For tube sound, which is more important: preamp or power amp?


I have always loved the “tube sound” - warmth, midrange, soundstage. Through the years (since about 1975), I have owned many tube and solid state amps and preamps, in various combinations. Presently, I have a tube amp and a solid state preamp. But like most of you, I am thinking of making changes, again.  Not to cloud the discussion, the specific brands are not important.  I also listen to acoustic music, females vocals, love mini monitors, EL34s, NOS tubes, and don’t care that much about bass.  So you can see that my taste fits the tube sound very well. But I have had systems that are too warm, not enough dynamics or details, and fat in the low end, too.

okay, now to the discussion.  To produce the tube sound, which is more important: the preamp or the power amp?  Let’s talk in general, and (if possible? May not be) not tied to one specific piece/brand/model of equipment.  I know there are exceptions to any general rule.  Not sure if it makes a difference to your comments, but I have no phono and am running line stage only.

As an attempt to prevent the conversation as going in a big tangent, let’s assume equality of price/quality. i.e. not comparing a $10k power amps contribution to a system to that of a $1k preamp.  Let’s also assume that the amp (tube or solid state) can drive the speakers just fine, such that compatibility does not limit the decision. And ignore mono blocks versus stereo amp differences.  

two follow ons: I have  the perception that preamps give you more bang for the buck - meaning that it takes less money to get a great tube preamp compared to a great tube amp.  Agree/disagree? And second, I have never owned a tube dac or CD player, and will assume that tubes in either of these is less critical than in a preamp or power amp. Agree/disagree?

i am interested in your thoughts.

Bill
meiatflask
Ditto to Wolf’s opinion of the 12 wpc Inspire . ABSOLUTLY amazing . But what really blew me away was Dennis ! 6 weeks ago , I was playing a new matches pair of Gold Lion KT-77’s ( 150 hrs ). I heard a pop , then another , fairly mild . Shut my stuff down and went to bed . Next morning , I switched the 2 tubes, installed a different driver and rectifier . Turned on my system and just let it sit there with the CD on pause. About ten minutes in , a pop in the other Chanel . So as I watched the amp and contemplated a bad tube , Kaboom ! At about 100 dB. Dove for the switch . No light show , just a trickle of smoke from the chassis . Pulled it apart and I had completely destroyed a couple caps , a resistor with such force that it snapped the terminal strip . I emailed Dennis , HELP ! 30 minutes later my phone rang . He said ship it to me and I’ll fix it for free . I said it’s 18 months old and it was my bad tube . He said , It never happens and I’ll fix it or build you a new one for free . I shipped it to him and it was home , fixed and return shipping for free in two weeks. I begged Dennis to let me pay him . He reluctantly said OK , 100 smackers ! How many times have I met a man like him ? Not enough . All he cares about is the Audiophile enjoying his music . Try his amp . Like I said on his EBay feedback - BEST 12 Watts I’ve ever heard ! Then I went to a lower rectifier and the KT77’s and Heaven . Imagine what top notch Mullards would sound like ! I do have NOS 6550 Tungsols , amongst 5 other pairs of various values . And the tube selection for my pre ! Same results with the single E88CC Tube in the gain stage of the Inspire . Flipping Sweet ! It would sound amazing with a good pair of small speakers and stands , and subs ! 


I have heard a recent new product from a well established company with very innovative approach to class AB amplification in my system for a 30 day trial. Incredible resolution. Super clear, dynamic, great soundstage...etc. but after some time too clinical; almost too perfect to the point where my brain disengages from the sound and I want to walk away. Too "high fi". Could not relax with this sound.This is NOT a direction I want my system to go in. I sent it back.

