Drip Electronics u73b Stereo Compressor

[Potato Cakes]

do you have a link for that? I could only find the 'public' manual without the schematics.

And you definitely don't need a varicom for stereo linking. The Manual of the original clearly describes that and I have done it with my original U73b.

If I could take a look at the schematic I could tell you how...

Michael

https://www.dripelectronics.com/u73b

Bottom of the page.

 

[Michael Tibes]

Ok, he didn't create his own schematic but used the original one, added his comments and took some 'unnecessary bits' away...

Pin 4a of the tuchels (one end of R111) needs to be tied together on both compressors for stereo linking.

Manfred's U73 reconstruction looks amazing and shows an incredible dedication! Thumbs up! Did you solve the release time issue? I got stuck there as well...

Michael

 

[hugo]

For release there is an errata « 220k between + and -«  meaning you have to put a 220k between the pole of release switch and the ground. Two poles of switch are together and they go to some free points that you can use . For ground there is a free point of gnd on the area

 

[jasavoy]

Hi, I'm hoping I can get a little help here- just completed my Drip dual u73b and got it fired up and got voltages to spec using this thread and help from Greg. (I have also built the Varicom but haven't gotten to the point of hooking it up yet). I ended up going with a 270 ohm resistor for R47 to get the 1.8V at the cathode and I used the V76 plate choke and the heavy duty PSU XFMR. The unit is working well but I can't get it to calibrate correctly using Drip's instructions. I know I'm supposed to be balancing the output between comp/limit modes but I don't quite understand how to do that and it's not working when I follow the instructions. Could someone please help me? Thanks!

 

[Sc]

Hi
Nice build ! Enclosed you find a short description of calibration taken from the original TAB doc's. In my case this worked well (with a modded input pad though) - not easy to find a generator with 22dB output. The good old HP tube generators do it . For setup just hook the generator to the input, and a decent AC - Meter to the out. Try and let me know, where your problems occur.
Cheers

 

[tomas.borgstrom]

I have also built the Varicom but haven't gotten to the point of hooking it up yet

How did you solve the part of the Varicom with 3 x E1008?

 

[Jase_Sanderson]

Hi, I'm hoping I can get a little help here- just completed my Drip dual u73b and got it fired up and got voltages to spec using this thread and help from Greg. (I have also built the Varicom but haven't gotten to the point of hooking it up yet). I ended up going with a 270 ohm resistor for R47 to get the 1.8V at the cathode and I used the V76 plate choke and the heavy duty PSU XFMR. The unit is working well but I can't get it to calibrate correctly using Drip's instructions. I know I'm supposed to be balancing the output between comp/limit modes but I don't quite understand how to do that and it's not working when I follow the instructions. Could someone please help me? Thanks!

Nice panel

 

[jasavoy]

Hi
Nice build ! Enclosed you find a short description of calibration taken from the original TAB doc's. In my case this worked well (with a modded input pad though) - not easy to find a generator with 22dB output. The good old HP tube generators do it . For setup just hook the generator to the input, and a decent AC - Meter to the out. Try and let me know, where your problems occur.
Cheers

Just seeing this, thanks! It's been sitting on a shelf in my shop pretty much since I posted this. I can't get the limit function to do anything either. But this is a big help- I'll try it out!

 

[jasavoy]

How did you solve the part of the Varicom with 3 x E1008?

Sorry just seeing this. What do you mean?

 

[Sc]

Just seeing this, thanks! It's been sitting on a shelf in my shop pretty much since I posted this. I can't get the limit function to do anything either. But this is a big help- I'll try it out!

Older thread but I still love the machine ... . If you have no function on limit - it might be the relay issue with the first PCB's (2018). U73b (drip) - 3 questions ?
The reason why you'd use the varicom is to keep the stereo-image on constant position - it will move with just double mono when you have strongly different signals.

How did you solve the part of the Varicom with 3 x E1008?

The original 3 X E1008 chain is probably just transient suppression - you can use any standard small signal diode 6X antiparallel.
Cheers