Drip Electronics u73b Stereo Compressor

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echoplex

Well-known member
Joined
Jun 29, 2011
Messages
195
Location
Germany
Hey Folks,

I am highly interested in building a Drip u73b compressor.
I can't seem however find a lot of info on this one around here.
Has anyone build one yet and can shad some light into the dark?
I am especially interested in how this unit actually sounds.
Looking for a bus-tube-compressor which is fast and has some magic in it.
Some audio samples of course would be cherries on top of the cake.

thank you
 
Thanks Weiss for the link.
I have seen this video and found it to be not very felicitous or revealing.
That’s why I opened this thread :)
 
I had one of these sets of PCBs then sold it before I even started ordering parts. I intended on this being a stereo mastering compressor with a single set of control knobs as the build example on the Drip website shows. The problem is to do stereo linking, you need a Varicom circuit, which wasn't included with the set at the time and as far as I know Gregory is still trying to sort one out. I had waited several months but I figured he was swamped with other work and that this was put on the back burner. You can still build two mono channels however would need additional control and PSU PCBs. The main board itself is scored to be separated for just that.

Thanks!

Paul
 
Potato Cakes said:
I had one of these sets of PCBs then sold it before I even started ordering parts. I intended on this being a stereo mastering compressor with a single set of control knobs as the build example on the Drip website shows. The problem is to do stereo linking, you need a Varicom circuit, which wasn't included with the set at the time and as far as I know Gregory is still trying to sort one out. I had waited several months but I figured he was swamped with other work and that this was put on the back burner. You can still build two mono channels however would need additional control and PSU PCBs. The main board itself is scored to be separated for just that.

Thanks!

Paul

AFAIK you don´t need a Varicom for stereo operation. At last not according the german U73 manual. The Varicom is used for program adaptive time constants in both channels which results in a different compression behaviour.
 
jensenmann said:
AFAIK you don´t need a Varicom for stereo operation. At last not according the german U73 manual. The Varicom is used for program adaptive time constants in both channels which results in a different compression behaviour.

During my conversations with Gregory, I was told that it is what was needed for stereo operation, at least for his boards. I had read through the manual several times and there was no mention of how things stereo linked other than the mysterious Varicom connection. On the the board itself there was nothing labeled as "Stereo Link," so if there was another way for stereo link to work with these PCBs I must have missed it. I also read where several owners of original models had Oliver Archut build them a Varicom circuit when he modded their unit for stereo operation. At any rate, the last communication I had with Drip was through his assistant Amanda who said he was working on getting a stereo unit up and running and then would pass along the information. This was months ago and I have since decided that it was probably best to move on and finish up other pending projects. I have checked back on their site several times (including today) to see if there were any updates and as far as I can tell a stereo unit still has not been successfully built by him. If it has I have not seen it posted anywhere on the Drip site or social media. The schematic and manual for his U73b is readily available for anyone who wants to look over it and see if they can figure out how the stereo operation could be implemented. I'm just not that smart.

Thanks!

Paul
 
jensenmann said:
The original U73/83 manual clearly states that stereo coupling is done by tieing both CV outputs together.

I have no doubt that it does. Of the very few examples that I have found they have used some sort of Varicom circuit to link them. I would love to know how to achieve stereo operation with this CV method and how it would be done using the schematic as a reference and learn something new, which is why I keep hanging around this wonderful forum.

Thanks!

Paul
 
Took an interest in this beast last week after drooling over DaveP's work of art, and sent Drip an inquiry. 
They replied saying that they have a varicom add-on pcb available, sold seperately.
 
boji said:
Took an interest in this beast last week after drooling over DaveP's work of art, and sent Drip an inquiry. 
They replied saying that they have a varicom add-on pcb available, sold seperately.

Interesting. Good know they have this sorted out. They never did get back to me regarding completing this circuit. I make have held on to my boards if that was the case. Oh well.

Thanks!

Paul
 
I have a pair of original U73b modules here and have been lusting for a Varicom for ages.
I'd be all over a functioning DIY kit, but the communication with drip so far has been a majour letdown.
No replies to questions whatsoever.

Has anyone here already successfully built such a Varicom à la Drip?

Thx

 
I won't get around to building mine until spring, however I must have caught them on a good week, as correspondence and delivery was quick.

Edit: Only info (and purchasing link) for the varicom is on their main page, not within the u73 subpages.
Build / cal docs for it must still be a work in progress.


Also stumbled on this page...so humbling!
https://www.manfreddeppe.de/menu/aktuell-diy/
 
I'm not affiliated with Manfred in any way but have had some chats with him.
Nice person!

His U73b is more a one-off if I'm not mistaken.
But has reverse engineered the Haufe T188 and there's supply me thinks.
Contact him via his website if you need to know more..
 
This threat might be dead already, but since I came upon it only recently, let me join in. I will continue building my U73b stereoset with Varicom(Z) in the near future. Combination of both has to be praxis-proven first, because the original manuals are explicit about the resistors to be changed when engaging the Varicom, but what about the release time switch of the U73b ?
My project is a one-off, yes, but I still have 2 sets of plates (the brass and the GFK) in stock and I will only need one.
Best
Manfred.
 
Potato Cakes said:
The schematic and manual for his U73b is readily available for anyone who wants to look over it and see if they can figure out how the stereo operation could be implemented. I'm just not that smart.

Thanks!

Paul
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
 

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