Benchmark managed to make a Class AB amp sound like a Class D amp. Quite an interesting accomplishment. Suck out the distortion with NFB and suck the life out of the music. There is no free lunch with NFB. 
  • Seanheis1, It seems that you have to be very judicious and careful with the employment of negative feedback (NFB). It can provide uber low THD and very high damping factor (DF) measurements that may impress some. The penalty can be dry, clinical and lifeless sound quality. Tread cautiously as it’s a balancing act for certain. Reminds of how some listeners felt about Halcro audio products. Keep in mind that  what is considered clinical and lifeless to one may be amazingly accurate and transparent to another. Subjectivity rules.
  • Charles
All I know is that whatever you get that has tubes it seems to be a blackhole for money if you want to tube roll
.I did not expect that as I was buying up tubes.
I still want more so now if someone in the family asks what I want for Christmas,Bday or Fathersday I'll say" Tubes ".
Between guitar  amps,The Freya and the Primaluna give me 6sn7,5692,12ax7,12at7,12au7 etc.el84,el34,kt66,kt77,kt88 or kt120.
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wow,similar fantasy for me.I worked at a TV Shop[actually 2] in the 80's and we had WALLS of tubes.I always wished I'd had the foresite to snatch up a few Peaches Crates full.Didnt mess with guitars then so I did not even dream I'd ever need tubes.The old guy that owned the first shop always said tubes wouldnt go away.If only for the Governments secret tube communication bunkers lol.I also have the same dream now for guitars and amps
I agree with tube amp but no longer wish to pay well over a grand for the Sylvania 6550's power tubes it was designed for . If you can even find them.

Some say the new Russian Tungsold's are fine, I say they must have never
heard even a GE from the 50's.
A tube pre  pushing a Belles 350 or 150A Reference sounds very near to live music .
Blue glass JJ 88s! I don't own any of those but I want some! I don't think you can discount the esthetic element of tubes…I'm using a great sounding pair of Sovtek 88s from my "back up tube stash" partly because they have a groovy blue glow inside. I'm also a fan of some vintage tubes (ones I've owned that worked) and like various recent vintages of Gold Lions, but spending big bucks on older tubes seems unnecessary these days.
@wolf_garcia  +1 about the Gold Lions.  I have two 12AU7s in my line stage and a GZ34 rectifier in my SACD player's outboard power supply.  Have you ever checked into sourcing them from Cryoset?  Ron Sheldon's GL's seem to last a long time and stay quiet in circuit.
Which is more important - you ask? 

It’s kinda like ice cream, it's about different flavors and what you like in the end. I was an all solid state owner for too long. Should have tried tube preamps sooner than I did several decades later. Today, I keep my tube Cary SLP-98 TUBE Pre-amp running 100% of the time as my front-end. And, now swap out a Cary V12R (12) EL34 Triode/Ultralinear TUBE amp for a Cary SA-200.2 SOLID STATE amp every once in a while. While the tube amp is glorious and lush, when I swap back to the solid state amp periodically - it brings another dimension of dynamics at times. In either case, I would have a very hard time going back to a solid state preamplifier though. Really like having a tube preamp on the front-end; particularly when each of the back-end amplifier types are specifically designed to work with a particular tube pre-amplifier. More "important" is finding a good "match" between any preamp or amplifier (tube or SS) as I learned the hard way through trial-and-error. Good luck.
For maximum 2nd order harmonic distortion (and since I mostly use a passive preamp), my answer would be tube power amp.

I think this is a false question.  There is a great deal of variation between tube preamps and power amps.  And let's not forget that tube power amps need to be paired with the right loudspeakers as well.  

I run a multi-amplified loudspeaker that calls for 8 channels at 60 wpc, which is prohibitively expensive using tubes, not to mention the cost in air conditioning.  So I run an Aikido design tube preamp and just enjoy listening.
tube preamps can add some degree of tube sound and frequency response. 
tube power amplifiers deliver the bulk of the tube sound especially the large vivid sound stage.   

