Transformerless Vari Mu Compressor build thread

[Script]

Don't have that noise either.

I did though when trying to add too much stuff including 2x VU meters plus active rectifiers plus backlights, etc, all hanging on the +/-15VDC (only 150mA or 300mA?? forgot). Altogether too heavy a load, I guess.

So instead I added another supply hanging on the unit's power input. No noticeable noise.

 

[scott2000]

When I ran the 24v (A+) out to a breadboard to dial in the LED resistors for each color on the GR meters

I'd have to look over everything again but iirc, the 24v is for the tube heaters too?...

 

[JMan]

Don't have that noise either.

I did though when trying to add too much stuff including 2x VU meters plus active rectifiers plus backlights, etc, all hanging on the +/-15VDC (only 150mA or 300mA?? forgot). Altogether too heavy a load, I guess.

So instead I added another supply hanging on the unit's power input. No noticeable noise.

As a matter of fact, I have added some bells and whistles much like you. But I also made a separate supply, and I didn't have any load hooked up at all to either supply, *and* I got the noise whether I had the second supply hooked up to power input or was just testing the main PSU in isolation. My secondary supply board made no noise when tested on its own.

Interesting that you don't have any noise while Scott recognized this as a known issue. (Issue might not be the right word..."thing that happens?")

 

[Script]

Hmm, well, could be there's some noise when turning on, also takes a bit of time for LEDs to light up and be stable (like charging up phase). After that nothing that is annoying and not constant, I think.

When overloaded with 'bells and whistles', however, it was like a constant ringing or whistling or squeezing and very noticeable.

Just checked. Can't hear anything coming from the unit. But if so, my low-setting air-condition is louder...

 

[Script]

Actually, I can hear the transformer in an old DBX ringing (should fix that), despite aircon being on.

 

[scott2000]

Hmm, well, could be there's some noise when turning on, also takes a bit of time for LEDs to light up and be stable (like charging up phase). After that nothing that is annoying and not constant, I think.

I really have to focus to hear the couple seconds of startup noise since it's in the case but both my units have it.. Definitely zero noise after that though..
Mine are built exactly like the docs though so idk...
I see Heikki hasn't responded in the forum. Has anyone tried emailing him?
I just assumed it was some kind of noise with how the Recom unit fires up but who knows...
I do remember Heikki saying it was normal though... Of course I'm second guessing myself now..lol

 

[Script]

Yeah, 'boot up' noise like Scott described. Quiet after that. Fully loaded.

 

[JMan]

I have yet to hook up the load, so we'll see if that solves it. Probably won't get around to that until this weekend.

 

[JMan]

Hooked the PSU up to load, noise vanished entirely. I don't even get the few seconds of startup noise that Scott described now. Time to finish this extremely labor-intensive wiring (my bells and whistles effectively doubled the wiring tasks) and do testing and calibration. Will post some photos when it's done, just for kicks.

 

[JMan]

It's up and running. I tried my best to keep the wiring tidy but that was no mean feat in this build! Goodness!

Anyway, all voltages are within 1%, calibration was a breeze, and this thing sounds incredible. Thanks to all those who built this before me, your pioneering and expertise made it possible for me to get across the finish line. And of course thank you to Heikki, though I'll have to tell him over on his forum since I guess he isn't on here anymore. I've got the Dual Comp boards as well, and although I probably need a break from these circuits for awhile, I look forward to building that at some point.

 

[scott2000]

I've got the Dual Comp boards as well, and although I probably need a break from these circuits for awhile, I look forward to building that at some point.

Stunning build!
I'm itching to try the dual comp as well. I have the original version of the diode compressor and love it. The newer version diode compressor looks to be on another level and it's circuit, albeit limited heh, is in the dual comp. Must be a sweet combo.

Gawd that's a killer looking build...

 

[thelivingroom]

It's up and running. I tried my best to keep the wiring tidy but that was no mean feat in this build! Goodness!

Wow, it looks fantastic!

 

[Script]

Unit looks really great

Congrats on having the guts and patience to come up with your own layout for the faceplate. Wiring all that up alone must have taken hours...

I really like the vertical arrangement -- could imagine it makes one work differently. Love it !

 

[JMan]

Thanks for the kind words, you guys. Definitely a labor of love, this one, and well worth it. I probably spent two hours last night feeling like a kid on Christmas morning, running program material through it and playing with the knobs and switches.

 

[inf0]

@JMan Beautiful build ! The layout as well , is just gorgeous !

 

[C H]

I've been bingeing on this thread and have bought a quad of 6SK7GTs, and filling my Mouser basket for the rest.

Can anyone confirm that the BJT alternative to the sidechain transformer works ok?

cheers

 

[scott2000]

Can anyone confirm that the BJT alternative to the sidechain transformer works ok?

I missed this option. Can you link to it?

 

[thelivingroom]

I missed this option. Can you link to it?

It was in Post #104. I remembered coming across that last night, while rereading the entire thread to make sure I didn’t miss anything before my front panel arrives on Tuesday.

 

[scott2000]

It was in Post #104. I remembered coming across that last night, while rereading the entire thread to make sure I didn’t miss anything before my front panel arrives on Tuesday.

oh yes...Forgot about that...Thanks and happy wiring....

 

[thelivingroom]

oh yes...Forgot about that...Thanks and happy wiring....

Thanks! It should go fairly quickly, as I have everything installed and wired in the case with the wiring hanging out of the front like in Heikki’s assembly photos, and pre-wired the sidechain boards with tails, as well. Fingers crossed that I can wrap it up before next Friday, when company arrives for Mardi Gras haha.