[Niteshade]

I like tube rectification as well as solid state rectification. There is a place for both and times when NOT to use tube rectification.

Having a tube rectifier means there is one more user-serviceable part in your amp or preamp. For technical reasons, that is an enormous boon. Less or no time in the repair shop is always beneficial! Solid state rectifiers rarely go bad. In fact, I have not had one go bad yet in anything I have made. I did have a pair go bad in a computer monitor. Easy fix!

What about the sonic impact of tube rectification within tube amps and preamps? The sonic impact of a tube rectifier is directly dependent upon how much current is demanded from it as well as the speaker-output section relationship. Remember, the power supply is the foundation of an amplifier. The amp section modulates DC from the power supply. So- in simplistic terms, you're amp is a device with turns DC into AC at varying frequencies based on its programming, the input.

Keeping that in mind, a tube rectifier has a much higher impedance than a solid state diode. In fact, there is no comparison! SS diodes will loose single-digit voltages across their junction while a tube rectifier can loose double and triple-digit voltages! Voltage sag is dependent on current demand. As  current demand rises, you will loose power due to a lower B+ voltage. The solid state diode will hold its own and be barely noticeable within the circuit as demand rises.

Sonic impacts:

Tube vs. SS in a preamp: Not any that I can tell with the Beacon series. I repaired a junked Fisher Coronet. The tube rectifier was replaced with a set of diodes: No difference. There is not enough current demand to produce a noticeable difference.

Tube vs. SS in amplifiers: Tube rectifiers can be thought of as cushions while SS diodes can be thought of as a concrete pad. The cushioning effect has the ability to make an amp sound more organic and smooth. Sometimes this is desirable. I like it best with high efficiency speakers and amplifiers that are 35 watts a side and under. SS diodes provide a more robust, punchy sound character. Remember, your speakers are part of the entire amp circuit. Current cycling back to the amp from the speakers rebounds back from a SS diode-based power supply like a basketball on a hard surface. WHAM! It's that fast! The tube rectifier is similar to playing b-ball on a wooden gym floor. You can feel the give in the planks. (I used to play high school basketball, so I know.) The slight give of tube rectifiers in high current circuits is enjoyable to many people. Just as many enjoy the more precise control of SS diodes. As you can tell, an amp is a complex machine. Everything is connected and all sections influence one another.

When not to use tube rectifiers: In amplifiers over 40 watts per channel. Tube rectifiers can be placed in parallel circuits. I have done it several times. However, to get the power demand necessary for high current demand amps, it will take at least four 5AR4's or 5U4's in a 120 watt total amplifier. Two in parallel will work, but it will not work as well with low efficiency speakers. I advise against it. The best route is solid state diodes for high power amps. Someone who is looking for a high impact listening session, greater speaker control and possibly using low efficiency speakers must use solid state diodes. Anything else will degrade performance considerably.

A word of caution: Pushing a tube rectifier too hard will kill it and fast! It could destroy your entire amp and possibly damage your speakers. Tube rectifiers usually arc and short and that's what creates the damage.

So- which one is right for you? Tube or Solid State rectification? I'll be happy to help!

[FullRangeMan]

WOW, Thanks for this article Niteshade, a very instructive one.
Gustavo

[pardales]

WOW, Thanks for this article Niteshade, a very instructive one.
Gustavo

Indeed. Clearly articualted and comprehendable to a laymen like myself. 

[guest1632]

I like tube rectification as well as solid state rectification. There is a place for both and times when NOT to use tube rectification.

Having a tube rectifier means there is one more user-serviceable part in your amp or preamp. For technical reasons, that is an enormous boon. Less or no time in the repair shop is always beneficial! Solid state rectifiers rarely go bad. In fact, I have not had one go bad yet in anything I have made. I did have a pair go bad in a computer monitor. Easy fix!

What about the sonic impact of tube rectification within tube amps and preamps? The sonic impact of a tube rectifier is directly dependent upon how much current is demanded from it as well as the speaker-output section relationship. Remember, the power supply is the foundation of an amplifier. The amp section modulates DC from the power supply. So- in simplistic terms, you're amp is a device with turns DC into AC at varying frequencies based on its programming, the input.

Keeping that in mind, a tube rectifier has a much higher impedance than a solid state diode. In fact, there is no comparison! SS diodes will loose single-digit voltages across their junction while a tube rectifier can loose double and triple-digit voltages! Voltage sag is dependent on current demand. As  current demand rises, you will loose power due to a lower B+ voltage. The solid state diode will hold its own and be barely noticeable within the circuit as demand rises.

Sonic impacts:

Tube vs. SS in a preamp: Not any that I can tell with the Beacon series. I repaired a junked Fisher Coronet. The tube rectifier was replaced with a set of diodes: No difference. There is not enough current demand to produce a noticeable difference.

