SET amp owners thread

213Cobra

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. Given your power problems, an isolation transformer might be in your future.

Kingrex/QUOTE]
Isolation transformer sound horrible. I have tried a few. They do knock noise down. But you hear them all. I believe it is better to get gear built to handle the noise. My other equipment does not seem that sensitive to it.

I just bought a new fluke meter. Been working with an engineer on how to rid spurious voltage that builds between the ground and neutral. You know, the voltage that just happens when you put 2 wires next to each other and pass current through them (inductance). I have been able to knock it down from 70 volts to 52 volts at a friend house. I need to do some more work to get it under 20 volts.

Harmonics off the utility are more a problem I cant solve without physical equipment. Physical equipment always seems to change the sound. It's just not as musical. So far. Great minds are still working on ways to solve the issue.

But I'm degressing. I do see a few of those Black Shaddow show up used. They appear to be 92 db quiet. Hmmmmm. The Whammerdyne says they are 115 db quiet. That's a big difference. I wish I know what my amps were to have a baseline.

Some isolation transformers sound just fine. A few improve an amp, rather than just isolating from noise. Bob Hovland makes an isolation xformer that is designed to operate close to its saturation point, on the theory that doing so makes a connected amp sound more relaxed. It does. No deleterious effects. The limit is that each xformer is rated for 2.5A steady, 4A peak, at 120v. Which is fine for me. But you might be covered by the power supply in your chosen amp, e.g. Whammerdyne.

Getting -115db noise in an SET amp is a feat and it is easier done with a 2a3 or 45 triode. -92db in a Black Shadow is pretty quiet for an 845. The high B+ voltage and the necessary filament supply make further noise reduction more challenging and you quickly enter into a zone of trade-offs between quietude, cost and tone. One thing that further mitigates the noise difference is that the Black Shadows have 0.7v input sensitivity, so even with a TVC, let alone an active preamp, the input level control will be turned way down to give the control unit useful range on the volume control. In practice the amp is very quiet. With SET you can also get RF noise that is not getting in through the power supply but sounds like it might be, simply because depending on your RF environment, SET amps are sometimes an effective antenna. In any case, yes my Black Shadows have more intrinsic noise than various 2a3 amps I've tried, but in exchange they deliver vastly more shove and the noise isn't a problem. On anything analog, amp contribution is overwhelmed. On digital, it's not enough to bother with. I recently had a pair of -117db power amps in. They were certainly quiet when listening to nothing. No source could really take advantage of that, however.

Phil
 

Kingrex

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You may well be right Cobra. I have by no means tried all the different power conditioning devices out there. It's such a situation, equipment dependant result. I had a SS amp years back and a Isotek Syncro sounded great on it. Not so on other amps or front end gear. Maybe it wouldbe more accurate to say I want to find quiet amps that don't take additional filtering on my end to make them work. I'm going to dig around more on 845 amps. I don't need to jump. Any other suggestions on brands to consider.
 

bonzo75

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You should get to 211 and 845 if lower powered tubes do not have sufficient headroom for you.

After single ended 2a3, there is NAF 2a3 as parallel 2a3 which has sufficient drive. If that sounds good, it will be better than 211 and 845 amps. If it lacks headroom, make the jump to 211. If that works, buy an expensive pair of Amperex 211 tubes will be a massive jump. For example, for horns universum, you need to go with even more wattage.

It all depends on the speakers.. Some just work better the lower you go, some work the opposite
 
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advanced101

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What is the minimum wattage you would recommend for the hORNS Universum?
 

bonzo75

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What is the minimum wattage you would recommend for the hORNS Universum?

Kronzilla. Maybe lamm will work it seems to have a lot of drive based on Tang's videos, given that his previous Ayon amp was 60 watts and the lamm seems to have more drive with lesser wattage.

Allnic a6000 will work and used price is great.
 

Exlibris

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You should get to 211 and 845 if lower powered tubes do not have sufficient headroom for you.

After single ended 2a3, there is NAF 2a3 as parallel 2a3 which has sufficient drive. If that sounds good, it will be better than 211 and 845 amps. If it lacks headroom, make the jump to 211. If that works, buy an expensive pair of Amperex 211 tubes will be a massive jump. For example, for horns universum, you need to go with even more wattage.

It all depends on the speakers.. Some just work better the lower you go, some work the opposite
I'm considering using the Unison S6 as an amp. EL34s in parallel, ultra-linear mode, for about 35 watts.
 

bonzo75

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The more power you require the more you can end up spending for good electronics. Ideal is to get a speaker that runs on lower power.
 
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the sound of Tao

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I thought both those were integrated amps? Are you saying the built in preamp section is not as good. I also have PAP Horn setup and was looking at LM integrated as an option. So your experience and feedback is greatly appreciated.
Even with a pre in play you are still using the LM’s input valves. I just prefer the LM via the Microzotl but also I prefer even going via the Shindo but this is not as beneficial.