ranking in terms of preference-

all tube based system
tube power amp / solid state preamp
tube preamp / solid state power amp 
OK.  Putting all the excellent theoretical knowledge displayed in this thread to practical use,  can you guys recommend some good 100W+ stereo tube amps to pair with an Emotiva XSP-1 preamp? 
Somehow I've avoided Cryoed tubes…seems to be an unnatural thing to put those poor tubes through, although I might try a pair anyway to see what's what. And Danaroo, check out a Schiit Vidar (relatively cheap at 700 bucks or so) maybe as there seem to be some good designs going on with those guys, as my soon to arrive Freya will hopefully confirm (I have a little Schiit Loki EQ that is amazingly useful and well designed). What I like about new gear is the fact that I can return it if it sucks (just returned some headphones that don't fit my fat head).
Thanks wolf.  Are there any tube amp idiosyncrasies I need to be aware of since this will be my 1st foray into this topology?
Danoroo, 
I don't believe that the Vicar is a tube amplifier. You may want to explore Rogue Audio and Quicksilver Audio .
Charles 
can you guys recommend some good 100W+ stereo tube amps to pair with an Emotiva XSP-1 preamp?
Yes, but a budget is the first place to start.
Tube gear opens up a gigantic barn door of idiosyncrasies that make up the fun part of the "tubist" cult. The Schiit Vidar certainly isn't a tube amp but it was designed to be used with their tube preamps so maybe it matches well with those. Not many reviews yet so who knows?  I don't imagine there is a sonically comparable tube amp at that price, although Jolida may provide a tube solution albeit at twice the cost. I like Jolida amps. It's hard to find a relatively powerful tube power amp (except maybe a used one) at relatively el-cheapo prices unless there are some Chinese brands I don't know about. If you can afford 'em, go tube. Otherwise, listen to some of the well thought out SS stuff until you can buy that Atmasphere amp you really want.
Matching pre and power with SS and tube can be a challenge like you said, especially if the equipment was not designed to go together. Vincent Audio hybrid integrated amps are an excellent step up from the Schiit and Jolida offerings. Vincent uses high current class AB instead of what I consider inferior Class D offerings that are becoming very common, even at higher price points.  
Danoroo,
The pertinent question has been poised, what’s your budget range for the tube power amplifier you seek? A good quality 100 watt tube amplifier doesn’t have to be necessarily expensive but they won’t be "dirt cheap" either. Good quality engineering, implementation and parts/transformers/power supply do have a cost that’s worth it in the long-term perspective.
Charles
Granted, YouTube isn't a reliable tool for judging sound but Tyco Dogg has some interesting tests with the Schiit Freya preamp switching between tubes and Jfets, and between different tube sets.

Here's one of the series:
https://youtu.be/1Slu3u0o4Aw

I seemed to hear a difference in tube sets, but not so much between Tung-Sols and Jfet, which seems odd
I now have my Freya, and at this early point I can say it’s pretty damn good. The passive and FET modes are very similar sounding in my early assessment, and the tube stage is nice and hot with more than enough gain to send my Fire Bottle amp into the red zone …I replaced the "input" tubes with new Tung Sols although the original "mystery" tubes (no writing on mine at all, but they do seem to be tubes) work OK…the Tung Sols are simply dead quiet little things and sound great. No noticeable hiss or hum in Tube mode unless you stick your ear right on the tweeter in which case you can tell the tubes are there…and all in all a great sounding preamp. My previous preamp was so good it's hard to tell if the Freya is really better, but I have 15 days to figure it out.
My now "resting" preamp is a Kavent S33, which is a rebadged (not sure why) Vincent SA-91…it even says SA-91 on the circuit board. These are fully balanced aluminum clad heavy monsters with a couple of serious transformers mounted in a separate shielded side of the preamp…it’s a large seemingly overbuilt thing, and has a 10 db adjustment to get higher output if necessary, and that’s the setting I used. I note that fact because the Freya has a more normal output level and the passive and FET modes are a more typical line level that I can actually run to max with my SEP amp (clearly my speakers aren’t THAT efficient), but the Freya tube setting is much higher gain to provide lots of headroom into my rig.
@charles1dad

I would like to keep the price around $1500.  Maybe $2000 if I could find a bargain at that price.  What is tube biasing and is it something I have to do regularly?
@danoroo  Are you running Paradigm Persona B's? If so are you sure you really need 100 tube watts? They list at 92db sensitivity and 8 ohms. Looking at used moderately powered tube amps in your price range listed here this jumped out at me:

https://www.audiogon.com/listings/tube-tube-monoblocks-lots-of-positive-reviews-4-000-msrp-2017-11-1...

