Re: Valuable 12AX7 and all this audio foo foo.


OOOhhhh, this has been the cause of some VERY hot debates on the audio newsgroups.

I certainly won't get into it here. I would LOVE to be the participant of a double blind, being the engineer at heart.

In my experience, the *biggest* impact on sound is the actual design of the circuit. Second on the list is the quality of the transformers (power, choke, and output - tube amps). Frequency response, phase shift, impulse response, core saturation, etc. all are very important in an audio transformer. After that, WAY down on the list are capacitors, then wire, tube sockets, resistors, etc. I've never been able to really tell a big difference between them.

Speaker quality is a huge impact, also. Good speaker drivers have lower distortion in the motor than cheap ones. Most commercial speakers measure really bad w.r.t. distortion.

But again, there is stuff going on that instruments can't measure. I can't explain that while my one cheap Sony CD player sounds pretty awful, but measures just fine, a second unit that has been upgraded with better capacitors in the power supply, better op-amps in the output section, and some other minor mods, sounds completely different. Measures the same, but sounds smoother, better pace and timing, just more toe-tappin' musical.

Has anyone ever wondered why Tek used Telefunken, Amperex, and Mullard tubes in their scopes and not RCA, GE, Westinghouse, or Sylvania, at least in the small signal positions? I would guess that they knew these were higher quality, more reliable, quieter, more linear, and more consistent. Those same parameters make a difference at 10kHz as they do at 5MHz.

Chris wrote:

I am with Dean on this one. �There is a special process called "double-blind
testing" where these sorts of claims can be debunked. �If I understand it
right, double-blind testing amounts to the listener not knowing what
configuration he is listening to and being required to choose between "A" and
"B" a LOT of times, enough to get a pretty good statistical picture of
whether things like tube brands, oxygen free speaker wire, and precision
capacitors REALLY make a difference you can hear. �Most audio nuts that I
know REFUSE to submit to double-blind tests . . . and I think we ALL know why
. . .

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