Allow me to answer by adding comments to Squier's response, because he
said some good stuff...
Post by SquierPost by JHow easy would it be to fit a master volume control to a fender 65 deluxe
reverb amp? Would this alone allow me to get that 'cranked up' sound but at
a lower volumes level for home practice? Anyone have a diagram for this?
J
If you are talking about an actual original 65 DR then don't do it. period.
If you are talking about the 65 DR reissue - then go ahead and mod away on it.
...but I think you'll end up being disappointed.
Post by SquierHere's the thing -- a Master Volume amp breaks down the amp into 2 controllable
parts -- the preamp gain (usually just called 'volume') and the
power tube output (the 'master').
A master volume amp with the master turned down low is NOT giving you
that classic power tube saturation/distortion. In fact most master volume
amps are made so that people can get cranked up pre-gain and not actually
get their tones from power tube output. In a Master Volume amp if you
wanted to get classic power tube section cranked up then you would still
be putting the master at high levels and adjusting the preamp gain to suit
your tastes.
And much depends on the design of the amps. GOOD master volume amps
don't just throw a volume control between the preamp and the power amp.
They design the preamp to get a certain type of distortion on its own.
When you throw a master volume on a non master amp, you often won't
even get the type of distortion you want without also modifying the gain
structure of the preamp, add/modify some tone filtering between gain
stages, and/or putting a boost pedal on the preamp.
Post by SquierTo get lower volumes you would crank up the Master to 10 but
then starve the power section with a low pregain input signal (with the volume
set to low... maybe 1 or 2 or 3). You really don't get a good sound this way
because you are stunting the pregain and sending a starved type of signal
on to the power section. (you would probably have to set the pregain volume
to around 4 or 5 to get it normalized as to what a 65 DR would be in stock condition).
So you are back to where to started.
a 'cranked' pregain section with a low master volume is NOT the classic
'cranked up' sound of the power tube section running all out.
these are 2 different things.
Yes and no. Depends on circuit design and speaker choice. There are
amps that get pretty dang close in tone. But it's not "the same."
The most common example of preamp distortion in the current crop of Mesa
Rectifier amps. The lead tones have heavy saturation in the preamp
tubes. It's not as simple as just stacking gain sections, but it is
done in the preamp.
Post by SquierWhat I would suggest and involves no mods is to get a power soak or
air brake or weber mini-mass or whatever attentuator you want to use.
That's certainly the most common option. I'll discuss another one below.
Post by SquierThis way you can play with the power section cranked up (a DR has only
volume which IS the master - the pregain is preset within the amp's circuit).
With an attentuator you can crank up the amp. An attentuator can (for example)
lower the output section to a few watts so you can get it cranked up at
reasonable volumes at home. But even 5 attentuated watts cranked up into a 12" speaker
is going to be fairly loud in a small room. Be advised on that.
And a standard caution: Rich Koerner, an expert on Fender amps that I
have lots of respect for, and who built my Super Reverb, calls
attenuators "TRANNY TOASTERS." Why? Because in the BEST situation, you
are pushing your amp MUCH harder than what you are hearing, and it is
very easy to forget that you're driving it hard. In less than the best
situation, your attenuator is not mimicking the response curve of a
speaker cab, and that *might* be harder yet on the output transformer
and output tubes.
This is a whole separate discussion, which I'm happy to go into if the
thread turns that way.
If you use the attenuator, resist the urge to dime your amp all day long
with bedroom output levels. That's the surest way to exceed the design
parameters of the amp, and possible cause some damage (including burnt
out output transformer and/or shorted output tubes).
Expect much shorter output tube life, just as if you were diming it
without the attenuator.
This is not a perfect analogy, but think of it as if you're driving your
car on the freeway in a low gear that puts your engine at the redline,
instead of the normal overdrive gear.
Some amps are more susceptible to failure. Here's a pic of the hang tag
that came on my JMP 2204 Marshall that I bought new in 1981:
http://tinyurl.com/2204-hangtag
I have two amps with built in attenuators. A Valve Junior that I did
many mods on, and a THD Univalve that has a hotplate circuit built in.
So I'm not opposed to attenuators as long as you realize that you're
PUSHING that amp!
Post by SquierMy other suggestion is for you to use the Deluxe Reverb 22 watts to play
out or for jamming with a band or friends or playing in a live band situation
and just get yourself a Fender Champ (silverface is cool) or get yourself
the new Super Champ XD and then use the Champ to play at home. It still
gets loud but with the smaller speaker and reduced wattage can sound good
cranked up at better 'home' volumes than a Deluxe Reverb.
That's a good option as well.
And here's my final option, but it will take a tech to do it for you:
POWER SCALING. This mod WILL get you power tube distortion at low
output levels. WITHOUT the stress on the amp!
Here's the FAQ on it: http://www.londonpower.com/pscaling.htm
Here are currently offered kits:
http://www.londonpower.com/catalog/index.php?cPath=7&osCsid=cd9c0f081db60dd6e463305f0e5a4bb0
How to pick: http://www.londonpower.com/catalog/about_our_ps_kits.php