Bmotorcycle,
Although you can certainly drive the Apogees with a tube amp -
the low impedance of the ribbon drivers makes tube amps
problematical. There are big brute tube amps, but they are
expensive.
More moderately priced tube amps that would normally be very
sweet may have trouble with the low impedance swings of the
Apogee drivers - just a "fact of life" with tube amps.
Beefy solid state amps work well. Apogee recommended Krells
and Classe; but Aragon, McCormack, Bryston, among others..
are known to pair nicely with Apogees.
Now that you have a short list; it's time to trust your
own ears.
Dr. Gregory Greenman
Physicist |
Murahman1,
Yes - one of my current systems is an Apogee Mini-Grand.
I've done extensive testing with several amps - monitored
the voltage and impedance... I've seen the response of
tube amps vis-a-vis solid state.
I currently drive the Apogee ribbons with a Class A
'x'-series stereo Krell.
Dr. Gregory Greenman
Physicist |
Muralman1,
I'm not saying that one can't use tubes - or that one won't
achieve a satisfactorily sounding system.
I'm saying that the impedance dips of the Stages, although
not in the same class as the Scintilla - ARE there and that
has an effect.
Although it doesn't sound bad - one may even have a preference -
but when you encounter an impedance dip - and the output
of the tube amp sags somewhat - then you just are not
ACCURATE!!
Some may like the sound - it rounds off the "edges" - gives
you a more "liquid" sound - but it's not accurate - real
music does have edges.
If one is a stickler for accuracy - then one is more likely
to find that with solid state on something like the Stages -
although I reiterate - there are plenty of tube amps that
can handle the Stages without blinking - but they cost.
Then there are tubes that are not as beefy - but they
sound nice to some even though they are struggling to
provide the current into the relatively low impedance load.
Tubes are generally more happy with the higher impedance
speakers.
Dr. Gregory Greenman
Physicist |
Muraman1,
You are correct - every type and design of component has
their strong points and weak points.
It always gets me when someone says "..X-type amp is best
for all speakers, under all conditions, for all music...."
Tubes do certain things well, others not so well - and the
same is true with solid state. Their strengths and weaknesses
are often complimentary.
Additionally, sometimes the "advantages" of one type or
another are actually distortions that someone happens to
like.
That's where you get into philosophy - do you attempt to
make the system accurate - or do you attempt to make it do
what you "like" - whatever that is.
I attempt to go for accuracy to the greatest extent possible
and not impose my prejudices on the artist's music.
Dr. Gregory Greenman
|
Cjfrbw,
Unless you do the measurements, you can't know what's going
on.
I've put current limited tubes amps on the Stages - have seen
the tube amps strain, and fail to deliver the current needed
to compensate for the depressed impedance, and had audiophile
friends gush over how "liquid" and "lush" the sound was.
Then you put on the hefty high current amps - and they do put
out the current to keep the Stages accurate - and the
attending audiophiles complain about "glare" and being
"etched".
I think some audiophiles just plain LIKE some of the natural
rolloffs that tubes provide.
Even the simplest single-tube amp is not perfectly linear;
the output characteristics of a tube are not perfectly
linear - they do "roll-off" at higher signal levels.
[That's why you hear that tubes clip more "softly" than
solid state - they are NOT linear up to the clipping point.]
It doesn't take a complex amp to have these non-linear
characteristics - the basic characteristics of the tubes
have these non-linearities.
If you like that sound, fine - go with what you like.
Just don't fool yourself that your system is accurate.
Dr. Gregory Greenman
Physicist |
Muralman1,
When I say "accuracy"; I don't mean just frequency response.
What I mean by "accuracy" is the shape of the voltage waveform
to the speakers is EXACTLY the same as the voltage waveform
that represents the music.
The frequency response is just the Fourier Transform of this
waveform. However, my definition of "accuracy" is more
detailed than that. In my definition of "accuracy" - the
voltage on the speaker's terminals has to look EXACTLY like
the music it represents.
There are tube amps that can reproduce accurately - depends
on the design and power capacity.
As for parallel universes, I'm afraid I don't delve into
cosmology - think the other end of the spectrum - nuclear
physics.
Dr. Gregory Greenman
Physicist
|
Murahman1,
Even the live performance may not be the ultimate.
When you attend a live event, you're not listening to the
artist play - you are listening to the artist playing as
reproduced by the venue's sound system.
If you are listening to an orchestra - that's one thing - a
big orchestra doesn't need any help making sound.
But if you are listening to an artist in anything but the
smallest club - where you can hear them acoustically - then
you are listening to someone's sound system.
