John Curl's Blowtorch preamplifier part II

[janneman]

Originally Posted by scott wurcer

Joshua,

If a designer can hear the difference and can remove it (to his ears) with some eqalization is he still disqualified? Same goes for fixing an oscillation caused by particular amp/cable/speaker combination.

I would think that if somebody can design an amp that always sounds the same, that wouldn't budge whatever cable is thrown at it, that would be one hell of an amp.
The notion that an amp that changes its sound due to a cable is somehow a good amp is totally alien to me. It would actually make me doubt the competence of its designer.

I do know that there are some cables marketed that have been deliberedly engineered to sound as different from another cable as possible and that the difference in itself is often interpreted by the inexperienced as 'better', but that's another matter entirely.

jd

[albin]

My own heretical penchant for flea powered Class D amps,leads me to ponder a class D preamp miight be fun.
I always admired those millimetric pcb techniques.
regards Max Albin
Ps I'll get my coat.
edit pps poppy

[janneman]

I should add that in the case of such a cable that has a clear effect on sound (and I have heard often these differences), I could always measure the causes, like a pathologically high capacitance in interlinks coupled with a finite output impedance of the source or preamp.
Even with a source or preamp with very small Zout, you still can have effects on stability with very high capacitance cables that can be audible sometimes. So I admit it is not always easy to design an amp or preamp that is immune to cable effects, but when there IS an effect with a good amp, my experience is that it is measurable, and not subtle.

jd

[Andre Visser]

Originally Posted by anatech

If we then allow the idea of altering the signal as some kind of tonal control, the very idea of transferring a signal from A to B has been violated. The other problem may come about defining which is the "best sounding" cable. In my books, a cable design that alters a signal is a failure as a design or application.

I believe most here will regard good cables as those that have the least influence on a signal. The problem is cables, or any equipment for that matter, can influence certain aspects in sound that are not easy or possible to measure.

Originally Posted by anatech

Remember, if you can hear a difference between cables, at least one of them is "damaging" the signal. Unacceptable.
-Chris

Do you have any suggestions which cables to use that doesn't "damage" the signal? I would be certainly be glad to finally find a perfect cable.

[Andre Visser]

Originally Posted by janneman

I would think that if somebody can design an amp that always sounds the same, that wouldn't budge whatever cable is thrown at it, that would be one hell of an amp.
jd

There are lots of them available, the easiest way to find them is to go and look at some of the furniture stores.

[john curl]

What is wrong here? Why are you talking about cables? I haven't mentioned cables recently, on this thread, and 'everybody' knows that it is not rational to talk about differences in cables.
I have been concentrating on phono cartridge loading. Apparently Syn08 has been, as well, as he designed quite an elaborate one with his phono amp project, available for view, just below this thread. In fact, his input loading is even more elaborate than the one that we put into the JC-80, 25 years ago.
Now, I am asking him for his reasons, especially those based on measurement, as to why he would add such elaborate loading to his design.
This is the question. Once this question is answered, THEN we can go forward and talk about cables, if you want.
Off comments so far, about cable, are riddled with subjective opinion that 'holds no water' here.

[john curl]

It would appear that I am not going to get further input on MC cartridge loading. I hope that some here, learned something new. It is not immediately obvious that MC cartridge loading has so few measurable effects, but that is the case. It is much the same as connecting wires, even though many here will not believe it to be a similar situation. Perhaps that is because it is difficult for someone to manufacture a special MC load box and make money from it. Not so, with cables.

[sawreyrw]

Can someone provide an accurate technical description of how cables effect sound?

[albin]

MC cartridges are low impedance sources,but surely someone will tax them,probably severly.
regards Max Albin

[SY]

Originally Posted by john curl

It is not immediately obvious that MC cartridge loading has so few measurable effects, but that is the case.

Do you know where there's any published data on this? I can think of a lot of ways that loading can change the measurements of the MC-preamp combo and would like to see what sort of systems don't show those changes. Certainly, it's less of an issue than the resonant circuit formed by an MM's impedance and the preamp's input impedance, but it's difficult to believe that there's no effect except in special cases.

In my own preamp, I saw a large difference between loading with 68R versus 680R for my 15R source impedance MC, but maybe THAT is the special case, not the sort of preamps that you or syn08 design.