Re: [Harp-L] lower mu tubes



The only place that current is typically important, in a harp amp, is if you 
don't have enough to satisfactorily idle your power tubes, or to drive your 
speakers at the OT secondary.

12AU7 typically form part of the voltage gain amplifier, the extra current that 
they draw is mitigated by the fact that they run much lower voltage than 12AX7 
in the same circuit & have a much lower amplification factor...as a wise man 
once said, "Ohms, it's the law" ;-)

Whether or not a 12AU7 allows you to extract more useable power from an amp will 
depend on several factors gain, number of stages, how hot the mic, even how you 
play...in some amps it will, in others it can cut power. But "power" isn't the 
be all & end all, people are typically more interested in the effects on tone & 
useability.



________________________________
From: Splash! <celtiac@xxxxxxxxx>
To: Harp- L <Harp-L@xxxxxxxxxx>
Sent: Tuesday, 2 November, 2010 17:59:21
Subject: Re: [Harp-L] lower mu tubes

That's why I prefer vintage 12AU7s.  They might have less 'gain' but provide
more 'power' because of their larger current.  Ohms - It's the Law!

Splash!


----- Original Message ----- Subject: Re: [Harp-L] getting high gain... no 
feedback


In some, unique circumstances, lower mu tubes can let you push the amp
harder,
but the idea that you are pushing the output harder is TOTAL BS, unless you
are
measuring a bigger output voltage at the speaker...even if you are, the
softening of the sound can still mean that regular mu tubes kick out more
sound.
In most cases output will only be nominally different. Low mu tubes run
lower
plate voltages, which sound less harsh, they also bring down the SE
distortion
component (even order harmonics) which makes amps sound smoother...I'm not
against their use, far from it, but they deliver a smaller signal to the
power
tubes, which in turn typically distort less at comparable power levels.


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