The combination of the LM 805s with Microzotl just happens to do everything right for me (most amps don’t do this for me) and this pairing sounds convincingly alive and natural and leaves me only enjoying more music and not thinking about where anything might be better or even different. But that doesn’t mean that a different SET amp might not be better again just this is working for me with the paps after a lifetime of wanting change.

I’ve left any thoughts of other upfront combos for the Pap horns or the Harbeths behind now. I am happily SET on these.

If I go ahead with diy horn project I’ll be aiming for a higher sensitivity again so I can then explore Type 50, 45s and 2A3 valve amps.
 
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Solypsa

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If that 'neohyb' circuit trickles down to sub $10k amps it could be perfect for this scenario ( kingrex PAP speakers)....

Aside from the Silvercore 833 I wonder if his 300b-xls amp would do it ? (15w)...
 

213Cobra

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You may well be right Cobra. I have by no means tried all the different power conditioning devices out there. It's such a situation, equipment dependant result. I had a SS amp years back and a Isotek Syncro sounded great on it. Not so on other amps or front end gear. Maybe it wouldbe more accurate to say I want to find quiet amps that don't take additional filtering on my end to make them work. I'm going to dig around more on 845 amps. I don't need to jump. Any other suggestions on brands to consider.
Generally, I agree with you about power conditioning. But pure isolation transformers are much more uniformly beneficial. Just magnetic / galvanic isolation.

I don't overall favor 845 SET amps; just a few. Most sound heavy-handed and sacrifice too much speed, agility and transparency to deliver their grunt. But the tube does deliver grunt. Spiritofmusic here has a large room and moved from Audion to NAT to get 70w instead of 24 from 845 PSET. He needed more drive for his room and now describes the Audion sound as a little lightweight. But I've never heard an NAT amp match Audion's agility, speed and transparency. You're just only getting that at 24w max. In your room, with your speakers and your preferences, that will be plenty -- IF you accept the rest of what comes with a high-current, thoriated tungsten filament and the sparky high plate voltage. The Sophia 845 mono amps can also sound very fleet and transparent if tubed for that goal. The latter production units were, I thought, an over-stressed design and $20,000/pair, with the sacrifice being to reliability. But used 1st gen units can be found well under your $6K target, and with one modification for reliability, plus prescriptive tubing, can also be quite similar and sonically satisfying. Even more than most tube amps, 845 SET are highly voiced by the choice of power tube, and there are several tuning vectors achievable given the differences between KR, Psvane, Shuguang, Full Music, Sophia, Meixing, Golden Voice, Elrog, NOS United, RCA, Amperex, Cetron, WE and then in many cases multiple flavors from a given brand.

Also if you can find one of the original Art Audio 845 SET stereo amps, you can get it within your budget, used. The reborn brand making new ones are much more expensive now. If you discount the plethora of Chinese brand 845 and 2a3 amps on eBay, the range of exceptional sounding options is relatively narrow. More options abound in 300B SET, but that is a somewhat different sound from what you describe you are seeking.

Phil
 

morricab

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I've made some inquiries and the Kronzilla SX is, unfortunately, beyond my budget. I'm going to look into the Aries Cerat Genus stereo amplifier.
My Odeon amp of choice :).
 

morricab

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I've been using SET amps for over 20 years but didn't originate my interest via the SET cult community. My speakers are 101db/w/m, so several db more efficient than PAP (which I've heard), depending on which version and vintage of the Trio 15 you have. It's true that a competently-designed and built 2a3 SET amp can produce truly excellent bass character and with Joourney-to-the-Center-of-the-Earth excavating depth. It's easier to get uncompromised deep bass out of a 2a3 than from a 300B design, generally. But when people say that 4-6 watts of triode power is perfect for a 90-96 db/w/m/ speaker, you have to start querying their true listening habits, particularly for how much they value dynamic life in their music listening, and then actually indulging in it. I don't know where you are, but for example, a Tokyo-dwelling SET / hi-eff speaker listener espousing the perfection of 2w 45 SET amps or 4w 2a3 sound, has to be inferred considering his or her context. They may have much different priorities than you.

In other words, a great 2a3 SET amp can qualitatively deliver convincing bass through your PAP trio 15s, but will it be musically-convincing if you value dynamic life in your music, and sense a looming ceiling on headroom? That depends on you, your room, your habits and expectations.

I stopped trying to get rich sound out of KT88 tubes 20 years ago. There is just something there that puts a little grit and gloss in sound that doesn't belong there. KT66 is more interesting and musical, along with its 6L6 counterpart, and of course the venerable EL34 when you can find good ones. I am not surprised you find your 811 amp too thick. I think for your speakers (what are your room dimensions?) a better combination of power and single-ended incisiveness is likely called for. You mention you don't want "lean and clean," but instead "warm and clean and accurate; truthful to the source." But isn't there a contradiction in that wish? "Warm" is almost never truly accurate, but it is euphonic. Can "warm" be truthful to the source if the source is "cold" or "lean and clean?"

I find that a well designed 2a3 push-pull amp can really help here. You'll get about 13 w, bass can be phenomenal, and if the design is simple, it will be absent the subtle grit of crossover notch distortion. But if you want that 4w purity with more oomph, you can have a 2a3 PSET amp built for roughly the same output. You need the amp to have an oversize power supply and simplicity for fast, agile, communicative sound. You'll get enough warmth without the bloat common in many (not all) 300B implementations.

