Interesting article on SET amps

[Poultrygeist]

Audio Note is in there, RGA.

SET Amplifiers and Speakers

[E-Stat]

Audio Note is in there, RGA.

Currently thanks to radar developments, here is an interesting SET cousin possessing very similar transfer curves found with the tube flavor.

First Watt SIT 1

[Poultrygeist]

With only one transistor it's gotta sound good, right?

[E-Stat]

With only one transistor it's gotta sound good, right?

The SIT is not just any transistor. Nor is it configured just like any transistor amp.

You really should read the entire article if that's your take away.. Here's some more info.

[LeRoy]

@Poultrygeist, thanks for the article/link.

@E-Stat, I might be able to listen to one of these SIT amps fairly soon. My local audio buddy and former audio dealer is good buds with a professional audio reviewer who as I understand...just got one of these amps. IF I am able to get a good listen to the amp then I'll post my impressions...

[E-Stat]

IF I am able to get a good listen to the amp then I'll post my impressions...

Pretty cool! Keep us posted.

[RGA]

Let's not forget the SET solid state amps already out there like Sugden's A21a.

It's not that SS sounds bad it just always seems to cost so much more than a SET tube to sound as good. I audition SS amps I like like Technical Brain, Pass Labs, Sugden Master Class, and I see Sticker price of $10k to $70k and I think does it sound better than the SETs I've heard for around $3k and the answer comes back no. So I don't see the point in spending many more times the price. But that is a value judgment more than a quality of sound judgment and each person attaches their own value to such things. But that is now.

I can't see why anyone into SET would dump on Pass or Sugden - anytime a company owner has EARS and knows that SET sounds best and tries to achieve that sound to me is a company to follow.

Of course the only problem with comparing a SS amp that is designed to sound like a SET is that SETS hardly sound like eachother - from brand to brand or tube type to tube type - or from the same tube type but different tube manufacturer.

The key issue is which amp sounds best with a specific set of speakers and source. I have preferred the Sugden A21a over many many more expensive tube amplifiers and virtually all SS high feedback amplifiers. Strangely some class D amps which claim zero feedback have sounded surprisingly off - after auditioning the Bel Canto many years ago and recently here in Hong Kong the on paper blather should make them sound good. They just don't. Really something strangely off about them but I can't quite figure out what it is. Maybe if I had them at home for a long period I could get into what it is that's wrong.

[LeRoy]

The key issue is which amp sounds best with a specific set of speakers and source. .. Strangely some class D amps which claim zero feedback have sounded surprisingly off - after auditioning the Bel Canto many years ago and recently here in Hong Kong the on paper blather should make them sound good. They just don't. Really something strangely off about them but I can't quite figure out what it is. Maybe if I had them at home for a long period I could get into what it is that's wrong.

RGA, my audio buddy and former audio dealer used to carry the Bel Canto lineup and I never, ever, could figure out what was so great about their gear. Never did sound right to me no matter what speaker or source was configured with the Bel Canto including other Bel Canto. The only three things I liked about Bel Canto was their name and they look cool too.

[E-Stat]

Let's not forget the SET solid state amps already out there like Sugden's A21a.

Let's not forget that the bipolar outputs on the 60's design era Sugdens amplifiers do not share the same triode transfer curves as do the current SITs.

[Poultrygeist]

Just joking with my transistor comment. I'm a huge fan of the First Watt F1 particularly with BL horns. It's vise like grip wrings even drop of bass out of the little 4 inch Fostex making a sub unnecessary. A SET can't do that so well with BL horns.

I'm happy to see that Mr Pass is into OB's these days.

[E-Stat]

Just joking with my transistor comment. I'm a huge fan of the First Watt F1 particularly with BL horns.

While the F1 (along with other First Watt models) has a single stage, it still uses a pair of MOSFET output devices. Consequently, its character does not closely mimic triodes like the SIT.

The Sugdens are less similar to the SIT models. They use pairs of conventional bipolar output devices, contain multiple cascaded stages and employ current feedback. Not even close to single stage, no feedback, single device triode behavior.

