40+ watts SET, cost is not a problem


Friends,

Hope everyone is well here. I am visiting after a long time. I have a query on behalf of a close buddy of mine. He is using a pair of TAD CR1x loudspeakers. Gorgeous speakers for sure. The source is an EMT 927 TT & JPA66 preamp. For the amplification things are getting tricky. He has tried the TAD M700s reference power amp and while it sounds very controlled, it doesn't have the openness and dimensionality of tone that a good tube/SET amp provides. We are considering trying a good SET for this system. Given that TAD needs some power blossom well and expand on effortlessly, at least 40 watts of SET power would be needed. The quick choices are Kondo Kagura & Wavac HE833 Mk2. But I need more suggestions on these and other comparative products.

1. Has anyone heard the Kondo and Wavac gears to suggest a comparison? I am just a bit worried on the amount of Silver used in Kondo. I have normally found that silver takes away something from the flow and harmonics. Tell me more about it.

2. What other options can be considered in this realm? No SS please. Looking for SET options primarily.

 

Room size is moderate 17 x 13 feet. Music preferred are classic rock, jazz, pop and some classical

 

pani

Check out 11stereo.com

Mikey is both a TAD dealer and a NAT dealer. They make SET amps that are powerful. 

"...silver takes away something from the flow and harmonics." LOL!  Another opinion not supported by Material Science.

So you want an SET amp? These typically have output impedances over 1 ohm and higher. Due to interaction with speaker impedance the result is a non-flat frequency response (Ohm's Law). The typical SET amp acts as a tone control as it tracks the speaker's impedance curve - something that is not desirable!

So you want an SET amp? These typically have output impedances over 1 ohm and higher. Due to interaction with speaker impedance the result is a non-flat frequency response (Ohm's Law). The typical SET amp acts as a tone control as it tracks the speaker's impedance curve - something that is not desirable!

What an SET amp does right far outweighs its limitations provided it has enough power for the load. If we make it an SET vs SS/Push-pull discussion, we will lose the discussion for which I started this thread. Lets do it after we have enough responses/suggestions for the OP 

 

If you are really insisting on SET, and want the best of that sound, to me it is low-powered SET, and anything close to 40 wpc is out of the question.  I have only heard a few 833 and 1610 and other high-powered SETs, and never in a system I am familiar with, and I did not think the sound was special.  If the speaker is not well suited to SET use, why would you want to either shoehorn in a less than ideal amp, or take the opposite approach--shoehorn in an inappropriate speaker into a SET-based system.

The best sort of higher-powered SET amps I heard were Audio Note Gaku-On monobloc amps (parallel 211 SET) that sounded great with a wide range of speakers, including somewhat difficult speakers like Harbeth 40.3s.  But, those amps cost as much as a house.

I personally don't subscribe to the notion that SET amps deliver the very best sound if one can live within their restricted power output.  I do like the sound of some of them (I own an Audio Note Kageki parallel 2a3 SET amp), but it is not even my favorite among my own amps; that honor goes to a 349 pentode amp.  The best ever amps I've heard were a custom built OTL amp and the very ancient Western Electric 59A amp (252 pentode amp).

There is a Golden Tube Audio SE40 amp available now on eBay for $1000. It uses three 6L6GC beam tetrodes in parallel per channel It is single-ended, no phase splitter. I own one. Tube replacement is far less costly than 300B's, 211's, 845's ... You might want to check it out.

@larryi ,

You mentioned:

“The best sort of higher-powered SET amps I heard were Audio Note Gaku-On monobloc amps (parallel 211 SET) that sounded great with a wide range of speakers, including somewhat difficult speakers like Harbeth 40.3s.  But, those amps cost as much as a house.”

Would the Audio Note Jinro 211 Set amp maybe be a possibility also , for less money?

@larryi when you refer to gaku-on, are you suggesting Kondo or AN UK?

Secondly, which other tube amp (non-SET) would you suggest with at least 80-100 watts which have top tier sound?

I have heard the Jinro in several systems, including one with AN-E speakers where I am familiar with its sound.  The Jinro is a good sounding amp, but, it seems just a bit too laid back and not as exciting and vivid as I like.  

