All things G1176 - the new "repost" thread.

[dirtyhanfri]

Edit: found the problem, related to the board traces.

 

[dirtyhanfri]

Hi

I'm struggling with a g1176, using REVH board by mnats.

The thing is, I have +29.1V and -9.5 as supply, and all transistor voltages are a bit off.

I'm using 1k2 resistor in R87 instead 1k1, maybe that's the problem?

 

[Nagskof]

Thanks to this forum, Mnats and Gyraf, built two Mnats Rev H in a 2U rack with push buttons, super proud  Both channels are identical and I double checked all components, connection etc. Both channels pass (awesome) audio, and compression is fine, however, the VU meter on the second channel jumps to different places in GR mode when I switch between ratios. 1:4 is at 0DBu reading, 1:8 drops 7 db, 1:12 drops further and 1:20 is full left. The meters are showing compression between ratio settings, but just at different places on the scale. I have no idea where to look, failed component maybe?

 

[Zebra_PD]

Been trying to find an answer for this question but haven't had any luck searching the forum.

The B11148 output transformer used in the original Rev F is has an extra winding then the B12614 used in the rev G/H right? but is this xtra winding needed for the G1176 design?

I know the current rev f offered my mnat is designed to incorporate the negative feedback design of the B11148 transformer but can't really figure out if the older mnat rev j board I'm using does to?

Im trying to get my build as close to the silverface I can and have couple of original b12614 I would like to use.

If anyone has the schematics for the G1176 rev 7 or the mnat rev j saved on there hard drive and perhaps could help me and/or perhaps share those I would be really greatful.

 

[gyraf]

VU meter on the second channel jumps to different places in GR mode when I switch between ratios. 1:4 is at 0DBu reading, 1:8 drops 7 db, 1:12 drops further and 1:20 is full left. The meters are showing compression between ratio settings, but just at different places on the scale.

Could be leaky FD333 diodes? Leaky (orientation?) 6u8 capacitor in that area? Wrong ratio-switch wireing?

Jakob E.

 

[hydroheinz]

hi ...i have build a g1176  unit .. and  was happy that i could calibrate it and it seemed to work.... but a ratio measurement  showed me that something must be wrong
i have rev D with lundahl output transformer

the ratios are not as they should be:



i hope someone can help me....

thank you ...Heinz

 

[gyraf]

Close enough, I think?

 

[hydroheinz]

Close enough, I think?

ok.. if you say that thank you for the fast answer..

 

[spdif]

Hello everyone!

So, I am building an 1176 compressor. It is not from Hairball. I downloaded the schematics and etching files from Mnats website. The version is RevH.

The build went smooth and it worked flawlessly for a few days. But recently 2, 3 days back I got a strange problem. The gain reduction according to the ratio buttons is not working. The JFET is "JUST" stable on the quicent bias. It doesn't vary at all. I guess I am having 20:1 ratio all the time. I have checked all the voltages on the transistors and they all look good. Replaced the FET too. The DC voltages on R74 and R75 are:

-1.3
-2.2
-3.5
-5.8

Please help!! Jakob told me to go through this forum because this problem might have been faced by someone here and must have been corrected to. I went through many pages (not all) but couldn't find anything related to my problem. I will really appreciate if someone comes up!

Thanx in advance.

spdif

 

[Maverick616]

Hi everyone, sorry for the necropost. A while back I started an 1176 build on stripboard and so far its been going great however because of limited budget and enclosure space, I'd like to avoid using an output transformer (for now). I've seen a few threads where people ask the same question however none have answered how to appropriately wire it up. I assume that I still connect X and Y to the GR circuit and don't need anymore components?  Thanks!

 

[Jonas05]

Hi!
I got some really strange distorion Problems with my 1176. They depend on the attack and release times. the quicker the release and the slower tha attack I get more distortion (in a really strange way).
Harder ratios lower distortion, outpot pot has no effect on the amaount of distiortion. DIstortion trim has effect on it and can make it even worse.

