[Dmason]

I have with me a new single ended triode amplifier from the bench of thermion wizard Roger Modjeski/Music Reference, for audition, and assessment. This is a 3.5 watt "spud" amp, (one tuber) using the 6EM7 vertical sweep tube. Roger has designed the circuit from the ground up, wound the output transformers, and bundled it into the sweetest little SET amp I have ever seen, about 12 X 5.5 X 4 inches, with the same cosmetics as the new 245 amplifier, seen on the front page of the Music Reference website  [ramlabs-musicreference.com]  in oiled Walnut, with black hardwood top and bottom. The layout of the amp is a work of art in itself! I was stunned at the innovation in using the top plate as a stablizing mechanism to the standoffs for the tube sockets, which are elevated, to above the top.

As the amp breaks in, it has completely exceeded any expectations I might have had. This little thing bites hard at the heels of the 45 tube, parked next to this one in a Korneff 45SE, with Emission Labs Solidplates, without the sonic signature endemic to the direct heated triodes, and it is worth noting here that a new pair of EML 45 solidplates cost about 1/2 of what this amp will go for, including tubes. Chief Bottlehead Paul Joppa once described the 6DM7/6EM7/13EM7 tubes as, "the poor man's 45 tube," but I can say that assessment is giving it pretty short shrift in this set up.

Roger's latest entry is part of his new SET line, currently comprising the 245, the forthcoming 2A3, and now the 6EM7 amplifier. It is designed to address the current swell of interest in SET amplifiers, offering a world class solution without the attendant cost, for those who feel they can live without the DHT sound, and to address the lack of affordable single ended tube amplifiers in general. This is an amazing solution to that situation, believe me, and its output, and overall grunt is way beyond ANY 3 watter I have heard, not having heard them all mind you, but Roger has completely outdone himself with this little monster.

I will have more to come in the coming days on this wonder of a little tubester. If your requirements for a tube amp can accomodate 3+ watts of pure SET ambrosia, there is now no need to save up for the high dog brands, this is the ideal compromise. A HIGHLY affordable, genuine Music Reference SET amp for an expected $900. More to come...

[PaulFolbrecht]

Very nice post.  Given your already stated very high op of the Red Wine Sig 30, I'd love to hear your thoughts re: the two of these side by side.

(Not expecting you to say one is "better" than the other, of course, but just wondering about the differences.)

[Dmason]

Actually, Roger's amp is tiny enough to sit on top of the Signature 30, with enough difference in depth between the two, to very easily change the speaker wire back and forth. (OTA single strand continuous cast magnet wire from Japan)

I really am not inclined to get into differences between the two, other than to say that one is a 3 watt SET using sweep tubes in Class A, and the other is a 30 watt battery powered switching amp, which is also exactly why I am not inclined... Both a fabulous. BOTH, stay.

What I will say is that Roger's implementation could make just about anyone forget about DHT triodes: the amp conveys the inner message of Prokofiev's more imaginative sketches, for example, with ease. No small feat, and about the highest praise these two ears could possibly bestow.

[PaulFolbrecht]

Ok, D.  Fair enough.  Soon I'll have my own RW Sig 30...

I'm extremely curious to see just how much like a DHT SET this thing sounds like.  You, Richard, Srajan, etc., all rave, of course, and I know it's superb, but the subtleties of distinction, it seems, aren't easy to put into words.  This or that is a bit different, but to what extent? 

Soon I'll be able to hear for meself.

[Les Lammers]

So how does it compare to the JK 45? 

[Zero]

Damn, I wonder  -  3wpc on a 89 db efficient speaker...      maybe if I click my heals three times?

[PaulFolbrecht]

What are you talking about?

You referring to me with the Gallos?  Of course I wasn't asking for thoughts because I would consider this amp for those speakers, but that doesn't mean that its sonics couldn't be contrasted with those of the Sig 30 via speakers sensitive to sing with both.  The original poster has both amps and hi-eff speakers.

[Dmason]

Paul,

I have found for some time that the sweep tubes in Class A SE, sound more similar than different, to the 45, of all the Fashion triodes. Not being DHT, they do not exhibit the holographic thang that those tubes do, but I could be VERY happy ad infinitum with this amp, with the right speakers. The fact that sweep tubes are out there literally in the millions, and can be picked up for $4-10 ea., makes this a pretty practical set up in the real world of sticking real tubes into amplifiers: there are only two. The 6EM7/13EM7 tubes have far more bass capability than any 2A3, and most 300B's, tho' depending on how well implemented the latter is, the sweeps have a very full and tight sound to them, and Roger's amp is the next step well beyond even the tricked out SEX amp, with Magnequest OPT, because I have heard both, actually I prefer the stock SEX amp, which I also own.

The vertical sweep tubes are interesting inventions, sometimes referred to as "compactrons," I believe this was a tradename of RCA... designed to operate in Class A, in TV, exhibit high resolution characteristics due to the nature of the useage, in a bandwidth in line with the audible one. One half of the tube is ~identical to the 6SL7, for a driver, and the big half is almost identical to a 2A3 for output side. So in one envelope you get pretty much the same result as using an Octal, dual triode 6XX7 driving a 2A3 output tube, which is the nicest combo for 2A3 sweetness anyway... Neat trick, no?? And for 4-10 bucks a tube, with 50% greater output than the average 45 tube, you see why I think these are cool....combine with suitable drivers, such as the Hemp Tones, and you really are getting into some sweet sound. Remember, this is a hand made, Music Reference SET amp with Modjeski circuit for 6EM7, for under a grand. This is something very new in itself!

Because of the interest in open baffle and wideband type speakers, Roger included a second set of inputs with a .01 shunt cap to HP the signal @ 100Hz, which now gives you a pile more smack and headroom, having relieved the OPT, and tubes of the strenuousness of processing LF information. [~40%>100Hz] When used with the 94db BIB's + horn gain, the 6EM7 is all the juice I need for endlessly musical meanderings, in my 15 X 13 music room.

[-Richard-]

I have heard Roger Modjeski's new 6EM7 amp along with several other of Roger's new
SET tube offerings... it sounds absolutely fantastic!!!

Roger's new series of SET amps all have several features in common:

They all sound incredibly rich, fast and holographic for one thing...
Roger is working on a 2A3 SET amp that is simply sublime... I am currently playing Roger's
45 (RM 245.1) amp which sounds utterly delicious, hypnotic and captivating ~

Almost every amp I have heard next to Roger's new SET amps sound anemic and dull...
devoid of an inner light that beams through Roger's amps like an energy that invigorates
every kind of music played through them ~

It is not just amplification... any decent designer can do that ~

It is about the inner intelligence of the music brought to life in a most emphatic way...
voices and instruments pulsate with life!!!!! They live!!!!

By now it must be obvious to anyone who reads Dmason's insights that he stands behind
every one of his "reviews" with integrity and good sense ~

Roger Modjeski is the real thing... he is a genius who understands circuits the way a great
poet understands the art of using words to bring a poem to life ~

Roger's SET amplifiers are works of art... owning one of them brings me a depth of
satisfaction that transcends even the exquisite rendering of the music itself...
no one knows how to make an SET amp like Roger ~

Warm Regards ~ Richard ~

[Srajan Ebaen]

For two pix Roger just forwarded on the baby sweep tube amp, go here: www.6moons.com/roger1.jpg and www.6moons.com/roger2.jpg (these are big files which I didn't scale so modem users will have to be patient) -:)

[Srajan Ebaen]

Actually, they were so insanely big that it just took too long so they're scaled now and less than 100MB so never mind