What’s the world’s best 2 watt amplifier?

[Hear Here]

Actually I have a pair of KR PX 25 tubes that I bought from a forum member for use in my Lampizator Pacific. I have heard great things about Art Audio SETs

I was fortunate enough to find myself an unofficial demonstrator (as opposed to dealer) for Art Audio for a couple of years as they had no representation in London. I had the use of the PX-25 and Carissa 845 SETs. Likewise, after Avantgarde's only London dealer lost (or surrendered) its franchise, I was unofficial demonstrator for AG too. One year, I took my AG Unos to a London Audio Show as Tom Willis of Art Audio had no suitable speakers to work with his amps. It was encouraging how many visitors to our room said that the sound was better than from Avantgarde's own room, where of course they were using their own SS amps on the bigger Duos.

I have no experience with other low powered tube amps apart from an unfortunate experience with an Audio Note 300B stereo amp - not their finest! Peter

 

[cjfrbw]

An uncommon tube to make about 1.3 to 1.5 watts is the vintage globe hung cathode 182b or a 183. If you wired your amp for 5V cathode, it would work. Sounds like a 45 with some extra viscosity (due to higher cathode voltage) but just as revealing. They are also 'relatively' inexpensive due to not being on the audiophile status groupie radar, but, unfortunately, aren't easy to source.

First Watt Sit 2 if you could find one, with your choice of a directly heated triode gain stage in front of it, but it's a hefty 10 watts. It winds up sounding pretty close to the DHT driver itself, with no transformers and some enhanced micro dynamics.

I'm building a DIY single ended Pass design using the vintage Sony VFET. I am curious to hear how it works out if it I don't ruin it with my building incompetence, about 8 watts or so.

 

[godofwealth]

I’m not sure why the First Watt designs generate so much heat, e.g., generating 200 watts of heat for producing 1 watt of output. I’d rather stick to tubes. He must be biasing these designs heavily into class A to keep them linear.

 

[BruceD]

Sakuma 1 Watt Triode

BruceD

 

[DasguteOhr]

Almarro a 205a is really a bargain sounds so sweet

6moons audio reviews: Almarro A205A

 

[christoph]

An uncommon tube to make about 1.3 to 1.5 watts is the vintage globe hung cathode 182b or a 183. If you wired your amp for 5V cathode, it would work. Sounds like a 45 with some extra viscosity (due to higher cathode voltage) but just as revealing. They are also 'relatively' inexpensive due to not being on the audiophile status groupie radar, but, unfortunately, aren't easy to source.

First Watt Sit 2 if you could find one, with your choice of a directly heated triode gain stage in front of it, but it's a hefty 10 watts. It winds up sounding pretty close to the DHT driver itself, with no transformers and some enhanced micro dynamics.

I'm building a DIY single ended Pass design using the vintage Sony VFET. I am curious to hear how it works out if it I don't ruin it with my building incompetence, about 8 watts or so.

All that sounds VERY interesting

 

[godofwealth]

Almarro a 205a is really a bargain sounds so sweet

6moons audio reviews: Almarro A205A

An increasing number of designers seem to be using pentodes in low powered designs. There’s a trade off here as pentodes are inherently less linear than the best triodes (e.g., 300B or 45s).

 

[iaxel]

Yamamoto A-08s is a great bargain.
"45"Single stereo amplifier A-08S (117.ne.jp)

I've owned the A-08s and one of the first production First Watt, and they sound nothing alike.

 

[DasguteOhr]

An increasing number of designers seem to be using pentodes in low powered designs. There’s a trade off here as pentodes are inherently less linear than the best triodes (e.g., 300B or 45s).

you don't necessarily need triodes to build a good amplifier. in the end what counts is what comes out. the little almarro has enormous potential. is popular is used more expensive than new. unfortunately no longer built.

 

[godofwealth]

Yamamoto A-08s is a great bargain.
"45"Single stereo amplifier A-08S (117.ne.jp)

I've owned the A-08s and one of the first production First Watt, and they sound nothing alike.

I’ve heard great things about the Yamomoto. I see it advertised in a “kit form” on eBay. Did you buy the kit version or the assembled version?

