

what coul'd be the cause of that?

 

[idylldon]

Anyone have front panel artwork for a dual-channel 1176 in one case? I'm still thinking about either having separate units or just putting two together, but the idea of having them in one rack unit appeals to me. I checked the meta threads, but didn't find anything that specifically addressed this issue.

BTW, if any of you have made a combined unit, feel free to jump in with photos and any problems/remedies it required.

Thanks,
--
Don

 

[yan_b]

ok i know i talk to myself here , but this is the conclusion

1. i'm a dumbass

2 i switched tl071 to tl072 by accident, that was the gr meter problem.

3. 2n5457 should be reversed to be pin compatible.

4. r66 was 82k instead of 182k that messed up the gr control amp, q14 base was getting 14v instead of 3.5v but it was hard to measure because th dc pulsated.

i still didn't finish all the test but it's seem's fine for now.

 

[orson whitfield]

Ok, I have very little output volume. Where do I start trouble shooting? The Q's?

 

[yan_b]

i would say take q1 out first, thats will take the fet and the side chain out of the equation.

 

[orson whitfield]

Even though I have little output wether in gain reduction, Vu or bypass mode?

 

[yan_b]

yes, and i found in really helps to use sockets for q1 and q10 for quick troubleshooting (ok other people sujested that but i did not believed them :sad: )

 

[orson whitfield]

I removed Q1 and the signal got much louder. I replaced it with another one but the volume died down again. Does this mean it's not the Q1 itself thats broken? What are the settings for testing voltages on the G1176? Bypass mode with the release and attack full CW? I'm having a devil of a time getting readings on my DMM's.

 

[yan_b]

http://www.groupdiy.com/index.php?topic=646&postdays=0&postorder=asc&start=210