Where do the tubes go?

Newbee,
We are all just sharing our individual experiences which surely will differ.
Amp- speaker match is of course a factor, but this applies to "all
amplifiers" not just tube models. Any solid state amp just can`t be
tossed into a system without some thought and consideration.Perhaps my
experience with tube amps were less problematic than yours or things
worked out differently for what ever the reason. I do agree that some
degree of research is necessary to get the right match. I however don`t
believe tube amps are some exotic beast that must be handled carfully
while SS amps have no concerns at all and just work with any speaker,
they don`t. Anyway we`re just two guys trying to be helpful with our
different perspectives, we both mean well. Sorry about your problem with
boat anchors-
high power tube amps, personally I much prefer the low and moderate
power tube amps with efficient easy to drive speakers.
Charles,

I would start with a tubed pre-amp or a self-biasing integrated amp. You will be able to roll tubes to experiment with little technical skill. Also Wolf Garcia's suggestion of Jolida which is easy to bias.

Most of the tube units that come in for repair from my experience have failed because of poor design. Sometimes not enough room inside, sometimes poor circuit board thickness, and poor overall design to handle what a component should be able to deliver without breaking down. Even some of the higher priced units I see are made poorly.

Happy Listening.

"1. Would most people recommend an all tube system, or do you recommend starting with only a tube component or two.

2. What are the relative merits and disadvantages of placing tubes at various stations in a system CD-->pre amp --> amp ?"

The only way to answer those questions is to go out and listen for yourself. If you do otherwise, you'll probably waste your money.

Fair comments Newbee.

I've owned ARC tube gear for almost 10 years. Perhaps I'm lucky, but the only maintenance issues I've experienced related to blown bias resisters. Fortunately, there's an ARC authorized service tech near my house who also happens to make house calls for a small extra fee.

Can't speak about other tube amp models, but I think ARC gear is extremely well built and dependable. So except for the periodic replacement of tubes and occasional bias adjustments, no problems.

Your point about electrical matching has been a vertical learning curve for me. For others who may be interested in tube gear, pull some of my more recent posts. I've raised most of the relevant questions. And our more tech knowledgeable and savvy members have explained in plain English most of the key issues and theory.

Let me at least respond to one point you just raised. It's true that electrical impedance matching between a tube amp and speakers is a key consideration. Having said that, at least ARC uses some local negative feedback (partial cathode follower) to achieve low'ish output impedance.

For example, in the case of my amp, the ARC Ref 150, output impedance off the 4 ohm taps is just .55 ohms; and 1.1 ohms off the 8ohm taps. That corresponds to relatively tight output voltage regulation: +/- .4 ohms off the 4 ohm taps; and about +/- .8 ohms off the 8 ohm taps.

What that means in plain English is that my tube amp can perform somewhat like a SS amp. According to Ralph Karsten's white paper, SS amps typically have very low output impedances and present a constant voltage source to the speakers, a/k/a Voltage Paradigm amps. They produce power by generating current, have high damping factors and tight voltage regulation.

So, going back to my example illustrating the ARC Ref 150, while not a true low output impedance, constant voltage source type amp, it performs somewhat like one. Hence, the Ref 150 may have greater utility in driving a wider range of speakers than a tube amp that has higher output impedance, a low damping factor and a wider range of output voltage regulation.

So ..., as Newbee says, a little more homework is needed when going the tube route.

Happy Holidays.

Bruce