[L0rdGwyn]

Placebo is always a possibility, but I experienced the same thing with my Woo WA6SE (2nd gen). Not proof by any means, but another data point.

Yeah maybe it is the quality of the rectifier, without measuring both and identifying if there are objective differences, its hard to say. To truly say whether or not changing rectifiers makes a difference, you'd have to find two that measure the same in terms of voltage drop within some predetermined tolerance, then blind test them in the same circuit. If you are using two different rectifiers that are altering the bias points of the tubes, which is often the case, that cannot be ruled out as the cause of perceived differences if that makes sense.

 

[protoss]

There's also a 5 part series on 'Sag.' If people are interested.

 

[ColSaulTigh]

Tube sag doesn't really exist in these types of amplifiers, SET amplifiers are single-ended class A, meaning the DC current draw on the power supply is essentially constant, which means there is a constant voltage drop across the resistance of the power supply. By Ohm's law (V=I*R), a current going through a finite resistance will result in a known voltage drop. If the current increases, the voltage drop will increase proportionately. BUT because we are talking class A, the current draw is constant and is defined by the DC bias points of the tubes. Since the current is constant, that means the voltage drop across the rectifier and power supply is constant.

Now, if you look at a class AB push-pull amplifier, once the amplifier enters class B, the current is no longer constant! The amplifier circuit now represents a dynamic load, the current drawn from the power supply will be variable.

What does that mean in terms of the voltage drop across the power supply? If the current is changing, then the voltage must also be changing, so the bias points of the tubes will be changing. THIS is sag, the voltage of the power supply will "sag" (i.e., go down) as the amplifier draws more current, which is undesirable. This is something that needs to be accounted for in designs that have a variable DC current load.

For single-ended class A tube amps, like headphone SET amps, sag doesn't occur since the current draw is constant.

In terms of what you're hearing when you change rectifiers, it could be as I described in my other post, that the bias points are being altered when you change rectifiers. A higher voltage drop rectifier might sound "slow" compared to a lower voltage drop rectifier as the tubes are at a colder bias point (i.e., lower plate voltage, lower bias current), which means higher internal resistance, which means a slightly higher output impedance and likely higher distortion. If you are using two rectifiers of the same type that are measurably identical in terms of their voltage drops, then I have no idea, and I will call that voodoo. Maybe material differences are causing an appreciable change in sound, maybe there is an element of placebo effect, I can't say for sure.

In the case of the WA6-SE, it's a single-rectifier amplifier. The Woo WA5-LE is a double-rectifier. I have two of them that I use specifically to A:B rectifiers (primarily before I got the WA5). With everything else being equal, I can definitely spot (hear?) differences in rectifiers, in some cases quite dramatic ones at that (which I assume is variation in the bias points you reference above).

Thank you for the education - I love learning more and more about this hobby!

 

[ardbeg1975]

I don’t get the impression my EC Studio B is rectifier picky but if so I don’t think my ears are up to the task. I can hear the differences between 300B tubes but I cannot I say l heard much swapping between JAN GE 5670s and WE 396As but I (perhaps out of audiophilia nervosa) pair the WE rectifier with the WE 300Bs and the GEs with the Elrogs.

 

[Wes S]

The number one reason to use a tube rectifier is because... they're cool but in basically every technical sense, solid state diodes are higher performing. Any technical advantage a tube rectifier might have (i.e., transformer snubbing, lack of switching noise, soft start characteristics) can be accounted for in a solid state supply.

They sure are cool, and they also give you another angle to tweak the sound by rolling them. Being able to tweak the sound from 3 different angles, (driver, power, and rectifier), really lets me dial in the sound just how I want it. It's even more awesome with my Cayin HA300mk2 having 4 rectifiers that don't have to be matched and I am running 2 of one brand and 2 of another, and I am getting the best of what both have to offer combined. I have heard just as much difference rolling rectifiers with my Pendant SE and HA300mk2, as I have with power and driver tubes.

