Nothing wrong with that choice, IMO. Generally tube rectifier failures occur in power amplifiers with high current draws. The Dynaco ST70 is notorious for eating Chinese 5AR4s. In a preamp there usually isn't enough current being drawn to worry about a tube rectifier failing. But there are exceptions. The 6X5, used in a number of tube preamps, is not very robust and I've had at least one fail.
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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@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. |
I used a Lamm L2 line stage for a number of years--solid state audio path, separate tube rectified power supply. Gorgeous mids, a bit rolled off at the frequency extremes, but you could not say it sounded euphonic or analytical-- it sounded very much like music. That model has since been updated. I'm currently using the Veloce Lithio 2.0 with the updated batteries and some other changes. I do roll the rectifier in my Allnic H3000- have quite a few grails. My preference, which is based in part on how the overall system is voiced, is a GEC u-52 cup base. I have a Mullard metal base (really a Philips-Miniwatt). Bass is phenomenal, far better than the bakelite version that followed, but lacks the finesse and airiness of the GEC in my system. Some of this may be system dependent. |
In our opinion, done correctly, tube rectification sounds better in our designs to our ears. In repairing components, we find that not using tubes was a short cut and cost savings. Once done right, it can be glorious. All designers who use tube rectification in our opinion, again, does not make the sound that we achieve in our designs, Lamm included. Not to say they sound not as good, but you have to hear the differences when compared to each other. @whart - agree with your findings, but those units can be upgraded to achieve the sound you prefer. Happy Listening. |
if you end up taking tube rectification, you may find that rolling tubes offers a very clearly different character and weight of presentation. The manufacturer installed NOS AZ4 tube in my 4w +4w SET from Japan sounds fine, yet a contemporary production AZ4 mesh plate from EML gives much greater scale and dynamics, totally transforming performance of the amplifier, and EML seem to last notably longer than expected. Others have reported on this. YMMV. |
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