5E3 cathode bypass cap question

[bluesbear]

I was looking over an amp I made a couple of years ago and found a mistake. The amp has a 5E3 power section, 6V6GT's with a 250 ohm cathode resistor with a supposed 25mf bypass cap. I must have been in a hurry because I accidentally used a 250mf instead. Obviously, it never caused any actual harm as it has literally thousands of hours on it. I'd love to know what difference this mistake of mine might make (250mf as opposed to the correct 25mf) in either the operation or tone of the amp.
Thanks,
Dave

[jjasilli]

Operation:  the presence of the cap helps keep the PP power tubes in balance; I don't think the value of the cap matters so much in this regard.

Tonally: bigger cap = more bass response. 

[triode]

It controls the low frequency cutoff, as well as jacking the gain a little... but the gain
is pretty constant above the cutoff frequency (e.g. put any cap, above f3, the gain is
pretty much the same)...

25uf, 25.47hz.
250uf, 2.547hz.

Keep in mind (for future reference), those numbers are f3, the frequency at which it is
3db down, not the start of the cutoff frequency. In guitar land, I doubt seriously you would note the
difference. You can go too big however, if it starts to take too long to charge up that capacitor with
the cathode voltage/current that the tube can give. Too big is relative though, how long is the amp
going to be on before you start playing? :) (probably 100,000uf is too big :)

[Shrapnel]

I've heard of people using up to 2,000uF for the bypass cap on the self-bias on output tubes. They claim it stiffens it up enough to sound awfully close to if it was fixed bias instead.

The larger values stiffen up the self-bias voltage too.

[bluesbear]

Well, I changed it from 250mf to 25mf. He plays tonight so I'll find out tomorrow if it makes a difference 30 year old ears can hear.
Thanks for all the info.
Dave