jjnunes wrote:

Bruce J. Richman wrote:

Tube amplifiers have both their proponents and detractors. Comments about
lack
of reliability and/or high repair needs from the latter group are, AFAIK,
not
supported by any empirical evidence indicating those claims are valid.

Lack of reliability or the converse is relative. Given equal design
attention to reliability, tube amplifiers are simply not as reliable as
solid state amplifiers, especially as regards power amplifiers. The natural
manufacturing variances in tubes themselves, the the increased heat produced
by
them, (meaning increased stresses on associated components) and the higher
voltages dictate the empirical facts of the matter.





For the average purchaser contemplating purchase of an amplifier, I would
suspect that reliability would be defined more practically by a manufacturer's
"track record". More specifically, factors such as build quality, attention to
design, as you mention, etc. may play a large role, whether the product be
tubed or SS in determining its "reliability". As regards heat considerations,
I've often heard it reported that many Class A amplifiers, for example, tend to
"run quite hot" compared to others and may require relatively massive heat
sinks to dissipate some of that heat. If this is true, then it would seem that
tubes are not the only item on an amplifier's parts list that can produce heat.

I would recommend that prospective purchasers try and get as much information
about the specific amplifier - and that manufacturer's reputation for
reliability - as they can, whether it be a SS or tubed amplifier.

Of course, if there are published empirical results indicating higher return
rates or service calls for tubed amplifiers
than for SS amplifiers - or vice versa - it would be interesting to see.

Those in a better position to answer this question re. reliability would be,
manufacturers who have been selling both types of amplifiers for years - e.g.
Conrad Johnson or Audio Research. Or perhaps audio dealers who have been
selling both types of amplifiers over a length of time.
In their experience, is there a significant difference in the relative %age of
service requests as a function of sales volume?
That is the type of data I'd be looking at, along with a given manufacturer's
reputation, rather than relying on generalizations based on a given bias (no
pun intended) for one class of products or the other.

Bruce J. Richman