E
Eeyore
- Jan 1, 1970
- 0
Guy said:That's not true. I do a fair amount of work in recording studios,
and a guitar amp with a microphoe in front of it is a common sight.
It's the norm.
Graham
Guy said:That's not true. I do a fair amount of work in recording studios,
and a guitar amp with a microphoe in front of it is a common sight.
Jon said:"Eeyore" wrote
FYI, Tube's break up differently than SS. Tubes have even order harmonic
distortion which is much more pleasent than odd order. This has to do with
how they clip... hence tubes are prefered over SS any time distortion is
involved. (and with the need for an overdriven sound for guitar it is
necessary)
Jon said:I guess you guys don't know much about guitar amps?
That doesn't follow. What we do know is that it is lot cheaper to
distort a signal with semiconductors and subsequently amplify it with
semiconductors than it is to amplify and distort it with valves.
Since you seem to be planning on building a valve amplifier for your
guitar, you presumably don't have a clear idea of what you are doing.
Adrian said:My own preference for P.A. amplifiers is a fixed dummy load, chosen to
just keep the voltages within safe limits and wired directly across the
transformer terminals. You lose a bit of power that way, but you don't
lose the amplifier when someone trips over the speaker wiring.
This can't happen with a built-in guitar amplifier until:
a) The loudspeaker goes O/C
b) Someone adds a switched extension loudspeaker socket and plugs in a
disconnected speaker.
...but you can still get an accidental O/C with a prototype on the bench
if you are not careful.
Um... actually I have build one guitar amp for my friend when he brought a
kit and couldn't get it to work... How many guitar maps have you built my
friend Jan?
It's the cathodes that are supposed to glow.
Real men build amps where the plates are at least cherry red. If they don't,
you are not pushing the envelope.
Tam
theres a fix for that.
a series of power diodes on each plate, anode to
ground and high voltage disk cap across them
plate to ground, stops back emf from transformer
from flashing over the tubes.
I'm supprised most of these guys here think that a transistor or tube can be
simply modeled with a formula.
Wrong type of distortion. Compare the transfer characteristics. Tubes produce more
even-order harmonic distortion, transistors odd. And odd order sounds horrible.
That just gives the 'fuzz box' sound.
Graham
Yep, but they are so hard to see.
John Larkin said:I suppose that people who don't know much about electronics can do all
sorts of weird stuff.
How long do they last?I'm trying to remember now. I believe it was KT88's that I set the
bias just at the hint of a plate glow ;-)
....
But what gets used "normally", if you can pick just a few examples of
"normal"?
Ever hear of a 6L6 operating upside down in a pail of water, running 800 V
on the plate?
Tam
Of course. We are talking about the subjective opinions of people who
are probably drugged-out most of the time and hearing-impaired all of
the time. None of which involves electronic design.
Jan said:Remember EL84 x 4 is at most 35 W.
John said:So, there are nonlinear transfer functions that only overloaded tube
amps and speakers can make?