@willywonka I don't know why tube equipment manufacturers don't use rectifier tubes such as the 3b22 or 3b28, I have had no problems with these rectifier tubes even if I leave them on 24/7 for months at a time, plus they can be used for high wattage power amps. These types of tubes also have very good regulation as they drop a constant 15 volts up to there operating limits, which are very high. I think the reason they are not used more often is the cost of the filament current that the transformer has to have.
Why tube rectification?
This question is directed at the distinguished members of the forum who design and build tube amps or those who have knowledge of tube amp design. All the tube amps I own/have built us two diodes for rectification. Diodes are cheap, compact and last the life of the amplifier in most cases. Examples include the Dynaco ST-35, the Decware Zenkit1 (which is basically a Decware SE84) and the Elekit TU-8900. All reasonably well respected amps. Yet many of the more expensive amps go with tube rectification, which obviously involves the downside of another tube, more power, more space.
These two competing solutions both supply the basic power to the audio tubes and output transformers, so only indirectly interact with the sound signal. I have not read anything that explains what tube rectification brings to the party. But it must have some upside to offset it's obvious downsides. If I changed over one of the above amps to tube from diode rectification what would I be likely to hear?
Showing 5 responses by invalid
@atmasphere there is no reason to have voltage sag at higher power with tube rectified equipment if the proper rectifier tubes are chosen. |
I like unconventional rectifier tubes, such as the 3b22, 866a, 3b28, also TV damper diodes work very well. The mainstream rectifier tubes don't even come close to the tubes I've mentioned, also these tubes can be used for a full bridge rectifier, and the mainstream rectifier tubes can't be because they all have a shared cathode. |
@larryi the 300b can work for lower power equipment like a phono stage. Power tubes can be used as rectifiers, I wouldn't use them for high powered tube amps, but they can make lower power equipment sound really good. |
@atmasphere most tube equipment manufacturers don't use the correct tube rectifiers for higher power amplifier, most of the mainstream full wave tube rectifiers drop too much voltage at higher power. |