Your journey with lower-watt tube amps -- Can a kit be good enough?

Thanks for the comments. Had a busy day. Need to think about @atmasphere comments bc the speakers I currently own have been driven pretty nicely with an 8w Sun Valley amp in a room larger than mine. (24 x 15 x 8 approx.). That said, there may have been additional tweaks that helped mitigate some issues you're mentioning.

Here’s a photo of them driving very similar (nearly identical) speakers to mine with the sun valley in the center. I’ll get back to the thread with more details when I can.

https://photos.fife.usercontent.google.com/pw/AP1GczNHf3PQV-V-aqEGWeygA7l6aycbB_8YIU8fzaz1k6x8Cap29ejjMN1e=w1441-h891-s-no-gm?authuser=0

@armstrod -- thanks for your advice. Good to try before sinking in that time and money!

@dougthebiker -- Elekit! Thanks!
@paradisecom -- thanks for the ank link
@yaluaka -- thanks for the link to the other thread. I’d not seen it. I had a different way of framing the question and appreciate the feedback here and the dialogue with others, including you.
@silverfoxvtx1800 I have heard these speakers with the Pass XA25 and the Sit-3. I agree they sound lovely and though there are differences, the Pass sounds similar to my ears. I’m curious to see if these lower-powered tube amps sound, well, different. It sounds like you are at the stage where you want to just be done with trying gear and listen to one more song! That’s cool, but I’m still curious about the variety of sounds which my speakers can produce with new dance partners. I’m not ready to "set it and forget it." 
@earthbound -- Thanks for the advice. I listen to what you listen to, mainly. This amp will be an addition to other amps that can fulfill the needs of Metallica -- or Mahler, Wagner. I’m a critical listener, not moving around the room. So, if this amp (whoever she is) comes into my life, I will be using it for the kind of music which suits the design.

@clio09 Thanks for your reply. You said to listen to atmasphere, and he said "It won’t matter if the amp is handwired or circuit board as far as sound is concerned." You then pointed out, "The whole point to point vs circuit board argument has many intangibles that need to be considered. It’s not black and white." What "intangible" factor are you referring to?

@decooney Thanks for commenting. I’m not giving up my Pass XA25 or my QS Mono 60’s so I won’t be out on a limb with this next amp. I also know that these speakers have worked fine with SET amps in a room around my size, so it’s a question of finding the right amp for these speakers in my space with my other gear.

looking at bottlehead, yes

Many thanks to the additional posters and to the additional advice. Lots of brands to consider (Yamamoto, wow!) and varying advice about kit vs. used, etc.

One thing I notice at work that puts people on different sides of an issue has to do with framing -- is an amp purchase like "getting a car" or like "taking a vacation"?

We want to have a good outcome with both, but we want a "car" to do "the job." We want a "vacation" to not be unpleasant, but we often want "surprise," "novelty," and to gain "new perspectives."

Some people want audio to do a job. Some want from audio what they get from an interesting journey or vacation. After a vacation, that money is gone. You don’t resell a vacation. You come out the other side a slightly different person. That’s what I want from audio. That difference might come from trying something that is not "end game" but will teach me something, and add perspective.

Thanks for the feedback and glad some like the vacation analogy.

I’ve heard from a reputable source that if a Dennis Had amp breaks he is near impossible to get in touch with and does not share schematics that this tech needed to fix it. Only after a long while did they finally hear back. This is not the kind of situation I want to find myself in.

@lafish thanks for the https://www.analogethos.com/diytubekit link

Thanks for the Dynaco ST-70 et al. suggestions. Since I am already running a Quicksilver Mono 60 with KT-77 tubes, I'm not sure this amp is really going to sound all that different. If I stick with the vacation analogy, I want to emphasize that I want to go somewhere really different and not have a "staycation."

@mattw73 Thanks for your detailed response. Very generous of you! The GU50 looks interesting and I like those guys too

Wow! Thank you @jetter and @atmasphere for the additional comments. The thread is really becoming a resource for others, as well as for me.

@cfarrow Thanks for relating all that. Really interesting.