Tube vs. SS in amplifiers: Tube rectifiers can be thought of as cushions while SS diodes can be thought of as a concrete pad. The cushioning effect has the ability to make an amp sound more organic and smooth. Sometimes this is desirable. I like it best with high efficiency speakers and amplifiers that are 35 watts a side and under. SS diodes provide a more robust, punchy sound character. Remember, your speakers are part of the entire amp circuit. Current cycling back to the amp from the speakers rebounds back from a SS diode-based power supply like a basketball on a hard surface. WHAM! It's that fast! The tube rectifier is similar to playing b-ball on a wooden gym floor. You can feel the give in the planks. (I used to play high school basketball, so I know.) The slight give of tube rectifiers in high current circuits is enjoyable to many people. Just as many enjoy the more precise control of SS diodes. As you can tell, an amp is a complex machine. Everything is connected and all sections influence one another.

When not to use tube rectifiers: In amplifiers over 40 watts per channel. Tube rectifiers can be placed in parallel circuits. I have done it several times. However, to get the power demand necessary for high current demand amps, it will take at least four 5AR4's or 5U4's in a 120 watt total amplifier. Two in parallel will work, but it will not work as well with low efficiency speakers. I advise against it. The best route is solid state diodes for high power amps. Someone who is looking for a high impact listening session, greater speaker control and possibly using low efficiency speakers must use solid state diodes. Anything else will degrade performance considerably.

A word of caution: Pushing a tube rectifier too hard will kill it and fast! It could destroy your entire amp and possibly damage your speakers. Tube rectifiers usually arc and short and that's what creates the damage.

So- which one is right for you? Tube or Solid State rectification? I'll be happy to help!

Hi Blair,

From what I have read about the debate between the two, with a tube rectifier, it warms up along tiwith therest of he tubes, while the Silicon rectifier has to be controlled so that the curren doesn't overwhelm the tubes in the particular device they are in.

I guess tube rectifiers do so I have been told can soften the sound of say a preamp, but if you don't notice the difference, then there is the question of using a standard diode versus the faster soft recovery types. Thanks for helping me figure out what to do when I buy a preamp.

Ray

[Niteshade]

Do not worry about cathode stripping with any audio tube. It's a RF tube issue. The 3CX and 4CX indirectly heated ceramic transmitter tubes require a B+ timer. Others built like them do as well.

The Beacon preamp series uses a system that isolates the rectifier from the filtering stages as much as possible. As a result, the 'rest of the system' doesn't care what kind of rectifier is being used. It doesn't really see it. For all purposes, it looks like it's 1,000 miles away. The result is exceptionally pure DC that is not influenced by external signals.

Sound softening is the result of B+ sag. It shaves off the peaks and fattens the middle during times of high current demand. The softening phenomenon is less pronounced at low volumes.

Note: We have a pseudo tube rectifier mod which simulates what a tube rectifier does with SS diodes. It's an interesting mod since it can be made to work with larger amps where it's impractical to use tube rectifiers. The sound softening aspects are better controlled to eliminate the down side of too much B+ sag often seen with tube rectifiers during high impact listening sessions.

[Niteshade]

What are your impressions of tube and solid state rectification?

This is interesting: Some early Bogen and Stromberg Carlson tube amplifiers use dual rectifiers even for 60 total watts output! I went this way with my commercial duty SEP. This is a bit of a tangent, but it is possible to parallel as many rectifiers as you want. A side benefit is that they last longer in power amplifiers when there is more than one. You'll still get that 'rectifier sound' quality, but less pronounced. Parallel rectifiers sound great!

[Guy 13]

Hi Blair and all other Audio Circle members…
I like the way Blair explain the sonic differences between tube and SS rectification.
Blair tells clearly the sonic difference between the two, so that you can choose the type of rectification that will give the best sonic result with the amplifier you want him to build for you.
Since Blair has listen to dozens of different configurations, which is not always the case for you and me, he can also tell you which option/up grade will shape the sound the way you like it, for the type of music you listen to and to other variables.
Unfortunately, the answers, comments and opinions from Audio Circle members to the original topic are not always like that; that’s what I have noticed since I became an Audio Circle member. This is just my opinion, for what it’s worth…
Too often, some members post their opinions and comments, which from post to post
drift slowly into other subjects or subjects that are not directly related to the original subject.
I wish Blair could do again the same as tube vs SS rectification, but for other parts (Circuits) of the amplifier (SE, SEP, PP) for example a power supply with and without a choke filter, extra capacitors and filtering, etc…
I am interested in the sonic difference versus the cost of the available options/up grades. Otherwise, I will have to buy the options or upgrades with a disable switch (If available) on one or several amplifiers and do my own evaluation, which will be costly, time consuming. I don’t have the experience in hearing the subtle differences with or without the up grade…
I hope all of you don’t think I am a weirdo and don’t know what I want.
Audio Circle was created to exchange ideas, share ideas, learn and also, have fun while doing all that.
Let’s all get our fingers moving on the computer’s keyboard and make our audio knowledge a notch higher.
Have a nice day.
Guy 13.

[Guy 13]

What are your impressions of tube and solid state rectification?

This is interesting: Some early Bogen and Stromberg Carlson tube amplifiers use dual rectifiers even for 60 total watts output! I went this way with my commercial duty SEP. This is a bit of a tangent, but it is possible to parallel as many rectifiers as you want. A side benefit is that they last longer in power amplifiers when there is more than one. You'll still get that 'rectifier sound' quality, but less pronounced. Parallel rectifiers sound great!