No affiliation with the seller just looks like a lot of amp for the money from a well regarded company. Good luck and happy listening!
@jond Actually I'm currently using a pair of Tekton loudspeakers rated at 98db sensitivity.
But, I like to play the music loud sometimes.  Will the 22W amps you linked to accomplish that?  I'm using a 200W SS amp now.
Hello Danoroo,
I’m with Jond 100 % with the Sophia Electric 845 SET(not push pull) amplifier and especially at that price! With your Tektons sensitivity and easy to drive characteristics, high volume shouldn’t be an issue. More importantly sound "quality " will be upper tier IMHO.

This is a well regarded manufacturer who utilizes good quality transformers and parts. In terms of true high level sound quality it’s very difficult to better this particular amplifier at this price, very difficult.

Many tube power amplifiers have an autobias feature but for those that do not biasing tubes is a pretty simple task to perform.
Charles
Danoroo,
Given the Tektons you have, here are 2 other options to consider. Dennis Had 12 watt SEP (KT 88 tube). Wolf Garcia has praised this amplifier a "few" times 😊😊.
Coincident Dynamo MK II version, 8 watt SEP (el 34 tube).
Yes they’re both lower power amplifiers but would mate well with your Tektons (Lores?) . Overall sound quality would be very good.

I must say however the 845 Sophia Electric mono blocks at that price is a genuine bargain if it’s in good condition.
Charles
@danoroo As Charles has stated those Sophia amps will have no trouble at all driving your speakers at 98db sensitivity they were designed to be driven by tubes. And you will find 22 tube watts to sound much more powerful than you might expect. I am driving 93db speakers with 17 tube watts as loud as I could stand to listen no problem. And thanks Charles it was pretty easy actually.  Tube Amp category and sort price low to high, under $2K they really jumped out at me! Good luck danaroo and you really do have tons of options with such easy to drive speakers!
Danoroo,
As I am sure you realize amplifier selection ultimately comes down to what type of sound character you want. Different topologies and designs have their own sound and presentation. Generally 100 watt tube amplifiers are push pull and very often class AB.

The 3 amplifier examples I mentioned above are
1Lower powered
2 Pure class A rather than class A/B
3 Single end rather than push pull
Either of these broad categories are capable of providing excellent sound quality. It truly depends on what "you" are seeking.

You are fortunate in the sense that your Tektons allow the use of either type of amplifier. In absolute terms there’s no universal "best" choice. Every listener has some degree of bias (I certainly do) as far as what sounds best, it’s all subjectivity pure and simple.

Its a shame that we can’t hear everything we are interested in before buying but that’s the reality in many situations, so reviews and word of mouth opinions are utilized.

As Jond said you have multiple options available due to your speakers.
I’ll say this, the Sophia Electric mono block 845 SET at that price is honestly a fantastic option to consider. Given my past experience of hearing many speakers and amplifiers I believe that the Tektons/845 mono block pairing would be quite special. Usually a good quality 845 SET amplifier new is going to cost 5 or 6 thousand(minimally) and definitely go up from there. These are no nonsense high voltage  designs that require very robust output transformers, parts and power supplies. This can’t be done cheaply. Sophia Electric makes very good quality amplifiers.
Best of luck,
Charles
@ charles1dad

This 845 SET amp can be driven by my Emotiva XSP-1 SS preamp?  The reason I want to use that preamp is because of it's bass management capabilities.  I would like to drive the Tekton Enzo 2.7s with a capable tube power amp while connecting subwoofers to the preamp.  Since I have never used tubes in my system and have no idea what sound characteristics they offer,  I would like to keep my initial foray as economical as possible until I'm certain this the presentation I want.  I appreciate you guys taking time to educate a noob.  Thanks.
@danoroo  A word of caution. You are trying to do two things at the same time. If this was just about your optimizing the performance of the Enzos, via a tubed amp, it would be one thing.

