TG-1 clone meters not tracking

[schrobbelbop]

I've build the DIY-racked DR-Zen2.

I've got the Sifam AL20-6-7 meters, but they don't track the compression right.
IF my needle is moving just a tiny bit i'm already in 6-12 db range of compression.
any ideas to look after for? the diy-racked tech, tells me there is nog cure and
it's part of the design but there must be something wrong!

attached the schematic

 

[Rob Flinn]

The meters you have don't have the right scales on them.  They should look like the ones in the attched pic.

 

[schrobbelbop]

The meters you have don't have the right scales on them.  They should look like the ones in the attched pic.

Ah i get it, the current TG1 versions must have an active meter circuit to drive those meters.
Weird that they spec those expensive meters for that build that won't ever work!

 

[Rob Flinn]

They are the same meters just with different scales.    When IJR made the original batch of TG boards someone got a bunch of replacement scales made as a group buy.  The Chandler is a modified version of the original TG & for some reasons they use regular VU scales.

 

[schrobbelbop]

They are the same meters just with different scales.    When IJR made the original batch of TG boards someone got a bunch of replacement scales made as a group buy.  The Chandler is a modified version of the original TG & for some reasons they use regular VU scales.

But then the needle should readout around that scale ? It doesn’t it starts a bit below zero an rises to max
4db on this scale. It should hang around in the center according to the scale you’ve posted ?

 

[Rob Flinn]

On a TG that is built to original spec the needle rises when you set the threshold, & the compression is displayed superimposed ontop of it's static position.

 

[schrobbelbop]

MAybe I could do a little mod and take cv voltage to a little meter driver circuit to drive the sifam Al20 meters? Such a shame of those meter not working correctly!

 

[axl85]

Hi Guys, hope this thread is still on...?
I'm building the Dr Zen2 at the moment. One channel is working already. The other channel does a loud thumb at transients when I set the fastest attack time. I've checked the usual suspects like cold soldering joints, diodes orientation, resistors...
So far I didn't find a mistake... Does anyone have a idea what could cause the problem?
Thanks a lot!!!

 

[schrobbelbop]

Hi Guys, hope this thread is still on...?
I'm building the Dr Zen2 at the moment. One channel is working already. The other channel does a loud thumb at transients when I set the fastest attack time. I've checked the usual suspects like cold soldering joints, diodes orientation, resistors...
So far I didn't find a mistake... Does anyone have a idea what could cause the problem?
Thanks a lot!!!

Did you try to swap the diode bridge between the channels ? Could be a diode mismatch. It’s also easy to swap all control boards and transformers if you used molex connectors.

 

[axl85]

Did you try to swap the diode bridge between the channels ? Could be a diode mismatch. It’s also easy to swap all control boards and transformers if you used molex connectors.

Thanks schrobbelbob! I just ordered a bunch of diodes and going to match them. Maybe that’s the problem. The control board work fine at the other working channel.