[Feanor]

...
The key issue is which amp sounds best with a specific set of speakers and source. I have preferred the Sugden A21a over many many more expensive tube amplifiers and virtually all SS high feedback amplifiers. Strangely some class D amps which claim zero feedback have sounded surprisingly off - after auditioning the Bel Canto many years ago and recently here in Hong Kong the on paper blather should make them sound good. They just don't. Really something strangely off about them but I can't quite figure out what it is. Maybe if I had them at home for a long period I could get into what it is that's wrong.

Do you recall which class D amps claimed to be zero feedback? Bel Canto isn't one of them as far as I can see. I'm curious to know which do: typically class D uses feedback though apparently there are different feedback approaches used by different technologies.

[Feanor]

RGA, my audio buddy and former audio dealer used to carry the Bel Canto lineup and I never, ever, could figure out what was so great about their gear. Never did sound right to me no matter what speaker or source was configured with the Bel Canto including other Bel Canto. The only three things I liked about Bel Canto was their name and they look cool too.

I've never heard any of the newer, ICEpower-based Bel Cantos. I did own a Tripath-based, Bel Canto eVo2i amp which had its downside.

The eVo2i was very transparent and highly resolved, however it was also a tad bright and mid-range sounded lean or "grey" as some people described it.

My current Class D Audio, IRS2092-based, SDS-258 amp sounds better. It's as highly resolved & transparent but the mid-range is a bit more full-bodied -- however I doubt anybody would mistake it for a SET or even a push-pull EL34 or KT88.

As for class D sounding "off", various reviewers including RGA have said this. I don't know what they're talking about, but then I haven't the established preference for tube sound that they have.

[RGA]

Do you recall which class D amps claimed to be zero feedback? Bel Canto isn't one of them as far as I can see. I'm curious to know which do: typically class D uses feedback though apparently there are different feedback approaches used by different technologies.

Ahh that may be what it was then - might also explain the other Class D amps - I just thought their claim to fame was zero-feedback.

[Feanor]

Ahh that may be what it was then - might also explain the other Class D amps - I just thought their claim to fame was zero-feedback.

Not the case.

[LeRoy]

mid-range sounded lean or "grey" as some people described it.

My current Class D Audio, IRS2092-based, SDS-258 amp sounds better.

As for class D sounding "off", various reviewers including RGA have said this. I don't know what they're talking about, but then I haven't the established preference for tube sound that they have.

Yes, I agree with your assessment of the B.C. sounding "grey". I used to have a T-amp (original version) and the BC sounded to me like a T-amp with more power. As best as I can recall the newer version of B.C. has more warmth to it overall but still lacks an "organic vibrancy/life" to it. I am just not drawn into the B.C. sound.

Very astute of you to point out some listeners prefer tube sound,,,,which I was already evolving toward when I heard the BC...and now I am totally in the tube camp.

Good to know your new amp sounds better than the B.C. I've thought about what direction I might go if for some reason I get tired of the whole tube experience I just can't (at the moment) justify going back to SS but that would only leave digital amps as an option. Now I wonder if there will ever be a marriage of digital amps with tubes?

[RGA]

Like most designs it comes down to whether they design with their ears involved in the process or do design from a text book - or the right text books.

SS I suppose is technically superior to tubes. Yet as Colloms noted In Stereophile that the best SS designers in the industry when listening under blind level matched conditions chose a no feedback tube amplifier for $100 over their $3,000 SS models. Not one - but ALL of them said the tube sounded more like actual music. It's also no great surprise that the article noted many of these designers have been reducing feedback in a major way - trying to sound like that $100 tube amp. Probably because they can't very well chuck it in the bin with too many owners they told had the best - they're too involved in SS to admit they were wrong.

But to me I never understand why people want to buy SS that tries to sound like SET/Tubes - If you want the sound of a SET/tube - then umm buy a SET/tube amp. The SS that tries fails - they all fail - some may sound "tubish" as in the stereotypical tubish sound but that to me usually winds up being a SS amp that sounds veiled.

