Tube Rectification

It is safe to say that excellent sounding single ended amplifiers have been built with both vacuum tube and solid state rectification. There is no one "formula" that one can use with convenient check boxes that will guarantee a good sounding unit. Many builders have a set of guidelines or personal principles they use to fulfill their own ideas of good sound and in many cases those focus on synergy with a particular brand or type of speaker.

Personally, I have violated much of my own personal audio dogma as a means of advancing or exploring other topologies and engineering ideas. For instance, my latest amp is a push pull, directly heated triode connected 5516 pentode, using RC coupling and only two stages of amplification from DAC to speakers and Triad output transformers.

I eschew popular tubes such as the 12AX7, 12AU7, 6922 family, 5AR4, 6SN7, etc. The tubes I use are 6AX4GT, EC86, 6F8G, EC8010, HY69 and 5516. Most of my amps use industrial power transformers and chokes and high quality output transformers from Tango, Tamura, Sansui, Electra-Print or Magnequest, but others use power transformers from Magnequest or Electra-Print. I don't mind experimenting with different power supplies and use both choke input or capacitor input depending on the application. I use Wima DC Link MKP4 capacitors almost exclusively in the power supply.

For single ended, my personal dogma demands a two stage amplifier (no preamp!) with directly heated pentode or triode output tube; low impedance power supply, direct coupling and a high transconductance driver tube capable of driving the output tube to clipping with an input sensitivity of 1Vrms.

2 stage SE, posted on June 11, 2022 at 16:21:00

andy evans
Audiophile

Posts: 4260
Joined: October 20, 2000

"For single ended, my personal dogma demands a two stage amplifier (no preamp!) with directly heated pentode or triode output tube; low impedance power supply, direct coupling and a high transconductance driver tube capable of driving the output tube to clipping with an input sensitivity of 1Vrms."

I agree totally on a 2 stage amp with no preamp. I'm getting away with 6SN7 into 2a3 because I have a smaller room and don't listen loud. The HY69 and 5516 are unobtanium in the UK. I used EL38 for a while but I don't need to since I can use a 2a3, which I prefer to 300b. As driver I've had quite good results with the E180CC. Haven't tried the EC86 yet but I have some. Not direct coupled, but teflon coupling caps which are as transparent as I can find.

For rectification I preferred a 5U4 overall, but I do actually use SIC diodes in the power supply for the driver stage when I put that in a separate chassis. Essentially it's a 6SN7 line stage and the SIC diodes 1200v sound very nice. DC Link caps as last cap in the PSU and for the driver stage.

Generally, "lower" is better, posted on June 11, 2022 at 16:50:44

Chip647
Audiophile

Posts: 2533
Location: The South
Joined: December 24, 2012

Lower resistance, lower capacitance, lower inductance, lower ESR Caps that achieve an acceptable level of ripple and regulation tend to sound better.

That being said, choke input filters can enable lower total capacitance while providing better regulation to achieve a ripple target.

Filters with a lower resistance do sound subjectively better due to better regulation. Even Class A has variation in current demand.

Tubes are higher resistance than solid state diodes. For tubes, people like damper diodes due to the lower resistance. The venerable 5AR4 is a lower resistance rectifier than tubes like the 5U4.

In the end, though, the effect is swamped by the circuit design, and build quality, parts and technique.

RE: Generally, "lower" is better, posted on June 11, 2022 at 17:45:21

Tre'
Industry Professional

Posts: 16794
Location: So. Cal.
Joined: February 9, 2002

"Filters with a lower resistance do sound subjectively better due to better regulation. Even Class A has variation in current demand."

Do you mean impedance? Class A has variations but most of them are periodic. The output impedance of a power supply filter is dependent on the capacitance value of the last cap. Think of the last cap of the filter as a "by-pass cap". As long as the impedance of the circuit is bypassed to the lowest frequency of interest then the power supply should not be a factor.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

yes, sorry, impedance, posted on June 15, 2022 at 06:30:59
Chip647 Audiophile Posts: 2533 Location: The South Joined: December 24, 2012	I do find that solid state rectification can be an improvement to the overall sound.

RE: 2 stage SE, posted on June 18, 2022 at 09:08:09
Palustris Audiophile Posts: 2382 Location: Cape Cod Joined: September 12, 2008	"The HY69 and 5516 are unobtanium in the UK." Those tubes are directly heated pentodes. I have to wonder if there are any European directly heated pentodes that might be real "sleepers" waiting to be discovered. Nobody seems to pay any attention to DHPs.

RE: Tube Rectification, posted on July 1, 2022 at 06:06:07

Kurorin
Audiophile

Posts: 2
Location: Dortmund
Joined: July 1, 2022

One of the best amplifiers that I�ve ever heard it was a crafted japanese with deutsch Telefunken DHT and rectification was solid state.
Just my preference continue in valve rectifier wit mercury gas: it has a special finishing, if you like.
I made a small modification in order to install the mercury gas valve rectification 83 in my amplifier (5U4G is the original and I can use both now).
I like both just I love mercury rectification more.
"Happiness is made up of little things: a small yacht, a small mansion, a small fortune". Groucho Marx

RE: Tube Rectification, posted on July 17, 2022 at 08:57:49
sony6060 Audiophile Posts: 1318 Location: USA Joined: August 8, 2014	Rectifier tube for the most part are superior with the right vacuum tube. However, Cree solid-state rectifiers have zero crossover distortion and in my opinion perform as well as tube rectifiers.

RE: Tube Rectification, posted on August 4, 2022 at 07:54:21

Todd Krieger
Audiophile

Posts: 37069
Location: SW United States
Joined: November 2, 2000

"Is tube rectification sonically superior for SET amps or do other variables impact the sound quality more?"

I believe it is....

But when Don Allen was around, he found that the 6BY5 and 6BY5G rectifiers just outperforms any rectifier that begins with "5"..... The 6BY5 is often called "damper diodes".... But I otherwise don't know the reason why, aside from the "extra volt" on the filament somehow making a major difference.

RE: Tube Rectification, posted on August 13, 2022 at 08:22:45
sony6060 Audiophile Posts: 1318 Location: USA Joined: August 8, 2014	CIS Cree are solid-state rectifiers with zero switching noise that are like tube rectifiers.

RE: Tube Rectification, posted on August 13, 2022 at 19:51:32
Spantou Audiophile Posts: 111 Location: Central Illinois Joined: October 5, 2016	Why do you love mercury rectification more? Audibly or visually?

RE: Tube Rectification, posted on August 14, 2022 at 13:52:17
Kurorin Audiophile Posts: 2 Location: Dortmund Joined: July 1, 2022	Visually is cool but listening is a different kind of finishing to the sound. I can use 5U4G rectifier tube or 83 mercury vapor and I just prefer 83 listening. "Happiness is made up of little things: a small yacht, a small mansion, a small fortune". Groucho Marx

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Tube Rectification

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