Silver Rock TVC
Passive Transformer Volume Control
Transformer with 24 logarithmically set up secondary windings
+6 dB gain version available as an option
3 switchable inputs
Silver wire coils
Very exotic magnetics
Very special winding techniques ...
... to achieve optimal filling characteristics and low losses
Very special assembling techniques
Distortion: Almost unmeasurable at all frequencies
The use of resistive elements for volume control leads to major sound deterioration !
First we would like to explain our general philosophy :
There always is one optimum for a given problem. It costs tremendous amounts of time to find it, but this is the only way to make real progress. If you want a cheap solution for your potentiometer in your sound system, then use carbon pots.They are more neutral than the expensive plastic ones and of course much cheaper.
If however you want the best possible solution to your potentiometer problem, then you should try our silver wired transformer - potentiometer that really is a world apart from other volume setting devices.
Some years ago, when we still were believing that we can achieve good sound with conventional potentiometers, we made a 100 Kohms 24 position stepped potentiometer using Tantalum resistors. This was a lot of work and we were proud of it.
We wanted to see how much better it was comparing it to a surplus graphite type pot. Even if it was very difficult to admit, the graphite type was better sounding and we decided that we need some fundamental research to be performed.
The first trials with transformer based systems were rather successful and we went on into that direction ending up with custom made iron as well as custom made silver wire.
This potentiometer clearly shows that it is useless to expect resistive systems to perform without major sound deterioration.
One should keep in mind, that a conventional 100 KOhms potentiometer, when set at medium position, places a 50 kOhms resistor in series with the signal.
With a 300pF cable or input capacitance, this situation leads to an attenuation of - 3 dB at 11 Khz.
The lower you go with the volume setting, the narrower the bandwidth becomes right in the audio band !
One finally understands why at low levels our audio systems sound so bad.
With a transformer - potentiometer you have the opposite situation. The lower you go with the volume, the lower the output impedance of you system becomes and the wider the bandwidth.
Besides bandwidth problems, we have noticed that putting resistors in series with the sound signal always results in dynamic constriction and loss of details.
On top of that, a transformer enables the discontinuity of grounds, which helps to keep RF and LF noise as low as possible.