Valve power - feel the force!

[jcbrum]

p.s. I have heard lots of valve amps you know as well as owning them myself in the sixties and seventies, and I do know what sp100's sound like, but I'll accept I haven't heard yours.

[Marco]

I thought you were looking forward to going to AVI ? what happened ?

I was, but Ashley read my account of listening to my valve amp with dance music at rather naughty levels and has concluded that I'm somewhat too uncouth to appreciate ADM9s!

I'm glad you're coming to have a listen. Prepare to have your misguided preconceptions rudely readjusted!

Marco.

[anthonyTD]

Just pointing out that the presense of the output transformer does slight alter the equivilance your analogy requires.

Though I wonder if the transformer is responsible for valve amps having seemingly effortless dynamics, the transformer itself is a store of energy (in its flux), so its a simpiler process for that to be dumped into the speaker. The output stage of a SS amp contains no sources of stored energy, and merely allow the energy stored in the power supply caps to flow towards the speakers. And then of course the flow of that current is restricted by the ESR and other problems that plague large caps.

And that another difference, to store the same energy the size of a cap in valve amplifier the cap can be smaller, as the stored energy is proportional to the square of the voltage, but directly proportional to the capacitance.

Hmm, maybe that was what you were trying to show with your anaolgy, I will get my coat...

quite right,
and i agree about the output transformer playing a big part in this, after-all, they have to reflect a relitively high impedence/high voltage/low current primary into a low impedence/low voltage[in comparison to the primary] high current capable secondary in order to drive the loudspeaker! as i stated in my original post i tried to simplfy things to get my point across to most of the folk on here, wether they be technicaly minded or not, it would seem i didnt go into things quite enough for some, but thats ok, and i am glad that you expanded the explanation. the point jc is missing with solid state amps is this,the reason they clip so violently and need huge amounts of power to overcome this problem is because of the amount of feedback involved in their circuitry used to linearise the devices used.
anthony...

[Marco]

He's trying to slither his way around that, though, Anthony.

Marco.

[jcbrum]

My favorite nosh is a small baguette, or two slices of a medium loaf "rustic crusty" variety, with a thin slice of "parma" type ham, any air dried is ok., with black pepper and lemon juice on it., and a large mug of tea, minimum milk, and a tbsp of Irish W.

[jcbrum]

He's trying to slither his way around that, though, Anthony.

Marco.

wtf are you on about ?

[Marco]

My favorite nosh is a small baguette, or two slices of a medium loaf "rustic crusty" variety, with a thin slice of "parma" type ham, any air dried is ok., with black pepper and lemon juice on it., and a large mug of tea, minimum milk, and a tbsp of Irish W.

I shall mention it to my chef

Marco.

[Marco]

wtf are you on about ?

Read Anthony's last post and attempt to discredit it, then, particularly this bit:

the point jc is missing with solid state amps is this,the reason they clip so violently and need huge amounts of power to overcome this problem is because of the amount of feedback involved in their circuitry used to linearise the devices used.

Marco.

[Ali Tait]

Plenty power for those then Marco.I still have a pair of B&W P5's that I used to use as my main speakers.These are 90dB,and I've driven them with an original wooden-sleeved Sugden A21(7 watts per channel with a tail-wind) to some pretty high SPL's.

[jcbrum]

quite right,
and i agree about the output transformer playing a big part in this, after-all, they have to reflect a relitively high impedence/high voltage/low current primary into a low impedence/low voltage[in comparison to the primary] high current capable secondary in order to drive the loudspeaker! as i stated in my original post i tried to simplfy things to get my point across to most of the folk on here, wether they be technicaly minded or not, it would seem i didnt go into things quite enough for some, but thats ok, and i am glad that you expanded the explanation. the point jc is missing with solid state amps is this,the reason they clip so violently and need huge amounts of power to overcome this problem is because of the amount of feedback involved in their circuitry used to linearise the devices used.
anthony...

I (respectfully for anthony only, as a fellow engineer) disagree entirely. Feedback has nothing to do with it, that simply sets the gain. The reason is that the rise times are MUCH faster in a ss amp, therfore allowing it to emulate a square wave much more readily. This is what produces the prodigious harmonics.

Because a valve amp has it's output transformer in circuit, that has considerable inductance which modifies the wave form to approximate a sinusoidal one rather than a square wave.
This is the whole problem with output transformer design, to allow a small enough inductive effect to pass the higher frequencies accurately, rather than suffer HF fall-off, which incidentally, since it's on Chinese transformers, Marco's amp probably suffers from as well.
Therefore the output from a transformer coupled valve amp clips in a "sinusoidal" fashion and produces "musical" harmonics.
Whereas the ss amp clips in a much more flat topped fashion, more approximating to a square wave, with horrible sounding harmonics.

BUT, if you make the ss amp very powerful so that it doesn't clip then it sounds the best of all. (providing you haven't got to like the sound of valves clipping and confuse it with "musicality").

p.s. all this is very easy to see on a scope and that is the way you can "educate" your ears !