FWIW, last night I did some listening comparisons comparing the Sun Valley 845 vs. QS Mono 60 w/ KT77 tubes. I used my solid state amp (very neutral) and my Holo Spring DAC. All of my descriptions relate to how things sound in *my* room, of course.

Main impressions: Sun Valley 845's tonality was a bit softer, more detailed, further back in the soundstage, and slightly narrower soundstage (but very good); the bass was weaker, sometimes too weak. It was a bit less snappy in transients but still quite good—not sloppy at all. Instruments and voices had a bit more texture. It was very easy to listen to; never strident or approaching strident.

QS had better transients and dynamics by a bit; it had much better bass, and instruments were more forward in the soundstage. Voices and instruments were detailed but not as much, a bit less warm and intimate.

Overall: hard to say which is better. They were different, though both obviously tube amps. I suspect that a tube amp like the Sun Valley with a bit more grip on the speakers which keeps the intimate/texture/smoothness and improves the bass might beat them both. 

Not sure if any of this translates for folks, but sharing just in case.

@alexberger Here's what my tech friend and amp builder said about your comment, in case you're interested:

"It doesn't [have an interstage transformer], but then again most single-ended amps don't have an interstage transformer, nor most PP amps for that matter, they are expensive. The 845 is hard to drive and since the SV uses a 12BH7 to drive it, there is less power than if driven with a larger tube or an interstage transformer. Clearly it is not "impossible" as the amplifier operates."

Just to let the thread know, the advice here from @atmasphere and others caused me to go find a newly built Dynaco ST-35. It should ship soon. I bought on Ebay. Here's the description:

"This beautiful, newly built amp is now for sale. I have used this amplifier for the past three months in my shop. It sounds so rich with the new matched set of Sovtek 6BQ5 power tubes. The pre-amp tubes are Sylvania nos 12DW7. The only items that are not new is the transformer set. These were happily donated from another Dynaco amplifier. Almost everything else came fr Kevin at Dynakitparts.com . All of the other parts, from the power cord to the protective cage are new!"

My local audio tech friend is interested, too. (He has the PBN speakers M2!5). When the amp comes in, I'll bring it down to him and we'll give it a good look over (and inside) and put it on his Audio Precision and other test equipment. Then we'll try it with his speakers.

So excited. Audiogon people help again!

@atmasphere Found a video related to your comment. Just adding in in case it’s of interest.

TITLE: Dynaco ST-70 Original vs. VTA Bench & Listening Test Comparisons - Stereo 70 Tube Amp

VTA vs. Original

Nice blog post on SETs recently, here.

A few excerpts. It’s not a long post and worth a read:

"The SET’s very existence calls into question fundamental beliefs and assumptions we routinely make about technical performance, sound quality, and the correlation between them. These amplifiers expose a crack in the edifice of audio engineering theory that is based on the conviction that an amplifier can be judged by its technical specifications or measured performance....

This paradox arises because the technical measurements that attempt to quantify amplifier sound are simply inadequate and incomplete....Predicting an amplifier’s sound quality or judging it to be good or bad based on existing criteria is like looking at a few still images from a movie and then attempting to discern from those static photos the movie’s plot, characterizations, dramatic arc, and meaning.

The SET exposes the fact that certain aspects of amplifier performance are not quantified by the traditional measurement arsenal....

Some will suggest that listeners are merely responding to the SET’s euphonic distortion—that the SET sounds good because of its distortion rather than despite it. There’s no question that the largely second-harmonic distortion component of an SET is much more sonically benign than the upper-order distortion components of Class AB solid-state amplifiers. But a first-rate SET amplifier’s magical qualities go far beyond this simplistic interpretation. The SET’s resolution of inner detail that, singularly, conjures up a strikingly vivid picture of the instrument creating the sound is certainly not merely a euphonic second-harmonic distortion artifact....

This essay is neither a renunciation of all amplifiers other than SETs nor an evangelical campaign for the world to embrace the single-ended-triode amplifier. SETs are limited in the loudspeakers they can drive, exhibit other practical drawbacks, and are certainly not for every listener...."

https://www.theabsolutesound.com/articles/the-single-ended-triode-paradox/

Thanks @atmasphere 

I would love to hear what Harley would say in response.

