Passive preamp vs TVCs - please can you clarify ?

[wackyraces]

Now I am completely non-technical when it comes to electronic engineering but may I clarify the following when it comes to using the simplicity of an NVA passive pre compared to the apparent superiority of a passive TVC ....?

The below was extracted from the net... Thanks.

Why use a TVC versus high quality potentiometer.

Most people find that the TVC sounds significantly better than even the best potentiometer or stepped attenuator.

And it's not a subtle difference; most people report that the TVC has such an open, deep and low bass, effortless sound that they would not consider going back to a resistive device.

Exactly why they sound better is because one impedance issues mention above and the fact that the TVC doesn't attenuate by wasting energy.

The TVC is like the gear box in the car. If you need to drive at a slow steady speed which method would you choose:

(1) leave the transmission in high gear and apply the brakes to keep from going too fast, (which how a resistive device works)

(2) downshift into a lower gear that will allow the car to go the desired speed with minimum effort (which how the TVC works)

THE TVC is essentially an electronic gearbox that operates without wasting significant energy. Potentiometers and stepped attenuators adjust the signal level by literally turning the excess signal into heat. On the other hand, when A TVC is adjusted for low volume level it actually makes things easier for the source, much like a low gear makes things easy for your car engine.

[Fretless]

What the @#?&! is a TVC?

[setting son]

Transformer volume control

Whats the source of that text?

[Fretless]

https://www.tortugaaudio.com/whats-wron ... e-control/

According to this, LDRs are better than TVCs.

[Dr Bunsen Honeydew]

Its bullshit, it is not superior to a good quality SA. Search in the archive it is explained. A transformer is a coil - a coil adds distortion - a coil can only be designed to be correct (flat) at one frequency - taps make that unpredictable and it get worst at frequency extremes - a transformers quality depends on quality of iron core and quality of wire, so best (silver) wire are EXTREMELY expensive - but believe who ever you want.

A quality SA has none of these faults. They just get better with better resistors and to a degree switch, top quality of both gets expensive.

[Dr Bunsen Honeydew]

https://www.tortugaaudio.com/whats-wron ... e-control/

According to this, LDRs are better than TVCs.

Even bigger bullshit, noisy, unreliable (drifting with time) and ILLEGAL in the UK due to Cadmium content of the LDR component.

[Fretless]

I'll stick with the stepped attenuator.

[wackyraces]

Sorry to ask yet another question...

do stepped attenuators tend to sound flatter the more you lower the volume because of the issue mentioned below ...?

output impedance changes as volume is changed.. as volume is lowered, that output impedance gets even higher. As volume is lowered, there is a point where the extremely high output impedance will affect linearity of the frequency response.​

[Dr Bunsen Honeydew]

Depends on the power amp. With NVA amps and most others NO. It depends on the input load in the power amp for the pre-amp, and cable capacitance as well which with a passive is important to keep low.. Valves always love passives (all), some transistor amps like Naim do not.

It is all marketing bullshit per usual, why do you want to read these eeediots, just borrow, loan, buy and return, use your ears with your music in your system. Why do you think these people know more than you do, they don't they just want your money. this thread is getting like Wigwam thread, there is only one answer to anything, you, your music, your room, your system, your available funds.

[southall-1998]

Used to have a Promitheus TVC years ago. The sound was 'OK' but nothing really special.

S.