Tube amp recommendation

What speakers will you be driving with the amp?

I'd say "provide a budget", but I'll just take the liberty of suggesting a used Sonic Frontiers Power 2 if you can afford it ($1,500-$2,000). It holds bias really well, can drive most speakers and features very high build quality, especially for the money. If you can't afford one, a used Sonic Frontiers Power 1 can be had for $800-$1,000. At 50 watts/channel, a Power 1 won't drive 86 db. efficient speakers to loud volume in big rooms, but it will do fine with most 88 db+ efficient speakers in average rooms and has all the qualities of its "bigger brothers". These amps use 6550 tubes, which are fairly cheap to replace ($80/pair) and you'll get a couple of thousand hours out of the tubes anyway.

A word to the wise - you need to be very, very careful in buying a tube amp, as the vast majority of them cannot control the woofers of typical speakers. Only very expensive tube amps (which are very expensive because they use high quality output transformers and beefy power supplies) can get it done. "Entry" or "mid-level" tube amps are almost always very compromised designs and you are better off going with solid-state if you are on a budget - at that price point, it is extremely difficult to buy a decent tube amp, while there are a number of good sounding solid-state amps available which will offer better overall sound.

FWIW if the amp is good, its good with rock, hip hop, electronic, classical- whatever.

Contrary to opinion above, the size of the woofer and the ability for the amp to control it really is a red herring. A small amp controls a big woofer just fine. But usually a small amp has less power- you're going to cause it to clip sooner. Some speakers are designed for the amp to have **lots** of loop negative feedback (IOW: transistor) and tube circuits, owing to increased linearity of tubes, often run less feedback, and in many cases, none at all.

This is a difference of design consideration and is not a matter of 'control'. See

http://www.atma-sphere.com/papers/paradigm_paper2.html

for more information.

If you want to get the most out of a tube amplifier, your tube amplifier investment dollar will be best served by a speaker that is 8 ohms or more. This is actually true of transistors as well, as long as your goal is sound quality and not raw sound pressure.

Look into Quicksilver products. Very reliable built like a"Mac Truck" and can be picked up at decent prices. I had a pair of V-4's that didn't require constant biasing, had no problems they were just plain easy to own. If they were a car they would be a Toyota( with apologizes to domestic companies)

Ralph: I did not write that there is a correlation between the "size of the woofer and the ability for the amp to control it". What I was trying to convey, but did not do so clearly, is that the vast majority of tube amps do not have the high quality output transformers or beefy power supplies needed to control the woofers of the average audiophile speaker, which these days tends to present a 4 ohm load or less on average in the bass. To fill in the blanks for this gentleman, it takes twice the current to drive a 4 ohm speaker than it does to drive an 8 Ohm speaker, all things being equal. In rough terms, the output transformers convert voltage into current, and in my experience, only the very good ones (i.e., very expensive ones) do this with the efficiency required to drive low-impedence speakers with authority ("authority" meaning tight, accurate bass). The role of power supplies is to house and supply the voltage that is processed by the output transformers, and big power supplies are needed to allow a tube amp to properly drive low impedence (i.e., 4 Ohms or less) speakers because such speakers require a lot of current. There are very well known 750 watt/channel monoblocks that cannot control the woofers of typical 4 ohm speakers because they use mediocre output transformers, while there are also 8 watt/channel tube amps featuring extremely high quality output transformers and huge-ass power supplies that can very effectively control the woofers of low impedence speakers.

In suggesting a speaker of 8 Ohms or more, what you are suggesting is not inconsistent with what I wrote. Of course, most of your designs are output transformer-less, which is why you advocate an 8 Ohm speaker. Again for the author of this thread, an "output transfrmer-less" tube amp is, as the name suggests, a tube amp that has no output transformer. The advantages of such an amp are greater purity and immediacy, with the downside being that, generally speaking, they do not do well with low impedence speakers (maybe your very expensive products can, but they would present an exception to the rule). The problem is, other than horns, the majority of audiophile speakers feature an average impedence well below 8 Ohms, which is why I provided the above advice, which I stand by. Please don't get me wrong - I know you build top-quality products and have myself owned a zero-feedback, triode power amp for many years now (VAC Renaissance amps) - but with a typical 4 Ohm speaker, which is most of them these days, I believe it takes a really fine tube amp, i.e., something with top-notch transformers and lots of capacitance, to provide tight bass.

