[Peter Wieck]

On Jan 16, 6:44*pm, wrote:
As a newbie, I decided to try a tube amplifier. So I obtained Antique
Sound Labs Wave AV-8 monoblocks (8 wpc push-pull) and hooked them up
to my Klipsch Synergy F-2 (95.5 dB sensitivity; 8 ohm impedance)
speakers. After just a couple of hours I had a vicious headache and
burning/ringing in my ears.

I wasn't playing loud at all - just normal listening levels. I
couldn't have been anywhere near max output of amp.

I've never experienced this before with my SS integrated amp. It's
rated at 27 wpc and it's described as a "BTL (Bridge-Tied Load)-
connected SEPP (Single Ended Push Pull) circuit."

Anyone know what could have caused this and how to fix?

Maybe my ears don't like push-pull tube amps? Would a SET be better?

Yikes...

From what you are writing, I cannot begin to diagnose exactly what is
going on. But I will venture a couple of guesses. They are in no
particular order and as you have given far too little information for
detailed answers, they are also wildly speculative.

a) Standing waves: This would be a function of room dimensions,
furnishings & decorations and speaker placement. If the *ONLY* thing
you did was change the amp, this is unlikely. But frequency-specific
standing waves can cause all sorts of sonic havoc including very, very
uncomfortable inner-ear responses.

b) The speakers are out-of-phase: Did you absolutely-for-sure hook
them up properly to the new amp? Some amps are +--+, some are +-+-, a
vanishingly few are -++-. If you connected the speakers to one to the
same as the other, the may not be in phase. As your amps are Mono -
this is also unlikely.

c) The speakers may be improperly placed in general, causing some
cancellation waves and some distortions. Again, did you move them _AT
ALL_?

d) There is something wrong with the amp. Those are OEM $99 Chinese
two-tube amps as I remember, unfortunately equipment from that source
varies wildly.

e) These Chinese amps have Chinese tubes in them. It is my opinion
that although the Chinese are capable of making decent tubes and have
done so on rare occasion, for the most part their tubes are fit only
for target-practice.

f) 8 (optimistic) watts from those amps against even highly efficient
speakers is barely enough for highly dynamic music sources. You _will_
be clipping a good deal of the time if you are listening to much other
than limited signal at quite moderate levels. If you are trying
something like the Saint-Saens Organ Symphony - just forget it. Your
head *will* hurt after a session using such sources.

As I noted in warning - the above suggestions are wildly speculative.

What you might try: Obtain/borrow a stock Dynaco ST-70 that has been
checked and is in good operating condition with a decent set of tubes
in it. Similarly, an Eico ST70, any of several Scott or Fisher amps,
even a pair of Dynaco MKIII or MKIV mono amps. Try and see if the
situation is any better.

If you have your heart set on flea-power, look for a Dynaco ST-35 or
SCA-35. Those are an (optimistic) 17.5 wpc @ 8 ohms and so might more
closely resemble what you have. The difference between 8 and 18 watts
is really only about 3dB anyway.

If you get the same results after checking speaker connections and
placement, then it is likely that tubes are not for you.

SET will be infinitely worse if you cannot tolerate PP in tubes.

I am still trying to understand "Single-Ended Push-Pull" as they are
mutually contradictory terms. Sounds like advertizing hype.

But, for the record, you picked a particularly limited set of amps for
your first foray into tubes. And that is the best thing I could write
about them in good conscience.

Peter Wieck
Wyncote, PA