Whammerdyne - maybe best...for a price...
Looking at Triode Labs for great price/performance.
New Audio Frontiers Performance 2A3 MkII - reportedly one of the best 2a3 sonics
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@edle The US was first to move away from SETs because superior technology appeared, developed in the US. Although SETs can be fun, they really don’t stand up to a other, later technologies, even on easy to drive speakers like the Duos. If you are looking for the nth degree in neutrality and musicality look elsewhere. One problem is any SET that is zero feedback has only about 20-25% usable power with respect to full output. This is because if pushed past that power level, any zero feedback SET will start to sound ’dynamic’ due to distortion appearing on the leaded edge of musical transients. This is a problem unique to SETs. In a smaller room this would allow Duos to work with a 2A3 amp depending on the music. Another problem is poor bandwidth, which results in phase shift at either end of the audio spectrum. Phase shift in the bass is heard as a lack of impact in the bass. Phase shift in the highs is heard as a darkness. Usually 2A3s are pretty good about bandwidth, but to really get it right without feedback you need full power bass response to 2Hz (to prevent phase shift at 20Hz) and the highs need to go to 100KHz (to prevent phase shift at 10KHz). There are tube amps that can do 2Hz full power but they aren’t transformer-coupled. That said, Whammerdyne hasn’t been mentioned yet and is one of the best 2A3 SETs I’ve heard. But you can do better than any SET on the Duos. There are even class D amps that more than give SETs a run for the money- every bit as smooth, more detailed, yet relaxed and involving.  |
Another vote for Moth, especially if you have Craig Uthus, the original designer, now at Eddie Current, do a power supply mod to it. I talked about this in SET Asylum but I'll recap it here. Craig created an outboard power supply connected via military-grade umbilical to the amp, mounted the 5AR4 rectifier on top of the PS box, and converted the amp from DC to ultra-high-frequency, 40kHz AC on the heaters. The power supply is regulated and much stiffer now, and the amp runs far cooler. It should last pretty much forever. Here's some of the technical info Craig sent me: The power oscillator board is comprised of a discrete 18 watt power amplifier designed to run continuous sine wave power. The amplifier has current limiting, and provides a soft start for the DHT's when they are cold. On the amp is a plug in surface mount crystal controlled 40kHz oscillator board with output level adjustment. A single twisted pair brings the high frequency sine wave up to the amplifier chassis. Inside the amplifier at the tube sockets are a pair of ferrite core transformers, which provide isolation from the power oscillator and drive the 2A3 heaters. The transformers are wound 2:1 so 5V in is 2.5 volts out. The high frequency is calibrated to exactly 2.5V at the tube socket with the tubes operating. I'm not a tech guy; I'm a listener. How does it sound? Fantastic. It's immensely improved, and it was really good to begin with. The sound is much more liquid and organic without losing any detail, and the sound stage has opened way up. The bass is tighter and more authoritative, and the amp is more dynamic and seems more powerful than before when driving either my 99 db Galante Silverdales or 96 db Omega Grande 8R speakers. Plus, it's absolutely *dead* quiet, which the original was not. I mean, with the attenuator wide open and my ear to the horn, I hear no sound at all. Amazing. Craig thinks this is now the most refined DHT amp he's ever heard, and he's heard just about all of them. He might offer a production version through Eddie Current. It won't look as cool as the Moth but it'll be reasonably priced at something like $2,800. It's really quite a mesmerizing amp. In the mean time, if you own or find a Moth S2A3, I strongly suggest you contact him about getting this PS mod. It's really something special and takes this already outstanding 2A3 amp to an entirely new plane. |
I like my parallel SET 2a3 monoblocs (Audionote uk Kagekis). They probably have more than enough power for the AG unos. There are plenty of other amps that would work well with the AGs. I've heard Duos with a variety of amps and they did not seem to be particularly difficult to match to amps. The Duos sounded different with each amp, according to the particular qualities of the amp, but they sounded good with almost everything decent. I particularly liked them with the Art Audio PX-25 amp and with the Viva Solista. |
Haipo, I second the vote for Audio Note kits, and I'd bet this would sound fantastic with Unos: http://www.audionotekits.com/PM_Integrated.html Resale is good and it's a hoot to put together. There are also many well-documented upgrade paths with this amp so that you can experiment and push the envelope--all the way to a full silver signal path with silver output transformers! Building and listening to this amp, you might find a new aspect of this hobby to enjoy. Doug |
I beg to differ with the assessment of "Made in USA" amps being "poor design, low parts quality". My Moth s45 uses excellant "stock" parts INCLUDING Electra-Print OUTPUT TRANSFORMERS that were designed specifically for this particular amp. Speaking of quality iron, Welborne uses Magnaquest transformers and yet you still feel that equates "low parts quality" - interesting. |
I agree with Edle that Audio Note makes very good SET amps, but not everyone can afford them. I agree with clueless, unless you know for sure you can live with a 2a3 for all the types of music you listen to, I would buy one of the consonance or bottlehead amp kits over the Audio Note. I also believe there is no 'best' it is all relative to the rest of your system, musical tastes and budget IMHO. |
I own a pair of Audio Note UK Neiro 2A3 PSE monoblocks and those are, without a doubt, the best amps I have ever heard! Prior to getting these amps, my favorite was the Kondo-made Neiro. The new UK versions better the Kondo product with greater resolution, tonal purity, dynamics, vocal clarity, soundstage width and depth, and no Kondo sugar coating. The new UK Neiro monoblocks also have more gain than the Kondo Neiro, so there is no immediate need for an active linestage. I feed my Neiros from an Audio Synthesis Passion Ultimate and the combo is great! The amps come stock with copper foil capacitors and I just upgraded them to the new silver foil versions. Wow! Even more clarity, definition, space, you name it! If you can afford it, you won't go wrong with these amps! |
