quiet hiss in backround?

Every once in a while a tube will go out so you might want a good tube tester and a few extras around. I would guess every other year you'll need to change them all out which is nothing more than screwing out the old ones and screwing in the new ones. Yes they require more work than SS but it's not a lot.

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My tubes have pins - they aren't threaded.

Thanks for the correction Macrojack. I'm SS these days.

The idea is it's fairly simple. Perhaps you could comment on your experiences?

Sure Mike,

Not much to tell. I have a pair of Audio Mirror 20 watt mono tube amps. They are self-biasing, SET amps and use a quad of output tubes every 2000 hours.

I'm using one of the better horn speakers on the market so my choice of amplifier is somewhat critical, or it would be if I was. Anymore I just turn it on and listen. By the way, I can hear a faint hiss sound in the background even when the preamp is muted. It sounds a little like the rushing sound you hear by holding a seashell up to your ear. Apparently the dbx Drive Rack PA that I use as a crossover/EQ/RTA is meant for pro amps and needs to be stepped down a bit for use with home audio. The tech advisor at dbx suggested Ebtech Line Limiters as a solution. Maybe your preamp is not an ideal match for your amp, Richard.

If you can get $6000 to $7000 for that amp, do it now. There are very satidfactory sounding products available for a fraction of that money. Same goes for the WPs.

thanks macrojack. i'm sure there are better sounding for less but as we were discussing, not sure what direction to go. miss the days of getting stuff to demo, this can be somewhat of a gamble. the more i read, the audio research 110 sounds like a fantastic match though. i do think it would be tough to replace the wp7's and be satisfied at a fraction.
the sound you describe is the same as my hiss. i have to lean toward the watt to hear it but i know it's there. just like the sound of a sea shell.

I have a suggestion that won't cost you anything more than minimal shipping.

Audition a pair of NuForce Ref9V2 SE amplifiers. They are the quietest amps I have ever heard. You can return them for a refund, less shipping.

If you still have a hiss, then you'll know the problem is elsewhere.