My first Tube Amplifier

@bdp24 : I've had Futterman OTL's  in long-term use with Quad 57's. They do sound great together, even though the impedance falls to <2 ohms at 20khz. Partly due to the Futterman's low output impedance (high feedback).

I heard that OTL tube amplifier has an excellent transparency to be suitable for planar speakers.

For the time being, I am happy with my Line Magnetic 508 SET amplifier with magical mid range sound.

@bdp24 : The inherent problem with Julius's circuit has been getting the two halves of the output stage to act in balance due to differing gain (one half acting as a cathode follower). And the circuit requires high feedback to have acceptable distortion (60db) - not a problem because of the low front-to-back propagation delay.

@bdp24 : Ralph Karsten's OTL amps are based upon the Wiggins Circlotron and are inherently well-balanced. But they do have an output impedance of several ohms! Not good because of interaction with a typical speaker's varying impedance! Best used (like Futterman's) with autoformers.

Bdp34,

Thank you for that. 

So, ESLS like Futtermans.

And the Futtermans like the Altecs because?

@unreceivedogma, if the Altecs are, as I suspect, a nominally 16 ohm load, that would be a good reason.

bep24:

yes, they are. 

Lot of interesting discussion about OTL amps.

If I find used one at nice condition, I may want to try out to find out how they sound in my system.

But without knowing system matching, I will not venture to try new one.

 I would say try an atmosphere. Probably the best and easiest resale

I will consider Atmosphere if I try out OTL amp.

Ralph has a good reputation supporting his customer.

1st, Jolida 102??  Long out of production.  I used it in a second system with Spica TC50's.  it's was below 25watts
2nd Jolida JD1000a which I still have and use as a backup. 100 watts of EL-34 power.
3rd VTL 300 deluxe mono blocks with either 6550 of KT-88's.4th and current VTL 450MKII with KT-88's.

@vegasears

You started with Jolida and ended up with VTL 450.

You may  try KT120 tube with VTL if it is fine after contacting VTL.

KT 120 tube give deep bass with wide and deep soundstage.

I have a pair of Primaluna mono blocks, and I could not be happier;


    https://www.primaluna-usa.com/prologue-premium-mono-power-amplifier/


I bought other tubes with the intention of improving them, and the last time I checked, I had the original tubes.

Great thread, fun to read of others' journeys through tube gear.  My first tube amp was a Harman Kardon Citation II, which got fully renovated.  Then did the same for my HK C-V.  They sounded wonderful, but I got tired of the heat they produced here in the desert and the hassle of biasing them so I sold them.  The cost of replacing the power tubes was a hassle too.  At the time, I felt the Modwright ss amp provided more resolution to the music I was playing through my monitor speakers.

I also had a Fisher 400c which I got recapped and I tell ya, that receiver had the most amazing low end frequency response imaginable... it just had flat out balls on the LF.  However, with its array of ~16 tubes, I was always taking it to the tube tech to detect and replace gassy tubes so I sold it.  Wonderful amp with a warm midrange.  

I had a CJ M45a that melted down at soon as the new buyer got it home, luckily which was locally.  Nothing special about that amp other than a very pleasant midrange.  I got it fixed and sold it to a very happy buyer.

I now have Spatial Audio M4 Triode Master speakers with a nominal impedance of 12 ohm and after hearing the speakers driven by Don Sach's KT88 amp, I am diving back into a tube amp!  My Platinum upgraded McCormack DNA .05 sound plainly two-dimension compared to the glorious articulation, extension, air, and three-dimension sound heard with the tube amp.  YMMV, depending on your speakers.  

I have for some time thought the magic combination in a system is a tube preamp and a ss amp.  With the right speakers and properly powered tube amp, tube amps are still awesome and can do what few ss amps can do.  

I hasten to add that there are several manufacturers of new tubes that are sonically equal to or better than many NOS tubes, which are in dwindling supply and are plenty pricey.  Shuguang, Psvane, and to a lesser extent, Genelex, make very good tubes that are reasonably priced and quite reliable.  

My first tube amps were a set of Dodd 120 monoblocks. I read a story in the Dallas Morning News about a local tube equipment designer that just started his company named Dodd Audio. I contacted Gary and before I knew it, I was listening to his new Dodd 120 monoblocks in his listening room at his house in Garland, Texas. He was using his quad 6SN7 based reference preamp and a pair of GR Research line array speakers. The sound was very impressive top to bottom. He sealed the deal when he played track 6 from Roger Waters Amused to Death CD, which I had never heard before. This is the famous water drop track. I was sitting about nine feet back from the speakers. I closed my eyes to listen to the sound-stage and the most unbelievable thing happened. A water drop appeared in the soundscape…directly to my left, next to the wall, about ear height. Yes, audio fans, we are talking about a 180-degree sound-stage. I found out later that this CD was recorded in Q surround sound.  The things I liked about Gary’s amps were that they had that organic tube magic but they were quick, had a refined clean sound, and the sound had weight but was not syrupy. I wrote him a check on the spot. Later on, I bought his reference preamp and then I bought his battery powered tube preamp. I eventually sold the reference preamp but the monoblocks and battery preamp are in my main system right now.  I also have a pair of ASL DT200 hurricanes. I have a small listening room now (16’ x 11’ x 10’) and my speakers are Kef LS50s. The difference in refinement is obvious between the Dodds and the Hurricanes. However, the Hurricanes have added authority that makes them very special in larger rooms but that’s another story.

I heard a Primaluna integrated at a local dealer matched up with some Klipsch La Scala speakers and fell in love with the tube sound. I wanted something a little less "syrupy" for lack of a better word and ended up with a second hand Audio Research VSI55 integrated which I enjoy every work day in my home office. After that I replaced the high powered class D amp in my main system with Rogue Audio M-180 monoblocks. I think those are staying for a while. 

@shkong78i bought of Joseph Audio Pulsars, which are a little more efficient and have a great midrange.  I’m using class D Bel Canto Ref 600m monos for amplification and couldn’t be happier.  Small, no heat, and they have power in low passages.