Speakers are a big determining factor in the amp decision. You should look to the Quicksilver silver Mono, V4, ARC VT 100, MKi, ii, iii, Reference line, VS110, VAC, and a handful of others. jallen

A couple of quick corrections to my most recent post, which I fired off in a hurry in order to make a train.

First, I did not mean to insinuate that Atmasphere (a/k/a Ralph) advocated an 8 Ohm speaker because his output transformerless ("OTL") amps do best on such speakers - Ralph has integrity and advocated such a speaker, as I read him, because such speakers are easier for any amp to drive, whether tube or transistor in design, all things being equal. As for OTL amps, they generally do require a speaker with a benign impedence (it is hard to generalize, but 6 Ohms at a minimum, 8 Ohms being better) and that is what I was trying to convey, albeit inarticulately.

Second, my last sentence concluded "with a typical 4 Ohm speaker, which is most of them these days, I believe it takes a really fine tube amp, i.e., something with top-notch transformers and lots of capacitance, to provide tight bass." I meant to write "a typical speaker that averages 4 Ohms in the bass". The impedance of most audiophile speakers varies up and down considerably depending upon the frequency, but the problem for tube amps tends to be speakers featuring an average low impedance in the bass (those also featuring steep phase angles in the bass add to the agony), as most tube amps can't deliver the requisite current (because of crappy transformers, puny power supplies, and oftentimes both).

you neglected to tell us two "biggies" your speakers and how much you want to spend.

Check out the CARY SLA-70 now for sale here on the 'Gon. It's self biasing, reliable, and CLASS A. Tubes last and are cheap to replace.

Rogue M-150 about $2,000 used. 150 watts ultralinear and 100 watts triode easy to switch on the fly. Easy to bias and holds bias well. Good control of woofers and American made. Good luck

FWIW if the amp is good, its good with rock, hip hop, electronic, classical- whatever.

I might respectfully disagree with you here, Ralph. I think we've discussed this; the exception I can think of is with low-powered SET amps which excel at certain specific qualities that are best enjoyed with more sparse and simple musical arrangements. Though they can certainly also sound "good" with rock, hip-hop, electronic, etc., my experience has been that denser arrangements are better served by different topologies delivering more current. I guess then your statement might imply that those SET amps are not "good" amps, which what I'd understand you are opining here (those amps which are not versatile enough to handle any type of music are not "good" amps). Correct me if I'm wrong. I understand that there are issues of distortion that also come hand-in-hand with many SET designs, particularly 2nd order harmonic distortions. These haven't seemed to bother me, or their bother is offset by the qualities I'm enjoying, I suppose.

From your paper:

In the world of speakers, efficiency of the speaker has been an issue that the Voltage camp has had to address, as the older Power Paradigm specification of 1 watt/1 meter was a 'chink in the armour'. The new Voltage Paradigm specification, Senstivity, illustrates the point: 2.83V/ 1 meter is the spec, resulting in a certain sound pressure level, expressed in db, just like the Efficiency spec. 2.83 Volts into an 8 ohm load is 1 watt. 2.83 Volts into 4 ohms is 2 watts. Thus, a speaker can have a senstivity rating that looks the same as the efficiency rating, but the speaker can be several decibels less efficient if the impedance is lower. This is an easy way to cover up how much power it really takes to drive a speaker, and also creates an expression that moves the efficiency issue into the Voltage Paradigm nomenclature. It would also seem to create a 'buyer be ware' situation: you have to know how to interpret the numbers to get to the truth of the matter.

From another thread, I mentioned that I'm using 9 watt SET amps pushing speakers in nearfield that are 92db at a flat 10ohms. The only times I've experience audible distortions has been in the low end, when bass gets very low and intense. I'd always assumed that it was the amps inability to move the larger bass drivers fast enough, but you seem to be implying something different here (or are you)? Am I actually pushing the speakers to distortion in other parts of the range and just not hearing it as much as in the bass? Oh, and is "Voltage Camp" like "Band Camp"?

Finally, a quick note to the original poster who has not chimed in with more specs. Another detail you did not mention is whether or not you already had a preamp and what that component was, or whether you were in search of an integrated tube amp. As others have indicated your budget and speakers might be good things to list. "Entry to mid-level" might mean different things to different people. I'd guess from re-reading your post that you are probably looking for an integrated tube amp. No idea of your budget though. I'd echo the recommendation of Quicksilver, but Mike's stuff is all power amps (require a preamp) - certainly huge bang-for-buck there. Ralph's amps are excellent as well, but I wouldn't put them into an entry to mid-level category (again, that is subjective according to your own budget). There are a whole bunch of good integrated tube amps coming from China if you care to go that direction. I'm more for supporting local myself, but offerings are not as plentiful.

