What's the greatest bargain in SET these days?

Hi, Gang,
I response to my recent review of the Reference 3A De Capo BE speaker, someone wrote that if you really want to hear them sing, you should try them with a SET amp, or words to that effect.
That got me thinking. The De Capo's are 92 db efficient, which (correct me if I'm wrong) seems kind of borderline for low-power SET amps.
In any event, right now I'm running mine with a pair of Manley Mahi mono-blocks. They are switchable from triode (20 watts) to "ultra linear" (40 watts). I run them in triode all the time, and in my room, the volume knob almost never goes past 9 o'clock; more would just be too loud.
All that said, what do you guys think of running the De Capo's with a SET amp? And if I did, what's the best bargain in SET's these days?
Greatest bargain? Soryy, no idea. But, if power might be an issue then perhaps check out the monoblocks at Audio Mirror:


Love the 45 Watt SETs on my 89db monitors. Plenty of power and sound terrific. (NOS tubes all around.)
A friend recently got a used pair of the Audio Mirror amps, his have the 6H13C tubes, 20 watts PSET. Seems to like them a lot but I haven't heard them.

I agree that 92db seems borderline with a low power SET. I have a 2A3 SET at about 3 watts that probably would not be enough, but 300Bs would give 8 watts which might work. I used to have a Manley Stingray which I believe is the integrated version of your Mahis and I like the SET better. It all depends on what you like.
(Rebbi - I PM'd you on AA)
Sebrof summed it up well, it just depends on what you like (simple
statement but true). My speakers are 94 db/14 ohms so pretty close to your
speaker's sensitivity. I've used three amplifiers with them.
40 watt el34 push pull (PP), 100 W ultralinear (PP)/60W triode mode (PP)
and an 8 W SET 300b. The SET is unquestionably the best sounding of the
three amplifiers. Just my experience, your taste or desires could be very
different from mine and you'd choose accordingly.

Once caution about SETs, don't try to go "too cheap" seeking
value. These amplifiers need good quality output transformers and stout
power supplies to maximize their very simple but excellent sounding
circuits. Poor quality parts and transformers won't get it done and you'll
just be disappointed. If your speaker is an easy load, a well lmplemented
high quality SET can make that speaker sing.
Good luck to you.
IMHO greatest bargain in USED SET amps was the Cary 300SEI but its popularity seems to have increased over the years. At one time these could be picked up used for $1500 to $1700 ... now you are lucky to get one for $2200

GREAT amp with the ProAc 1sc I used it with. Not a perfect match on paper but sonically excellent. The 1sc is an 87db speaker but I used them in a small 12'x10' room
Rebi, I have a pair of deCapo Bes. They are sitting idle in my bedroom, along with a coincident dynamo amp and a Denis Had Inspire KT66. I also have 8 WPC Coincident Frankenstein amps. Give me a couple days and I will give you a rundown on how the 3 amps drive the deCapos.

I suspect the Frank's and dynamo will be fine, and the KT66 may be marginal.

Charles is correct with respect to transformers, but the inspire and dynamo are both decent inexpensive amps.
Hi Brownsfan,
I was recently wondering how these DeCapo BEs compare to the Coincident Triumph Extreme II, both are highly respected stand monitors.
Israel Blume said that despite the lower cost of the Dynamo it has good output transformers. I'm interested in how it and the Dennis Had amplifiers compare in your opinion. Brownsfan, it seems like you're having a ball of fun with your system these days.
I don' trust this SET story and I would be very careful to make an unknown investment. I have such Reference 3a speakers and they run with a lot of amps but not with flee amps. I think, you have a top combination with your Manleys .... The VERY best sonic result I ever had with these speakers (and still have) was with Lamm M1.2R mono amps...
I have a spare pair of 20 watt Audio Mirror amps that haven't been used since coming back from the factory. If you want those just say so in this thread and I'll put up an Audiogon ad. These are parallel SET and use the 6AS7 output tubes. I have maybe 20 spare output tubes. BTW, these have upgraded Jensen Superior caps. I'm certain they would meet your needs nicely.
So it sounds like the consensus is that "cheap" SETs aren't worth the trouble. I'll just have to keep an eye on the used market, I guess.
The Manley Neo Classic SE/PP 300b's are more than 9 big ones! Not in my future any time soon, short of hitting the lottery. ;-)
I was impressed with sound of glow audio amps I heard at a show a couple years back.
92 db is borderline for a set but might play fine to moderate volume with a lot of music.
I used to own DeCapo speakers and thought they were under powered with my Audio Note Meishu 300B driven SET (8 wpc) a bit flat it was and the Meishu is known for being a robust 8 watts...

