Tube Amps!

[johny747]

Hi,
I'm new to tube audio. Planning on buying a tube amplfier. What r the aspects I should look at when i'm buying?
Appreciate you help!

[risabet]

Tube type-- EL-34, KT-88 (my choice), 300B, and many others.
Topology-- Single-ended, Push-Pull, triode, ultralinear, etc.
Biasing-- self-biasing, manual biasing
Power
You speaker/amp interface

These are some of the more important aspects of tube amp buying, IMO

[Feanor]

Hi,
I'm new to tube audio. Planning on buying a tube amplfier. What r the aspects I should look at when i'm buying?
Appreciate you help!

If the latter, there is no real reason for tubes in this day & age. Better to go with at fine quality SS amp.

For fine quality I think you're looking at $1000+, (same would be true for a decent tube, so little difference in that respect). For SS, don't spend too much time on the likes of NAD, Rotel, Adcom, Parasound lower price models. Instead, I'd check out the "digitals" first:

• PS Audio
• Bel Canto
• Accoustic Reality
  
• Jjaz
• NuForce
• H2O

Other than these, lots of people like Odyssey.

[E-Stat]

If the latter (a music lover), there is no real reason for tubes in this day & age. Better to go with at fine quality SS amp.

Funny, I have the exact opposite reaction. While tubes can be expensive and cranky, I find them worth the hassle for what I find to be a superior rendering of unamplified music and voice.

rw

[Feanor]

Funny, I have the exact opposite reaction. While tubes can be expensive and cranky, I find them worth the hassle for what I find to be a superior rendering of unamplified music and voice.

rw

My point is only an hardcore audiophile is likely to care about the difference between as good SS amp and a comparably priced tube machine. So why not avoid the hassle? You feel its worthwhile; you are an audiophile: OK

[E-Stat]

My point is only an hardcore audiophile is likely to care about the difference between as good SS amp and a comparably priced tube machine.

Perhaps you'd think differently if you had more exposure to tubes.

What I responded to is your suggestion that musiclovers and audiophiles are mutually exclusive groups. I've been on vacation for the past ten days and listened to my Sony Walkman CD player virtually every day to get my music fix.

rw

[RGA]

JoeE

I run the ASL MG head -- it's the quietest amplifier I've ever owned -- so for that matter is my Oto. In fact when my house had some kind fo cable grounding problem my SS amps were the ones humming along and the ASL was unhampered. The ASL MG head is so quiet in fact that I could run it as a preamplifier using a 1/4 oin to rca adapter ($15.00 cable) to my Arcam Delta 290 (used as power amp). You'd be impressed. The only let down is that it doesn;t have tremedous bass capability but ASL has upgraded the unit to provide an OTL switch and so it gives more bass but at the cost of midrange purity from what I've read.

The problem with tube versus solid state arguments is that when discussing technical merrits of tube amplifiers they're simply going to lose. If you read the review in the latest issue of Hi-fi News Martin Colloms reviews the $29,000.00GBP Audio Note Ongaku (UK) -- the thing measures from the stone age - is incredibly fussy to the speaker (read match it to an Audio Note or other 95db real flat impedence or don't bother) and nor is it free from hums and other anomolies. Yet he notes

"It(Ongaku) addresses our instinctive love for harmony and spatiality, for vitality and musical artistry. It provides a tantalising glimpse as to how good reproduced sound really can be. Achieving this in practice will require a compatible temperment, some tolerance for hopefully minor flaws, consonant programme, a compatible system, and care with location and use. The remarkable sound quality commands admiration and respect.../...Verdict -- With such limited power outpu, this amplifier needs to be properly matched with sensitve speakers. But in the right system, and certain kinds of music, is is surely a contender for the title of world's best."

Looking purely at the measurement's it's nothing special(in some cases not even particularly good) -- but then again I owned a Pioneer Elite receiver that measured brilliant ala krell and sounded awful. This is why I'm not an uber fan of the measurements currently being done -- if you take JA of Stereophile if a speaker measures great or it measure weak -- the long term listening sessions don;t favour either measured result. The wonky measured De Capo is wonderful sounding and planty of flatter ones don't sound even remotely good to me -- Stereophile likes both. You have Magie and John Marks doesn't like them.