845 amps provide another path for SET with much more shove. Not long ago, most 845 tube options brought anywhere from a little to a lot of thickness with them. That's been changing. Psavane, Elrog and KR have exotic (and expensive) options. But Tube Amp Doctor has the relatively new Shuguang 845C Iron Plate 845 built for 95w dissipation rating. The earlier 70w dissipation 845C metal plate had a bright, fleet-footed voicing but many 845 amps had to be re-biased for it lest it cherry with short life. The new iron plate has higher heat dissipation and can be dropped into almost any 845 amp. It is noticeably quicker than the 845B and other graphite tubes, and when combined with an intrinsically fast and transparent design like the Audion Black Shadow, it delivers a particularly objective sound.

Another option is something I haven't seen on the market yet but which I am thinking about commissioning. The KT150 tube is the best sounding of the modern production kinkless tetrode tube designs I've heard. A single-ended tetrode amp using the KT-150 should yield a solid 25w. Paralleled, you can get to 40-50w. Push-pull, 60 - 75w. Single-ended pentode-and tetrode amps can resolve the conflict between SET purity and pentode/tetrode push-pull compromise. And you get some interesting alternatives aside from KT66, EL34, 6L6. The NOS German EL156 and F2a are particularly interesting for their combination of bandwidth, linear performance and exceptionally long life for power tubes.

But I fully understand if you want to stick with SET. Before you commit to 4-6 watts via 2a3 SET, understand the priorities of the person recommending that, and find a way to listen to your system, in your room, on music that is vital to you, to determine whether it works for you. For me, on 101db/w/m speakers and a 21'x14'x8.5' only partially bounded space, a 4w 2a3 SET amp is one tool in the shed. But most of the time it would be benched, because the headroom ceiling is palpable on highly dynamic music.

Phil
I think IconAudio is making a KT150 SEP.
 

morricab

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Lamm and Kronzilla are obviously more money.
The 18 watt Lamm ML2s will be borderline. The Genus will be sufficient and cost less than half the price (ok European price...not sure what they are asking in North America). Konzilla SX might be ok but it is not as powerful as it looks on paper. Genus has an atomic powerplant inside as it is seemingly endless (until you compare it to Aries Cerat Concero 65 monos) in power delivery (despite the 25 watt rating).
 
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Exlibris

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The 18 watt Lamm ML2s will be borderline. The Genus will be sufficient and cost less than half the price (ok European price...not sure what they are asking in North America). Konzilla SX might be ok but it is not as powerful as it looks on paper. Genus has an atomic powerplant inside as it is seemingly endless (until you compare it to Aries Cerat Concero 65 monos) in power delivery (despite the 25 watt rating).
Does the current production Genus now use an 845 instead of an 813? If so, has anyone compared the older model to the new?
I'd love to hear one before buying and that's largely because I've never heard a 211 or 845 amp that I've really liked. I've always been more of a 300B, EL34, 45 guy. Even when it came to tubes I'd prefer the warmer and sweeter varieties of the tubes to their new (clean and powerful) counterparts like the EML 45 solid plate or the 300B XLS.
 

Exlibris

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Does the current production Genus now use an 845 instead of an 813? If so, has anyone compared the older model to the new?
I'd love to hear one before buying and that's largely because I've never heard a 211 or 845 amp that I've really liked. I've always been more of a 300B, EL34, 45 guy. Even when it came to tubes I'd prefer the warmer and sweeter varieties of the tubes to their new (clean and powerful) counterparts like the EML 45 solid plate or the 300B XLS.
I also always preferred the sound of 45s in my amp over the sound of 2A3s.
I say all this just to indicate what I'm looking for in a new amp. I think it's the sweetness, musicality, flow, emotion, and humanity that I gravitate to and, though I want power and headroom, I don't want to sacrifice the former.
 
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morricab

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Does the current production Genus now use an 845 instead of an 813? If so, has anyone compared the older model to the new?
I'd love to hear one before buying and that's largely because I've never heard a 211 or 845 amp that I've really liked. I've always been more of a 300B, EL34, 45 guy. Even when it came to tubes I'd prefer the warmer and sweeter varieties of the tubes to their new (clean and powerful) counterparts like the EML 45 solid plate or the 300B XLS.
Yes, current production uses the 845 (from Elrog I believe). I haven’t heard it yet but word from Aries Cerat is that it is slightly more forgiving than the 813 but the main qualities remain intact. The change came because of supply issues with 813s.
 
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bonzo75

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I also always preferred the sound of 45s in my amp over the sound of 2A3s.
I say all this just to indicate what I'm looking for in a new amp. I think it's the sweetness, musicality, flow, emotion, and humanity that I gravitate to and, though I want power and headroom, I don't want to sacrifice the former.

I like both 45 and 2a3 and 46. With 2a3 you get a bit more power where required. If not required I would stay with 45 and 46 and try type 50
 

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