I would stick with 20 to 30 watts imo.
Then there's this:

I used to own DeCapos and paired them with a Line Magnetics 218IA in a 3,000 sq. ft room. The LM 845s, the 218ia, 518 and 219 could be a consideration for you. LM SET amps overdeliver in their power ratings. The 218IA is a bargain in SET amps. The DeCapos are such an easy load that I never pushed the amp. I also tried the 218IA with speakers ranging from 86 to 99 db, 4 to 12 ohms with fantastic results. LM 845 SET amps provide numerous tube options to tailor the sound to your liking. Google Steve Huff's review of the 219. The 218IA and 518 offer similar perfotmance at a bargain.
Brownsfan has three SET amps he's going to audition with your same speaker, that seems very worthwhile for your search.Power ratings can be misleading, quality of design and built can trump mesured specifications sometimes.
Line Magnetic is another brand you may want to consider in addition to ASL.
I have the di cappos paired with an asl parallel 300b. The sound is pretty darn good and there is more than enough volume produced. The only down side is the amp requires 4 300bs. I have been happy with this combination....floats my boat you could say.

ASL is a decent valued product. Build is good and its all point to point inside. If you are inclined to DIY, then these amps can be improved quite a bit. If you know how to solder its really just..out with the old, in with the new.

SO, in response to your question, best bargain? Id say, see if you can get your hands on a used AQ1010 from asl. Even new they are affordable. There is enough power there to drive the di cappos.
Depends on the SET what you can drive. I have no problem driving 85dB (if that efficient) Infinity RSIIb speakers with an SET, to louder than I'd ever need. Just need lots of power supply storage (400+joules), 2500volts B+ and 62lb output transformers...
Brownsfan: Eagerly awaiting your results!
I was very impressed with the line magnetic 22 watt per channel SET amp I heard at Pitchperfect in LA. Brand new I think it is 4,500 bucks.

Looked very nice and sounded good.

The Shindo SET was freaking fantastic but big bucks.

I have been way impressed with almost all the SET's I have been in front of.
Actually, I believe that Brownsfan's Inspire KT66 is a SEP, not an SET. I tried Dennis' Inspire KT88 SEP with my 91 db efficiency speakers, and the sound was very disappointing. I really wanted to love that amp, I thought it would mate well with my Cary SLP-98P F1 preamp.

I tried all sorts of driver, power and rectifier tube combinations to try and get it to open up, alas, I could not get decent sound in my room. To his credit, Dennis gave me a full refund. I do know of others that love his amps, so it is still probably worth a try, even though it did not come close to working for me.
This is what I mean, these low power amps cover a wide spectrum from poor to sublime performance.Some have said the Had amps lack good quality transformers(I have no personal knowledge to confirm or deny). I sure wouldn't judge SET/SEP amps on this one example. This is why I believe Brownsfan's three amplifier comparison driving the same speaker is going to be quite interesting.All 3 with the same power rating but very different design and parts quality approach.
JMC, you are correct regarding the KT66, but I did want to throw it into the mix since I have it on hand. If it turned out to be a stellar performer with the deCapos, I'm sure ReBbi would want to know, SET or not.

With a very quick, initial listen back a couple months ago, the Inspire KT66 was much better with my Coincident Triumph Extreme IIs (94 dB) than with the de Capos. That was a 10 minute audition a while ago, so I think a more serious listen would be prudent.

