First Tube Amp

Will Vincent of Idaho makes some superb tube amps - both PP and SE! I have one of his SE 45's! Great sound and build quality but limited power output (1.75 watts!). Works well with my vintage Klipsch Heresy's!

By bloom do you mean harmonics. Atmosphere, I think I found the corresponding website ;-) how would something would sound with loss of “low-level detail” which is what happens with push pull amps. I’m guessing more “bandwidth” is more frequency response or range?

Do SET,s lose their”bandwidth” or fail only when pushed to hard/loud?

@recluse 'Bloom' is an audiophile term that often refers to 2nd harmonic distortion. Often but not always.

A loss of low level detail will take some of the life out of the 3D soundstage as room ambiance is often part of low level detail. IOW quieter sounds that are part of music.

'Bandwidth' is akin to frequency response. This can be important to getting things like the soundstage correct, as phase shift can occur as an artifact to 10th the cutoff frequency (so if its good to 20KHz, down to 2KHz) and to 10X the low end cutoff (so if good to 20Hz, up to 200Hz). Phase shift messes with instrument timbre and soundstage width and depth.

For this reason, 2Hz to 200KHz is required to really get the soundstage right, and to assure impact in the bass.

SETs have troubles making bandwidth on account of their output transformers; its a real trick to make an output transformer that allows for power and bandwidth at the same time; 7 watts is about the practical limit. It is for this reason that the smaller SETs are also the best sounding. This really limits the speakers you can use, since one of the best sounding platforms for SETs is the type 45 triode power tube, which is good for about 0.75 watts at full power. There is a bit of a diminishing return  here, as a speaker that is usable with that kind of power won't be able to play any bass anyway. But these days people often supplement the bass with a powered subwoofer. 

When pushed hard, SETs don't loose bandwidth, but they do make considerably higher distortion. As a general rule of thumb, to really get your amplifier investment dollar out of an SET, the speakers used should allow you all the volume you need while the amp never goes above about 20% of full power. If you follow this rule, the amp will not make appreciable distortion. If you break it, you will experience the 'way more dynamic than it has any right to be for that kind of power' that you hear many audiophiles and reviewers describe about almost any SET.

(I may have ruined it for you by letting you in on this fact, as you may now be aware that some of the 'dynamics' you hear from SETs is really just distortion.)

The reason this happens is because the higher ordered harmonics (5th and above) start to show up about about 20-25% of full power. The human ear uses these harmonics to sense sound pressure, so if the amp is making them, it will sound louder. This is why many people have loudspeakers that are not efficient enough for the amp, but claim that its 'loud enough' for them- the harmonics are convincing them that its loud. A sound pressure meter reveals the truth of the matter!

The thing is, if you really want to experience high end audio properly, the system should **not sound loud** at any volume (and this is quite possible with SETs with careful speaker selection)! You should find yourself yelling at someone else in the room to be heard as a first indication that the volume is up. The reason this is possible is because if you use tubes, you can build a system that is free of the higher ordered harmonics.

Recluse, your experience is more common than you think. about 5 years ago was in similar boat. used only high end SS power since I had super inefficient speakers. Sold the speakers, but kept the amps, until one day a friend let me borrow his chinese amp. Like you, was floored at the sound quality I was getting.

That event set me off on a whole series of trials with Chinese tube amp purchases, including a model similar to the EL34 amp you have. With a few exceptions, all of the Chinese tube amps I tried sounded good, some better than others.

But you still have not heard your Yaqin amp yet. Solder in some Jensen copper foil coupling caps to replace the inexpensive caps installed by the factory. You will be floored again at the sonic improvement, especially with speakers as efficient as yours are.

best.

Thanks for the detailed information and suggestions. I am intrigued by these tube amps, especially the SET - however wondering if I would tolerate it's limitations - as you mentioned with large orchestras.

Many of your descriptions/positive traits of the SET seemed to parallel my impression of the push pull amp: I picked up more low level detail versus the SS amp, single instrument solos seem to stand out better in the symphonies I listened to. The distortion was overly pronounced during break-in and when it was cold - ear-catching to say the least, but finally  leveled out to a pleasing level. I wondering if all of this will be even more pronounced with an SET. I will be looking at  some that have been mentioned over and over again on the forum like CJ, Cary, PL, etc - unfortunately I will have to stay away from items that will need upgrading or soldering and the used market is non-existent where I live. 

Still trying to rationalize the decision to send back the Yaq. Been listening to it biased at 40. I noticed not all three of the cylindrical transformers where equally hot- just the one forward one of the trio. The volume adjuster is a little too sensitive. And there is no phono stage. These issues are minor as I mainly listen to CD's.

Lastly, took the chinese amp off-line and have been listening to a powerful hybrid amp(3-4 times the cost of the Yaq amp)and am not as impressed except for the strong bass, holding up very well, albeit clean and sterile, at at high volumes. It fall short on too many other levels.

Thanks again. If anyone can recommend an SET or 300b amp that works well with DI's or speakers of similar sensitivity - please chime in :-)

My speakers are 98 db 1 watt 1 meter as well and I find 30 watts to be the minimum power to use! My room is about 17' x 21' and moderate liveliness.

If your room is smaller and more lively you might be able to get by with an SET, but if it were me I'd go with an amp with more power. Our M-60s would work nicely on that speaker and perhaps our S-30 as well; if on a bit of a budget I would look at a refurbished Citation 2 from Jim McShane, a Dynaco St-70 or the venerable RM-9 if you can find one.