ElectraPrint PVA (passive voltage amplifier)

franjy · « **on:** 24 Feb 2005, 03:38 am »

I presently am using a 1K, stereo, stepped, shunt attenuator from a 2 volt source (CD) to a 10k SS amp (which could be changed shortly to a tripath battery amp) and it works quite well. I'm interested in possibly trying a transformer from Electaprint but am unaware of the complexeties of installing them and their interaction in my system. Can I use my present stepped attenuator with the tranny? Will it indeed be an improvement? I really know less than nothing about them and would appreciate being enlightened. Is there a picture or sketch somewhere that would give me some idea how this thing looks installed?

[/b] http://www.electra-print.com/electraamp.html

mgalusha · « **Reply #1 on:** 24 Feb 2005, 04:23 am »

Your best bet would be to contact Jack Elliano at Electra Print. You could also order a back issue of AudioXpress from audioxpress.com that has his recent article on the PVA.

The example in the article used a 10K pot (I'm pretty sure) and was designed for a higher impedance load, perhaps 100K, like many tube amps. That said, I know that custom winds are avaiable and IMO you really should contact Jack to find out if he has anything that will work. A 10K Zin might be too low for this setup though.

mike

franjy · « **Reply #2 on:** 24 Feb 2005, 03:57 pm »

I did. Unfortunately the reply didn't answer my questions.

Frank,
The Passive Volume Amplifiers (PVA preamp) work best with sources that have low output impedance (100 to 300 ohms). Tube sources probably will not work. However most all current CD players have their outputs driven by an OpAmp -- these are perfect. Lift the hood and take a look inside your player. Other wise, go onto our web site and there are instructions on measuring the output impedance of your source. The PVA units will happily drive either tube or solid state amplifiers. I'm sure you will be pleased with the results in your system!
Regards,
Jack

I guess I'll write him again.

mgalusha · « **Reply #3 on:** 25 Feb 2005, 04:31 am »

I'll dig up the article and see what it says about impedance matching. I do remember him writing about low source impedance, which isn't a problem with most CD players.

franjy · « **Reply #4 on:** 25 Feb 2005, 06:51 am »

got back another message from jack more to the point.

Frank,
Transformers used in our PVA only work under a 10k constant load. Attenuators such as ladder or series provide this. Shunt attenuators change the impedance at each setting and will not be satisfactory these transformers.
Our transformers are inserted between the signal source and the volume control (10k). Is very simple to accomplish.
Regards,
Jack

Electra-Print Audio
4117 Roxanne Dr.
Las Vegas, NV 89108
Phone: 702-396-4909
Fax: 702-396-4910
Website: www.Electra-Print.com