 

[karangovil]

I don’t get the impression my EC Studio B is rectifier picky but if so I don’t think my ears are up to the task. I can hear the differences between 300B tubes but I cannot I say l heard much swapping between JAN GE 5670s and WE 396As but I (perhaps out of audiophilia nervosa) pair the WE rectifier with the WE 300Bs and the GEs with the Elrogs.

Craig did mention that using 274B rectifier in Studio B will sound spongy as it has a larger voltage drop although it will work fine.

 

[senseitedj]

Yeah maybe it is the quality of the rectifier, without measuring both and identifying if there are objective differences, its hard to say. To truly say whether or not changing rectifiers makes a difference, you'd have to find two that measure the same in terms of voltage drop within some predetermined tolerance, then blind test them in the same circuit. If you are using two different rectifiers that are altering the bias points of the tubes, which is often the case, that cannot be ruled out as the cause of perceived differences if that makes sense.

My amp comes equipped with a current meter for both channels, not sure exactly where the current is being measured in the circuit, but changing the tube rectifier affects the current value being outputted. Here is a short list:

Sophia 274B (clear glass version, non-aqua) - 58mA
GEC u52 - 62mA
JJ GZ34 - 70mA
SS PSU - 68mA

Obviously the current measured is just one piece of the puzzle to the final perceived sound, but thought it would be interesting. The amp builder did mention something along the lines that changing out the rectifier affect the bias points of the tubes, which may be a contributor for audible differences.

 

[Galapac]

Ok, I guess you can count me in as an Elrog ER300B fan.

What I find best about these is both a blessing and a curse.

These are great for all rock/EDM genres as the bass extends further than the Western Electric and instrument separation is some of the best I have heard in the 300B class and that says a lot for a new production tube.
The strength it gives in the instrument separation also can be bad if your recording is not up to snuff.
Many rock recordings suffer from this and now that I can hear the faintest of details it can be a distraction.

That being said, when the recording is good, there is magic to be had as you are rewarded with details you may have never heard before in songs you have heard hundreds of times.
I think if you were going to own 2 sets of tubes, one being the Elrog, the other one could be Western Electric as both bring something different to the table.
The WE are still hard to beat in overall soundstage in my opinion and are best suited to classical and jazz genres as they seem to do a great job in this regard with their light and airy presentation.

I may need to sell my EMLs but time will tell if they can fit into the big league rotation.

 

[ColSaulTigh]

Ok, I guess you can count me in as an Elrog ER300B fan.

What I find best about these is both a blessing and a curse.

These are great for all rock/EDM genres as the bass extends further than the Western Electric and instrument separation is some of the best I have heard in the 300B class and that says a lot for a new production tube.
The strength it gives in the instrument separation also can be bad if your recording is not up to snuff.
Many rock recordings suffer from this and now that I can hear the faintest of details it can be a distraction.

That being said, when the recording is good, there is magic to be had as you are rewarded with details you may have never heard before in songs you have heard hundreds of times.
I think if you were going to own 2 sets of tubes, one being the Elrog, the other one could be Western Electric as both bring something different to the table.
The WE are still hard to beat in overall soundstage in my opinion and are best suited to classical and jazz genres as they seem to do a great job in this regard with their light and airy presentation.

I may need to sell my EMLs but time will tell if they can fit into the big league rotation.

Another fine zealot for the Cult of Elrog!

 

[protoss]

@Galapac

Like the way your amp looks. So interesting looking. Halloween and Christmas all in one box

 

[incredulousity]

I’m hopeless. I will buy the WE, just to witness the blue glow in person. Even though the only tubes I actually still need are the Elrog ER.

 

[ColSaulTigh]

I’m hopeless. I will buy the WE, just to witness the blue glow in person. Even though the only tubes I actually still need are the Elrog ER.

"need" is a relative term. Also, the blue glow is soooo pretty. Do it!

 

[incredulousity]

"need" is a relative term. Also, the blue glow is soooo pretty. Do it!

I’ll wait for some used ones to become available. Current ones. Not the silly overpriced NOS.

The Elrogs I’ll buy new. Priorities.

 

[wjhen]

Here is my Elrog'ed system with a small dosis of Western Electric elegance and 3D holographic soundstage....

 

[wjhen]