"Essentially, you are saying that provided the Q of the system is kept reasonable, the difference between a tube amp and an SS amp is negligible."

I am not sure I would draw that strong of a conclusion. What I am trying to say is that when the damping factor differences between tube and SS amps is removed they become much closer sonically. I would not state that one is always better the the other, I think that there will be trade-offs in every situation and even between different SS or tube amps.

For example, I had a guy over at my house to show me some very expensive speaker cables he want to demo (and then sell me). We hooked them up between my 200 watt SS amp and my Fostex FE-208 Sigma ML TL speakers. I had alway found these speakers to be lacking at the very top end and was considering adding a super-tweeter. His cables made a huge difference and the highs sounded great. Much better then my own cables. Then we swapped the speakers to my Focal two way with the inverted metallic dome tweeter. His cables produced a painful high end, absolutely terrible drove us from the room. Changing cables back to mine, my cables sounded great! So who's cables are better? Depends on the rest of the system.

If you buy into the arguement that a tube amp or a SS amp (with correction circuit) can be used with a Fostex or Lowther full range driver, then I have made my point. The significant advantage I see in SS is the degree of adjustability that the circuit allows to get the response just right for the speaker system, the amp, the interconnects, the room, and the listener's personal taste.

One more example, my audio buddy Pete was over last night to listen and offer opinions on the Lowther ML TL. When he arrived I had the PM2A drivers installed and playing. I demomstrated the variable BSC I am using now and first shorted the BSC out of the system. No bass, Lowther shout big time, really bad sound. Then I dialed the resistance up to balance the SPL and things were much better. He liked the mid range and top end of the PM2A but felt that the mid bass was a little recessed in the ML TL. I tend to agree with him. So 15 minutes later, I swapped to the PM6A drivers and again dialed the correct series resistance and the bass and mid bass were excellent. But the very top end, the air, was not as good as the PM2A. We listened for a while and I asked him which he liked better, he liked the PM2A better because he is a sax lover and it really shined on the horns. He is not a bass lover and really listens to the mids. But the PM6A was not hard to take. A great evening!

"One last question, have you ever done a listen-off between a SET and an SS on any of your speakers? If they sound essentially indistinguishable (with proper compoensations applied in each case) then you are totally right. It would be interesting to do such a listen-off. You know, take a pair of speakers, and put the relevant amp/network combos in fornt of them."

I have never done this, I don't know anybody locally into tubes. It would be a great experiment and would really go a long way towards resolving the question in my own mind or maybe even raising more questions. I have been to the one or two "high end" stores locally and they don't sell tube amps. With my adjustable BSC this would be a very easy thing to do, I'll keep looking for an opportunity to run this test and report the results if I can find an tube amp.

"Also, the whole 1 watt amp thing...to me it's just the usual audio hype. The fact that some vendors are "excited" about this and call it a "breakthrough"...well... i can tell you what i think they are excited about, and it begins with a D----- and is colored green."

Obviously Nelson Pass is a very talented audio designer, his contributions over many years are amazing. There is hype everywhere in audio and it is interesting to see the positive response in the 6moons article and on the AA HE forum. When I have propose SS with correction circuits several times over the past few years, I usually got flamed. One of the big reasons I totally stopped participating in several audio forums and only occasionally in others. I am definitely not one of the sheep at AA, well maybe a black sheep.

Good discussion,

Martin

==I want your prescription.

>>What do i do with my 4 tube amps?

==Sell on a-Gon to get more prescription.

>>Also, the whole 1 watt amp thing...to me it's just the usual audio hype.

==Well it is really a NO watt amp except the minute impedance he adds to the output creates miniscule voltage swings. Study power supply design to find the virtues of low power. What the engineers cannot measure is musics dynamic contrasts. NP knows this and does not try to point to grahs and explain this. His music is his guide.

I thought you liked the sound of 45's. 45's have some of the highest leverage against a voice coil resulting in excellent clarity. 45's are about the closest you will come to a no-watt amp.

>>The fact that some vendors are "excited" about this and call it a "breakthrough"...well... i can tell you what i think they are excited about, and it begins with a D----- and is colored green.

== Spliff? ah, prescription filled.

--------------------------------------------------------------------------------

MY RESPONSE TO ABOVE:Not sure what you are trying to say. Are you saying active crossovers before the amp are better than passive crossovers after the amp? In some cases that is a well known and well accepted concept. Many people biamp or even triamp. I fail to see what is new here.

TC WROTE: "You cannot push clarity through a resistor, although you can push a flat signal. "

MY RESPONSE TO ABOVE: Coould you please elaborate what aspect of the signal is harmed by the resistor, in terms of signal propoerties. For example, is it the phase?

TC WROTE: "That's also why he builds one of the worlds most elaborate and expensive active crossovers, because you cannot mess with an output circuit of a conventional amp and maintain ultimate clarity. "

MY RESPONSE TO ABOVE: Is the active crossover that he builds expensive in sense of the retail price he charges or in the cost price to him? Could you please elaborate how you know it is one of the world's most expensive?How does it compare to, say, Marchand crossovers? What parts does he use? What kind of circuit is it?