Yes, you are absolutely right. The good old US did created the 2A3/300B and even the SET amp but those are accient history........ But they also the first one to abandon it......... Back in the 1920 or so, all those hard-working Bell Lab engineers/scientists are the true pioneer/inventors in this field. They are creating a whole new technology. I don't see there are any corelation between them and the current designers or copiers. Please look underneath their SET amp if you know what you are looking at. Poor parts, poor circuit design and poorly design tiny output transformer(mass produced in Taiwan). It doesn't take a rocket scientist to figure out how it sounds. The Japanese are constantly refining the SET amp since the mid 60's. French are doing the same since the mid 70's. And the US are doing it recently(early 90's). Don't you think they are just a baby! Thanks for reminding me to crawl back to my hole. May be you should go out from your hole more often. |
Josh Stippich's amp. See it at: http://www.electronluv.com/hostedsites/electronluv.com/ (Can't seem to get the picture to show up here via HTML...) -Ed |
There is no "Best". How much do you want to spend? How much have you listened to SETS? I have never heard an amp that is best for all applications or all types of music. For the price of an expensive SET you can easily get two or three great SETS and tweak them into great ones. Most all are compromises of one sort or another and differ with regard to circuit design and therefore sound. The Bottlehead Set mentioned above, for example, uses SS rectification and "parallel feed" which lightens the job of the transformer. Not 'better" or worse", just gives a distinct sound (It is a very nice piece and quite different in its approach.) In my opinion that kit would be a great place to start with SETS if you want excellent sound and you want to learn what SETs are about. If you do not want to solder every once in a while my advice is to not blow the bank on your first SET. Get a used unit that has good resale in the secondary market(easy to sell when you make the next step). Do a lot of careful listening and see what you like about it with various types of music. Learn a little about about how they work. Again, one nice thing about SETs is that they are comparitively simple. You can tweak them fairly easily to suit your own ears/room/music. This is a great advantage if you ask me. It's like home cooking. You can cook to your taste for 1/15th the cost of a big name restaurant. You can have a 300b and a 2A3 and more. If you take the "best that $$ can buy approach" you will spend a lot of money. The biggest thing you pay for is the low number of units sold (thus no volume and a high per unit price.) If you have not interest in tweaking I guess this doesn't help. Finally, I hesitate to say this, but the one guy who posted above (nothing worthwhile in the US/ $$ will buy everything) sounds like a complete fool to me. Cheers, |
The best sounding 2A3 SET I've heard is the Fi 2A3 designed and built by Don Garber. I drove a pair of Kochel horns with the Fi 2A3 monoblocks and the sound was nectar. RCA NOS and KR 2A3's sounded better than the stock Chinese tubes, and although the amps sounded great stock, I swapped the stock Magnequest OPT's with Tamura with a noticeable improvement. I demoed/heard most of the above mentioned 2A3's and thought the Fi sounded best. This is a VERY simple yet elegant design. Contrary to the above post, I heard Cary, Wavelength and Wellborne and thought they were excellent and well designed and have the utmost respect for Ron and Gordon, clearly not beginners. In fact Gordon Rankin and Don Garber have been harbingers in SET design and quietly pushing forward for years, well before SET's "came" into fashion. You have quite a few outstanding products from which to choose. |
"Forget about the Cary, Wavelength or any SET amp that are made in USA(they are beginner in SET amp design!" Funny - Last time I checked, it was the "novice" engineers in the good old U.S. that created the entire series of 2A3 and 300B tubes to begin with - oh about 70 or so years ago. You're saying that current crop of U.S. audio technicians and engineers can't make a decent SET Amps? Go crawl back into your hole. |
Best is very subjective. Here are some good choices (kit and assembled) at varying price points. The prices are list for new items. Shopping used can get you up to 50% off. Bottlehead Paramour Monoblocks ($550 for kit) AES SE-1 (Approx $950 as kit or $1150 assembled. Plays 2A3 and 300B) Sun Sv 2A3 ($950 for kit, $1750 Assembled) Bottlehead Paraglow Monoblocks - Parafeed ($1150 for Kit) Wright WPA3.5 Monoblocks $1430 Welborne Moondog Mono's(Approx $1600 for kit or $2095 assembled) Moth Si2A3 (Integrated) $1995 Cary CAD-2A3-SE Monoblocks $3500 Wavelength Gemini (Plays 2A3 and 45) $5000 I personally like Monoblock designs with tube rectification but you will get "heated" arguments over this. Finally, do not equate "best" with higher price. This is not always the case. In fact, many DIY-ers will say that they can build themselves a home brew 2A3 better than anything that's out there for well under $1000 in parts. My advice - Audition as many as you can first,check out local audio clubs and talk to the DIY folks. Good luck |
For your hi-end Avantgarde 2.1, you should use the best 2A3 SET amp that money can buy. Forget about the Cary, Wavelength or any SET amp that are made in USA(they are beginner in SET amp design!) - poor design, very low quality parts that including the output transformer! *Cary designed a 300B amp that give out 15 watts/channel. I don't think the designer understands the 300B tube at all. It is a complete joke! If you have the $$$, the best is: Audio Note "Japan" 2A3 SET amp JC Verdier 2A3 SET amp and similar 2A3 SET amp from L'audiophile And remember always use NOS 2A3 tubes, please don't use any modern 2A3 tubes........ |
I purchased a Cary 2A3 SI from Kevin Deal at Upscale Audio. It is a great integrated. My intention is to upgrade my speakers to a pair of Unos later this year. Kevin recommended the Cary. I am still breaking it in, but it already sounds terrific -- and it looks spectacular as well. Nothing like turning off the lights and listening to some great vocals by the light of the tubes!! |