Yamamoto Sound Craft Vacuum tube power amplifier [Assembly kit] JAPAN | eBay

Yamamoto Sound Craft. â Yamamoto sound craft vacuum tube stereo power amplifier "A-08S" [kit specification]. The predecessor, the A-08, has gained a high reputation since its release, and received a SOTA award in the US internet audio magazine 6moons.

www.ebay.com

 

[iaxel]

I’ve heard great things about the Yamomoto. I see it advertised in a “kit form” on eBay. Did you buy the kit version or the assembled version?

Yamamoto Sound Craft Vacuum tube power amplifier [Assembly kit] JAPAN | eBay

Yamamoto Sound Craft. â Yamamoto sound craft vacuum tube stereo power amplifier "A-08S" [kit specification]. The predecessor, the A-08, has gained a high reputation since its release, and received a SOTA award in the US internet audio magazine 6moons.

www.ebay.com

The assembled version.
I’m not good with soldering…

 

[cjfrbw]

I've mentioned this small creature before for sheiss and giggles, likely inappropriate for a place like WBF. Couple hundred dollars with compactron tubes that cost about 6 bucks apiece. The tubes contain both the driver pentode and the power output pentode. Claims 3 watts, but some guy on the internet measured it at more like 1.7 watts at full volume output. Apparently uses a switching power supply.

I won't make any grandiose claims for it, but it sounds excellent on my big ribbons and it is the integrated that I use in Santa Cruz with some efficient open baffles in a small room. Has tasty pentode crunchiness and attack as compared to the royal elegance of other types of SET. I really like it. For size comparison, it sits on my MD 572 Wavac.

I think Thomas Meyer has a compactron amplifier ouvre, too, built to his stellar standards.

 

[godofwealth]

I've mentioned this small creature before for sheiss and giggles, likely inappropriate for a place like WBF. Couple hundred dollars with compactron tubes that cost about 6 bucks apiece. The tubes contain both the driver pentode and the power output pentode. Claims 3 watts, but some guy on the internet measured it at more like 1.7 watts at full volume output. Apparently uses a switching power supply.

I won't make any grandiose claims for it, but it sounds excellent on my big ribbons and it is the integrated that I use in Santa Cruz with some efficient open baffles in a small room. Has tasty pentode crunchiness and attack as compared to the royal elegance of other types of SET. I really like it. For size comparison, it sits on my MD 572 Wavac.

I think Thomas Meyer has a compactron amplifier ouvre, too, built to his stellar standards.

This looks like it might be worth exploring. Do you know who makes it?

 

[VinylSavor]

Thanks for mentioning me and recommending my amps.

I am still offering the 46 amps which are mentioned in this thread. But I believe that my latest 300B amps with TM300B tubes offer at least the same sound quality but with 7-8W of power.

I think Thomas Meyer has a compactron amplifier ouvre, too, built to his stellar standards.

Yes, I have built several different amps based on compactron tubes. They are not listed on my product page but can be built on request of course.

Some of the compactron tubes I used:

6HS5, 6GE5, 6KN6, 6AG9, 6BE3

There are plenty more compactron tubes which are very interesting and a nice alternative to main stream tubes

Best regards

Thomas

 

[bonzo75]

Thanks for mentioning me and recommending my amps.

I am still offering the 46 amps which are mentioned in this thread. But I believe that my latest 300B amps with TM300B tubes offer at least the same sound quality but with 7-8W of power.




Yes, I have built several different amps based on compactron tubes. They are not listed on my product page but can be built on request of course.

Some of the compactron tubes I used:

6HS5, 6GE5, 6KN6, 6AG9, 6BE3

There are plenty more compactron tubes which are very interesting and a nice alternative to main stream tubes

Best regards

Thomas

hi Thomas, what are your thoughts on Eimac tube amps which are much higher powered compared to lower watt amps (where both amps can drive the speakers of course)

 

[VinylSavor]

Hi!

Most of the Eimac tubes (at least those I looked at) would require Class A2 operation since the tubes are designed for zero bias or positive grid operation. This puts a huge demand on the driver stage as it has to be able to deliver the grid current. This brings a whole set of issues which need to be solved and I think the compromises needed to make the driver capable of handling this would negatively impact the overall sound quality. I prefer to keep the output tubes in Class A1 operation. This way the grid is a constant load for the driver which does not change during the cycle of a waveform. Well in reality it does change too but not as dramatically as when the grid needs to be driven positive. therefor I employ beefy driver tubes and preferably another power triode to drive the output tube.

