[Odin412]

My guess is that the tube rectifier injects a lot of 2nd harmonic distortion (which is believed to the pleasing to the ear) during the process of converting the power from AC to DC. Different tubes may inject different quantities of harmonic distortion at different frequencies and that's why it changes the sound quite a bit.

Interesting (and plausible) theory, but aren't there voltage regulators in the power supply circuit that would suppress these harmonics (as well as other noise)? Either way, it's fun to try different rectifier tubes.

 

[senseitedj]

Interesting (and plausible) theory, but aren't there voltage regulators in the power supply circuit that would suppress these harmonics (as well as other noise)? Either way, it's fun to try different rectifier tubes.

Voltage regulator units just regulate voltage but don't usually do any noise filtering. It is also likely that these frequency harmonics are not fully filtered out by any other noise suppression circuits in the amp power supply. That's why we still hear these changes in sound caused by the different harmonics produced by changing tubes. Just my theory.

On another slightly unrelated note; I listened through the interview with bottlehead amp designer in Youtube in Passion for Sound channel. He said the key for making nice sounding amps is not about lowering THD figure as low as possible, but rather, having more even order harmonics over odd order harmonics, which solid-state amps normally tend to produce the latter. I thought this finding was very interesting.

 

[Odin412]

On another slightly unrelated note; I listened through the interview with bottlehead amp designer in Youtube in Passion for Sound channel. He said the key for making nice sounding amps is not about lowering THD figure as low as possible, but rather, having more even order harmonics over odd order harmonics, which solid-state amps normally tend to produce the latter. I thought this finding was very interesting.

Yes, the famous amp designer Nelson Pass said something similar as well. He also said that the phase of the 2nd order harmonic distortion vs. the original signal matters and normal vs inverted phase (of the distortion) sounds different. Interesting indeed.

 

[senseitedj]

Yes, the famous amp designer Nelson Pass said something similar as well. He also said that the phase of the 2nd order harmonic distortion vs. the original signal matters and normal vs inverted phase (of the distortion) sounds different. Interesting indeed.

Yeah amp design is abit between like science and black art. The basic principles can be found on a textbook, but what makes amps sounds nice is not fully understood. Like transformer design theory has been around for awhile, but only a few people know how to make nice sounding transformers.

 

[jonathan c]

Yeah amp design is abit between like science and black art. The basic principles can be found on a textbook, but what makes amps sounds nice is not fully understood. Like transformer design theory has been around for awhile, but only a few people know how to make nice sounding transformers.

A situation which parallels the first sentence of ‘Tao Te Ching’ (Lao Tze): “The Tao that can be told is not the eternal Tao.”

 

[jonathan c]

 

[RobertSM]

What tubes are you running in your WA6 in this picture?

 

[jonathan c]

What tubes are you running in your WA6 in this picture?

The rectifier is a Mullard GZ34 (guess what, rebranded Adzam !). The drivers are ‘brown base’ CBS/Hytron 5692. The adapters are 6SN7=>6DE7 and are made by Woo Audio. [The 6DE7 tube sockets are the reason that I sought Gen.1 rather than Gen.2. I wanted to use 6SN7 / 5692 / Melz 6N8S (the last are in the LTA MZ3).]

 

[RobertSM]

The rectifier is a Mullard GZ34 (guess what, rebranded Adzam !). The drivers are ‘brown base’ CBS/Hytron 5692. The adapters are 6SN7=>6DE7 and are made by Woo Audio. [The 6DE7 tube sockets are the reason that I sought Gen.1 rather than Gen.2. I wanted to use 6SN7 / 5692 / Melz 6N8S (the last are in the LTA MZ3).]

Nice!!

 

[UMN]

Nice!!

All this talk about 6SN7’s made me want to try my Sylvania VT-231‘s on my WA6 with my GZ32 rectifier and Hifiman HE5xx. Woo adaptors. Wow. Beautiful imaging and soundstage: deep and wide. (The last time I tried this tube combination was with my HD6xx. However, it’s a better fit with the HE5xx.) I will leave this combination in for the time being. I love tube rolling on the WA6….

 

[jonathan c]

A bit of $$$ and backup is always good - especially with NOS tubes. These are conscripts for WA6 duty.

 

[RobertSM]

A bit of $$$ and backup is always good - especially with NOS tubes. These are conscripts for WA6 duty.

Excellent tubes @jonathan c

And I agree, if you find a sound you like, a tube or tubes that suit your taste and play well with your system. Then absolutely go get that back up tube or back up set of tubes. Shoot, depending on availability a back up for the back up is sometimes in order.

 

[jonathan c]

Excellent tubes @jonathan c

And I agree, if you find a sound you like, a tube or tubes that suit your taste and play well with your system. Then absolutely go get that back up tube or back up set of tubes. Shoot, depending on availability a back up for the back up is sometimes in order.

As the old saying goes: “they don’t make ‘em like they used to” (or at all ).

 

[jonathan c]

Well, the WA6 (1st Gen.) has met the Synergistic Research Purple fuse and the results are majestic! @Wes S has eloquently waxed on the SRP’s many beneficial sonic contributions to his listening experiences. Here are my ‘Cliff Notes’ as to what SRP brings to my listening ‘table’: greater dynamic range, lower noise floor, more realistic note decay, clearer positioning of instruments and voices - all told, more THEREness. I can only surmise that the WA6 rectifier tube has an easier time in AC->DC conversion with the SRP ahead of it.

 

[jonathan c]

Not only did ‘lil Wooie WA6 get a SR Purple fuse but also a NIB Mullard GZ32 / CV593…more than ready for showtime!…