Odyssey Khartago vs. C. Johnson's 2250A??

To J135, So far, nothing done. Will keep you posted. Thanks, Jim

Sorry Zen, a link to the description of THD does not answer my question. I was curious as to why you think the difference between .1% and .04% is significant, and determines the CJ amp is inferior.

T1s49,
Lower distortion is a good thing so the THD specs for both units speak for themselves.
I never said the CJ was inferior. In my experience with both amps I liked the Odyssey. I would be very happy with the CJ also but given a choice.
I have a CJ PV-10 that I am currently using and I think it is a great sounding preamp. They are a first rate company that has been very helpful anytime I need help with any of their products.

Zen, sorry if I misunderstood your post about the CJ, must have been that “light years” thing, and you are certainly entitled to your opinion about THD. Guess I’m in the camp that as long as it’s reasonably low, differences like the one cited here are just meaningless. It is interesting that some well respected companies don’t list the THD, and others say something like “typically less than 1%”. Also, speakers produce much more distortion than electronics at moderately loud listening levels, but you rarely see any of these specifications published.

I agree with TLS49. I would go further and say, as someone with an extensive technical background and someone who certainly recognizes the value that specs can provide (especially in identifying combinations of components that are likely to be poor matches with each other), that THD numbers for amplifiers are generally worse than useless.

Extremely low THD numbers are commonly accomplished by heavy-handed application of feedback, which in turn will worsen Transient Intermodulation Distortion (TIM), which is not normally specified, and for which I believe measurement standards have not been defined. And which well respected researchers, starting with Dr. Matti Otala (who is generally credited with first identifying TIM during the 1970s), as well as many respected high end designers, consider to be more relevant to music reproduction than sine wave-based THD measurements.

Also, THD numbers say nothing about the DISTRIBUTION of the distortion among different harmonics. It is well established that extremely small trace amounts of certain odd order harmonic distortion components will be vastly more objectionable than much larger percentages of low order even harmonic distortion components.

Basically, IMO, the only potential usefulness of THD numbers is that they can suggest caution in choosing an amplifier having exceptionally "good" numbers.

Regards,
-- Al