Adding sub control via the preamp may lead to coherence and timing issues and perhaps slight sound signature differences. I don't know the level of control you have via your preamp and your subs.....If you have a high level of software control, then perhaps the integration will be easier to achieve.
@david-ten 
I run Dirac Live to clean up the anomalies you mentioned.   Also, looking the specs of most tube power amps it seems the S/N ratio isn't nearly as good as SS amps.  The THD numbers aren't as good either with 1% at full power not uncommon.  SS amps' specs look considerably better.  Is this typical?
@danoroo Yes this is typical tube amps never measure as well as SS amps, however they often sound better. I would caution you to not buy gear solely based on specs.
Danoroo,
Those specification numbers will reveal very little in regard to component sound quality. You must listen and judge by what you hear. Again I find myself agreeing with the wisdom of Jond.

I once owned a Symphonic Line which is a highly regarded German SS amplifier. It had excellent specifications and very good sound. Well my 8 watt SET amplifier took my sound quality and listening enjoyment to a higher tier. The SET's measurements/specifications on paper would be reconsidered clearly inferior to the Symphonic Line.

Numbers said one thing and the ears said another, the ears won decisively. Now its definitely possible you could prefer the SS amp over the SET . My point is that listening is required to make that judgement not test bench results.
Charles
The most important is the synergy between they two.  Power amps just need to be powerful - clean, no or very low distortion, hopefully slam, etc.  Preamps need emotion.  
The Had amp I bought has no specs…it's specless, except for the 12 watt per side and Single Ended Pentode claims in the Ebay description. Specless.

My solution is to bi-amp, using a SET for the tweeter/mids, and a Push Pull for the woofers.

And I use a PS Audio SS pre-amp, but in passive mode most of the time, which keeps me all tube. Only when I really want to blast the Stravinsky, do I add some preamp transistor.

This set up pleases me a great deal.
Also, looking the specs of most tube power amps it seems the S/N ratio isn't nearly as good as SS amps. The THD numbers aren't as good either with 1% at full power not uncommon. SS amps' specs look considerably better. Is this typical?
The problem here is that the ear puts a different weighting on what harmonic distortion is present. IOW, it almost does not care about the 2nd harmonic, but cares quite a lot about the 7th and other higher ordered harmonics. So a tube amp tends to have lower orders to which the ear is less sensitive; solid state amps have more of the higher ordered harmonics than tube amps.

The ear translates all distortions into tonality. So the 2nd contributes to 'warmth'; the higher orders contribute to brightness and hardness. Both are colorations!

The bottom line here is that although solid state amps appear to have less distortion, the distortion that they do have is far more audible and objectionable to the human ear. This is why tubes are still around decades on after they were supposedly 'obsolete'.
i 100% with avanti1960. the majority of the tube sound/magic/characteristics comes from amp.
Interesting that this topic should come up again just now...Here's a copy of a question I logged on to ask...
"I'm using a Rogue Audio Cronus Magnum 2 biwired to Vandersteen model 2cs...I have a chance to pick up a Hafler DH200 cheap. Seeking opinions as to whether biamping with a solid state amp to the low end will be a net loss or gain...I'm guessing that it will tighten up the bass, but I'm worried that it will detract from the signature tube sound of the Cronus. Opinions?"
My best (remembered) sound was a couple of decades ago with an earlier iteration of the Vandersteens, a CJ tube preamp and the DH200 with Musical Concepts mods. (Mid fi...I know) Anyway, I'm going to pick up the Hafler and try it again...I'm not expecting an improvement, but we'll see...I'll post the perceived results on this thread if that's OK...
Getting the two amps to work together properly will be a bit of a challenge. Unless you use an active crossover, I think you will find that to a very difficult task. The problem with using an active crossover of course it that its not actually tailored to the speaker, and every one that I've heard has imposed its own signature, which is why I try to avoid them unless they are used in a subwoofer.