>In the third paragraph you state that SET's cause a reaction with >the speakers but If you re-read the post I wrote SS not SET's.
I meant SS. Sorry. Basically all i am saying is that leaner, high efficiency speakers like wide range setups and horns benefit from SET richness. Neutral speakers that are highly efficient, (if they existed..maybve the legacy focus? ) would probably make SETs too overpoweringly rich.
In general amp interaction with speaker is very important I think.

>If you observe any typical SE schematic you should see that one leg >of the transformer is fed from the bypass capacitor thereby forming >a feedback loop.
I think that's the grounded leg. If that's the case, it won't be a feedback loop. Caps block DC but pass AC untouched. A pure feedback loop with a cap only in an AC circuit won't work. We'll need a resistor as well, i think.

>The term Neutral to me implies that the amplifier; or any link in >the chain reproduces sound that does not deviate from the recorded >master tape. Is that an acceptable definition?
Yeah that works for me. That implies very low distortion and flat frequency, and a host of other measures some of which may be audible and some not.

thanx!
-akhilesh

Anyways, I recently bought my first SS amp..a yamaha ca-1010. This was the top of the line yamaha (or maybe one step doen) in the late 1970's. It has a pure class Aoperation of 18W and AB of around 90 Watts. It sold for around $700 in 1978.

I got it 4 days ago, connected it, and played some of my usual tracks. AS my earlier post shows, I found A) the imaging to be very significantly worse, and b) the sound to be thin. THe more experienced among you can probably guess what was going on, already!

My aim was to see if SS is indeed as bad as it's made out to be. My initial impression was it was pretty bad. I then rationalised that it couldn;t really be THAT bad, it sounded so bad on my setup becuase of the thinness of my speakers that SETs somehow compensate for with their richer more even order distorted sound. TH edifference eas pretty dramatic.
Well...last evening, I listened to the SS amp again, and agin, the imaging was non-existent. Tracks that imaged well on the SETs seemed to emerge from two different speakers. MY speakers usually disappear quite well (esp the home brews). With the Yamaha amp, they were definitely there, in fact sound was coming disctinctly from each speaker, and the sound was thin. LAst evening, it occured to me: it can't be THIS bad. Check the phase!
Sure enough, the speakerswere wired out of phase in the Yamaha!!!!!
My only excuse is a busy week!
Anyway, after correcting that,the imaging was great, and the sound of course became much fuller. At least now I can do a reasonabke A/B comparo with a SEt amp in detail.
My revised imitial impressions of the YAmaha now are are: very good imaging, nice neutral sound, still not as rich as a SET, but in some caes, sounding better..the difference in neutrality versus richenss is now much more subtle....the Yamahas have better detail, better bass control.
A more detailed, level matched comparo review will follow soon.
Overall, i am very happy now with the small amount I paid for the yamaha...it really is a great amp, not to mention great for working out when you move it (35 + pounds).
Just thought this may offer some entertaining education for the rest of us!
-akhilesh

One of these days, we might bring your amp to my place and let you hear it on my seven π's. I used to run seven π's with JBL Pro drivers on a Yamaha receiver in the early 80's and it was an incredible system.

Wayne

Did you increase the parallel resistor in the BSC circuit with the SS amp to make up for the higher damping factor? I think you need to do this to get an apples to apples comparision with the warmth of the SET.

Martin

BTW, I don't have a resistor in parallel with the speaker in my homebrews. The circuit (C1) is an inductor with a resistor in parallel with the inductor. ALso, i have a supertweeter with a 6 db crossover in parallel with the C1-woofer combination.
thanx
-akhilesh

My theory is the major differences between SS and tube amps has to do with the amps damping factor. In other words, the internal series resistance that the amp places in series with the speaker and cables is significantly different in the two styles of amps. This is not the only difference but I believe it explains a lot of the perceived properties of the bass produced. Typically people report that a tube amp is warmer and a solid state is cold and analytical. The speaker is not changing but the amp's influence on the response can be dramatic. If you look at my Project #5 you will see that I recommend different resistor value ranges depending on the style of amp.

Most people using tube amps also use high efficiency drivers which means a big magnet and a low Qts. If a tube amp is used then the internal series resistance "increases" the Qts producing more bass and a warmer presentation. Connecting this same speaker system to a SS amp often produces a weak bass and shouting painful midrange response.

When a multiway driver system, typically lower efficiency with a smaller magnet and higher Qts, is connected to a tube amp it produces a bloated uncontrolled bass response. Connecting the multi-way speaker to a SS amp and the performance is much better. These lower efficiency multi-way speakers are typically used with high powered SS amps.

I arrived at the observations above after reading many years of posts on different forums describing how inserting a tube or solid state amp into an existing system changes the speakers performance. Typically it improves the full range speaker and degrades the multiway speaker. This is not absolutely the case in all situations but is a significant trend I have observed.

So my reason for suggesting adding more series resistance to your speakers when using the SS amp is based on the difference in damping factor. You have built and optimized your speakers to perform well with your reference tube amp. The amp and the speakers are a consistent pairing that creates a high performance system. When you connect these same speakers to the SS amp, you have removed the internal series resistance and the combination is not optimized. MY hypothesis is that if you added 2 or 3 ohms of series resistance when you use the SS amp then the difference in what you hear will be much smaller, you have an apples to apples comparision of the "same" speaker with each amp. The differences can be contributed to the construction and circuit design in the amp and not masked by a difference in damping factor. In essence you would be running the experiment that I should be doing by inserting a tube amp in my variable BSC Lowther ML TL set-up.

Hope that helps,

Martin