Rebbi, I just got back in town after a whirlwind tour of the upper midwest. 1480 miles in three days, trying to get 3 kids back to school in two different states. I will get on this tomorrow evening and get you some preliminary results over the next couple days.
Very kind of you. Recover from your travels and take your time. :-)
I tried decappos with quicksilver 300b amplifiers in a 12x16 room. Not enough poser. Distortion at higher volumes.
Maybe a 211 type amp.
Peter_s: What kind of output power on those quicksilvers?
Just 8 watts per amp. Very good transformers on the Quicksilvers. I would experiment with 845s or 211s.
If your into great value for money, and not glitz factor. This guy in Japan makes some very good SE and PP tube gear, and has a large underground following.

I've done some tests on his earlier 2a3 se and they were very good and are solid well made designs.


Cheers George

Hello George,
880.00 is an exceptionally low cost for a 300b SET and a total amplifier
weight of "19 pounds" is very light. This would suggest that the
transformers are quite small and compact. Most high quality 300b amps
are considerably heavier due to the robust and heavy duty transformers
and power supply they require. These factors are the heart and soul of
SETs and separate the excellent from the mediocre. Given your familiarity
with this brand, how good is their drive capacity and sound quality across
the full frequency spectrum? I'm curious as really good 300b SETs don't
come dirt cheap. At least that's been my experience so far. I'm not implying
amplifier weight is the sole factor, however transformer and power supply
size and quality are crucial for successful SET performance. Just a relative
comparison, my SET has a total weight of 68 pounds for the same 8 watts.
Look at the weight of Line Magnetic, Border Patrol, Viva, Mastersound,
,Wavelength and other highly regarded SET models. Could this small amp
be a David amongst SET Goliaths?
Thanks George,
Hi Charles, as you may have noticed he makes uses and sells is own R-Core output and power transformers, people and some hard core techs I know swear by them, far better than toriodal and better than EI core, is their responses. From what I Googled quickly, R-Cores are half the size and weight for the same EI spec, but have the advantages that both have and none of the disadvantages, but are very difficult to manufacture (wind) compared to toroidals and EI's for small companies like this guy Shoichi.

The 2A3 SE I had here for a while (it's at the bottom of his page discontinued I think.) Was for me impressive on a pair of NS1000's I had here, up to a point, they were after all only 2 or 3w.

Then I (under cover)took it around to a friends place who owns a pair of massive 4 or 5 box Goldmund Speakers the one with the cradle frame that staggers the boxes up to the ceiling. I told the owner to go away for a 1/2hr while I wried up the 2A3 so he couldn't see it. When he walked in he was floored by the sound.


Myself I'm still a big current high biased Class A Solid State lover.

Cheers George
Hi George,
Thanks for your reply. My SET uses double C-core transformers. I don't know how they compare /contrast to R core types.Regarding your choice of amplifiers, that's what I love about High End audio. There's something available for all of our preferences.
Charles just found some one who can explain why R-Cores make for very good output transformers, for triode SE amps here's what he said.

"Actually they appear to work and sound very well.
Maybe they are not so popular because you get lower inductance in comparison to Fe cores (of comparable size). This is more o less the same for other amorphous cores.
However they have a much smaller coercive field (near to zero) and tighter hysteresis loop that makes them more linear devices. In other words they have lower eddy currents losses and lower hysteresis loss. The permeability is higher and more costant (as function of the induction B) however when you place a gap for DC application it reduces to smaller values than those of a conventional core (i.e. same turns = less inductance).
They work very well with low impedance devices, like triodes, much less with pentodes.

One factor that definitely works against the R-core is the difficulty in winding. The coil former has to be placed on the core first, only then can the coils be wound. That's why you'll see a plastic gear on the formers."

Cheers George
"I run them in triode all the time, and in my room, the volume knob almost never goes past 9 o'clock"

Keep in mind that this has very little to do with the power of the amp, and everything to do with the input sensitvity and voltage gain.

I appreciate that explanation about R core transformers. I'm going to do
some reading and get a basic understanding of the various transformer
types. My amplifier builder definitely prefers double C core. Certainly each
person would cite the advantages of their respective transformer choice. As
usual, implementation and execution matter significantly regardless of the
transformer selected.

