What's the greatest bargain in SET these days?

Ok, I'm sick in bed today, reading, listening to my Dynamo right now, playing Capitol's Great Gentelmen of Song, Nat King Cole, Louis Armstrong, Dick Haymes, Sinatra, Martin, Bennett, well you get the idea.

I usually enjoy Dick Osher; but he is way off base here. Something was definitely out of kilter with his set-up. I have the Primaluna and the Coincident beats it out in nearly ever parameter. Consolidating what Charles stated from Olsher, the review is wacky. Believe Tim Smith from 6 Moons and the Enjoy the Music, reviews you can trust that were thorough and used better mached speakers. And I am not impugning Dick Olsher something was wrong.

Remember my comments: the Dynamo was used. It had Gold Lion KT77s, a Phillips 5R4GYS rectifier (not recommended for use by Blume) stock Shuguang 6SL7. The sound was ok with that set-up, my wife did not like the bass, nor did I.

So, being the tube roller that I am since experience has taught me that you
can almost always improve the sound with different tubes, especially NOS (part of the fun of tubes), I rolled. This is what I did: the first thing I did was replace the rectifier tube with a NOS Mullard 5AR4 from 1960s. Wow! Significant improvement. I also had in my tube stash some NOS Military Sylvania 6SL7s. Boom! Another leap forward. Then, I purchased NOS RFT Siemens (Tim Smith, 6 Moons liked these best of EL34s, 6CA7s), "fatter, fuller, better bass". I prefer the Shuguang Black Treasure 6CA7s.

I still have some experimenting to do (going to try the RCA Red Base, a couple of of other rectifiers).

My system as currently constituted sounds remarkable. Purity of tone, natural and organic, the music flows with ease, great textures, big, well defined soundstage (wall-to-wall), deep, coherent, lovely midrange, bass tight and fast, PRat, highs that are never fatiguing (Tekton speakers), rich, full, smooth, neither Yin or Yang, just right to me in my room. This amp will play anything, rock, classical, chamber, Jazz, Louis, Ella, in the room,duke's piano never sounded better.

I'll mention that I was a professional musician and have listened to all types of systems from great to small. This is an amp that most everything tight. Must have sensitive speakers, you will enjoy the music.

P.S. I used Tekton 4.5s, mostly M-Lore, Lore. No problems. Also used my Infinity Prelude Compositions, 6ohm, 96db. No problem.

01-06-15: Charles1dad
I wonder what accounts for such a high output impedance of the Dynamo. The Frankenstein has an output impedance of 1.8 ohms, quite a difference.

Good question, Charles. I don't know the answer, of course, but if I were to hazard a guess, and assuming that the 10.2 ohm figure is correct, I would say that the need to minimize the size and cost of the output transformers probably has something to do with it.

Best regards,
-- Al

It's always about the amp/speaker synergy...always. That is why, for example, the Inspire amp may not sound as good on a particular set of speakers. All about the synergy. Dennis uses good trannys on his Inspire amps as an FYI.

I love this thread as I read the whole thing last night! My speakers are 90db efficient and 8 ohm. They to not dip below 6 ohms and are pretty easy to drive. I have tried several 7 - 12 watt SET amps and find I get enough volume....with the right music. The type of music played is a factor we need to add to the amp/speaker synergy equation.

If one listens to jazz, small ensembles etc, then I found 8 watts was plenty with my moderately efficient speakers. This type of music is not as demanding on a system. Now play some music that is dynamically challenging, then the lack of watts and lack of headroom is readily apparent.

So in addition to the room size and prefered volume level, one needs to take into account what type of music is played most of the time.

Rebbi, I think you made a wonderful choice with your AN kit and view your blog almost daily. Someday I will build a nice SET amp and actually looked at yours pretty seriously. I wish AN offered the same essential amp with no electrolytics and no circuit boards as a kit. It would most likely require a larger chassis to fit the ASC or GE oil caps etc...

Are any of you aware of a SET kit that uses all point to point wiring and no electrolytic caps? I would also like to try transformer coupling or direct coupling in this SET amp.Not sure such a beast exists in KIT form?

Interesting spec on the Coincident EL34 amp. I think Al is spot on with his answer as to why. It is cost related and gives the builder an opportunity to make the best quality output tranny within a smaller range of ideal operation.

A typical SET amp has an output impedance of some 3 ohms (no feedback) with many under that. Speaker matching is especially critical with this amp. I think Dick O. got it right in his review warning folks to be careful and clearly showing the sonic results of mating this amp with a "typical" speaker. Not sure it is his responsibilty to hunt for a particular speaker for the review? Maybe it is?