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I bought one of these off eBay and waited 2 months for surface shipping - which is the cheapest way to get something from China. It arrived safely and was well packed.These are sometimes advertised as SINGLE ENDED amps, but they are PUSH PULL! This amp is NOT an ultralinear design, just a pure tetrode topology. The FU29 is an 829 dual tetrode. This is a beam power tube that was used in radar sets of yesterday as a keyer, and also used as output stage in 40's/50's VHF transmitters. etc. There are only two output tubes on this stereo amp so some people may think it single-ended, but note that each tube has TWO plate caps; there are TWO tetrodes in each tube's glass envelope.
The amp is biased class A. Construction quality was so-so. Cosmetics are very nice, however.
It puts out about 30 watts a channel. Sound on my Quad ESL-57's was pretty good. Had better low end extension than I expected. Actually, it had much better bass than I expected. It was not up to the bass power of my Citation II, but it was not thin sounding. Mids were nice, treble clean.
I tried this on a number of speakers. It sounded OK on my Quad ESL-57's, but really they want more power.
Then I connected a pair of budget speakers -Polk RT25i - and, wow! There was definite HIGH END sound. Budget high end, certainly- no sub-bass extension was in evidence. But GREAT musicality. Something about the interaction between the crossovers and drivers in these Polks and the Audioromy amp made some real magic. The warmth, the silky highs, the richness of the mids and the soundstage- just great for a budget system. WAY better sound than $500 worth of gear had any right to sound. Played loud, too.
I didn't have any other box speakers at the time to try it with, but I can heartily recommended it with the Polk Rt25i- which you can pick up for a song.
Trying some solid state amps on the Polk RT25i gave me better bass, but were very disappointing otherwise. Even a pair of bridged class-A Monarchy SM70 (the original, true class A SM70 amps-) did not sound as warm or engaging as the Audioromy. And, trying a re-capped Dynaco ST-70 on the Polk Rt25i did not sound as good either- the highs from the Dynaco sounded muted and lacked detail. The highs from the Audioromy FU29 had real good detail, and silky sparkle - yet were not etched sounding or sibilance-exaggerating. It had "modern tube amp sound" compared to the venerable Dynaco.
SO: this is a pretty good sounding amp, and with the right speakers will give you what you look to a tube amp to provide. Looks nice, too.
After a month, one of the preamp tubes failed. $12 and $3.50 shipping from some online tube store fixed that. Otherwise, no reliability issues at all with this amp, it is in daily use.
Edits: 03/26/11Follow Ups:
Well back to the Audioromy FU29.....
I sold it a while back; I liked it but just didn't have a system where I could use it. So I sold it to a friend. He's been using it DAILY for over two years. A 6N2 tube went out about a year ago, he replaced it. The other channel's original 6N2 died a week ago. Replaced that 6N2 and now the amp is working well again. The 6N2's that died were Chinese. They were replaced with Russian tubes. Maybe the Russian tubes will last longer; or maybe the tube is under stress and so one 6N2 failing per year is par for the course. Not a big deal- Triode Electronics sells 6N2's for $6.95 a piece.
This Audioromy FU-29 amp still sound great on small 2-way speakers. A real bargain.
New old stock GE 829 output tubes can be bought for $20 or so.
Where else can you find a good-sounding tube amp that is so reasonably priced, has good reliability, and uses tubes that won't cost you an arm and a leg?
I wish I had some high-efficiency speakers to try this amp on. I bet it would sound good on some classic horn designs, like Altec or Klipsch. 30 watts / channel would be big power for speakers like those.
Hi,
How are things going with your AUDIOROMY FU29? I am considering one of these and did a little research online. I found a couple of reports of a resistor in the power supply burning out and power tubes red-plating. Have you had any problems with yours?
Is there a bias adjustment for the power tubes?
Many thanks.
Peter
I am familiar with these amps and they definitely have their purpose and price/performance ratio.From what I gather,you definitely prefer the Deuce on the ESLs,correct?
Diversity of opinions on any one technical subject,almost always causes confusion for the listener.
