From: dam@dcs.glasgow.ac.uk (David Morning)
Newsgroups: rec.music.makers.guitar
Subject: Re: Tubes vs. Transistors
Date: 16 Nov 92 10:30:04 GMT
Organization: Glasgow University Computing Science Dept.

META000 <META@UNB.CA> writes:

>In article <1992Nov12.010212.24138@eecs.nwu.edu> ray@eecs.nwu.edu (Jim Ray) writes:
>>I need a new amp.  I have heard tubes are the only way to go.
>>Transistors are much more reliable.  Is there a way to get the same
>>effect of a tube amp at a small signal level or even digitally and
>>then use a transistor power amp to get the volume?
>>
>This question of reliability is one ofthose myths that persist
>despite evidence to the contrary.  I bought a 59 Fender Princeton in
>1976.  It worked flawlessly at that time, andsince then, I have
>changed the speaker, and little else.  Will someone explain to me
>how this "unreliable" tube amp has gone so long with so little
>maintenance?

You've been lucky and treated it with care probably.

>  In 1983, I boughta mid-60's Fender tremolux, also
>vintage tubes, etc. andheld on to it for a few years, without the
>need for any maintenance whatsoever.  At present, I have recently
>acquired a 59 Bassman, and the only problems in it seem to stem from
>dried out capacitors in thepower supply.

..which is just about the most common cause of failure of a tube amp.

I think much of this depends on how you define 'reliabililty'. If you define
the tubes themselves as 'replaceable items', much as you would define tyres
on a car as 'replaceable items' then on the 'tube wear and replacement' side
it would be a bit unfair to term this unreliable just as it would be unfair
to refer to a car as unreliable because you have to change the tyres.
There are problems, however associated with the high voltages present in
a tube amp such as tracking between pins on the tube sockets, capacitors as
you have pointed out. Also the fragile nature of a tube makes it more prone
to physical damage if you don't handle it with care. Heater filaments can
go if it's thrown around too much or if it get's hit by a large voltage
surge in much the same way as a light bulb filament.
In addition, they require periodic adjustments to the bias to keep it working
top notch.

All this would be acceptable if you looked at cars and the way they are viewed.
But if someone came along with a car design that never needed adjustment,
handled all sorts of wild physical abuse and never wore out its tyres would
you not start to redefine the terms of 'reliability' in relation to current
cars?

>If you LIKE the sound of solid state amps, that's one thing.  If you
>like the light weight, and ease with which features like channel
>switching are incorporated cheaply, that's another. But NEVER assume
>that a solid state amp will somehowbe more trustworthy, last longer,
>abreak down less, and be cheaper to repair, than a tube amp. Make
>your choice based on the sound, features, and design.  Arguments
>about reliability are moot when it comes to guitar amps.  Now, would I
>buy a tube television?  A whole different kettle of fish.

I'd go along with your comments regarding the SOUND of tube amps but I'm sure
that it'd be pretty straight forward for someone to churn out MTBF figures
for tube vs transistor amps which would show that the figure is a lot less
for tube amps. What you've got to remember is that for every mid 60s Fender
currently sitting in someones house, there are X lying on the scrap heap.
Time has filtered out most of them leaving the 'creme de la creme' still 
working.

Dave

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