I posted the following request on rahe but it did not garner any
responses there, hence this "cross-post" to rec.audio.opinion -Pranay
************************************************** **********

Hi,


I have a B&K 307 receiver driving a pair of Magnepan MG-IIIA speakers.
Though the B&K receiver has high current output stages, its power
output at 4 ohms is not 2x or even 1.5x its 8 ohm output (It is rated
to deliver 150 w/ch into 8 ohms going up to 185 w/ch into 4 ohms.) Even
with these figures the MGIIIA - B&K combination sounds quite
satisfying, "satisfying" of course is my subjective opionion, but I
sometimes feel the need to play the B&K fairly loud to "open" up the
Maggies.

Considering the MG-IIIA's inefficiency and 4 ohm power requirements, I
wonder if another dedicated high power amp for pure stereo listening
would work better with the maggies much more at all listening levels.

I would then use the B&K with more efficient speakers than the maggies
for home theater and use it purely as a preamp driving the dedicated
amp mentioned above hooked up to the MG-IIIAs for stereo listening.

Budgetary constraints ( $450 US) rule out monoblocks or any high-end
stereo amp that would have the required power characteristics. However,
I do have an opportunity to pick up a used Proton D1200 amp in my
budget that seems to have a design that can deliver peak/transient
power levels going in the vicinity of 1kW/ch (continuous power rating
is 100w/ch). If you are familiar with the Proton design you may
understand what I am referring to. However I have not been able to find
much material on the web on this amp that would indicate whether this
amp would really make a sonic difference over the B&K. There have also
been some posts about the parts quality / reliability of Proton
equipment. I am also scheduled to relocate overseas to a place that
will not have Proton dealers around, so reliability is of importance to
me. The Proton D1200 seller is saying that his specific Proton D1200
has never required service, though.

Should I go for the Proton D1200?

thanks,

Pranay

"Pranay" wrote

I have a B&K 307 receiver driving a pair of Magnepan
MG-IIIA speakers.... Even with these figures the MGIIIA
- B&K combination sounds quite satisfying, "satisfying"
of course is my subjective opionion, but I sometimes
feel the need to play the B&K fairly loud to "open" up the
Maggies.

Ok.


Considering the MG-IIIA's inefficiency and 4 ohm power
requirements, I wonder if another dedicated high power
amp for pure stereo listening would work better with the
maggies much more at all listening levels.

Yes. The impedance is actually 4 ohms in the bass
and 3 ohms (pure resistive) for treble with sensitivity
around 83-85dB. The recommended amp was 50 to
200 watts, but I had no difficulty using 550 watts per
channel.


Budgetary constraints ( $450 US) rule out monoblocks
or any high-end stereo amp that would have the required
power characteristics. However, I do have an opportunity
to pick up a used Proton D1200 amp in my budget that
seems to have a design that can deliver peak/transient
power levels going in the vicinity of 1kW/ch (continuous
power rating is 100w/ch). If you are familiar with the Proton
design you may understand what I am referring to.
However I have not been able to find much material on
the web on this amp that would indicate whether this
amp would really make a sonic difference over the B&K.

The Proton D1200 provides 100 Watts/channel 8 ohms
and 160 into 4 ohms with 6dB of head room. In 1988
this was the top of the line power amp for Proton ($700).


Should I go for the Proton D1200?

Unknown. When you say "need to play the B&K fairly
loud to "open" up the Maggies" I think what you are
looking for is greater lower midrange and higher
overall resolution from your power amplifier. A tubed
power amp, mid to higher powered output, would do
this but not at your price point ($450).

An alternative which would accomplish this, at your
price point, is the Carver TMF-55 power amp (380-600
watts) manufactured in the early to mid 1990's (MSRP
$1K).

"Powell" said:

Should I go for the Proton D1200?

Unknown. When you say "need to play the B&K fairly
loud to "open" up the Maggies" I think what you are
looking for is greater lower midrange and higher
overall resolution from your power amplifier. A tubed
power amp, mid to higher powered output, would do
this but not at your price point ($450).


Maggies are not renowned for their fabulous dynamic character.
Which BTW suits my listening needs very well, but obviously the OP is
in search for something more dynamically sounding.

Which could end up in buying other speakers, presumably of the cone
driver type.

--
Sander de Waal
" SOA of a KT88? Sufficient. "

"Powell" said:

Should I go for the Proton D1200?

Unknown. When you say "need to play the B&K fairly
loud to "open" up the Maggies" I think what you are
looking for is greater lower midrange and higher
overall resolution from your power amplifier. A tubed
power amp, mid to higher powered output, would do
this but not at your price point ($450).


Maggies are not renowned for their fabulous dynamic character.
Which BTW suits my listening needs very well, but obviously the OP is
in search for something more dynamically sounding.

Which could end up in buying other speakers, presumably of the cone
driver type.

--
Sander de Waal
" SOA of a KT88? Sufficient. "

Hmmm... I haven't read much positive reviews for most Carver gear, much
less their amps. I would like to steer away from Carver if even 10% of
what I read is correct.

The touted ability of the Proton D1200 to handle transient loads well
in excess of it continuous power rating was what caused me to consider
trying it with MG-IIIAs. For what it's worth- I like panel meters - the
Proton has those as well.

I am going to stick with the Maggies and try to get an amp that can
work well with them, not the other way around. The B&K receiver I
currently have is not too shabby in that regard, I was looking for an
improvement. The Carver seems like quite a step down from the B&K.

Other in-budget possibilities that have recently appeared on the used
gear landscape area are a Roksan Caspian M Series-1 120W/ch (4 ohms)
amp, a Musical Design D-75B 75W/ch amp, a B&K EX-442 Sonata 350W/ch (4
ohms) amp. I wish I could manage an Aragon 4004- but that's running a
bit above the max I can go.

Let me know what you think,

Pranay