[zybar]

Biamp with tubes on top Barry.  You get to keep your tight ss bass and "color" the mid/top to your flavor! 

You can't bi-amp with the TacT 2.0S.  You need the TacT 2.2x or 2.2xp for that.

George

[Scott F.]

....We all have our favorite colorations. We just don't always admit it....

You are exactly right. Music is about emotion, it needs to touch your soul somehow. For some of us, those wonderful second order harmonics touch us deep down. For others, they don't care for that sound. It doesn't matter whether its tubes or solid state, if it stirs your soul, thats all that matters.

[PaulFolbrecht]

Scott,

Now you've really pulled the top off the worm can.

I don't buy the "THD sounds good argument", for a few reasons.  One, studies have shown up to 3% of 2nd-order HD (which is most of what SETs produce, of course) to be simply inaudible.  Can't tell if it's there or not double-blind.

2nd, there is the notion that speakers produce more distortion than amps, that is also mostly 2nd harmonic, and that, by the laws of wave addition, most of the time, at most frequencies, the total 2nd order HD will be LESS with an amp producing substantial HD than one not!!  Get it?  A speaker's, say, 2% HD + the amp's 2% will be, on average, additive to a total of less than 1%.  And if the amp was producing next to none, there's nothing to cancel what the speaker is doing, and your total HD is higher!  (Most speakers, in fact, can produce much more than 2% HD at higher volumes.)

I do not know if that is true in practice to that extent.  I read a paper on the subject once, and it made sense and the math was corrent.

It seems that it's not the total HD content that matters, but how it's distributed.  A HD series high in 2nd order, with content tapering after that, is natural and sounds natural to the ear.  Removing the even series ot emphasize the odd (as with push pull) is NOT natural and makes the brain, to put it technically, go "Yuck!  That's not real music!".  Higher higher-order than lower-order (as with transisters) is even worse.

I don't know any of this for certain.  It's stuff I've read and to me, it explains why SETs not only can but usually do sound so good and so *natural*.  When mated to appropriate speakers and not pushed near clipping, where the distortion most likely IS noticable.

[WEEZ]

Scott,

Very well said. Music is indeed about emotion. If it doesn't touch your soul...it can simply be a distraction.

I agree also that 2nd order harmonics are pleasing. There is a danger, however, if the second order distortions get too high. As I've posted before...too high, and a saxaphone will end up sounding like a kazoo.  

Back to transparency for a moment. To clarify my previous posts...it has nothing to do with 'tube' sound or 'solid-state' sound. Both can be 'transparent'.

WEEZ

[Scott F.]

Paul, you almost did a complete 360 I know what you were trying to get across though. Trouble is with the tests you read about, there are so many variations of amplifier topology and types of speakers that the test is only valid for the one(s) the tested, so who really knows for sure. Not negating what they found by any means, just elaborating that it may not hold true in all cases. In any case its good to see somebody trying to explain (scientifically) what we are all hearing.

Weez, you're right, I've heard both be very transparent.

[PaulFolbrecht]

How did I do a 360?  You mean, in that post?  Or my preferences?

What it comes down to is what we hear, for sure.  For me, the "scientific" part is a curiosity, nothing more.  But, having been interested in the "ephonic distortion" argument at one point, what I found lead me to believe it doesn't explain SET sound.

[WEEZ]

Paul,

2% in the amp plus 2% in the speaker sounds like 1% to the listener? How can two wrongs make a right? I'd like to read that article. 

While I agree that single ended triode equipment can sound wonderful; so can push-pull equipment. (yes, even solid state.... ). But there are examples of both topologies that will force one to floss after listening, as well.

WEEZ

[PaulFolbrecht]

That's exactly right, Weez.  This is wave addition - it is only additive when exactly in phase.  If the THD of the speaker & amp were exactly 180d out of phase and the same magnitude, they'd cancel completely.