The moral is that few agree which is why there is so vast an array of design.

If you get more musical enjoyment out of whatever it is you're choosing to go with then it doesn't matter if it uses tubes or not.

[JoeE SP9]

Hi,
I'm new to tube audio. Planning on buying a tube amplfier. What r the aspects I should look at when i'm buying?
Appreciate you help!

Whatever you do always audition it first. I use tube amps and a tube preamp. To my ears tubes sound better in the midrange and treble. I have found that solid state works better for bass. The higher current output of SS (solid state) amps is the reason. If you are going to go with tubes the earlier they are in the amplification chain the more benefit you will get. A tube preamp will have more benefit than a tube power amp. Tube preamps generally do not like driving long leads so keep that in mind. I found audio nirvana with my ARC SP-9.

[Feanor]

First of all let me say: Nice system you've got . Secondly, if I could afford an Audio Research tube pre-amp, I might just go for it.

You're one who thinks that tubes do more earlier in the amplification sequence, i.e. the pre-amp stage. (I won't get into whether tubes actually sound better than SS -- maybe it's true.)

However tubes earlier in the chain seems to dilute the oft-cited argument for the superiority of tube over SS. This explaination goes that SS amps have notch distortion and need high levels of global feedback. So let me ask, were that the actual reason tubes are better, wouldn't it be more advantageous to put the tubes where the most amplification occurs, that is at the power amp stage?

I don't have a lot of experience with tubes but it is my suspicion that the real reason tubes improve the sound is that they filter nasty sounds, especailly high frequency ones, and/or add agreeable low, even order distortion????

[risabet]

Having used both SS and tubes (currently all tube) I find tubes to be more consonant with the gestalt of the music, IMS. That being said, unless you are willing to deal with tube issues than go with a good SS amp and a tube preamp for about 70% of that tube magic.

[RGA]

Feanor...the preamp is still an amplifier and controller. Remember that saying the first watt is the most important watt -- well the preamp is the first .1watt. SS is more effective at high level and worse at low levels.

Tube amplifers are not worse in the power amp stage - but tube amps "generally" don't like impedence swings. So On my speakers my OTO has no trouble driving treble impedence dips or bass impedence dips (where impedence dips generally occur in most speakers) simply because my speakers never fall outside a very narrow 9 ohm range 5ohms to 14ohms. My amp on a speaker that goes from 2ohm to 40ohms is going to be a rather futile attempt and will cause both frequency shifts as well as a pure and simple lack of power which means a lack of bass and a lack of treble.

This is why I dislike it when people say tubes are better as if this is some automatic in the high end world. It is a total disaster with the wrong speakers being matched up at volume levels many would deem acceptable And some tube amps just are not all that good -- just as not all SS amps are all that wonderful. Though SS amps tend to be "closer" to one another across the board than tube amps. Take a listen to the Jolida 302B and the ASL AQ1003DT - bioth use the same gernal topology and the same tubes -- they could not be more different in sound -- the ASL is a smoother than SS razor edge grip a speaker solid state-ish sounding tube amp. Indeed, it's a safe amp in that Solid State lovers could put this on and not feel a compromise with most speakers. The Jolida is more stereotypical with a full tubey sound with a big midrange softer bass and a slightly recessed treble. It is a "pleasing" and a little veiled amp. I recommend both because hey I don't know what someone is going to like. I would buy the ASL because while I hate added in grain of SS billowy softness can be having one want to hear more crisp detail of attack on instruments. SS tends to do decay badly low level resolution badly and treble generally badly to me at the givn price range.

I don;t think you're being fair to tubes as you have stated you've heard few of them.