TC WROTE:"In his circuits the compensation affects the output yes, but only in the frequency current domain entirely without affecting back electromotive force (emf) into the amp circuit as do other circuits. And without any kind of the signal clouding effects of the ceramic resistor media needed to balance a hi Q driver as in example #3 which NP and myself agree would be detrimental to clarity "

MY RESPONSE TO ABOVE: "What do you mean only in the current domain? As oppposed to what? Voltage? What voltage and current are we talking about here, since we have active corssovers...the source or the amplifier? Finally, what back EMF force are you talking about? The speaker, to the best of my knowledge becuase of conservation of energy, CANNOT generate any back EMF force on the amplifier. Maybe I am wrong. Please elaborate.

TC WROTE:"Once an output signal sees the ceramic matrix, it is split into smithreans never to be assembled correctly again. Far far better to adjust the circuit ANYWHERE but the final output circuit like before the amp (actively). "
MY RESPONSE TO ABOVE:" What matrix are you talking about? Is this the same concept that the "resistor" hurts the signal? Splitting into smithereens along what aspect of the signal? Frequency? Phase? PLease elaborate.

TC WROTE:"So yes it's the same game of adding RLC to tailor response. Only he has changed the rules to maintain absolute clarity. Something passive circuits with conventional amps both tube and SS cannot do. "

MY RESPONSE TO ABOVE: Can you please define clarity, and why you think an after amplifier network will hurt it more than a before amplifier one? Again, please keep in mind, many people have been using biamping & triamping for decades. I cannot see anything new in here, but maybe i am missing it, and would really appreciate your elaboration.

thanx
-akhilesh

Like the big block Olds, I have some really powerful and clean solid state amps and big multi-way horn speakers. It's the same gear that's used when I attend fine musical presentations. I was always impressed with that kind of gear, so I bought it myself. The power is awesome, and this kind of system simply would not have been possible in the WWII era and before.

And speaking of the WWII era and before, I have several nice tube amps that I really enjoy. Lots of old tube radios too. The radios are so nastalgic, I find myself listening to them almost every day for a little while. And the tube amps I have are really nice to listen to, especially with vocals and intimate music.

To me, my hifi tube amps are kind of like Mazda's rotary engines. They're different than the big iron, and they'll really surprise the uninitiated. They are simple and they have finesse. I just love 'em. The booklet called "A Taste of Tubes" does a good job of describing the feeling I get when the tubes are glowing.

So my point is that I usually find good things in more than one approach. Each has its strengths and its weaknesses.

I certainly feel this way about loudspeakers. I enjoy some single driver designs. I enjoy some large multi-way horns. There are many speakers of different design types and price points that impress me. Naturally, I'm biased towards my own design choices. I've spent a lot of time developing them. I made choices I thought sounded best and performed best. But I do realize also that there are many design choices that have merit.

The amplifier and loudspeaker form a filter circuit. There's no way around it. One can minimize it or embrace it. Either way, it's a fact. For that matter, the loudspeaker itself is a filter, even if the amplifier is a perfect current source. The loudspeaker is highly reactive and nonlinear over a great deal of its range.

So to me, the real issue is not whether passive components are good or bad. In a sense, I don't have any choice in the matter. The speaker itself is a reactive passive component, acting like a fairly complex LRC network. I can manipulate the loudspeaker's virtual LRC network values with my cabinet and the driver's electro-mechanical properties. I can also manipulate the LRC values by including electrical components. Both are reasonable design choices, in my opinion.

I can sure understand the choice to use only raw drivers in the output circuit, avoiding additional passive components like Terry describes. This means the only reactive component is the driver itself. That's cool.

I can also understand Martin's choice to use passive components in the design. After all, the amplifier/loudspeaker circuit is a complex filter even if there are no extra passive components. So it makes some sense to tailor that filter. Adding a 1 ohm resistor, for example, is like having a voice coil wound with a smaller conductor. It's an easy way of having your OEM build a whole new driver without having to do that. So that's cool too.

==The speaker(load and circuit) does generate it's own electrical (inductance, resistance) signals that are introduced to the output loop of any amplifiers circuit. In low power ANY back EMF significantly affects the pprimary signal. This is usually ignored, but exists nonetheless. Since we are talking high efficiency, we are talking low power regardless of amplifier power.

The reason people biamp triamp whatever is to maintain direct connection to an output circuit to avoid the problems of passive components in a circuit (yes this has been done since amps and spkrs were invented). It always maintains ultimate possible clarity and provides for better control of the spkr. Most of the time this is an effort to increase dyanmic range and power output capability. You can always go passive but it's not -better-.

TC

>>So to me, the real issue is not whether passive components are good or bad.

==ANther thing that has to be accounted for is efficiency. Most of your designs probably hover well over 100db in the high freqs. Over 100db passive attenuation has dynamic "headroom" for lack of a better word, working on it's side. Passives have a far more benign negative effect on *really* high efficiency systems. Still they all sound clearer and more dynamic actively crossed (nothing new). But passive components CAN work better as efficiency rises. The ratio of "power available" to "needed power" needs to be vast NP thought that with a passive system 300 watts is a good place to start, to minimize spkr x-over effects on an amp.

TC

I had several RX-2's in the seventies and eighties. My first car was a stock RX-2, and I liked it so much that I bought several more through the years. I put a different intake manifold and carburetor on them, headers and ported some of them. I must have rebuilt four or five Wankle engines and made hotrods out of every one. My favorite RX-2 was really clean, had Koni shocks and repositioned front shock towers. The stock RX-2 understeered pretty badly but if you pulled the shock tower top mounts back about 2", they were perfect. That plus a high-performance engine and clutch made a pretty slick little car.