For a non-SET amp with 100 watt or so power, I am a big fan of the Synthesis Audio A100 amp (KT 66 tube).  This is a punchy, lively, and warm sounding integrated amp that also has a built in DAC that is pretty decent.  That it is a screaming bargain makes it hard for some people to consider it in a very high end system.  Perhaps one of the Synthesis separates, then, for those who want to spend more than the price for the A100.  

The Gaku-On that I am familiar with is an older Audio Note (uk) amp.  It is a quite versatile amp that sounded good with any speaker I heard it paired.  I have not heard much Kondo gear.  The one extensive experience I had was when I auditioned a pair of Stax 007 Omega2 headphones.  I bought the headphones based on the audition, but, when I told the dealer I was not getting as good sound from the phones as I heard in his audition, he replied: "of course not, you heard them through a Kondo M-10 and you don't own anything like that."

@pani A 40 Watt SET will have real problems making bandwidth. That is why the smaller SETs sound better as @larryi  pointed out.

Do yourself a favor- if you want to get the most out of your amplifier dollar, its not going to happen with an SET of that sort of power, and throwing more money at it won't overcome the problems you have with the larger output transformers needed to make that sort of power (and output transformer designer can tell you this). Either get a speaker that can be driven easily by an SET of much less power, or get a PP amp that can do the job properly.

There is no reason a PP amp can't be every bit as musical and involving as the best SETs out there; power notwithstanding. Its all a matter of good engineering and execution.

Here is something else to think about: when SETs are compared to PP its usually apples and oranges. The PP amp likely isn't class A, uses pentodes and probably also has feedback. How about level the playing field? How about a PP amp that uses the same power tubes as the SET, is also class A and zero feedback? When you level the playing field in this manner, you find out real quick that SETs just really aren't that good, while the power tubes themselves really are. Do you see what I'm saying?

 

@pani try and have a listen to the new Airtight ATM-1 2024 model. Heard it over the the weekend at Axpona driving some Franco Serblin speakers that I found very enjoyable. Lovely sound with good bass control and very open and transparent sound. Went back 3 times and each time it impressed me.

Apollo Audio systems (google them, audiogon won't allow a link) is reporting excellent results with high power SETs. He is a typical small amp company run by the genius and enthusiasm of a single gifted individual. I have no affiliation with them.

Jerry

If cost isn’t a concern, and best performance is, take a look at the Convergent amps. Nothing better overall, IMHO of course. Give Ken Stevens a call, or have your buddy call him. He may have some compelling insights for you.

I’ve never heard them, but the Cary 805s (monoblocks) reportedly sound glorious. I am thinking that they put out around 50 wpc of SET. I think that they are now going for around 12k per pair. You can check on that by going to Carys web site. I think it is carydirect dot com.

@pani 

Trying to stay with your stated quest, Aries Cerat Diana Forte. PSET 845 with 60 watts per channel. At the very least they are worth a look.

Charles

@pani

Ralph does make an interesting point. Most tube push pull amplifies are class A/B with NFB. So a pure class A zero NFB PP topology could be a potentially wonderful option with the TAD speakers.

Charles

There is no such thing ,a true 300 B SET is roughly 8 watts with big quality transformers and chokes ,you can run in pure class A using 4 tubes around 18 wpc 

thats it .. look up Radu Tarta he builds by hand 1 at a time as well as DHT preamps. I have bought from him several products all far better then commercials 

products and prices much better ,without the high markup.

Have you tried any other set amps with the TAD’s just to make sure that you actually need 40watts of SET? Sustained and peak current delivery kinda rules all in most of these equations, provided the ps is sufficiently healthy.

But yeah, 1 ohm dips can be a real beatch for amps not rated for it.

 

@audioman58

I have owned a 300b SET for 15 years and simply love it. However any DHT can be utilized in a SET amplifier. 2A3, 45, 211,805,GM70 etc. SET is not limited to300b.

Charles

Charles dad any 40 watt amp is not a true  SET it is considered A2 - 2 stage class ,

which still can sound good but not as clean Very high voltages up to 1500 volts..

 

@charles1dad reminded me of the GM70 so I went to Lampizator site to reread about it and they seem to be focusing on the 211 now (GM70 is Soviet, and I guess the war).  Their 211 SET makes 85 wpc.  

Apollo (mentioned earlier) only claims 50 wpc from their 211 SET but says "It depends how hard you want to run them."