The ASL and the Jolida are very nice entry level Tube amps -- but they are certainly not the end all of the technology and even here as entry level as they are under $2k US they're in with anything SS I've heard and considering both are only $1k - to me that;s saying a lot. And unlike the SS counterparts -- at least these you can actually upgrade and make substantially better from what I understand.

We had a shootout a while back and the owner of a digital amp HCA 02 or whatever it's called much preferred a set of Oddysey Stratos amps. Now for the speakers being run (gershman's) I would take the Stratos monos over a 30 watt tube amp sure -- but if you have sensitive speakers -- then I'd take the 30 watt tube amps on pure sound quality over the Stratus which are muscle amps -- not the least bit subtle or insightful. The low powered tube though would just huff and puff and bag out on the speakers so all things considered big SS is better with those speakers.

SO if you have those speakers you have to go SS and it will likely sound better. If you have easy to drive speakers and tubes -- you probably will never ever go back.

[theaudiohobby]

Feanor...the preamp is still an amplifier and controller. Remember that saying the first watt is the most important watt -- well the preamp is the first .1watt. SS is more effective at high level and worse at low levels.

The tone of your post is generally okay, but please this oft-repeat myth is just that a myth, Many amplifiers do worse at high levels than low levels irrespective of active component topology, it is all about optimal operating conditions, Some amplifiers perform much more poorly when driven outside these conditions, some are more graceful, it all about the distortion signature and clipping characteries of the overdriven component. The most important watts are the watts that are in continuous use, as any inherent distortion will be passed along.

Johnny, if you are minded to buy a tube amplifier, then as RGA mentioned, make sure that you try them with your speakers, output and input impedance interaction between the amplifier and speaker is very important , The sound quality will be very much determined by this interaction, as a rule tubes amplifiers have a much higher output impedance than SS cousin and as a consequence are more sensitive to speaker input impedance characteristics, however these can lead to some rather very surprising euphonically pleasing and (sometimes ideally compensated) pairings.

[JoeE SP9]

First of all let me say: Nice system you've got . Secondly, if I could afford an Audio Research tube pre-amp, I might just go for it.

You're one who thinks that tubes do more earlier in the amplification sequence, i.e. the pre-amp stage. (I won't get into whether tubes actually sound better than SS -- maybe it's true.)

However tubes earlier in the chain seems to dilute the oft-cited argument for the superiority of tube over SS. This explaination goes that SS amps have notch distortion and need high levels of global feedback. So let me ask, were that the actual reason tubes are better, wouldn't it be more advantageous to put the tubes where the most amplification occurs, that is at the power amp stage?

I don't have a lot of experience with tubes but it is my suspicion that the real reason tubes improve the sound is that they filter nasty sounds, especailly high frequency ones, and/or add agreeable low, even order distortion????

Good tube amps do not filter high frequency sounds. Neither I nor do most other tube users want an amplifier that is a tone control. You can get rid of most if not all notch distortion by biasing a solid state amp heavily into class A. Feedback has nothing to do with notch distortion. Notch distortion is caused by the output transistors being switched of and on. Lots of feedback is used to lower harmonic distortion and to help with stability. A pure class A amp has no notch distortion. The transisters conduct current all the time unlike standard amps.

I bought my SP-9 used. I buy lots of gear used. You can save a bundle of money that way. I am not the only one who thinks that tubes give more benefit earlier in the chain. Most tube-o-holics prefer tubes as early in the amplification chain as possible. Tube power amps that have output power in the 100 watt and above range are very expensive. I personally believe that tubes are better almost every where. I use SS on my head amp for the low noise level. I am currently building a tube head amp that should have acceptable noise levels. I also use SS to drive my subs. The only tube amps I know of that can control a 12" woofer (high damping factor needed) are the OTL amps. If I could afford it I would use OTL's for all my power amps. Although I am a batchelor I do have other interests and obligations so cost is a factor. It may be a small factor but it is a factor.

[Feanor]

... Most tube-o-holics prefer tubes as early in the amplification chain as possible. ...

I didn't me mean to imply that you were unusual in that opinion! I know it's widely held.

