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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?

[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

[Arny Krueger]

wrote in message


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.

Probable causes, in order of importance

(1) The recordings you were listening to
(2) The room you and the speakers were in
(3) The speakers themselves

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

Maybe yes, maybe no.

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."

Seems like even the SS amp is fantastically low-powered and odd.

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

If you don't like how the amp sounds, get rid of it?

Maybe my ears don't like push-pull tube amps?

Maybe there wasn't the surplus of power you expected?

Maybe the tubed amp was not conservatively rated for power?

Would a SET be better?

I think something that was designed to have low distortion and noise would
be better.

[MC]

I'm not familiar with those amplifiers, but I'd be inclined to put an
oscilloscope across a speaker to see if by any chance you have some
high-frequency oscillation, above the limit of your hearing but able to
irritate your ears.

[Sonnova]

On Thu, 17 Jan 2008 14:51:22 -0800, Peter Wieck wrote
(in article ):

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.

You can say that again. My VTLs came with Chinese 807s. The build quality was
TERRIBLE. Take the amplifiers plate cap sockets off the top of the tube and
the TUBE'S plate cap comes with it leaving but a wisp of wire sticking out of
the top of the tube's envelope (the cap is inside the cap socket). Try to
pull the tube out of its socket by grabbing the glass envelope and you will
find yourself with a glass bulb in your hand with 5 broken wires coming out
of the bottom and the phenolic tube base and all the pins will be firmly
remained in the tube socket! I replaced all of them with NOS JAN 807s from
WWII. Haven't had one of those fail in YEARS. As for sound quality though, I
noticed no characteristics in sound that I could or would attribute to either
the Chinese or the JAN 807s.

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.

That is exactly is what I suspect is happening. I think the amps are
clipping badly. OTOH, I remember as a teenager, a friend's dad had a big
Klipsch corner horn. One afternoon we took one of those little 5 or 6
transistor radios that all the kids carried in the late 50's, early sixties
and connected it's earphone jack to the Klipsch. The amount of volume that
the speaker produced from less than 100 milli-Watts was astounding! I recall
that the Klipsch ads in those days boasted that the corner horn was 50%
efficient, and that it took only 2 electrical Watts to produce one acoustic
Watt (one acoustic watt is defined as being equivalent to 107.5 dBSPL at four
feet from an omnidirectional source). That's pretty damn efficient.
Unfortunately, the Synergy F2 to which the OP is referring, is not a
Klipschorn corner horn and though its still an efficient speaker, I wouldn't
want to drive it with anything shy of 30 or so clean Watts. 8 Watts aren't
enough.

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.

Yes, any of the amps you mention should drive these puppies quite nicely.
I've not heard any Klipsch products for many decades, I wonder what the F2s
sound like? I was never fond of the original Klipschorn sound for the same
reason that I always disliked Altec-Lansing speakers (especially anything
using the Altec treble horn).

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.

I don't think that's enough for these speakers either. A stereo 70 or
equivalent is about as small an amp as I would use on these speakers unless I
listened at very low volume levels.

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

Not ones that small, anyway. For his complaint, tube or transistor would not
be the issue.

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

Again, it depends on how much power the SET amps have. I know of several SET
amps which use large transmitter tubes to produce 50 Watts each. But these
aren't cheap and it seems backward to mate a $650/pair pair of relatively
efficient speakers with a multi-thousand dollar pair of SET amplifiers just
to drive them!

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.

Agreed.

Peter Wieck
Wyncote, PA

[Frank Traut]

Peter Wieck wrote:

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

I believe he is suffering due to a lack of spectral dynamic
range common with a small/inexpensive setup like his. And
totally agree about him not liking SET over PP. I currently have
a pair of Klipsch RF-3's that sound wonderful with my low power
SS Yamaha receiver. Some fatiguing still (they're used just for
home theater anyway), but not as bad as when I had them hooked to
an Antique Sound Lab Preamp ($1400 model at Audio Advisor) or a
Golden Tube Audio 50wpc integrated. I had rolled so many tubes
also, I lost count. What an expensive and not always gratifying
hobby this can be!

A lot of newbies/people want tube amps because they have heard
from others that they are the way to go. But what many of these
people don't tell others is that you need to carefully pair
components up in order to get that "tube" sound or "that" sound
you are looking for period. I currently have that "tube sound"
with a SS Tandberg preamp, SS Margules amp and ML Ascent
speakers. Best combo I have ever had in my life and more "tube"
sounding (without the negatives mind you) than any other tube
gear I have ever owned.

The biggest mistake most people make in regards to low power tubes
(I too do not think highly of those ASL monoblocks) is that
they pair them with cheap, subpar speakers. Even though Klipsch
looks wonderful on paper for tubes, I have found them to sound
about as good as their price point would suggest. Second major
factor when it comes to these new tube products from China is
the use of cheap transformers. I would say that the quality of
the output transformers is difference between good and bad sounding
tube gear and there's more of the latter than the former now-a-days.

I'd say you are better off with a simply designed, medium to high
efficiency loudspeaker if you keep the ASL's. Smaller B&W's for
instance. OR perhaps a single driver or a model with no crossover
like Bizzy Bee Paul sells.

Or you can ditch the Klipsch's, which is probably the better long
term listening decision he'll make. They image horribly and
their Tractrix horn loaded tweeter can sound like bacon frying in
a pan. Not usually a problem with the rolled off highs of cheap
tube electronics though.

-Frank

www.coinopdreams.com

BTW: After not reading this group for so long (thanks partly to
the many MP3 and/or non-high end discussions) I find it ironic
that Bose 901's are being talked about here. Guess I shouldn't
be surprised anymore. Isn't there simply a rec.audio newsgroup?

[BEAR]

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?

The top choice is a parasitic oscillation in the amp.
A scope is required to find out if that is happening.

Most Klipsh products will sound way better on a tube amp than solid state.

You might be clipping the **** out of the amp.
Don't believe the manufacturers spec on efficiency.
So, play it much much lower and see if that helps.

Also, clipping the amp may introduce a parasitic - saw that about a month ago on
a nice old British guitar amp. Would take ur ears off.

An ST-70 Dynaco is a good place to start with tube gear.
A few mods puts it in good shape to compete with better tube gear.

The next step is to learn about how to build your own tube gear.
Or solid state gear, if that floats ur boat boys! :_)

IF the Klipsh will biamp, put the tube amp on the tweeters, and the
other amp on the bottom end and see how that flys?

Oh, your 27 watt unit is simply a cap coupled output using single polarity
transistors, as done in days of yore, but set up to run as a "bridged" amp
internally. What that means in practice is that there are two identical amps,
out of phase with each other and each one tied to one side of the speaker
(load). Don't try to connect either output terminal to the chassis ground, that
will blow up the amp. :_) That makes the amp push-pull.

So, that also makes the ouput *voltage* twice what a single amp will create, off
the same supply voltage - the swing is now doubled in to the load, so the power
is increased by 4x. In other words that's a pair of about 7 watt amps in bridged
mode, making ~27 watts... :_)

Btw, most all modern commercial speakers require much more power to play at
"realistic" levels. There are some pro speakers with high sensitivity and some
"vintage speakers" (Altec 604s for example) that actually have reasonably high
sensitivity, but even those need more than 7 watts to drive in practice.

_-_-bear