Hi Blair and all other Audio Circle members…
I like the way Blair explain the sonic differences between tube and SS rectification.
Blair tells clearly the sonic difference between the two, so that you can choose the type of rectification that will give the best sonic result with the amplifier you want him to build for you.
Since Blair has listen to dozens of different configurations, which is not always the case for you and me, he can also tell you which option/up grade will shape the sound the way you like it, for the type of music you listen to and to other variables.
Unfortunately, the answers, comments and opinions from Audio Circle members to the original topic are not always like that; that’s what I have noticed since I became an Audio Circle member. This is just my opinion, for what it’s worth…
Too often, some members post their opinions and comments, which from post to post
drift slowly into other subjects or subjects that are not directly related to the original subject.
I wish Blair could do again the same as tube vs SS rectification, but for other parts (Circuits) of the amplifier (SE, SEP, PP) for example a power supply with and without a choke filter, extra capacitors and filtering, etc…
I am interested in the sonic difference versus the cost of the available options/up grades. Otherwise, I will have to buy the options or upgrades with a disable switch (If available) on one or several amplifiers and do my own evaluation, which will be costly, time consuming. I don’t have the experience in hearing the subtle differences with or without the up grade…
I hope all of you don’t think I am a weirdo and don’t know what I want.
Audio Circle was created to exchange ideas, share ideas, learn and also, have fun while doing all that.
Let’s all get our fingers moving on the computer’s keyboard and make our audio knowledge a notch higher.
Have a nice day.
Guy 13.

[rpf]

WOW, Thanks for this article Niteshade, a very instructive one.
Gustavo

I third the above sentiment. Your posts on amplifier design are informative and well written, Blair. Thank you.

[Niteshade]

Something I forgot to add: We can make a tube amplifier with switchable tube or solid state rectification. You can have it both ways and there are absolutely no compromises with this upgrade.

Read the first post on this subject for the qualities of tube and solid state rectification.

Note: I further stress that you do not have to worry about damaging audio tubes with solid state rectification. Cathode stripping is an issue related to certain ceramic triodes and tetrodes for Amateur and commercial amplifiers or transmitters. The amplifiers in question have slow start circuits and the time delay is counted in minuets, not seconds.

[Guy 13]

Something I forgot to add: We can make a tube amplifier with switchable tube or solid state rectification. You can have it both ways and there are absolutely no compromises with this upgrade.

Read the first post on this subject for the qualities of tube and solid state rectification.

Note: I further stress that you do not have to worry about damaging audio tubes with solid state rectification. Cathode stripping is an issue related to certain ceramic triodes and tetrodes for Amateur and commercial amplifiers or transmitters. The amplifiers in question have slow start circuits and the time delay is counted in minuets, not seconds.

Hi Blair and all Audio Circle members.
When you mention slow start circuits, is that standard (Included) with all your amplifiers, especially the NS-SEP20 and NS-40 ?
Your slow start circuit, is it the equivalent of the stanby run switch found on some (Guitar) amplifiers?
Can the NS-40 work with a single (5AR4) tube rectifier?
Guy 13 

[Niteshade]

Oops- Didn't see these questions

I do not use a soft start circuit in any of my tube equipment because it is completely unnecessary. Soft starts are required only for two situations:

1] Some ceramic triode or tetrode transmitting tubes
2] When a filament has a very high startup inrush current (I.e. 3-500z)

Audio tubes do not require soft start circuits. They work at relatively low voltages- usually under 600V and have a relatively light filament current draw.

The NS-40 can operate with a single tube rectifier. The output power would be diminished to about 25 watts per channel. It would be best to have the ability to switch between tube and SS rectification.

[Audioexcels]

Wanted to add my .02.  I have used both quite extensively since I have the drop in Weber Cap SS rectifier as well as a 5U4 tubed rectifier.  I would recommend those that enjoy tube rectification and do not mind or even enjoy SS rectification to swap them just like swapping input tubes.  Though I don't think the sound difference is exactly huge, there is indeed a slight difference that others may feel is large enough to swap depending on the mood or whatever makes one swap this tube.  The Weber makes it very easy to do just this type of swapping, much like swapping input tubes, so you can listen to different rectification whenever you please.  I'm no rep for Weber or am I here to discuss it, but just stating that we all have different ears and while mine say one thing and I primarily stick with the Weber SS, I will interchange to a tubed rectifier at times and I think others would benefit in the cheap Weber to be able to do the same thing.

Great article and hope my .02 is ok to keep in this thread.

Cheers!

[Guy 13]

Hi Blair and all Audio Circle members.
If the main power transformer compensate with a higher voltage secondary winding  tube rectification then won't dmininish the watts power output.
Am I right ?

Guy 13 

[FullRangeMan]

I would like inform the impressive low price of a powerful SS Rect.
Just $3.50 each for 50A & 1000V and it dont need heating:
https://www.rfparts.com/kbpc5010-kest.html