I did not built the unit by myself and it doesn't look really good. I already installed a star Ground but the power trafe might cause the Problem, low Quality wires… I don't know.
It's a Stereo unit and I have the same Problem on both channels. Has anybody a hint where to look?? Im Fighting with this unit for over 5 years…

Here are some Sound samples:

https://soundcloud.com/analogmixing/sets/1176-distortion-problem

 

[AmosMoses]

Got a problem with gyrafs 1176. I'm using his pcb layout.

I'm getting the signal through, but it is very compressed, and input and output pots are responsive but all they do is make it audible or not, but the is always over the top.

The meter is responsive, although I can't get GR to 0, but in GR and in VU the meter is responding to the sound. And it seems the attack and release are responsive (at least it looks like it).

Checking the voltages I have all the valteges ~correct, except in the are shown in red ( lower) and blue ( higher) any thoughts? The Q8 and Q9 BD139/38 i accounted the different pinouts and they are correct to my knowledge.

Any thoughts and or advice?

Best regards.

 

[e.oelberg]

Hi all !

I have a G1176 sitting on my bench. The unit somehow works nevertheless GR meter mode doesn't. Meter just stays  down.

any hints ? 

best Nicholas

 

[bernatvm]

Hi everyone. I finished my unit some time ago and, although it works, I've always had a problem of too much sensitivity and compression starting at low value for input pot. Today I measured the dynamic linearity transfer function and the results are.. strange. Can anyone take a look and tell me if their unit behaviour is similar?

From what I read, my compressor is doing 20:1 on all ratio positions, only with different threshold?
For all mesurements neither input or output where ajusted, ration knob was the only change.

 

[bernatvm]

After further looking, I noticed Q15 voltages are bad, E being greater than B by 0.2V or so.

Bad q15?

 

[Meto]

Hi,

I have a G1176 pusherman board. The sound have no bass it's like an hi-pass at 500hz. I also have really weird things with the vu meter, I have random response and sometimes the needle go hardly to the left. (In all positions 4-8-12-20)
I've checked over my wiring many times, as well as the values of all the components, and I can't find anything wrong.
The sound is flat after the output pot so I've check in the line amp section and sound is flat again (behind C15 all is ok).
At the input of the LL5402 it's a good flat sound (pin 1) but at the output it's hi-pass (pin6)

I'm thinking things happening with transformer output and Gr meter driver amp...
Can somebody help me please ?

Thanks,
Tom

 

[1wildthing]

Hi guys, I've decided to try to build an 1176 clone using the Gyraf's board. I'm collecting parts at the moment and I can't make a decision about the psu. I've seen many post on this forum talking about transformers but many suggested options are not available anymore.
I'm based in EU so 230VAC is concerned. Has someone recently built this baby and is willing to give me some advice about a suitable transformer? As I'm a noob I'm scared about making the wrong decision and then burn the house down  ;D

 

[hydroheinz]

Hey...

i have build a G1176 Unit and it seem to work ..i can hear the Compression and also the Changes when i move the Attack/ Release  and the Ratio Knob.

but when i do a Ratio measurement i am getting a Problem

i put a 1khz Sine Wave with (3du ) 1,094V on the Input and get 0,3V on the Output..
but as longer the unit is on, then higher the Voltages go..
till i got the Input Voltage also at the output and have no more Gain Reduction... especially at 4:1

what could be the Problem?

i have no GR Meter installed now but this should not so important ...or?

this is the last Thing in my Box of Shame  ..if i get this Unit working  i am a free Man...( in my Mind)

cheers Heinz

 

[thewotan]

Hi!

Quick question....

I'm about to dive myself into building a G1176, but I can't find the correct resistor wattage for most of the resistors... Original Gyraf's schematic says "All resistors values are in Ohms 1/2 W 5%". But in Mnats BOM (and in some posts around here), the wattage is 1/4W...

Could I live with 1/4 W resistors? I have a lot of different values lying around (1/4w), and it would be nice if I can use those (of course, I'm not talking about specific resistors which are rated at higher wattage).

Thanks!

 

[gyraf]

1/4w are fine. Except the 1K1 1W resistor at the psu..