Thanks Invalid, everyone else I mention this to just thinks it is crazy. After 24 or so years of running tube gear, the first tube "failure" I've had is those pair of 300B rectifiers; a shelf collapsed on to the power supply unit which has the tubes out in the open and both tubes got crushed.
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?
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If the equipment is already designed with solid state rectifiers then yes, there are HEXFREDs rated at 1200V with plenty of Amperage.
@sounds_real_audio This is really debatable (I’m doing it right now...). I’ve found that using properly snubbed semiconductors in the power supply sounds better and measures better than a tube rectifier. They have different design requirements of course (apparently not everyone understands how to snub them for example). If used correctly I find no tradeoffs. FWIW, one of the best tube amps from the vintage era was the HK Citation 2, which employed a solid state supply. It was a Voltage doubler style which was common with many American tube amps (ex.: Fisher). |
@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. |
@invalid This is an interesting assertion. If you were building a 60 Watt PP amp based on KT88s what rectifier would you use? |
- 35 posts total