Comparing your own piano to piano played on your own
speakers in the same room would be interesting. If you
can get a real good recording of your actual piano in your
own room - and then have the opportunity to play back that
recording in the same room - that would tell you a lot.
The Scintillas are excellent - a case of going "all out" in
the design - without regard to certain practical limits -
like the impedance - which is why they end up at 1 ohm.
The Stages are excellent too. The only speakers that I have
actually heard that are as "real" sounding as the Stages,
are some very expensive Wilsons [ X-2 and Maxx-2 ]. The
Stages were a lot less money - so they are an excellent
value. Too bad Apogee went out of business.
Dr. Gregory Greenman |
Muralman1,
You can certainly run a small tube amp on the Stages, and get
something that "sounds" fine. However, when the Stage starts
to demand current - and if the tube amp can't provide it -
then accuracy is the first casualty. If the low impedance
load causes the voltage on the tube amp to sag below what
it should be - i.e. the product of the gain and the input
voltage - then you don't have accuracy.
If the amp can't supply the current the Stages want - like
the big amps that Stereophile, et. al. champion - then
you don't have accuracy - even if you like the sound.
I'm sure there are more amps on the market that pair well
with Apogees other than those that were around when Apogee
was still in business. I wonder how some of the newer
"switching" amps like the Bel Cantos do on loads like the
Apogees.
However, what the low impedance of the Apogee driver needs
is current. That's something that you are much more likely
to get accurately out of a solid state device for a price
that is reasonable, vis-a-vis a tube amp.
There certainly are tube amps that can handle an Apogee -
but with the current hungry Apogee - you are not playing to
a tube amp's strong suit.
Although a successful pairing of tube amp and Apogee is
certainly possible - it certainly requires more care and
attention.
It would be "safer" for the Apogee owner to stick with the
beefy solid state designs. A greater fraction of the
solid state amp market will pair well with Apogees, than
the fraction of tube designs that will.
Again, the current demands of the Apogees are just not the
strong suit for tube amps - although most certainly there
are tube amps that pair well with Apogees.
Dr. Gregory Greenman
Physicist |
Cjfrbw,
I think the "alliance" between Apogee and Krell goes back to
the days when Apogee was producing speakers like the Scintilla
and the "Full Range" which had very low impedances.
The Krells were practically the only amps around that could
drive these low impedances without going unstable. [ There's
a point a which an amp turns into an oscillator if the load
impedance is low enough. ]
That was Dan D'Agostino's and Krell's original claim to
fame - they were about the only thing around that could
drive Apogees without blowing up.
However, for many years Apogee recommended Classe' amps
instead of Krells. Although the Krells did an excellent
job of driving Apogees, and Apogee went to Krell for the
built-in amp of their "statement" product - the Grands;
they probably wanted to offer their clientele a more cost
effective solution. Classe' amps did a very good job for
less money than the Krells - although Classe' amps were
not cheap by any measure.
Measuring well is a necessary - but not sufficient
condition for accuracy. If something measures well, that
doesn't mean the system is accurate.
However, if the waveform presented at the speakers input
terminals doesn't measure well because the amp can't keep
up with the current demands of the speaker - then there's
no way that can be accurate - no matter how it sounds.
It may sound nice to some - the attacks and edges of the
music being rolled off, which some like the sound of; but
it can't be called accurate.
I'll look into the North Creek crossovers.
Dr. Gregory Greenman
Physicist |
Muralman1,
I drive my Apogee MiniGrands with a Class A,
Full-Power-Balanced, "cx"-series stereo Krell.
Dr. Gregory Greenman
Physicist |
Cjfrbw,
I agree with your last comment that one has to let one's
ears be the final guide.
All I'm saying, is that many tube amps when confronted with
the complex impedance dips of the Apogee ribbons will not
have the current reserves to drive enough current through
the ribbon so that the voltage is what it is supposed to be.
Once the amp can't put the required voltage on the speakers
input terminals - then all bets are off with respect to
accuracy.
Accuracy isn't a limiting concept. The music signal being
sent to the speakers is encoded as a voltage. If the amp
can't put the correct, and I do mean correct; voltage on
the speaker's terminals - then you are doing something
inaccurate to the music.
Now you may like what you hear - but if your amp is not
putting the proper voltage on the speaker's terminals -
then all the great qualities that you are ascribing to the
music - are not qualities of the music - because the
musical signal isn't being accurately represented to the
speaker. Once that inaccuracy creeps in - there's nothing
the speaker can do to correct it.
However, you may like what the speaker puts out - you just
have to accept that it, of necessity; it is something
different than what the musician intended; regardless of
how much you may like it.
Dr. Gregory Greenman
Physicist |
