PRR Vari-Mu help thread

[slowbass]

Hello,
Is it ok to use 14VA toroids transformers for this project (2 channels) or is it too low ?
Thanks !

 

[SIXTYNINER]

8)

 

[buschfsu]

what up with the  in all the varimu threads.  do you have a question?

 

[slowbass]

I answer my own question (two posts above) : Yes, it's ok with 14VA. I could have calculate it, also...

I've built one vari-mu with Edcor WSM 600:600 and Monacor LTR110 transformers.
To my years, puting Edcor in and out "eats" a lot of highs, whereas having LTR110 at input distorts quite easily. So I ended up with Edcor inputs and LTR110 outputs...

I had 100 µA meters (instead of 100 mA) so I'm not sure how to use them... I replaced the 22R resistor with 22K ! Well, I don't know what I'm really measuring now but it's moving

 

[phishman13]

Just and FYI

AllElectronics.com now has the Radio Shack branded ground loop isolators for $6! (includes bonus adaptors!)

http://www.allelectronics.com/make-a-store/item/GL-15/AUDIO-GROUND-LOOP-ISOLATOR/1.html

 

[bernatvm]

Just finished my compressor and, though it passes audio and compresses it, i have a band pass filter problem. My transformers are car isolators ones, with center tap. I tried feeding the sidechain in the center tap and I get the same result as I would with the 3k3 r4 and r33 resistors. I attach a schreenshot of the frequency response. Note pink is the compressor (Left channel) and blue is the transformer alone using aligator clips from my interface and back to it.

I imagine there's some kind of impedance problem with my transformers but i don't know where to start looking. Thanks!


EDIT: question moved here https://groupdiy.com/index.php?topic=111.140

 

[bernatvm]

I don't have the pot rn. I'm using fixed resistors for testing: 4k7 for attack and 470k for release.

 

[Blue Jinn]

Quick question, trying to do this with parts on hand including 6ES8 tubes and a different PSU, including a different spec transformer that can't do 12v heaters. I have dinesh' boards. I've already installed the 1:1 isolation transformers (an eBay buy years ago, but guy said they are audio isolation not modem transformers.) The "Bluebird Mod" uses the 6ES8 but also uses I think a 4:1 on the output. Is there a particular reason I can't use the 1:1 and ?lower the gain? on the 5532?

This saves me about $US60 on parts -a pair of 12AU7s and the dual primary transformer.