Re: [Harp-L] Differences in Same-Model Amplifiers

["scooter" <10hole@xxxxxxxxxxx>]

Add to that the tolerances of capacitors (typically 5% - 20%) as well as 
poor grounding from time,
stiff or loose speakers, good or drifted filter caps, different tubes or 
weak tubes, etc.....

Older amps are much worse as far as consistency is concerned but even newer 
amps will vary.
On the Meteor I even go so far as cutting all of the tube and control wires 
to the same length to
try to get the best consistency. Wire has a capacitive value and the same 
amp with long wires will
sound different than one with short wires. Even with the overly anal 
assembly procedures, there
will always be a variation in sound between amplifiers.

Scooter


Here's a point which helps to support/explain your statements:



Leaving all of the other variables out of the equation for now, I wanted
to point out something about resistors.



Most of the resistors used in vintage amps were the carbon composition
type, and had a tolerance of +/- 20%. This means that the 470 ohm plate
load resistor of a Fender Champ could have a legitimate rating of
anywhere between 376 and 564 ohms! Two Champs side-by-side, one biased
using 376 ohms and the other biased with 564 ohms would certainly sound
different. VERY different.

Tossing all the technical mish-mash aside, consider that the tweed 5F-1
Champ had 12 resistors in it, and that EACH of these had the potential
to very by

+/- 20% . The potential existed for an incredible amount of variance
from amp-to-amp, all things else being equal. The '59 Bassman 5F6-A had
about 28 resistors!  I am no math genius, but I can say that the odds of
two identical amps rolling off the assembly line were not too good. And
that is solely based on the resistors' inherent discrepancies, and
doesn't take into consideration the multitude of other contributing
factors.



John Balding



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