You're right regarding the volume control settings and usable range.
Amplifier sensitivity, gain, speaker sensitivity and preamp gain level (also
source voltage output) are all important variables.
For an example, very high sensitivity amplifier input voltage =0.5v.
A low sensitivity amplifier input voltage=3.0v.
Rebbi, I’ve had a chance to get some listening in over the last couple days. I have a lot of thoughts, but I will try to confine them to the relevant questions.
1. Can an SET amp satisfactorily drive the deCapo Be’s ?
2. Would such an amp represent a substantial improvement over your Mahi’s?

I have some preliminary impressions to share. First of all, let me give you a brief summary of the system into which the 3 amps were inserted for comparison.
The source was a ModWright Sony HAPZ1, feeding a Coincident Statement Line Stage preamp via VH audio Symmetry ICs. The preamp fed signal to the amps via a VH audio Spectrum Ag IC. Signal out to the speakers was via Coincident CST 1 cables. My Coincident Triumph Extreme II monitors were available for reference. The 3 amps available were Coincident Frankenstein 300B monoblocks, a Coincident Dynamo stereo amp, and a Dennis Had Inspire KT66 amp. In addition, I have recent memory of the deCapos driven in the same system by my now departed Cary 500.1 SS monoblocks, which are 500 WPC into 8 Ohms.

Music used for the evaluation were the following albums played back via the MW Sony HAPZ1. Shostakovich, Symphony No 13, Babi Yar, Mahler Symphony No 3, Neil Young, Live at Massie Hall.

At the outset, let me say that the Inspire KT66 isn't going to be suitable for anything but low dynamic range acoustical music with the deCapos. I evaluated both the KT66s and EL34s, and both 6SN7 and 6SL7 inputs. The 6SL7 was certainly a better choice. The KT66 tubes were better than the EL34s, but really, no matter what I did, mid bass and below was very soft. It is not an SET, but it was around, so I threw it into the mix. The amp mated well with the speaker above the mid-bass, producing some heavenly tones utterly incoherent with the soft, slow, muddy lower registers. It gave a plausible presentation with the Neil Young, but utterly failed on the Mahler and Shostakovich.

The Dynamo was a much different story. Keep in mind that the dynamo is brand new. Last night was its first time out of the box, so there is still some break in to be had. Keep in mind also, that this amp is using the cheap Chinese new production tubes that are supplied, and they also have no break in time. All that said, I immediately perceived some synergy between the dynamo and the deCapos. I am pretty excited about this pairing for my bedroom system, especially since the dynamo has volume control and won't require a preamp for a single source system. There were some issues. The upper registers became hard and unpleasant when driven too hard, say, 94 dB+, and there were indications that the Dynamo fell short in the lower registers at high volume, although the low strings were generally well reproduced. I suspect the harshness in the upper registers will be addressed with burn in and tube selection. Perhaps the lower register issues can be mitigated also with better tubes (especially the rectifier). That said, the Dynamo drove the deCapos well through the first movement of the Mahler 3. The sharp, quick, tympani attacks were handled well. Of more concern were the sustained low strings passages. These were not handled as satisfactorily as when the deCapos were driven by the Franks or the Cary SS amps. There were some stunningly beautiful moments. At about 10 minutes into the final movement of Babi Yar, there is a bassoon solo followed by a violin solo. The Dynamo/deCapo combo reproduced this with a harmonic sophistication unmatched by any other combination of amps and speakers I tried. Yes, even the Franks with the deCapos or the Triumphs with either the Franks or the Dynamo, did not match the level of shear beauty in this short passage. It is important to reflect on this, in that it underscores the importance of system synergy. It is also important to note that the beauty of this passage hit my emotional response button in a big way. It is that response that fuels my obsessive expenditure of cash, so this was a big deal for me. It is also important to not take this out of context. For most of the rest of the music, the Franks were far superior to the Dynamo.

My very preliminary listen to the deCapos driven by the Coincident 300b Frankensteins was more than satisfactory. Again, this was a quick preliminary listen, but the Franks drove some clean 99 dB peaks in the treble with no distress. My thinking with the Dynamo is that one should probably go no louder than 95 dB peaks at the listening position, in my case, back about 11 ft from the speakers.