My Sugden A48b was noted as being "Valve-like" - yes it sounds way more like a Stereotypical tube amp than the A21a or for that matter most tube amps.

I certainly respect SS makers who want to try to sound like a SET - they know what the best sound is - so it's admirable and illustrates that they can hear.

Perhaps they want to get that sound but in a package more people can live with (ie not having to change tubes or deal with the things) - that is reasonable to me - that's why I like the Sugden A21a (The circa 1990 versions seem to be favored over the older ones and the newer ones). I know Halcro works hard on Feedback - their amps have it but they at least know that feedback sucks. But it's been 10 years since I've really auditioned a Halcro - personally they're too expensive but they at least seemed to make sense.

One of the reasons I am leaning towards Line Magnetic amplifiers is due to the variety of tubes you can use in one machine.

I mean really why not have a few different amplifiers - we don't have to choose just one solution for all occasions. I have a High damping factor SS amp, I have a surround sound receiver, they serve purposes.

[E-Stat]

Yet as Colloms noted In Stereophile that the best SS designers in the industry when listening under blind level matched conditions chose a no feedback tube amplifier for $100 over their $3,000 SS models.

I love it the way stories get considerably embellished over the years.

The eight tubes used in the KT88 based Michaelson and Austin TVA-1 (which was likely NOT a zero feedback design) alone were worth $100! I think you'll find the amp sold for just over $1000 in 1978 (!) when this test occurred.

The "pricey" SS amp used in the test was a NAIM NAP-250 along with a Quad 405. These were representative of the best SS designers in the industry? Too funny.

The Real Story

[Feanor]

...
But to me I never understand why people want to buy SS that tries to sound like SET/Tubes - If you want the sound of a SET/tube - then umm buy a SET/tube amp. The SS that tries fails - they all fail - some may sound "tubish" as in the stereotypical tubish sound but that to me usually winds up being a SS amp that sounds veiled.
....

Funny you should mention that -- my own experience inclines me to agree.

My previous s/s amp, the Monarchy SM-70 Pro is acclaimed by some pundits, (notably Morricab at AA), as sounding much more tube-like than most s/s and therefore preferable to them. The SM-70 Pro is a high-bias, zero global feedback design.

The SM-70 Pro is a pretty nice nice amp and certainly beat the likes of NAD C270 or Adcom GFP 555II in every respect. I also preferred it to my preceding Bel Canto eVo2i on about 70% of my recordings. But the odd thing was that 30% of recordings that sounded better on the Bel Canto were the better recordings.

Finally I concluded that the SM-70 Pro was a bit veiled; it lack both ultimate resolution and the ability to convey full instrument timbres. That's what prompted me to try another class D design, (my funds precluding the likes of a Pass Labs model.)

When I got my current Class D Audio SDS-258 what I decided was that I prefer it to the Monarchys for about 70% of recordings, (a magic number?). But in this instance the 70% including all the best recordings.

Further, now that I have very clean source, my latest cheap DAC, the percentage I prefer with the Class D Audio is nearer 100%. All this inclines me to speculate that the principle advantage of tube circuits is their ability to hide grunge rather than actually deliver a purer signal.

[bobsticks]

I love it the way stories get considerably embellished over the years.

The eight tubes used in the KT88 based Michaelson and Austin TVA-1 (which was likely NOT a zero feedback design) alone were worth $100! I think you'll find the amp sold for just over $1000 in 1978 (!) when this test occurred.

The "pricey" SS amp used in the test was a NAIM NAP-250 along with a Quad 405. These were representative of the best SS designers in the industry? Too funny.

The Real Story

How dare you try to interject a note of truth into some perflectly good historical revisionism.

[RGA]

I love it the way stories get considerably embellished over the years.

The eight tubes used in the KT88 based Michaelson and Austin TVA-1 (which was likely NOT a zero feedback design) alone were worth $100! I think you'll find the amp sold for just over $1000 in 1978 (!) when this test occurred.