Ralph,

Some irony in your "If an amp is good..." quotation.I once owned an S-30 (very early production) that was terrific with Merlin VSMs...so long as there was no deep bass content. With my Verity P/E, the amp sounded very good ONLY on a limited variety of program material.

While your point is taken, the fundamentally different power requirements between -for example- acapella voical music and the synthesized deep bass in some dance music may make an amp (speaker combo) that's great with the former unsuitable for the latter. IME, there are many amp/speaker combos that have proven much better suited to small scale music.

In this sense, at least, I'd say your comment is an overstatement.

Marty

I think we are diverging from the original question.

For the money and quality...and what I think will fit your listening needs, get yourself a McIntosh 2102 amp.

100 watts/channel, runs problem-free and is somewhat sensitive to tube rolling (ditch the stock tubes that come with it...) and you will be very happy.

I own two of them and am running them bridged so there is one for each speaker.

Look at Rogue, Cayin or Jolida

Hi Jax2, my point has to do with equipment matching. An SET driving a 92 db speaker is going to get clipped a lot if you listen to demanding musical passages. On a speaker like that, you would need a lot more power- 60 to 100 watts, in order to get to appropriate levels. There are not a lot of SETs that can do that, and IMO those that do don't sound very good. Lower power SETs really require a speaker 10 db more efficient than the ones you have/had; then you can play hip hop on them all day, but don't expect a lot of bass with a speaker that is that efficient! That's why those speakers we had at T.H.E. Show are such a nice deal, though they are anything but cheap :)

IOW if an amplifier is good, its good for any kind of music, perhaps a qualifier is needed- as long as it is being used with a speaker that matches that amplifier (whatever it is) properly. So I am saying that such an amp will play classical as well as any rock. The amp does not care what someone's taste is- its all electronic signals to an amp :)

To Raquel's comment about output transformers- I agree that better, more expensive transformers will do a better job with the bass on 4 ohms, but such an amplifier will still sound better on a speaker that is 8 ohms or more all other thing being equal. That comment I made about impedance relates to all amplifiers, even transistors, so long as sound quality is the goal. IMO, as soon as 4 ohms comes up, sound quality is no longer the goal. At that point its all about the amp being somehow more brutal or something. My experience with high end audio is that it is all about sound quality and to get that you need higher impedance speakers, regardless of the amplifier technology.

I want to second Ralph's comments about higher impedence speakers lending themselves to better sound quality, if only because they can be driven by low or no feedback amplifiers. Absolutes are a dangerous thing in audio, but my experience is that negative feedback, which is present in virtually all high-powered solid-state amps (and too many tube amps - hello Audio Research), is the single most deleterious design feature in high-end amplification. So why do amp designers use it? Because most speaker designers emphasize linear frequency response, which means they have to dampen down the efficiency of driver cones so that a given cone puts out even volume throughout the driver's bandwidth. This means a lot of 86 db. efficient speakers (and a "laid-back", as opposed to "live-band" sound), which require an amp that can put out some serious watts. As soon as you start to get north of 125-150 watts/channel, you need negative feedback in order to have a stable amplification circuit. The result is the lifeless, uninvolving sound that you get with big solid-state amps and 86 db. efficient speakers. Compared to that, Ralph's OTL zero-feedback triode amps paired with good horns or with a very high-end, easy-to-drive speaker like the Escalante Fremont provides extremely dynamic, open and vibrant sound that is much closer to live.

Hi and thanks for all of the responses. I haven't been able to reply until now since I had a few meetings to attend and a snow storm to deal with. I will look at the various recommendations (particularly the car, sonic frontiers and the jolida)

As for the various questions...

Speakers... I have an old set of 8 ohm speakers that claim to have 90 db sensitivity. However, I have been looking at various things lately.

My Goal... quality watts not a quantity of watts

Budget... 1000-1400 or so (spending less is ok as well). I like my music, but want to keep a limit because of the current economic climate.

Style... I should have said integrated in my first post

I have been looking at various jolida products and then I saw this
posting (particularly the third photo) and started to wonder if I had to calibrate the bias each time I wanted to do some 'chillaxin'.