Jerry

I am personally a big fan of a well designed Class A triode wired pushpull amp using a variety of tubes, EL34, KT77, KT66, 6L6, 5881. And I agree those aren't good speakers for an SET amp.

@audioman58 , this is someof what Cary says about the 805Rs:

the tube complement,per monoblock is

 

2 - 6SN7 input tubes
1 - 300B driver tube
1 - 845 output tube or (Please choose 845 or 211 during install)
1 - 211 output tube (Please choose 211 or 845 during install)

 

Circuit Type Single-Ended Pure Class A
Power Output 50 Watts Pure Class A

@jond Yep…..but like in most things… transformers matter… Roger Modjeski wound them himself.

@atmasphere Ralph… zero nfb glad to hear you utter those words…. ha.

@atmasphere @charles1dad @jond and others, it seems people are not warming up to the idea of SET here. And also there seems to be very few seriously good tried and tested choices beyond 25 watts. So what are some really good options for push-pull tube amps operating in class A with zero negative feedback?

Antique Sound Lab made some excellent SET amplifiers back in the 2000’s. You may want to research them as they can frequently be found for sale on the used market. Best of luck 👍

I purchased the NAT Audio Magma M mono block amps from OCD Mikey in Atlanta. They are SET and have two power settings, 50 WPC and 130 WPC. Mikey demoed them with the TAD bookshelf speakers and The TAD’s sounded really great! After hearing them together, Mikey and I both said we could have lived with that combination in our final rig.

I had the NAT Audio 805 Generators previously. They are also SET and push/pull. As awesome as those amps sounded, the Magma M’s are on another level! Just incredible! They’re definitely the last amps I’ll ever buy for the main rig!

The synergy with the TAD’s was really good but the synergy with Magico A3’s really blew me away, the match up is tremendous. Over the last three years, I’ve tried about 8-9 amps with the A3’s.

The comparison between the TAD’s I heard at Mikey’s place and my Magico A3’s is not a fair match up of speaker type. As I said before, had I owned the TAD’s and not the Magico’s, I wouldn’t be looking to replace the speakers after hearing them with the NAT Audio Magma M’s!

NAT Audio is still kind of a secret and good value in the hifi world. However, that is starting to change. I spoke with Mikey the other day and he told me that NAT is discontinuing the Magma New mono blocks. That model was one level above the Magma M’s and retailed for 40k. Mikey said NAT is coming out with a new SET mono block amplifier. It will be called the Magma EVO and the retail price will be 96k per pair.

There are pictures of both the NAT Audio Generators and Magma M’s in my virtual system.

I highly recommend consulting with Mike Powell (OCD Miley). He is a straight shooter that cares very much about his clients. He bends over backward to make things right if a problem arises with the gear he sells. He shares his honest opinion of what gear works well together and if that hurts feelings, so be it. I appreciate his honesty because I just want great sonics and if that means changing gear around to get there, that’s what I was willing to do.

I am not a tube amp expert.  I am being inundated with Upscale Audio ads.  I just saw a Western Electric integrated.  Has to be special ordered, so that could be a problem.  20W, 49 lbs.300B made in USA at their plant.  Sorry if I'm not on target, but this is a nice looking amp.

Email Paul at Bottlehead.  [email protected]
he can build you a SET with any power you want. 
he built me 33 watt per channel 838 monoblocks. 
He just finished a pair of 88 watt 833 tube amps. 
I listened to them the other day. They sounded amazing. I have a pair of 450tl tubes he said that he would be able to make a pair of SET amps that would put out 200 watts per channel. 
I’ll probably start ordering parts slowly and have him build me a pair.

 

I have not heard the new WE amp myself.  But, an old-school Western Electric fan who knows a lot about amps did hear it and thought it sounded quite bad.  You must hear it for yourself. 

As for non-SET alternatives, I mentioned the Italian brand Synthesis.  I have no idea about the specific topology, but, I do think that they sound good.  At a local dealership, a shockingly expensive array of amps have been traded in favor of much cheaper Synthesis amps, including Jadis and Audio Note amps that cost more than twice the price.  There are custom builders that probably can make something that would fit your requirements, such as Aric Audio and Don Sachs.