Yes on the ESL-57's the Audioromy FU29 and the Citation II had a similar sound at moderate levels, but pushed at all and the FU29 quickly became harsh and the bass folded up. The Citation II sounded better at anything beyond moderate (i.e., background) levels. Quad ESL-57 has an efficiency of around 82 dB/ 1 watt, so they want a little power.(I have the Wayne Piquet Zener protection boards in my Quads, so I don't have to worry about arcing them when using 60 watt amplifiers.) The FU-29 did better on more efficient speakers like those Polks, plus there was an euphonius interaction between the Polk and the Audioromy FU-29 that I really liked. Since the Audioromy amp is not an "ultra-linear" design, I suspect there is less overall feedback and so interaction with speaker/crossover impedance will be a little more exaggerated than with ultralinear or other designs that feature a little greater overall feedback. In a sense you're doing speaker / amp matching to act as a kind of "tone control" but it's more than just a changed frequency response curve, in my opinion, that results- there is a change in the character of the sound that goes beyond a simple EQ curve when you pair certain tube amps with certain 2- and 3-way speakers. The tube amps do things with harmonic content - their residual distortion has a character that can "sweeten" the sound in some cases- and with the right amp and speaker you get a frequency response curve and harmonic "treatment" from the tubes that can produce a more "lively" illusion from the recorded music. Is it more "accurate?" No, probably not. Does it sound good to listen to? Yes, it certainly can sound very nice, and with certain tube gear/speaker pairings this "good coloration" also produces sound that is very non-fatiguing, something which, paradoxically, the more "accurate" gear sometimes fails to do.Typically, I use a Soderburg-modded Forte 4a on the Quads. But sometimes I want the Citation. The solid state, class A Forte amp has better bass and yet sounds quite "tubelike" in the mids and treble- except it's treble is more extended. The Citation has a slightly more laid-back treble and 'rounder' bass which I also like sometimes. I have a switch arrangement so I can select which of the two amps suits my preference at the moment.
I also have an AMC CVT-2030 which is a class-A hybrid amp with MOSFET drivers and EL-34 output stage. I think this is a very under-appreciated amp, it sounds really wonderful on the Quads, but it lacks just that little bit of extra power I want at times, which I can get from the Citation.
I have also tried the AMC CVT-2100a which again is a class-A hybrid amp, this time using MOSFET drivers into KT-88's. It was OK, had good power, but somehow it was not as satisfying as the Citation II. It was not just a higher-power version of the CVT-2030 sound, it didn't have the same 'liquid mids' as the EL-34's in the CVT-2030.
Edits: 03/26/11 03/26/11 03/26/11
Does your citation amp have the McShane upgrades? It sure makes a difference. I did all the levels to my pair that I am running on the CLXs. I run them in parallel at 4 ohms strapped.From 100hz on up, the pair of McShaned citations are firing the panels and from 100hz on down,goes thru the logan subs with SS amps.I have run them down to 55hz on the panels and its very good but,I think I like bass more thru a woofer.
I will be building a pair of folded bass horns to use with the Logans and I can place the bass cabs in the corners and that should balance nicely.
Diversity of opinions on any one technical subject,almost always causes confusion for the listener.
Yes the guy I bought it from did the McShane "level 2 plus" power supply mods and also changed all the coupling caps to West Cap PIO's and also increased decoupling capacitors to larger sizes.I got a schematic from Bob Carver that I would like to try some day, it disconnects the screen grids from the output transformer taps and supplies them with plain DC, which makes the amp "pure pentode" instead of an ultralinear design. Carver says he talked to Stu Hegeman who designed the amp back in the 1950's, and Hegeman wanted a non-ultralinear design but Harman Kardon marketing said it had to be ultrlinear because that was the "flavor of the day" and also allowed them to get more RMS power under test so they could rate the amp higher. Carver says the non-ultralinear design actually provides more current to the load but measures worse. Carver also has a bias mod he calls "DC restoration" which allows a lower idel bias point but increases bias under signal so the amp is actually (effectively) biased higher than stock, but runs cooler. I would like to try the "pure pentode" mod but am not so certain about the "DC restoration" thing. Still, Bob Carver knows way more about amp design than I do so maybe I will try it.
Here's the schematic Carver sent me, fyi I asked him if it was OK to post & share and he said SURE, OK.
Edits: 03/26/11 03/26/11
The amp you bought sounds like one of the ones I rebuilt.Did your citation come from Florida?
Diversity of opinions on any one technical subject,almost always causes confusion for the listener.
Ha ha it could well have been from you! The guy i bought it from was "Mike" and part of his email address was " merccougar8..."
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