Have you ever spent any time listening to a true Class A solid state
amplifiers ?

Any comments on how it sounded compared to any other types ?

Graham

Eeyore wrote:
Have you ever spent any time listening to a true Class A solid state
amplifiers ?

Any comments on how it sounded compared to any other types ?

Hotter ?

I can't remember the models - it was a while ago. Only audible difference
to me was that the AB one sounded harsher when louder. But the Class A
ampcouldn't actually get that loud anyway, so not fair comparison I guess.

geoff

Geoff wrote:

Eeyore wrote:
Have you ever spent any time listening to a true Class A solid state
amplifiers ?

Any comments on how it sounded compared to any other types ?

Hotter ?

I can't remember the models - it was a while ago. Only audible difference
to me was that the AB one sounded harsher when louder.

Not too surprising.

But the Class A
ampcouldn't actually get that loud anyway, so not fair comparison I guess.

Did you notice any differences at lower levels ?

Graham

Eeyore said:


Have you ever spent any time listening to a true Class A solid state
amplifiers ?

Any comments on how it sounded compared to any other types ?


I have extensive listening (and building) experience with hybrid amps,
a tube driving (one or more) complementary pairs of MOSFETs biased in
A.

Because they're my own designs, I don't know how to compare them to
commercial amps, since it's been a long time since I listened
extensively to a commercial amplifier at home.

From recent demos I did with them, the most comments I heard were
"effortless sound, somewhat restricted, but detailed and powerful when
necessary".
Also, the terms "forgiving" and "smooth" were uttered.
Some people preferred them above a pair of modified Hypex UcD400AD,
though. And of course, others did not.

I guess that means they do color the sound a bit.
In fact I know they do, I *intended* them to sound like that ;-)

I still think my KT88 monsters that came ready recently, beat them
wrt. placing and detail, but they're rather sensitive to the kind of
speaker attached, and do deliver less power because they're wired in
triode.
The hybrids are more "forgiving", they easily drive 2 Maggies in
parallel per channel.

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

Eeyore writes:

Have you ever spent any time listening to a true Class A solid state
amplifiers ?

Any comments on how it sounded compared to any other types ?

5-6 years ago I went through a rather extensive amp eval period, trying
serveral different solid state and tube amps, the most expensive being a
$6K Levinson and the cheapest a $400 Parasound. Power outputs ranged from
20 wpc to 200. Load was a pair of soffit-mounted Tannoy SGM10Bs with
Mastering Lab crossovers. The room is treated, and has few problems
and reveals much.

Most of the amps sounded pretty good. The tube amp, a Bel, I believe, had
some nice qualities in the mid range but was otherwise dull or muffled
sounding. All were AB, with one exception.

The winner was the 30 wpc class-A Pass Labs Aleph 3 -- not because it was
"oooh" this and "ahhh" that, it simply was the least colored. Once you
"heard" its transparancy, it was the other amps that started to sound
colored.

Its failing, however, had to do (apparently) with less than ideal LF
damping and/or lower power. This, as well as some LF IM problems attached
to the Tannoys, disappeared once I added subs and biamped (had to mod the
active xover -- good design, crappy parts), crossing over just above the
Tannoy port frequency at 60 Hz. (This is a hybrid 3-way system -- active
LF xover, but passive for the mid and top.)

It's a hell of a system for the money, and nice to mix on.

Class A has it merits if you can get into it for a reasonable price and
know some of the negatives (such as heat and weight).

Frank Stearns
Mobile Audio


--

Frank Stearns said:


Class A has it merits if you can get into it for a reasonable price and
know some of the negatives (such as heat and weight).



Just as with tubes, I think class A is best suited to the DIY-ers who
know what they are doing.

Oh, that would rule me out. Sorry folks ;-)

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

In article ,
Eeyore wrote:
Have you ever spent any time listening to a true Class A solid state
amplifiers ?

Yes. A mate drove his ESLs with a Sugden. One of the cleanest sounding
systems I've ever heard. Wouldn't shake the windows, though. ;-)

--
*Hard work has a future payoff. Laziness pays off NOW.

Dave Plowman London SW
To e-mail, change noise into sound.

"Eeyore" wrote in message
...
Have you ever spent any time listening to a true Class A solid state
amplifiers ?

**We all have. Pretty much every amplifier operates Class A to a few tens of
milliwatts. Plenty loud enough for quiet listening. Some high bias Class A/B
designs operate to a couple of Watts in Class A. Even with 90dB/W/M
speakers, this is pretty loud. For my own part, I am very familiar with an
amplifier which has user switchable Class A operating points. Since the
design eschews the use of Global NFB, it is far more sensitive to bais
current changes than most high Global NFB designs. Once the Class A
operating point goes beyond 10 Watts Class A, there is bugger all
difference. Except, when using the thing on a US power receptacle. At 100
Watts Class A, the power consumed from the mains supply is too high for
regular US outlets, without losing mains Voltage. At 100 Watts Class A, in
the US, the sound becomes slightly 'compressed'. Pretty much anywhere else
on the planet is fine.


Any comments on how it sounded compared to any other types ?

**IMO, Class A is used by so-so designers who can't figure out how to design
an amplifier properly. Once bias current is set above the 'knee' of the
device (around 100mA for BJTs and 1 Amp for MOSFETs) any more Class A bias
is superfluous.

Think of it this way: A badly designed Class A/B amplifier will probably
sound better when operating in Class A. A well designed Class A/B amplifier
will probably sound slightly worse when operating in Class A.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

I used to own Krells. My gut reaction (totally unsubtantiated by any sort of
comparative listening tests) was that they had a "tight", "controlled",
effortless sound.

We all have. Pretty much every amplifier operates class A to
a few tens of milliwatts. Plenty loud enough for quiet listening.
Some high bias class AB designs operate to a couple of watts
in class A.

The Parasound A21, for example, is class A up to 8 watts (not Watts) per
channel into an 8-ohm load. That's fairly loud, unless you have rather
insensitive speakers.