Is the color in the amp , the preamp, the souce?

I have a hard time understanding (all specifications being equal) how an amplifier can sound different.

First let me say that I second and applaud Bryon’s admonition to others who may respond.

Here are some reasons that come to mind as to why similarly spec’d amplifiers may sound different. There are undoubtedly a great many others, both known and generally understood, and unknown/unexplainable:

1)Amplifier specs are generally based on the assumption that the speaker has a resistive 8 ohm or 4 ohm impedance. Real-world speakers have significant reactive (inductive and capacitive) impedance components, which vary widely among different speakers, and, for a given speaker, vary widely with frequency. Loads having significant reactive impedance components are more difficult to drive than purely resistive loads, and different amplifiers will have differing degrees of success doing so.

2)Harmonic distortion created by an amplifier is commonly spec’d in the form of TOTAL harmonic distortion (THD). However, the audible significance of THD is highly dependent on WHICH harmonics are present in the distortion spectrum, and to what degree.

3)Different amplifier designs use differing amounts of feedback. Feedback can reduce THD, improve linearity, and lower output impedance. However, it can introduce or worsen Transient Intermodulation Distortion (TIM), which is not generally specified and which subjectively can be more objectionable than the effects that are helped by feedback. A high quality design will need little or no feedback to minimize those effects, and will therefore have minimal TIM, but will tend to be more expensive.

4)Amplifier output impedance (equal to “damping factor” divided into 8 ohms) is a parameter that is fundamental to the interaction of amplifier and speaker. Although damping factor is usually specified, the specs for different amplifiers vary widely, and precise prediction of what combination of output impedance and speaker will be most synergistic is generally not possible.

5)Different amplifier classes are subject to differing kinds of distortion.

6)Amplifier power supplies generate high frequency noise, due to an effect known as “rectifier commutation,” which, depending on its frequency components and amplitude, can radiate or couple into circuit points in other parts of the system, with unpredictable results.

7)Ultrasonic or rf spurii that may be fed into or picked up by the amplifier can intermodulate with the audio signal, resulting in effects within the audible spectrum. The degree to which that happens will be dependent on the bandwidth, the circuit topology, the physical layout, and other characteristics of the amplifier.

8)Unspecified stray capacitances in the amplifier’s power transformer will affect sensitivity of the system to ground loop-related hum and buzz (subjectively affecting background “blackness”).

9)The behavior of different amplifiers when over-driven or clipped will vary significantly, particularly when comparing tube and solid state designs.

10)Amplifiers have differing amounts of “dynamic headroom,” meaning the ability to deliver greater amounts of power than their continuous power rating, for limited amounts of time. Dynamic headroom may or may not be specified, but even if it is, amplifiers with similar amounts of specified headroom will vary widely in terms of how long that increased power level can be supplied for.

11)Parts quality will affect sonics in ways that are not readily specifiable or predictable.

As I said, there are many more known and unknown reasons for sonic differences between similarly specified amplifiers, but hopefully these will give you a general flavor.

Regards,
-- Al

I think it is safe to say that no two manufacturers of amps produce identical products. This should be obvious even if they use similar circuits.
t is common knowledge that the measurement parameters despite obeying the laws of physics are not neccesarily meaningful as percieved by the listener. This fact is perplexing but I am sure you will agree if you listen to a variety of amps with "good" measurments, You might even find that some with the most power and lowest distortion are not the ones you prefer.
Not just to be a contrarian -there are indeed, "low" power SS amps that garner much praise. Thus the assumption that high a power amplifier,is a "better" one, should probably dismissed while exploring, what as Bob_bundus aptly elaborated, is the best total system that suits your preferences.
I am of the school that believes that " high fidelity" as in closely resembling the actual music played is only a matter of approximating the original. The rest is highly subjective. And there is nothing, absolutely nothing wrong with that.

Baxter-178

I agree with your basic premise. I've always attempted that the Power Amp should primarily be matched to the requirements of the speaker, and, it should be as close to a "neutral" sound as possible. of course "Neutral" is in the ear of the listener.

I then have tailored the overall system character by using specific upstream gear, primarily Preamp and Interconnects.

I myself lean toward large solid state power amps driving in my case my long time preference of Planar speakers.

I then dial in the overall sound with a "CJ or CJ Like" tube based preamp and of course cables.

Obviously, depending on the power amp's "neutral-ness" or lack thereof, upstream choices are affected.

Once I become very familiar with the preamp/poweramp/speakers overall sound, it's pretty easy to experiment with source gear and determine how a given DAC/CDPlayer etc. affects the "base" system sound provided by the preamp/poweramp/speakers combo.

Just my 2cents, YMMV, Don't try this at home, yadda yadda yadda.

Don't worry about what color,find the color you like,sit back and enjoy your music.

I like Almargs explanation - clear, concise, and responsive. But, for a broader view, I really like Bob Bundus comments. For me, they represent a seasoned view on the subject of system synergy, i.e. getting it to sound as you would like it.

FWIW I hung out with the spec's crowd when I used SS stuff. But it was clear (and frustrating) that all similar spec'd amps don't sound the same when you put them in use, if for no reason other than how it interfaced with your speakers and how they interfaced with your room. Eventually I learned that the best starting point in selecting an amp was to contact the speaker manufacturer and ID the amp he used in the speaker design process. I figured that was as close to 'neutral' as I could expect to get, assuming the speaker designer had neutrality in mind when the speakers were created.

Once that level of neutrality was obtained I got my color upstream. Then I found tubes ......:-)