The "pricey" SS amp used in the test was a NAIM NAP-250 along with a Quad 405. These were representative of the best SS designers in the industry? Too funny.

The Real Story

The first three letter of ASSUME boys - maybe ask before you jump all over every post

Actually the real story was that it was a 25WPC Radford amplifier

A Future Without Feedback? | Stereophile.com

[Poultrygeist]

I love this quote from the article which sums up my feelings toward single ended triodes:

"More precisely the SE units' sound over the broad mid-range - in point of fact, over most of the significantly audible frequency range - reaches a level of purity and intrinsic musicality that inspires near religious fervor"

[RGA]

I love this quote from the article which sums up my feelings toward single ended triodes:

"More precisely the SE units' sound over the broad mid-range - in point of fact, over most of the significantly audible frequency range - reaches a level of purity and intrinsic musicality that inspires near religious fervor"

Well he's right - I'm not religious but something is going on when as I said somewhere on one of these forums when a $650 2 way box hooked to 211 tubes in SET can move me profoundly emotionally listening to a given CD (yes even CD) and using the exact same CD in a system with $20k pro studio monitors and a PP tube amp leaves me listening to notes and audiophile pseudo language - the ultimate experience is disconnected and has me trying to focus on several things at the same time rather than have it wash over the ears in a "real way."

I read the Zu site and they seemed to indicate that SET was what it was made for as well. So the next time I go back I will try a SET. Fortunately the store has all the Line Magnetic SETs and Melody SETs including their Ongaku copy called the Aoxdin (or something) that is basically a lower powered scaled down version 16 watts.

I like the idea of trying all the Line Magnetic variations and Melody and Rogue and Almarro amps (that is what they carry) as well as a few others but I forgot the names.

I found their complete line-up. I must say that the 3 watt 218mini integrated is somewhat appealing - it's mainly a headphone amp but also apparently easily drives the ZU Audio speakers. He claims it drives the ATC quite well but not too loud. I'd have to heard that myself. Trying to build that budget system so I will at least try it out.

I am also debating whether the 216 and 211 PP integrated amps they sell would be close if running them in triode mode as they have the options. I have never had an amp that had this feature. From my reading on the net everyone seems to always prefer the Triode mode.

http://www.lmaudio.net/cp_l.aspx?dyiji=10

Also as a DIYer I would like to know what in the hell you do with this tube powered field coil woofer - Line Magnetic TA-4151 Field coil woofer with built in power supply

It look neat.

Edit: Well it seems others are on board - perhaps the Line Magnetic gear really is as good as I thought it was when I heard it. Some of the boys at Audiokarma put their money out for it

Line Magnetic Audio 216AI integrated amplifier - AudioKarma.org Home Audio Stereo Discussion Forums

[E-Stat]

The first three letter of ASSUME boys - maybe ask before you jump all over every post

Mea culpa. You pointed out a comparative report by Collums in Stereophile. I found a similar one.

Yet as Colloms noted In Stereophile that the best SS designers in the industry...

First of all, the Radford is not a zero feedback design. Of the list of "industry leaders" who participated in the 1975 test, only two designed SS electronics (Naim and Meridian). They were the "best SS designers in the industry"? That's certainly not what Collum claimed. I can remember hearing a few exceptional SS amps from 1975 not designed in the UK such as the Levinson ML-2, Stax DA80 and Yamaha B-1.

Understand that fundamentally, I agree with your position. I've used tube gear of one sort or another in my system for over thirty years. Your penchant for fabricating details , however, doesn't help your position.

[Poultrygeist]

Here's a link to 2a3 SETs which are a great match for Zu's. Don Garber's Fi X 2a3 is beyond unique and loved by every reviewer. The Almarro EL84 SE not shown in the link I covet deeply.

It takes a pair to tell your audio buds you've upgraded to 3 watts!

http://home.earthlink.net/~jeremyeps...f/sp15_2a3.pdf