It can be shown mathematically that more often than not, they cancel.  It's either 1/3rd or 2/3rds of the time, depending on how you've got your speakers wired.  In other words, if you're getting 1/3rd cancellation, reverse the leads and you'll get 2/3rds.  Of course, I've no idea how to measure that. :-}  And - who cares?

[andyr]

Andy, that's what I meant by sounding transparent but still colored. Forwardness and/or bringing the singer in the room is a coloration. Nice, maybe, but colored just the same.

(good point, Gary. My system meets G. Holt's definition. It lacks my favorite colorations)

WEEZ

Hi Weez,

Mmmm, not sure I'd agree that bringing the singer forward into the room is a "colouration" ... surely it means it makes it sound more like you are actually there in the recording studio?  Which is where we want to be!!  (Especially if the singer is Annie Lennox or that "angel with big tits (as Andrew Loog Oldham famously called her)" ... Marianne Faithfull!!

I do like G Holt's definition, though ...

Regards,

Andy

[Scott F.]

How did I do a 360?  You mean, in that post?  Or my preferences?

Ooops, I misread your post  Thats what I get for speed reading.....

Never mind (said like Rosanne Rosanna Danna)

What it comes down to is what we hear, for sure.  For me, the "scientific" part is a curiosity, nothing more.  But, having been interested in the "ephonic distortion" argument at one point, what I found lead me to believe it doesn't explain SET sound.

I agree. Even though SET's and tube amps in general measure horribly, its inexplicable (to me anyway) why I think they sound better.

[WEEZ]

Andy, point well taken...

I wasn't clear regarding 'in the room' with 'forward'. There's a difference. "In the room' is fine. 'Forward' may or may not be a coloration. Generally, 'forward' IS a coloration if all recordings sound that way. That was my point. (some recordings place the vocalist further back in the mix....) YMMV............

Paul,

All my equipment is wired in phase. (yeah, I checked. checked by 'ear' also, just in case). Without having read the article or theory you refer to- I really have no clue what you're talking about.

I'm a simple guy. I just want to turn on the system and play music. I don't want audible distortion. Nor do I want to fiddle with my speaker wiring for each track I play. Hell, either the system sounds right or it doesn't. Mine sounds pretty good. My pre-amp is single ended triode with no global feed back. My amplifier is push-pull MOSFET with modest global feedback. But that matters not a wit.

One thing for sure...it's transparent to the source. That's a good thing, IMHO.

Link that article for us. Sounds like an interesting read....

You are quite correct, in that traditional measurements don't tell a whole lot. Almost nothing, in fact.

WEEZ

[andyr]

All my equipment is wired in phase. (yeah, I checked. checked by 'ear' also, just in case). Without having read the article or theory you refer to- I really have no clue what you're talking about.

WEEZ

Hi Weez,

Can you expound on what you mean by your statement "All my equipment is wired in phase"?

AFAIK, there are 2 kinds of "in phase" situations which, for best sound, you need to get right:

1.  "Absolute phase/polarity" ... ie. none of the amplifying modules in your sound chain invert polarity (or you have even numbers of modules which do - which gets you back to "correct" polarity).  Trouble is, the klutz sound engineers might've recorded a particular track with reversed polarity ... so you're still stuffed!  Or even worse, the microphones used for that track were connected up with random polarity - so you get an aural stew!   

I used to obsess about this but now I just play them how they come!  A CDP with a phase reversal switch would be nice, though!   

2.  Mains polarity - which is basically ... which end of the primary of your power transformer is connected to the 'active' side of your mains and which end is connected to 'neutral'?     Rather than me explain it, I recommend you read this article:
www.boundforsound.com/tweak.htm

Regards,

Andy

[PaulFolbrecht]

Weez,

I'm a simple guy, too (although, for some crazy reason, I've spent more than $10,000 on a stereo system).  I have never fiddled with my speakers' phase in an effort to minimize distortion.

