| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 1781.1 | Partially educated guess | SMURF::BENNETT | Towers Open Fire! | Mon Apr 16 1990 18:43 | 2 |
|
30 - 40 watts
|
| 1781.2 | What??? they're glass!!! | CMBOOT::EVANS | if you don't C# you'll Bb | Wed Apr 18 1990 11:36 | 16 |
|
It's a bit funny this. Tubes (valves to us UK types) were often
rated in terms of the max voltage they could stand anode to cathode.
El34 run about 400v a-k in my Marshall. The output transformer then
steps this down into less volts at more amps so the power delivered is
a function of the a-k volts & the impedance of the output primary
winding less the transformer efficiency.
I'm too young to know this you realise :-)
Any ex service radio types in here, I'm really a Bipolar/FET man these
days.
Cheers
pete.
|
| 1781.3 | | IOENG::JWILLIAMS | Welcome to the Bush League | Wed Apr 18 1990 15:23 | 19 |
| Tubes are very similar to FETs in their operation. They have a
breakdown voltage, an on resistance, and a gain. ( Not to mention
some of the more esoteric stuff )
Because they are characteristically a variable impedance, they hit the
rails a lot softer giving a warmer tone. Most tube amps are also a
push pull circuit with a bias circuit on the gate that produces cross
over distortion when overdriven. For example:
____ ____ _
/ \ / \ / Peak distortion
_/ \____/ \____/
__ __ _
__/ \__ __/ \__ __/ Crossover distortion
_/ \__/ \__/
Personally, I think tubes are unreliable and expensive.
John.
|
| 1781.4 | .2,.3 | SMURF::BENNETT | Towers Open Fire! | Wed Apr 18 1990 15:41 | 9 |
|
Any of that tech talk help this guy get a guess at what kind
of power that amp is gonna throw into 8 ohms?
.3 - unreliable as hell - I just yanked a 4 month old 6L6GC
outta my amp last night `cuz it was glowin' hot enuf to melt
tolex 5 inches away. Izzat enough to make me go solid state?
I don't think so. That tube will see more duty in a lower power
class A amp and survive another 30 years.
|
| 1781.5 | another vote for old tech | HUNEY::MACHIN | | Wed Apr 18 1990 15:49 | 8 |
|
Yup -- saying tubes are 'unreliable and expensive' is like
saying 100-year-old Malt is extravagant and gives you a headache!
I'd buy a tube amp for its sound -- even for its smell -- but never
for its cheapness or its reliability relative to jumped-up transistors.
Richard.
|
| 1781.6 | Low...but dont worry about it | ELESYS::JASNIEWSKI | This time forever! | Thu Apr 19 1990 15:23 | 9 |
|
From my experience, you'lll get about 14 watts out of a pair
of 6BQ5s.
Yet, some of the most screamin' amps I've ever put together,
from trash, used this output. Dont shortchange what you have cause
of the low "Watts" number.
Joe Jasniewski
|
| 1781.7 | | IOENG::JWILLIAMS | Welcome to the Bush League | Thu Apr 19 1990 16:35 | 10 |
| I'm not going to battle the purists. I was only stating a simple fact.
Tubes are significantly less reliable than transistors by a couple
orders of magnitude. The filament burns out ( this is often a function
of how often you turn it off and on ), and the structure comes loose
( this is often a function of how loud you play ). A smack in the wrong
place and you've lost your vacuum.
But, whatever turns your crank, eh?
John.
|
| 1781.8 | | TCC::COOPER | MIDI-Kitty-ADA-Metaltronix rack puke | Thu Apr 19 1990 18:39 | 9 |
| Seems to me the answer is in a hybrid modular system...
Ya know, like an MP1 (for that tube sound) and a SP1000 for that
reliability and power... Rack mounted for durability.
Potent, lightweight, tuff, and killer_sound.
I gotta agree that old tube driven heads are unreliable.
jc (Who sez have a rack attack!)
|