So can a flee watt SET drive the deCapos? I would argue yes, based on my limited experience in driving them with the Coincident Frankensteins and Coincident Dynamo. Some of this will depend on music preference, room size, listening levels, and ancillary equipment, but it is something that can work very nicely.

I could make a case that the Franks drove the deCapos better than the Cary 500.1s. This is not just a simple case of WPC. The Triumphs were clearly better than the deCapos with the Cary SS amp, but the gap closed substantially when the two speakers were driven by the Coincident tube amps.
I appreciate the effort, time and patience it requires to carefully compare
three different amplifiers with a speaker and listening to multiple
recordings, thank you. My gut feeling for the Dennis Had amp's diminished
bass region and symphonic music performance is traceable to the power
supply and transformer quality. The Dynamo and the Had amplifier have
identical watt ratings yet you noticed a considerable performance gap
favoring the Dynamo. The Frankenstein's higher level outcome isn't
surprising, it doesn't have the cost constraints and can utilize superior
parts(and bigger/better transformers) without that concern. Symphonic
music at 99 db SPL peaks
presented "cleanly" with the monitor sized 92 db sensitive
deCapo is very impressive. Interesting your comments in comparing it to
the 500 watt Cary SS amplifier in terms of driving this speaker. The brand
new Dynamo should get quite a bit better with adequate burn in and better
tubes as you noted.
Charles and Rebbi, when I first purchased the deCapos, the Cary SS amps were all I had around here to drive them with. Based on their performance with the Cary's I had a hard time figuring out why so many people were so enraptured with them. They were good, but clearly a notch below my Magnepan 3.7Rs. When I picked up the Triumph extreme monitors, they, to my ears, really separated themselves as superior to both the Maggies and the deCapos.

It seems the deCapos are a different animal driven by tube amps. I am very pleased with how well they pair with the dynamo. I suspect that paired with a good source, this will be exactly what I wanted in my bedroom system.

What I can't answer is how does this relate to the Mahis? I've heard the neoclassic 250s, but not the Mahis. I suspect the Franks would be a good step up from the Mahis, but this exercise taught me not to presuppose results. I can't even begin to speculate on the Mahi's vs the Dynamo.

We listen with our ears and our brains, not with our brains alone. What is also unpredictable is how a given individual will respond to a given presentation.
How amazingly generous of you to take all this time and trouble! I really appreciate it. And thanks for the notes about the Concident amps. I wasn't aware that Concident even marketed amps, I'd only heard of their speakers.
I have been in touch with both Tash Goka of Ref 3A and Steve Deckert of Decware.
Tash says that the Antique Sound Labs ASL AQ 1005 DT (8 wpc) was designed with the De Capo in mind and will drive it quite nicely. It's a 300b based SET. It retails for $3000.
Steve Deckert recommended his 6 WPC, EL34-based SET, the Decware SE34I.4, which he said would sound twice as good (!) as the Manley (for a variety of reasons which he enumerated) and fall to the Manley only in terms of overall power. In other words, if I wanted to "crank it" then the Decware wouldn't play as loud as the Mahi's. But, he added, "in the end it will sound so good you won't care." The stock SE34I.4 goes for only $1300 with one input and one volume knob. Other inputs can be ordered at extra cost in order to negate the need for a preamp altogether.
Brownsfan (and everyone), what'cha think? ;-)
Rebbi, no problem, my friend. It was a lot of fun and provided a nice diversion from some mind numbingly boring chores. It also gave me a chance to firm up my plans for my bedroom system. I'm sticking with the deCapos, and I will be driving them with the Dynamo.

As for what I think, I will offer two thoughts.
1. I think you will be very happy with what you hear if you pair your deCapos with a good SET!
2. I think Coincident makes very good SETs, and both the dynamo and franks are excellent pieces at their respective price points.

I haven't heard the ASL or Decware amps, so I can't comment on them.