Of course this is not to say Class A2 can't be done. I actually have experimented with that myself but found I can get a higher overall sound quality with tubes meant to be used in Class A1

 

[bonzo75]

Hi!

Most of the Eimac tubes (at least those I looked at) would require Class A2 operation since the tubes are designed for zero bias or positive grid operation. This puts a huge demand on the driver stage as it has to be able to deliver the grid current. This brings a whole set of issues which need to be solved and I think the compromises needed to make the driver capable of handling this would negatively impact the overall sound quality. I prefer to keep the output tubes in Class A1 operation. This way the grid is a constant load for the driver which does not change during the cycle of a waveform. Well in reality it does change too but not as dramatically as when the grid needs to be driven positive. therefor I employ beefy driver tubes and preferably another power triode to drive the output tube.

Of course this is not to say Class A2 can't be done. I actually have experimented with that myself but found I can get a higher overall sound quality with tubes meant to be used in Class A1

is there any reason you have not used 5u4g/274b which is otherwise a popular driver tube?i know you make the GB not haven’t seen an amp use it

 

[VinylSavor]

is there any reason you have not used 5u4g/274b which is otherwise a popular driver tube?i know you make the GB not haven’t seen an amp use it

These are not driver tubes, they are rectifiers. Being popular does not necessarily mean the best for a certain purpose. I know this will be a very unpopular statement: But in a very well designed amplifier the rectifier tube will not have a big impact on the sound. This is not saying that they will not be audible but that can be reduced to a level so that other things become more important. For me the TV damper tubes I use are the best rectifiers. They are low noise, have low voltage drop and very slow ramp up of the output voltage. These are properties directly heated rectifiers like the 5U4 or 274 do not have. Direct heated rectifiers like the 5U4 and 274 have a large voltage drop which can vary significantly from brand to brand and also from tube sample to tube sample of the same brand. Unfortunately many amplifier designs use op points for the tubes which are very sensitive to small shifts. This results in a change in sound when changing rectifiers since the resulting supply voltage to the circuit will differ.

But still I use them, for example ER274B in 300B amps:

SE 300B Mono Amplifiers

Hi! Here another set of amps which will be shown at the Munich High End next week. These are similar to previously built 300B amps ...

vinylsavor.blogspot.com

Or ER274A in 845 amps:

SE 845 Mono Amplifiers

Hi! Here some photos of newly finished single ended 845 mono amps. Like a previous set of such amps these use a specially...

vinylsavor.blogspot.com

Or in 211 amps:

Power Supply with ELROG ER274A

Hi! Here some photos of the first power supply I built for the ER274A rectifier. The owner of one of the sets of 211/211 amplifiers...

vinylsavor.blogspot.com

Even in a DAC:

The Digital to Analog Converter

Hi! Here some photos of the first customer ordered DAC to be shipped soon. Besides the black color for the transformer covers and c...

vinylsavor.blogspot.com

 

[cjfrbw]

This looks like it might be worth exploring. Do you know who makes it?

I surmise they are Chinese in origin.
ALL PRODUCTS / AUDIOPHILE

GEMTUNE APPJ PA1501A MINI TUBE AMPLIFIER​

Gemtune APPJ PA1501A Mini Tube Amplifier | Audiophile | Amps | Drop

Drop exclusive price and reviews: Gemtune APPJ PA1501A Mini Tube Amplifier | Released earlier this year, the APPJ PA1501A is the latest tube amplifier from...

drop.com

They sold them on Amazon a while back.

Reviewing the Gemtune APPJ PA1501A 6AD10 Stereo Tube Amplifier

I recently picked up an interesting little tube amp via a group buy on Massdrop, the Gemtune APPJ PA1501A stereo tube amplifier. Try saying that three times fast! It’s a cute little single-en…

retrovoltage.com

 

[charles1dad]

@VinylSavor
“But still I use them, for example ER274B in 300B amps:”

Given the shortcomings that you clearly acknowledge, why do you nonetheless use them? What do they provide that you find beneficial?
Charles