All things G1176 - the new "repost" thread.

[shmuu102]

Im having a problem with my 1176 that maybe someone could help with..

the release knob acts like a second output volume knob.... even in bypass.


i have replaced both fairchild diodes.. checked all the wires, pcb.. voltages on the transistors seems "close" to what everyone else is getting. nothing so far has seemed to help... anyone got any suggestions are where i should look next ( what parts i should start "hanging")?

 

[deanp920]

the release knob acts like a second output volume knob.... even in bypass.

It sounds like the release pot is changing your Qbias voltage. Measure DCV between the release pot wiper and ground while turning the release control to see what the voltage does. It should stay around -2Vdc, varying only a tiny bit.

I suspect that you have a component or wiring error surrounding and or including the release pot. Look at the schematic when checking.

Dean

 

[Apache5]

Thanks Dean! I do like you said and I calibrate it :grin: its a little complicated, yes.... I found that its more easy (to me) starting with zero meter pot CW and track CCW. I adjust the point of 6db reduction with zero trimer and next the 0vu with the track trimer... doing that operation iteratively I reach the correct adjust.... Now I must look at ratio switch, I have problems with it (like it is reverse), Im in it

Thanks!!

Arnau

 

[Apache5]

Hi to all. My unit seems to work correct, not much hum, but im not sure of what is a low hum and what isnt tolerable...
I rotate the ratio switch and I cant see more ore less compressión (looking GR in meter). How can I be sure that the ratio compressíon switch is working correct? I thinked that I saw a double gain reduction if I pass from 1:4 to 1:8... but I cant see that diference... it maintains the same ratio, well... it changes for a moment but then it returns in the same reduction than before (seems to be a cap charge... i dont know).
How you block the last two positions of ratio switch? or simply dont rotate it more than the 4 first positions?
Thanks!

Arnau

 

[gyraf]

Arnau,

You "program" the lorlin switches by lifting and rotating the stopper pin that is located under the mounting nut.

The ratio switch also changes the threshold, so you will have approx. the same GR at different ratios. Your unit seems to act normal.

We've covered this either earlier in this thread, or in another thread. Be sure to read through it all:

http://www.groupdiy.com/index.php?topic=155

Jakob E.

 

[Apache5]

:grin: I suspected something like these on the ratio function but I must to be sure... thanks Jacob. About Lorlin programation... yes, sorry, these that you say sounds me... I must read more acurately. Thanks again :wink:
I must take pics and post it because now I think that is finished... and its my first DIY project (and not the last, im sure).

Arnau

 

[kdawg]

Would a linear pot on the input gain cause it to:

A. have less gain than a log pot at a lower number (Counter clockwise)

or

B. have more gain than a log pot at a lower number

I'm asking because I'm thinking I may have a linear pot in there by accident, and I want to know if I replaced it with a log pot if I would be able to turn up the input more before the threshold would be reached.

Thanks

-kdawg

 

[al_p]

hi

i'm putting 2 G1176s in one box. [8" deep] with my meters, i'd have to either mount them atop one another, or side by side lengthwise, which would bring the output tranny of channel 2 less than an inch and a half away from the toroid. the other config i was thinking about was mounting the power transformer on the back leaving plenty of room to tweak the positions of the mainboards.

i know dean has had good luck with the stacked boards, but i'd like to have easy access to all the cal points. so what do you guys think? will i be OK that close to the toroid? or should i go for a rear mounted power tranny. if so would a non-toroidal [lets say a hammond 167J50 cause i have one here...] work fine?

thanks

 

[orson whitfield]

My Vu meter is hovering. (Sifam AL-29) The unit is working though. It compresses very nicely. Sometimes, it hovers dramatically as if there was a ghost singing into the mic at a loud volume. It hovers back and forth not just down. This happens only when it's in GR mode. All the other pots can be at any setting and it still occurs as long as the GR mode is selected. Even with the volume pots fully CCW it happens. When I am singing and it start going crazy my voice sounds perfect. It's as though the meter is not reflecting fully whats going on in reality. If it hovers while I am singing into the mic, it registers the compression but still dances around while doing so.
Sometimes this behavior stops for a while. I can't find a pattern to it. If I had to though, I would assume this happens only after the unit has been on for a while. I should really test this out to see if it happens consistently after a certain amount of time but I haven't gotten around to doing this yet.
What is causing this behavior?