I've got a pair of Ref 3A MM de Capo i speakers that I've run with a number of different amplifiers. They are very sensitive to amplifier quality and as Brownsfan has noted, they seem to "click" with certain amplifiers. Low power SET amps do well and it might be that they're tuned for amplifiers with the relatively low damping factor of SET amps with minimal feedback. The best sound that I've gotten out of mine is using a restored Threshold FET 10e preamp and a homebrew 2A3 SET amplifier based a design out of the old Sound Practices magazine. I've also listened to them with a Shindo Apetite - a push-pull 6V6 integrated amp and that combo also sounds very good. But the 2A3 SET has a certain charm that I miss when listening to the Shindo. If starting from scratch, I'd suggest getting a 2A3 SET amp or perhaps the Coincident amp that Brownsfan recommended. I see some decent used 2A3 amps on the Gon right now. No connection to any of those sellers.
It seems you have a number of very good options and the blessings of your speaker's builder(recommending the ASL 300b SET) as regards to SET/SEP amplifiers. The key take home point is "quality" of the particular amplifier as Brownsfan confIrmed with his listening results. You will obtain exceptional sound quality driving your deCapo with the appropriate SET or SEP(Dynamo or the Decware).The marvelous Frankenstein(6K) may be overkill for your stated goal(bargain price).I have a bias/preference for DHT tubes over pentode tubes but that's just me. The SEPs are generally less expensive than a good SET(DHT).Either way, you will do fine.
Charles and I have had similar experiences. SET amps are not created equal. IMHO there is more variation among them than among SS amps, for example. It is as if the simple circuit and low power of the SET design makes it more susceptable to the components chosen - starting with the power supply, the output transformers, and the rectification and including the tubes themselves. Along these same lines, it is as important to match the SET with the speaker. It is not just the power, but the execution of the design.
Yep, Just looking at the number of watts can be misleading. There's certainly more to take into consideration. Amplifier- speaker matching can be very specific.
Rebbi ;
Please keep me apprised as to what you finally decide upon .
PM if you want . As we discussed on AA , we are interested
in the same thing here .

Brownsfan ;
I would be quite interested in knowing how that Dynamo works
out after everything is run in . Please PM me if you wish .

Happy Tunes
Saki, Will do. Be patient, the dynamo is for a bedroom system for which I have not yet bought a source. However, I think I will leave it downstairs and use it for background music during the day while I am working around the house so I can get some hours on it. It is shockingly good for the money. I really want to see what some hours and a better tube complement brings.
Saki: Will do.
Rebbi, you might want to take a look at Audion. Good value, very well built.
Drubin: Thanks for the tip. Gorgeous stuff but out of my price range, sadly.
"It's shockingly good for the money"
Brownsfan, one might get the impression you like this amplifier, LOL.
Would it be fair to call it a Frankenstein jr? Or son of Frankenstein?
Charles, good question. I'm inclined to say no, it's not a Frank Jr. I like the dynamo a lot, and have listened to it for hours on end for the last 3 days and have really enjoyed it. The more hours I put on it, the more some of the harshness at high frequency subsides, so it is clearly not close to being burned in yet. Yet, when I put the Franks in, Oh my! They are most certainly in a different league, and are worth every penny of 5 x the cost of the dynamo.

The incredibly rich harmonic pallet, seemingly endless power reserves (no, that is not a joke), and the beautiful air, breathtaking decays, etc that make the Franks what they are won't be there in the Dynamo.

Think Monet vs Ansel Adams. Both great artists and I love them both, but they are very different.

To me, the Franks don't sound like a tube amp. They certainly don't sound like a solid state amp. They don't sound like any other amp I have ever heard. I guess that is what Israel means when he says the sound like nothing.

The dynamo sounds like a good amp, with all the clues to let you know it is a tube amp. You get enough of that big beautiful, fat, tube bloom in all the right places to let you know its a tube amp. It has me wanting to see what kind of tube loveliness I can dial in with some tube rolling.

With the Franks and a great piece of music, I just sit there in awe. When I run for president, my platform will be "A Frankenstein in every house!" Wonder how that will play?