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Looking for 5AR4 rectifier tube most like solid state

I have the Cary SLP-05 preamp (with the Ultimate Upgrade), which sounds exceedingly good in most respects. Unfortunately, it's sorely lacking in rhythmic excitement (what various British companies call Pace, Rhythm and Timing, or PRaT).

I suspect that the 5AR4 tube rectifier is at least partially to blame. In general, tube rectifiers exhibit "sag". This helps some aspects of the performance, but is likely dulling transients that are needed to create faster dynamics (e.g. percussive envelopes).

Cary has told me that I cannot insert an equivalent solid-state rectifier, as it would require a power supply redesign. Instead, I'm hoping to find a 5AR4 tube that mostly closely behaves like a solid state rectifier. I don't want it to be warm, or smooth, or anything like that. This preamp already has an overabundance of those qualities. Instead, I want it to be fast, dynamic, rhythmic, and exciting, with a real sense of "boogie".

Any suggestions?

128x128boxsoft
blisshifi's avatar
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blisshifi
1,164 posts
 

EML 5U4G usually can be used in place of a 5AR4 and is very, very linear. You may want to look into that!

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atmasphere
11,740 posts
 

@boxsoft

That preamp should put nearly a constant load on that rectifier. So Voltage sag really isn't a concern unless the rectifier is shot.

If the power supply is properly designed (bypassed), the character of the rectifier will be very heard to discern!

If this is an older preamp it might simply be that some filter capacitors in the power supply have degraded.

The actual audio tubes in the signal path are far more important to how the preamp sounds!! What brands are in there right now?

 

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blisshifi
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I’m just re-reading and seeing this is about the SLP-05. I owned a similar unit with the ultimate upgrade and actually paired it with Ralph’s Atma-Sphere S-30 on a high efficiency system for a little while. Unfortunately, the preamp wasn’t a keeper for me due to the characteristics you describe. Regardless of the tubes and cables I put on the SLP-05, it felt slow and sluggish. It is colored is a very pleasing way, but I couldn’t live with what it did to the timing the way it over-colored the presentation. Best tubes I used with it to speed it up as much as possible were Sylvania VT-231 for all the 6SN7 and the EML 5U4G in rectifier position. 

danager's avatar
danager
923 posts
 

Different take but you should investigate the Space Tech Labs STR. (super tube rectifier). I’ve heard it and it’s the real deal. The HIFI cave and the Decware forum talk about it with both giving very positive results.

gs5556
1,229 posts
 

The sonic signature of your preamp is mostly the 6SN7 tubes. Voltage sag is not an issue (I think) because those tubes maybe draw 5mA each idle and maybe swing to 10mA on full signal. So the highest plate current is about 80mA for all 8 tubes which you do not hit unless playing full volume.

The 5AR4 drops the least amount of voltage for a given plate current than other standard issue rectifiers. At that plate current it's only about 5 volts, which should not really affect the linearity of the 6SN7 tubes. Rectifiers are more carefully chosen for power amplifiers, but in preamps I don't think will make much of a difference.

 

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