dummy me-i have heard that ss or tube rectifier has no influence on the sound since its not part of the audio signal.
wrongum boyo?
s
The rectifier circuit is
not part of the audio signal path, but it
does have influence on the audio signal path circuit. The rectifier is the part of the power supply that converts the AC to DC (a vacuum tube, like a SS diode, will only pass current in one direction, but a dissertation on rectifiers is well beyond the scope of this thread). The difference is that the SS diode is way more efficient at passing this current and as such delivers a stronger current flow than a comparable vacuum tube,
particularly when the amp need a spike of juice, or when it's running at peak or close to peak output. This is also why the SS rectified 2000S is rated at 150 watts vs the tube rectified versions 120 watts.
Any current used to produce
heat is current
not getting to your audio circuit, and we all know how much heat a vacuum tube produces. The result is that the tube rectifier can/does starve the audio circuit for current under the before mentioned "high load" conditions causing a phenomenon generally called "sag" which affects the tone in a similar fashion as a rheostat or a variac would, by restricting DC to the gain stages, generally increasing harmonic distortion proportionate to overall volume, sometimes referred to as “browning” or “brown out” or “brown sound”.
Sag is generally not as pronounced as the intentional browning cause by a variac or power scaling, and it’s variable dependent on specific gain stage power demand at any given time, but it will
indeed effect the tone of an amp.
I personally prefer a SS rectifier. As a bass player, I normally prefer the additional headroom and more controlled distortion of a “well fed” power amp stage to the power demand induced sag of a tube rectifier in most situations. I do have both SS and tube rectified Sunns, but I generally use Weber Copper Caps in lieu of tubes in the tube rectified ones.
On the positive side of tube rectifiers, they do provide for a "soft start" (the rectifier tube slowly ramps up the power to the amp as the tube heats up, as opposed to the jolt to the cold circuit when the SS rectifier slams it with full power instantly at startup) and can arguably extend component life in the amp. Also, I sometimes like the sound of a amp sagging, for example; it seems to make it easier to make a clean tone get all snarly when you get aggressive with the strings, which I think can extend your "touch" dynamic range in quiet gig or studio settings.
