845-Amp-IT-Coupled

[Magz]

In my 833C amps I use (7) 1000uF 450V Panasonic T-HA caps in series, with 47K equalizing resistors in parallel with each. This runs at 2300V B+ as the last cap in an LCLC arrangement.

So far, so good after 7 months of use.

 

[MFF]

After a few months listening my 845 amp,
I want to upgrade the drive stage by replacing the 100K Pot by a TVC.
The drive stage is one D3a at 18mA with IT LL1692a ALT S.
Any suggestions on which TVC should I use
Once again thank you all for your precious help!

 

[45]

After a few months listening my 845 amp,
I want to upgrade the drive stage by replacing the 100K Pot by a TVC.
The drive stage is one D3a at 18mA with IT LL1692a ALT S.
Any suggestions on which TVC should I use
Once again thank you all for your precious help!

I would look at a Sowter:

SOWTER ATTENUATOR TRANSFORMERS TVC VOLUME CONTROL

You have many options, including the 9395 with 6/12 dB gain which is what you were looking for sometime ago, I think. In this case you trade some frequency response for stepping-up however the FR is still very good (10Hz and 50 KHz at -3 dB).
It's high quality mu-metal core with very low intrinsic distortion (typically 0.005% or lower over the full audio range at 1 V rms output).

Only thing you have to be sure is: you get negligible DC offset from the source as this TVC won't tolerate DC (as will be the case for most of them, I guess).

 

[kevinkr]

Dave Slagle makes some very nice TVC as well. (intact audio)

 

[Magz]

Dave Slagle makes some very nice TVC as well. (intact audio)

I just put his silver wired AVCs (Bent Audio modules) into my 26 preamp, replacing the copper versions I use as a parafeed OPT/volume control. Sound is a lttle more transparent and detailed with the silvers, with more HF info (but not too bright). Not cheap, but if you're going for the last few %...

 

[MFF]

I would look at a Sowter:

SOWTER ATTENUATOR TRANSFORMERS TVC VOLUME CONTROL

You have many options, including the 9395 with 6/12 dB gain which is what you were looking for sometime ago, I think. In this case you trade some frequency response for stepping-up however the FR is still very good (10Hz and 50 KHz at -3 dB).
It's high quality mu-metal core with very low intrinsic distortion (typically 0.005% or lower over the full audio range at 1 V rms output).

Only thing you have to be sure is: you get negligible DC offset from the source as this TVC won't tolerate DC (as will be the case for most of them, I guess).

I was looking for documentation to see how I should do the connection of the TVC,
just found this application not in the attach.
Should I keep the 100K resistance connected to the grid as shown in Sowter appn.