[vortrex]

I am going to experiment and see if I can drive my ST's with my phono pre direct to my new amp (no active pre-amp).  I will be adding volume control to my phono pre.  the question is, will I have enough gain to drive my ST's to moderate levels?  the tube amp is 55w with 25dB of gain nominal into 8 ohm.  output impedance of the phono pre is 200 ohm and the input impedance of the amp is 215k ohm.

[avahifi]

You will also need to know the gain of your phono preamp and the output level of your phono cartridge to make any useful calculations.  Also keep in mind that the recorded level of records varies widely from sample to sample.

It would also be useful to know what kind of a load your phono section output expects.  The capacitance of your interconnect cables, volume control, and amplifier intput added up may very well affect the accuracy of RIAA circuits in your phono preamp, depending upon how they are executed.

Of course the easy way is to just try it.  It might work just fine as you hope for.

Best regards,

Frank Van Alstine

[vortrex]

the cart is 2.4mV and the phono pre is selectable for either 38dB or 44dB (I use it at 38dB now with my integrated amp).  it looks like my phono cable is 67pF signal pair and 130pF ground. 

for the volume control it says...

"The output impedance is low enough to drive a volume control directly, thereby facilitating phono-only systems without the need for a line stage preamp. The Volume Control is a shunt device that puts two fixed, low value Audio Note resistors in the signal path, preserving the balanced/unbalanced output versatility. The variable shunt element is custom constructed from a 23 position Seiden switch and discrete surface mount audio-grade metal film resistors. Only one resistor is present as a shunt element at each volume control setting in each channel."

[charmerci]

Many, many moons ago, Frank (above) said that he had never had a "in-field" failure of any of his power amps. I also had one of his own modified CD players that had a volume control. I fed the CD player directly into his (at the time) top-of-line amps. It worked for a while.

Then - something went wrong. So, I was the first. As Frank has said before, just remember you may be dumping in unknown distortions and signals that your power amp may not be able to handle - possibly passing it through to your speakers. Be careful.