I know that notch distortion and the effects of high global feedback aren't the same. From what I've heard and understood, gobal feedback has a couple of common problems, and I like to hear what you have to say about it.

First, it stands to reason the global feedback might limit transient response. Secondly, I have heard that it causes relatively high, (compared to tubes), high order and odd order harmonic distortion which have been shown to be detrimental to good sound.

I would like to do some listening to tube equipment but I don't know anyone with a good system around where I live. (I haven't lived in the area for very long.) Given that I am very please with the sound of my current integrated amp, a Bel Canto eV02i, I'm not likely to go out an by a tube kit on speculation. But as a matter of interest the Bel is a digital hence doesn't have any notch distortion per se, also its design doesn't employ global feedback.

[JoeE SP9]

I didn't me mean to imply that you were unusual in that opinion! I know it's widely held.

I know that notch distortion and the effects of high global feedback aren't the same. From what I've heard and understood, gobal feedback has a couple of common problems, and I like to hear what you have to say about it.

First, it stands to reason the global feedback might limit transient response. Secondly, I have heard that it causes relatively high, (compared to tubes), high order and odd order harmonic distortion which have been shown to be detrimental to good sound.

I would like to do some listening to tube equipment but I don't know anyone with a good system around where I live. (I haven't lived in the area for very long.) Given that I am very please with the sound of my current integrated amp, a Bel Canto eV02i, I'm not likely to go out an by a tube kit on speculation. But as a matter of interest the Bel is a digital hence doesn't have any notch distortion per se, also its design doesn't employ global feedback.

The idea that you can cut and or reduce distortion by feeding an inverted portion of the output to the input to reduce distortion is what feedback is. To my ears and many others global feedback tends to smear the sound. The better sounding SS amps use little or no feedback and what is used is usually confined to a stage. There may be feedback in the driver stage or the output stage or both but usually there is not a global feedback loop. I use an ARC SP-9 because it is/was the best sounding preamp I could afford at the time. I use my radically modified Dyna MKIII's to drive my ES panels because they just sound better driven by tubes. My MKIII's have only the transformers and output tubes in common with the originals. So they are not representative of any amps commercially available. My SS gear has also undergone substantial modification. If anyone is interested I would suggest reading The Audio Amatuer, POOGE article. POOGE means progressive optimization of generic amplifiers. Any switching amplifier ie:digital has notch distortion by definition. Notch distortion being that caused by switching a transistor on and of. In digital amps the switching frequency for the transistors is high enough that notch distortion becomes a non issue. Switching amps usually don't need very much if any feedback. that's the nature of the beast. If you are happy with what you have it doesn't matter if it is a LIRPA, a Conrad Johnson, a Pioneer or a Krell. Pleasing your ears is what matters.

[E-Stat]

Hi,
I'm new to tube audio. Planning on buying a tube amplfier. What r the aspects I should look at when i'm buying?
Appreciate you help!

The most important consideration is compatibility with your speakers. As previously mentioned, tube amps usually have a lower damping factor than SS amps. For speakers having a roller coaster impedance curve, the result can be a couple db variation at various frequencies. Stereophile magazine speaker reviews usually show the impedance curve.

Consequently, I prefer using a Threshold Stasis with Double New Advents and the tube amps with the Sound Labs. I'll agree with theaudiohobby concerning RGA's statement about SS amps and low level resolution. I found the reverse to be true when comparing my Stasis to a Conrad Johnson MV-75A long ago. While the CJ was arguably better in the mids at higher levels, it lost its cool at low levels. Conversely, the Stasis runs cascode class A below a couple of watts (where it always runs in that system) and excels at low level resolution. You really need to audition the candidates.

Like JoeE SP9 (I also have a MK III myself), I would not hesitate to buy a used amp if it is from an established company. Since you live in the states, I can highly recommend Audio Research and VTL as they have been in the market for decades and their products can be maintained for as long as you please. I have no experience with the crop of lower cost models coming from China like the Jolidas.

Good luck hunting!

rw