The article I cited I found extremely interesting, and frankly brought a perspective that I would imagine 90%+ of audiophiles have never considered.  #1, it is quite natural that speakers produce more distortion in general than any electronics, being mechanical in nature, and #2, the fact that their largely 2nd harmonic products will cancel those produced by the amplifier(s) is something I have never once seen alluded to by any of the bashers of SET/tube amplifiers (some of whom are extremely naive in their pursuit of lowest-possible THD as a metric of sound quality!!).

I'll see if I can find it again.  It was probably nearly a year ago that I read it.

Paul

[WEEZ]

Andy,

I was referring only to absolute phase & polarity. I am familiar with Marty's 'main's' polarity article. Thanks for the link, though. You are also quite correct regarding the recording and correct phase. I believe this happens often. (along with other 'hurry up and get it done' techiques employed in the recording studio that are responsible for absolute crappy sound. If I were one of the musical artists that was a victim of some of these loud and distorted mixes...I'd sue).

Paul,

I hope you can find the article. I'll admit to being skeptical...but one never knows. I agree, that speakers will have higher distortion than most electronics today. I just have trouble getting my head around the theory that more distortion in the electronics will reduce it to the listener. My thought would be, that one would simply not 'notice' the distortion in the amplifier as much.

WEEZ

[95bcwh]

See this article:
http://www.soundstage.com/noisy04.htm

He wrote:
"How do you mix tubes and solid state? Solid state preamp and tube amp or tube preamp and solid state amp? My personal opinion is that a solid state preamp combined with a tube amp brings the worst of both technologies into sharper focus. You drive a tube amp with a low distortion, wide frequency range audio signal with perfect bass performance and the tube amp will reproduce the (probably) lifeless midrange, make the bass less good that it was when it left the preamp and not be able to "fix" the less than pristine/delicate highs the solid state preamp is likely to make"

How many people had tried it both way and ended up agreeing with him?

[WEEZ]

Hi 95,

Over the years I've found that if there is one 'truth' when it comes to audio; it's that there are few 'universal truths'.

WEEZ!

 

[andyr]

See this article:
http://www.soundstage.com/noisy04.htm

He wrote:
"How do you mix tubes and solid state? Solid state preamp and tube amp or tube preamp and solid state amp? My personal opinion is that a solid state preamp combined with a tube amp brings the worst of both technologies into sharper focus. You drive a tube amp with a low distortion, wide frequency range audio signal with perfect bass performance and the tube amp will reproduce the (probably) lifeless midrange, make the bass less good that it was when it left the preamp and not be able to "fix" the less than pristine/delicate highs the solid state preamp is likely to make"

How many people had tried it both way and ended up agreeing with him?

Hi 95bcwh,

A few years ago, I wouldn't have understood what you were talking about as I believed "tubes" were yesterday's technology ... ss is the ONLY path!!  )  And yes, I listened to only vinyl, then ... as I do now!

However, now having "tasted other cuisines" apart from ss, I'd have to say that tubes certainly have their place!!   

Sooo ... let me tell you what experiences have led to where I am now!!:

1.  A tube-based head amp, to my way of thinking, is just too noisy.  IE. the inherent noise level of tubes is just not appropriate for tiny signal levels.  And yet I have a friend who has also listens to vinyl, has the same amp and preamp that I do ... but much prefers his tube-based head amp (and I used to have the same one!) to my ss head amp!      It takes all sorts!!   

2.  The preamp we both use is a hybrid: an ss gain stage succeeded by a unity-gain tube follower.     The interesting thing about this pertickler device is that you can take the output from before the tube ... or after the tube.

Before-the-tube-output is boring - lifeless - compared to the "normal" after-the-tube output.  So you wouldn't feed your main speakers from this output!     However, it certainly does not have "less than pristine/delicate highs"!!   

Yet if you feed subs (or bass drivers in an active system) from the after-the-tube output, you get less dynamic, muddy bass compared to the "before-the-tube-output".  IE. the tubes do not deliver the sharp bass transients which the ss stage can.