@decooney asks a good question for @atmasphere 

One thing which seems to hang on this answer is when and whether the general audiophile precept that "simpler is better" is true.

@atmasphere Thank you for your additional comment!

I hooked up my Dynaco ST-35 to my speakers and did some listening. 
97 db speakers -- JBL 16inch woofer and Beyma AMT tweeter.

HEARING: 
Very strong grip on bass. Amazingly good. 
Mid range less warm, intimate than I expected. 
Highs pretty clear, though perhaps some slight roll off. 

Overall, there is a slight lack of finesse, smoothness in the mids and highs that I am looking for in a lower-powered amp.

I think I'm not hearing this amp at its potential and it may be due to the tubes it came with: 

Sovtek 6BQ5 power tubes (4)
Sylvania nos 12DW7 pre-amp tubes (2)

If anyone has suggestions for good alternate tubes for this amp, I'm all ears.

Thanks @atmasphere. I need to check into those things and I have a friend/tech who can help.

Interesting reaction I got from my tech about your idea: "That is an option and can be done. It is relatively simple and keeps the amp using only cathode bias, but if the EFB article is to be believed, the output transformers are not optimal for the EL-84 in that mode. (http://www.tronola.com/A_New_Look_At_An_Old_Friend.pdf). The EFB is kind of a hybrid, the cathodes are still connected but then tied to a regulator that allows bias adjustment for minimum distortion. The upside of individual cathode resistors is less need for a matched quad, though it's still important."

I don't have the expertise to weigh in, I just thought it would be cool if you and others on the forum saw some techie back and forth.

@atmasphere Thanks! I am passing along to my tech 

@atmasphere We tested the amp for distortion and found that the left channel had a magnitude more distortion than the right; @5 watts it was 3.5%! So, we opened the amp up and there was a mis-wired tube socket with reversed leads. Green went to blue and vice versa. Someone did not do due diligence. After fixing that, everything was fantastic -- very low distortion and balanced between channels.

UPDATE: Got my Dynakit ST-35 up and running after a local tech did a bunch of work on it -- firmed up weak soldered joints, replaced wobbly tube sockets with good ones, and added the EFB kit that Atmasphere mentioned. Oh, and added a grounded plug. Also put in NOS Russian military grade EL84 tubes (NOS Reflektor 6n14n-EB Russian EL84/7189A equivalent, c. 1985) We measured distortion on this amp on some sophisticated equipment, and it hits 1% at full power and was about 0.15% at 1W. It will spend most of its time well under 1W. Very nice performance.

Report on initial listening of ST-35: This is one stunning little amp. Played it with my solid state preamp (built around the Burson Audio Buffer) and my Beyma AMT/JBL speakers (97db), using for about an hour -- classical, jazz, vocals, rock. It did amazingly well.

Soundwise, I’d say the grip on the bass is decent-good. Not fuzzy, not super tight, but notes are clear enough and there is full presentation with no gaps. Midrange is really warm and inviting; not quite as delicate and gentle as the KT77 tubes in my Quicksilver, but way more inviting than my KT88 or KT120’s. Really sweet. Highs were never harsh, very delicate and clean. Never bright -- just about perfect. Lots of good toe-tapping, engaging transients, a sense of excitement and a magnetic draw to the music. Put simply: this little amp was kicking some ass.

I’m excited to try this amp on my Fritz Carbon 7 SE Mk. II speakers today.

@atmasphere I need to check on your question. No buzz or noise or hum so far. Quiet as a mouse.

@atmasphere I have a very talented tech, Mike from Prairie Audio.

https://photos.fife.usercontent.google.com/pw/AP1GczPjsXq00IlHiWOaDt7sDsMJ0Ssx5pn8sXmzABJ9GxLb9Ab81LzyilHQ=w985-h1054-s-no-gm?authuser=0

@atmasphere I'm sorry but it is impossible to link to photos for me. I've tried it three ways and now I'm giving up to focus on other things.