 

[Gustav]

Making only one panel at a time now of the G1176, and almost out again. Anyone up for doing the working cut in the gerber ?

Gustav

 

[gyraf]

Gustav,

I'm working on it. I'll get it ready in a week or so, I hope.

Jakob E.

 

[deanp920]

Orson,

My Vu meter is hovering. (Sifam AL-29) The unit is working though. It compresses very nicely. Sometimes, it hovers dramatically as if there was a ghost singing into the mic at a loud volume. It hovers back and forth not just down. This happens only when it's in GR mode. All the other pots can be at any setting and it still occurs as long as the GR mode is selected. Even with the volume pots fully CCW it happens. When I am singing and it start going crazy my voice sounds perfect. It's as though the meter is not reflecting fully whats going on in reality. If it hovers while I am singing into the mic, it registers the compression but still dances around while doing so.
Sometimes this behavior stops for a while. I can't find a pattern to it. If I had to though, I would assume this happens only after the unit has been on for a while. I should really test this out to see if it happens consistently after a certain amount of time but I haven't gotten around to doing this yet.
What is causing this behavior?

Is this something that has come up recently? I had a similar problem at different times on both of my channels. I noticed that touching the diode in the GR Meter Amp(CR11) with a little pressure caused the needle to fall down and jump back up even more. Replacing the diode fixed the problem. I think I may have fractured the diode by jerking it down onto the PCB, or I overheated it while soldering. Now it floats off the board 1/8" or so.

You might replace the TL071 as well just to rule it out.

Dean

 

[gyraf]

Also dirt/moisture around the meter FET can cause the meter to behave strange. Try cleaning the area around it with a bit of isopropyl alcohol..

kdawg,

A linear pot will be 50% down (-6dB) at centre position. A log pot will be 80% (-12dB) down at centre

Jakob E.

 

[thedug]

Hey,

I remember that the thread over at Tech Talk had some instructions on Grounding & Transformer Mods.

Does anyone have those?

If they are somewhere in this thread, just let me know.

d./

 

[gyraf]

Dug,

See the "meta" for the 1176 project, found in the sticky "meta-meta" on the top of the first page in this forum:

http://www.groupdiy.com/index.php?topic=1277

Jakob E.

 

[keithcamilleri]

Hi Guys,

Can anyone help me on the toroid transformer I found this one from jaycar but I don't know if it wokrs on the G1176... the product number is MT2114.

The pots are another problem it seems that I cannot find audio taper can anyone help me out on these as well....


Regards

 

[keithcamilleri]

If anyone is looking for the BD517 & BD518 ....you can find these here

http://www.fibra-brandt.com

they have them in stock about 2.70 euros. each...

 

[romeojesus]

hmm!

finally my sifam vu meter arrived from meterdistributor.com

it came with the wrong bezel

plus the meter seems to be broken....

i have voltage across m+ and m- on the
1176 meter pcb, but the meter does
not react in any way...

somebody have a hint??

thanks

christian

 

[Rob Flinn]

i have voltage across m+ and m- on the
1176 meter pcb, but the meter does
not react in any way...

That is correct because the meter has a bridge rectifier in it so that it will react in only one direction to an AC signal, which is what you are feeding it. If you have the facility to hook it up to an audio output (maybe a CD player in series with a 3K6 resistor you should find that it works !

 

[romeojesus]

ok...try to help me out here ,please..

i have a voltage on m+/m-
value depends on unit bypassed (0)
or in gain reduction mode and adjustments of
gr pot and tracking pots on pcb...

so on this side everything seems to be ok...

but there is no vu movement no matter
what m+/m- polarity


??