Although some Atmasphere output transformerless (OTL) amps are voice a little bit leaner than my personal preference, they make wonderful sounding amps--extremely lively and immediate sounding without being harsh or analytical.  I liked the MA-2 model I heard.  But, because they don't have output transformers, they tend to have a high source impedance that may not work well with low impedance speakers so you should consult with them.  Every serious listener should at least experience the sound of a good OTL amp even if they don't ultimately fit one's bill.

Post removed 

@brandonwade ,

I think you could have gotten your point across without swearing like that.

Yes, I find it offensive, crude, unnecessary, devaluing to your point and also against forum rules.

Audio Mirror / 45 watt single ended monoblocks using 2x 6c33 per block.
Used can be found for $2 - 3K. Good used value, sound fantastic and great customer service from Vlad.

Hey there, my name is Brandon Wade and I am the owner of Apollo Audio Systems, a Seattle based SET amplifier company and think I could offer some choices in higher output units. We are currently in development of 30w 211 ($6k per pair), 50w 810 ($14k per pair) and 88w 833a ($30k per pair)SET monos with the first of the 833a units built and ready for production, the 810 on the bench right now for the final massaging, and the 211 coming soon. Our goal at Apollo is to get fine SET gear into the hands of those who may not have been able to find them approachable due to both affordability and output power. For those who struggle to get full bandwidth response I say, that's too bad for you. Not a problem for us. Our -3db points often hover around 8hz and 22khz, full bandwidth power. Just about anyone can make a decent amp, not many can make them extended and refined. Another advantage of our amps is the way that distortion is delivered. The curve is exponential and starts ramping very close to clipping, this means that it stays low until your are really pushing them close to clip. This is MUCH better than about 95% of amps we've ever tested. I currently use our 20w 811a monos on Tekton Ulfberhts and it's enough to play me out of the room. If I move to any the larger models it's pretty over the top. I hand build each amp, offer custom powder coat and accent options for integration with our chassis or just to stand out, VCap coupling caps, Alpha silver clad point to point wiring, limited lifetime warranty and optional NOS tube compliments. I hand deliver and set up the 50w and 88w units for you as well. Images of the aesthetic of our devices can be found on our website. SET, for me, is just what my ears want to hear, it's why I changed my entire career path haha. I've owned Bel Canto, TONS of bottlehead, NAT, custom SET builds, and now our Apollo line. I listen to Apollo now. I love to talk about this stuff so let me know if any of this is sounding interesting to you and we can start a build to your specs. Thanks for your consideration. Brandon Wade - Apolloaudiosystems.com

 

@thecarpathian 

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What’s most disturbing is voicing a $30k Amp through a pair of Tektons….   

Audio Mirror / 45 watt single ended monoblocks using 2x 6c33 per block.
Used can be found for $2 - 3K. Good used value, sound fantastic and great customer service from Vlad.

+1, from personal experience and long-time owner of these amps. But if you have the budget pick up a new pair - still a great value.

I have been down this road many years ago and found a place where I have remained settled throughout the years since the end design for the Commission Built Amp's have been realised.

In my early days of Audio System Building, I migrated from SS to a Valve Pre Amp and PP Power Amp.

After the Honeymoon period, I ventured into the world of Valve equipment very deeply and was influenced by the SET Designs > Horn Speaker / Cabinet Speakers I was encountering. Following the profound experience a Tim De Paravicini Demonstration had on me, a whole new way of thinking about how I was to move forward appeared.

I was very much more aware of the Speaker Type I wanted to continue with, and how I wanted these to be driven.

I took the discussion to a very experienced Valve EE, and the Journey was embarked on to what was to become bespoke built 845 PP Monoblock Power Amp's.

These are a design optimised for the 845 at a 25 Watt Output, (following description might be a little off, its been a while), they are Class A, Linear, Feedback used ?? Point to Point Circuit with Hand Wound Power and Output Tranx.

At the time of these being produced there was little like them on offer as a Product, and one Brand was offering a 211 Monoblock @ approx' £50K.

I have not heard many set ups that can produce Headroom like these Amp's and have compared them to other Amp's over the years, they have always remained very impressive, and really get the best out of all Speakers met to date. 

The Thread in the Link, has covered the design / build of a 300B as a joint venture between two time served EE's specialising in Audio Equipment.