Thanks again.

In your price range, for a tube integrated you're probably going to do best with something used from China (Jolida, Prima Luna. Sophia, Cayin, Mysterie, among others). The Jolida 102B you are interested in requires manual biasing (a simple monthly task with a digital volt meter). Most af the Jolidas require a manual bias while other options, like Prima Luna, may have an auto-bias circuit. The 102b only puts out about 20 watts which may be a bit low for 90db at 8ohms depending on the size of room, type of music and typical level you listen at. Generally I'd be looking for 40-60 tube watts if I were you (Jolida 302B or 502B would do). If you'll be looking for new speakers too then you can better tailor the selection of both.

Hi Jax2, my point has to do with equipment matching. An SET driving a 92 db speaker is going to get clipped a lot if you listen to demanding musical passages. On a speaker like that, you would need a lot more power- 60 to 100 watts, in order to get to appropriate levels. There are not a lot of SETs that can do that, and IMO those that do don't sound very good. Lower power SETs really require a speaker 10 db more efficient than the ones you have/had; then you can play hip hop on them all day, but don't expect a lot of bass with a speaker that is that efficient! That's why those speakers we had at T.H.E. Show are such a nice deal, though they are anything but cheap :)

I would love to have a pair of John's speakers, but alas, not only is it not in the card$ at the moment, but I'm also dealing with a smallish listening space in my home. The WAF would negate anything the size of a dishwasher or larger. My wife used to call my LaScalas, "The Dishwashers". I used those at work and they were highly modified, and yes, they certainly could do more with demanding music...but I still prefer my current nearfield setup. It is pretty rare that I can hear it strain. There are only two tracks I can think of, and I know exactly where they will tax the system, and just in the bass. Otherwise I do not hear it clipping at all (unless I'm missing something - I don't think so because Peter's observed the same thing, as has my other Nervosa inflicted friend). That said, I'm sitting 8 feet from my speakers which are only 2.5 feet from the back wall.

IOW if an amplifier is good, its good for any kind of music, perhaps a qualifier is needed- as long as it is being used with a speaker that matches that amplifier (whatever it is) properly. So I am saying that such an amp will play classical as well as any rock. The amp does not care what someone's taste is- its all electronic signals to an amp :)

I think I get what you're saying here. I completely agree about speaker matching with amps. I don't know that what I think you are getting at overall is how I experience two contrasting amps though. Maybe I'm just delusional. As I said, my SET amps (still have'em) can play rock just fine...enjoyable even...I just think it's more enjoyable on some SS amps I've tried, for instance. Whereas something more stark and simple sounds much better on my SET amps (to me). The illusion of space, presence and realism is far more effective to me with the SET option. That illusion is there to a great degree when playing more challenging, more dense music, rock say, but it occurs to me as more congested than when that same dense is played on a good SS amp in the same system and space. By your definition of a 'good amp' both the SET and SS amps I've used in this space need not apply. It may be all electronic signals to an amp, but it's not that at all to any of us who are listening to the music. We put all kinds of meaning into just how those electronic signals are translated into music. I digress........

Hi DennyC - I would highly recommend the PrimaLuna Dialogue 2 integrated. It is auto-biasing, and can take many different kinds of tubes, so you can tube roll to your heart's content if you want without having to worry about biasing. The amp is very good sounding (on the warmer side), and has two modes, an ultralinear one putting out 35W a channel, and a triode mode putting out 21W. You can flip back and forth between them at the touch of a button, which is a very nice feature indeed. It also has a soft-start feature to prolong tube life. I have had one for more than 9 months now and am very happy with it. It is a perfect way to get into tubes, and will be powerful enough to drive most speakers out there. I think they still run a little over 2600 new, but you could probably find a used one here cheaper.

Hi Dennyc,
If you want a a very good tube amp I will suggest RaySonic SP-120 tube integrated amp. RaySonic is a Canada based company and has very good reputation for making truely high end products. The amp outputs 50 very sweet watts yet seems immensly powerful. It uses 4 KT-88 output tubes and heptic output transformer. Looks gorgeous too. I have driven 86 dB (8 ohm) speakers to a great satisfaction. It will drive your 90 dB speakers very efficiently. The sound of this amp is extremely involving.

If interested please email me, I have one for sale. It is almost brand new condition. Thanks,