Tube questions, step up/down

[Doug Tymofichuk]

On Tue, 21 Dec 1999 18:08:44 -0600 Bill Layer 
<blayer at uswest.net> wrote:

> Hi Doug,
> 
> Why not use transformers for step up/down use? Obviously 
> the xfmr would  be pretty useless at LFO frequencies, but 
> at 20Hz up, an audio-quality part should work fine. Take 
> the 150V tube sigs down to 15v, and the 0-15v up to 150.. 
> Has the added benefit of excellent DC isolation for the 
> circuits, and introduces the prospect of using the 
> differential output of the transformer to drive a balanced 
> line to the next module, or to the mixer/recorder... 
> excellent for keeping s/n high at this point in the sound 
> creation process..

Well... I don't have any suitable transformers on hand, but 
I do have resistors for voltage dividers and building an 
extra tube gain stage is pretty minor for me. But I was 
experimenting last night with Eric's VCA circuit and I am 
finding that with both the VCA and the VCO I can get good 
results with 0 - 15 volts to the inputs and dividing the 
outputs down 10-1 with a couple of resistors. So I think I 
will design the complete system for 0 - 15 volt signal 
levels.
----------------------
Doug Tymofichuk
dougt at cancerboard.ab.ca