Don Sachs Linestage
- 12 posts total
- 12 posts total
Just a FWIW: there is no good argument for a tube rectifier in a home audio preamp. The reason is simple- the only real advantage of tube rectifiers is that they are lower noise than solid state, if the solid state rectifiers are not treated correctly. This noise might be heard as a buzz.
But that really is the only advantage. Otherwise tube rectifiers have a voltage drop, which varies with load (the more current, the more voltage drop). This makes them very desirable in a guitar amp intended to play the blues, due to the additional distortion introduced by the sagging power supplies. But in a preamp there's not that much current, and not really any reason to have a tube. If you use modern rectifiers like HEXFREDs or the like, you get less voltage drop and the power supply voltage stays more constant. Plus you can also handle larger filter capacitance values, as this is a further limitation of tube rectifiers.
ralph, by your explanation, then why are rectifiers used in some tubed power amps as well? the notion of the undesirable voltage drop would seem to be even more of a negative in higher power applications where distortion is not wanted...
i recall when dan wright (modwright) was starting out, he made quite a splash with a standalone 5ar4 rectified power supply for many of his cd player modifications (which in turn powered his 5687 triode output stages) - these were absolutely some of the loveliest sounding cd players ... so the tube rectification in your view is undesirable and unnecessary?
i thought there was something about the benefits of the tube rectifier being slow and smooth at turn on, and so there was less electrical ’shock’ to the downstream circuits at turn on...