Any Differences Between Two Identical Amps?

[WhyIsPBassBest]

So, it seems to be a well-known fact that two identical bass guitars can have slight differences that make them not truly “identical.” The woods used, as well as set up make a difference to the sound, weight, feel, look, etc.

Would anyone say that the same applies to amps or cabs?
Say I play through two identical combo amps, with the same EQ settings.

Would there be any difference at all in sound?

I would assume that between the amps themselves, there would be such a microscopic difference that nobody could tell (with today’s mass-produced gear).

But the cabinet is made of wood or mdf or what have you.
Plywood is likely more consistent than solid wood, but still, there’s a slight difference there for sure.
I’m guessing you wouldn’t hear the difference at all though.

Last I can think of is the speaker, but these as well are probably so consistent nowadays that it would be impossible to hear a difference...

Well, those are my thoughts. Just curious, what does the rest of the TB community think?

 

[agedhorse]

I can give a pretty definitive answer based on testing data on thousands of "identical model" amps...

Yes, there certainly can be small differences between identical models simply because of the tolerances of some of the parts.

just for example, pots are typically +/-20% which in the case of a volume control can result in small positional differences for identical volume between amps. This is especially true with log and anti-log tapers where the relative tracking can be a challenge.

When designing an amp, many designers consider these issues and may specify a tighter tolerance for dual pots where the tracking can be essential to circuit performance or stability (especially for log/anti log tapers). There are classes in engineering that deal with tolerances and the statistics associated with the distribution of tolerances within a circuit. We will sometimes model a circuit and sweep the tolerances of a part (or group of parts) to verify that the overall performance remains acceptable. Of course, this adds to the cost of an amp.

Every part has tolerances, often we can design circuits that reject much of the tolerance error, and where we can't we may have to use a tighter tolerance part or approach the circuit differently (ie. loading the part to make the response less tolerance dependent).

Generally, the better quality parts have tighter tolerances, but in some cases the part is simply not available or is so costly as to be impractical.