3.  Tube preamps typically high much higher output impedance (Zout) than ss preamps.  If you plug a tube preamp into an ss power amp, you therefore typically do not have the ideal "following" ratio of Zout to Zin.  This can cause HF rollout with high-capacitance ICs.  (However, the Zout of my preamp is a very reasonable 120ohms, compared to the 47K Zin of my ss power amp - so I'm fine!     )

4.  Tube power amps typically have a much higher Zout than ss amps.  Hence they do not exert as tight control over the driver (compared to an ss amp).  This means they do not deliver the bass definition than an ss amp does.

5.  However, tube amps can deliver a better "thereness" than ss amps ... particularly SETs, which I would have to define as a tube-amp-in-a-class-by-itself!  (But unfortunately, sooo low powered!)

So my recommendation is tube preamps but ss power amps.

Regards,

Andy

[seraph321]

I used to be anti-tube on principle. It just wasn't logical to me. Then I finally started demoing modern tube systems. I listened to Audio Research, McIntosh, VTL, etc. Now I'm planning to add a tube preamp to my system.

I'm currently running: Bolder modded SB2 with Basic PS -> EA Modded Carver zr1600 and Gallo SA Bass Amp -> Gallo Reference 3s

Soon I hope to add a Modwright SWL 9.0se between the SB2 and the Carver. I actually tried out the Audio Research SP16 discussed above and experienced a very simliar improvement in presence and air, but a degredation of bass.

I believe the Modwright will be better that the SP16 in general, but I also am very interested to experiment with bypassing the tubes for the bass by continuing to run the SB2 directly into the Gallo SA. I think this would mean I'd have to balance the two amps' gains and then only use the SB2 digital volume control. I'm not sure that would be worth it.

Any thoughts on that?

[WEEZ]

seraph321- check the input z of your amplifiers. If you're planning on running (2) amps from a vacuum tubed pre-amp- that may be causing a frequency roll-off. Some solid-state amps have an input impedence of only 10kohm. If you run two; the load drops to 5kohm.

Check with the makers of your equipment for compatibility...or you could be disappointed with the results.

WEEZ

[Steve]

Wow, interesting conversations, widely varying opinions, but I think there are a couple of misconceptions.

1) SS preamps, or amps, especially DC coupled ones, are by design, bass heavy. If one were to do an actual listening test, this will be verified.
Even tube preamplifiers can be bass heavy by design.

2) Higher damping factor is not always good, especially with cone speakers, with varying impedance (Z).

From RCA Radiotron Designers Handbook, 1960, page 881.

"Thanks to the shape of the triode characteristics, the rise of impedance at the bass resonant frequency decreases the distortion, and althuogh the power output from the valve is lower than at 400c/s this is counterbalanced by the rise of loudspeaker efficiency at this frequency. The rise of impedance above 400 c/s results in a tendency towards a falling response, but loudspeakers specially designed for use with triodes are capable of giving fairly uniform response up to their limiting frequency."

"The ratio of the nominal load resistance RL to the output resistance Ro of an amplifier is not unimportant." (This is the damping factor.)
"If RL/Ro is very high, the loudspeaker is being operated with nearly constant voltage at all frequencies. If RL/Ro (the damping factor) is around 2 or 3, the voltage applied to the loudspeaker is slightly greater at frequencies where the loudspeaker impedance rises-- this is generally an advantage."

(Because the power applied is more constant, not lowering which would be the case with a low output Z, or high damping factor.)

What this means is that with high damping factors, as the impedance falls, generally from resonance through about 150hz, more power is actually applied, so the response is actually not flat, but heavier through the upper bass. As the speaker Z rises, the power supplied is reduced, which again is not good.

With a lower damping factor, the signal voltage falls along with the falling impedance and rises along with the rising impedance of the speaker, so the power supplied is actually fairly constant.

---

The main problem with the SS amp's input Z isn't so much the R, but the input capacitance. Even 20K amp input Z is not bad for a properly designed preamp.