A offer has even been made of a very late in the development prototype, that would be a great experience, and possibly one that may be a keeper as I have found with my own experience.

 

nin  

Pani,

Your speakers are not exactly easy to drive at 85db 4 ohms. I'm going to echo what many have already said, and that is you night not be happy with a SET amplifier.....you may have to drive it hard to get what you are looking for, and that may take the "magic" out of a SET amp.

You have some really good recommendations, and I'll add one more. I'd give Aric Kimball a call at Aric Audio (Google search for information), to get his input. He gives very freely of his time, and sells a bunch of amps you may want to consider: a couple of 300B amps, a 2A3 amp, the Transcend "Push Pull" (is what I own), a KTand a pair of monoblocks.....several might be excellent for what you are looking for. He also loves custom builds, many of his current lines started out as custom builds

I know you said no solid state, but at least look at the specs of the CODA S5.5 class A SS amp......I have had one for about a month, and it's truly amazing; huge current delivery on hand

@brandonwade ,

Tap any post and a ’report this’ icon will appear. It will tell you to select a reason it should be deleted. One of those reasons is ’it contains profanity’.

Your foul language is against forum rules.

Capeesh?

"What’s most disturbing is voicing a $30k Amp through a pair of Tektons…."

😂

I have owned a 300b SET for 15 years and simply love it. However any DHT can be utilized in a SET amplifier. 2A3, 45, 211,805,GM70 etc. SET is not limited to300b.

@charles1dad 300b is about as powerful as you can get and still claim hifi bandwidth. The thing is, if the amp doesn’t employ feedback, you’ll get phase shift down to about 10th the upper cutoff frequency (-3dB point) and 10x the lower cutoff. This is filter theory.

The ear is terrible hearing phase by itself, but over a spectrum it can interpret it as tonality.

Phase shift in the bass due to a cutoff frequency not low enough is audible as a lack of bass impact. Phase shift in the highs due to a lack of HF bandwidth is heard as a darkness. So you need bandwidth well beyond the audio band to really get this part right; with no feedback ideally 2Hz to 100KHz or better.

@atmasphere @charles1dad @jond and others, it seems people are not warming up to the idea of SET here. And also there seems to be very few seriously good tried and tested choices beyond 25 watts. So what are some really good options for push-pull tube amps operating in class A with zero negative feedback?

@pani There is nothing wrong with feedback if its properly applied! The problem is, it usually isn’t. As a hint you can’t apply it to the cathode of an input tube since that tube will distort the feedback signal. That will cause IMD and higher ordered harmonic generation, both of which are not musical. This is one of the reasons feedback has a bad rap, but its not feedback’s fault so much as poor execution.

An advantage of zero feedback though is you get a ruler flat distortion vs frequency curve. This is important; if there is a rise in distortion at higher frequencies the ear will interpret that has harshness and brightness because the harmonics will not be masked (as they usually are in an SET). I know a PP amp that is zero feedback isn’t that hard to find. Take a look at the ’300b lovers’ thread on this site.

If you do feedback correctly you can get a ruler flat distortion vs frequency curve just like a zero feedback amp, but with lower distortion overall; just as smooth as any zero feedback amp, just as laid back, but with greater resolution since distortion obscures detail.

@atmasphere

300b is about as powerful as you can get and still claim hifi bandwidth. The thing is, if the amp doesn’t employ feedback, you’ll get phase shift down to about 10th the upper cutoff frequency (-3dB point) and 10x the lower cutoff. This is filter theory.

On technical grounds I won’t even try to dispute what you stated. I can only rely upon what I have heard. I’m very familiar with in particular two PSET 845 amplifiers (50 watts for each pair) that could suffer the bandwidth limitations you mentioned. I can genuinely say however that both of them sound superb and so natural reproducing music.

I am referring to the Absolare Passion 845 mono blocks and the Viva Audio Aurora 845 mono blocks. I don’t know how they conquer/manage the potential bandwidth limitations. I can attest that listening to music, Both are stunningly terrific! No doubt their respective designers/engineers could explain how they accomplished this.

Charles

@pani 

I own the Coincident Frankenstein 300b SET mono blocks. They also build a 211 push pull  (Class A zero NFB) mono block named the Dragon. It’s 75 watts per channel. By all accounts it is fabulous sounding.

Charles