1176 gr problem

Hi,

I've been working on the g1176 as my first project, and have run into a problem I can't seem to sort out. My unit is working as a gain amp, as in signals go from the input to the output, and I can adjust the levels with the pots. However, I cannot get it to compress. The VU works great in monitoring the output, but when I try to zero the meter in GR mode, the needle will not go past -10, nowhere near 0.

My DC voltages all look fine, I had no problem with the Q-bias adjustment, and I have replaced the TL071 and Q10, thinking there was something wrong with the GR driver circuit.

I'm using OEP transformers in and out, and mnats board.

I've been working on this problem a good week now with no progress, so I'd really appreciate some assistance.

Thanks alot.

Warren

What kind of meter are you using?

I used a cheap Modutec meter from Mouser, and had the same problem with not getting it to get close to 0. I ended up finding some used VU's on eBay and they worked great. They also cost the same as those cheap Moductec ones.

The unit could be compressing, but it just isn't metering it correctly.

Hi,
I also bought my meter from ebay, it's a NOS Diyson VU, looks like an Ampex meter. The meter works exactly as expected in output monitoring, I can get it into the red by cranking the in/out pots. When I listen to the unit, even at extreme settings, it doesn't sound like it's compressing at all.

One thing to note, is I originally said my voltages look OK, but my -10 on the TL071 is about -9.6V, which to me looks close enough, but I just thought I'd mention it in case that isn't "close enough". All my other voltages are pretty much bang-on to what the Gyraf schem shows.

Warren

Is your wireing to the rotary switches corect? Check your resister values near the ratio switch.

I checked all my resistor values on the ratio board, and they are all correct.

Still puzzled...

Warren