Re: why am I suffering from listener's fatigue?On Thu, 17 Jan 2008 14:51:22 -0800, Peter Wieck wrote
(in article <fmom5a01jme@news4.newsguy,com >):
> On Jan 16, 6:44 pm, pa ...@hotmail,com 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
>