Howdy,

Well, after a 10 year absence from this hobby, I was thrust back in
yesterday when my beloved Sumo Andromeda III blew the left channel
rail fuses, and subsequent replacments blew as well. I've been told
that fixing it will be tough, particuarly finding replacment parts.
As such, I think it's time to begin looking for a new amplifier.

Being away for a while, I'm not up on new technologies, but I see that
the Krell's of the world are still peddling $10K amplifiers. Way out
of my price range unfortunately. I'm hoping that those of you who
have remained engaged in the hobby might help me narrow my research.
With that said, I'll let the questions fly!!! 8)

1. What's this new technology called ICEpower that is evidently being
embraced by Rowland, eAR, B&O and others? I remember connecting a
500/wpc Carver amp to some Martin Logan's, and the load choked the
amp. Is this new digital technology capable of driving complex loads?
How can such a small, mid-priced amplifier deliver 1000/wpc with
little heat? Is this for real?

2. What's the deal with "commercial" amplifiers, like those from
Crown? I owned some Crown equipment many moons ago, and at the time,
it was considered "high-end." How does something like this differ
from a Krell or Levinson? There's only a handful of ways to skin a
can so-to-speak, so from a technological perspective, are the designs
similar? What do you get from a Krell besides the exotic exterior?

3. Sumo offered the magic blend of "high-end" for the average Joe;
power, sonic performance and value. Is anyone doing this today, or
has the high-end gone completely high-end?

4. Recommendations for an amplifier in the 200/wpc+ range would be
appreciated.

This will be powering Von Schweikert VR-4's (the original) in a very
large room. I need something to control the low-end of the VR-4's to
make sure everything is tight, and I do want something neutral that
has sufficient current to deliver good power.

Thanks in advance!!!

Coincidentally, there is a general discussion about amplifiers under "Any
Opinions on an Adcom".

I don't have direct experience with the the original VR-4, but I have helped
a friend of mine select an amp for the current VR-4. Unfortunately, many
"bright" amplifiers synergize poorly with these speakers, while "smooth"
amplifiers provide inadequate definition.

If tight woofer control is a priority, this mandates either a large bipolar
amp, or a Hafler Transnova MOSFET design. However, such a choice may result
in concommitant nastiness in the lower treble. MOSFET designs work well in
this range. You might consider biamping -- use of a commercial bipolar amp
on the bottom, and a MOSFET choice up top. Hafler P-series amps are cheap
and extremely good. You could start with one full range. If you find the
combination has low treble harshness, you could add a conventional MOSFET
amp in a biamp configuration.

Another choice we found extremely pleasant is full range use of a Hafler
XL-600, rated at 306 watts/channel/8 ohms, clipping at 426/channel/8, 450
watts/channel/4 ohms. A very, very smooth amplifier, with very good bass
control, just shy of excellent.

Another amplifier my friend liked was the Odyssey, although it was not my
favorite. Unfortunately, this unit is built in the modern, "faux" style,
with huge heatsinks that barely connect to anything inside

These are amplifiers I've actually tried with something close to what you
have.

The high end of sound reinforcement can be quite rewarding. Beware of the
cheaper stuff. Although I've never heard a modern Crown amp, I would not be
hostile to it. But your speakers are hard to match to.

As for whether a top-notch sound reinforcement amp is the equal of a Krell,
I, too, wonder. The differences are undoubtedly fine. Synergy is probably
more relevant than universal optimality. For this reason, I would beware of
any choice of new technology, such as a switching amp, that you cannot
audition with the speakers.

As an aside, I know someone who is completey satisfied with a Hafler XL-280
running VR-7's. I am surprised bass control is satisfactory, but this person
assures me it is. This amp is also available very reasonably on eBay.


wrote in message
...
Howdy,

Well, after a 10 year absence from this hobby, I was thrust back in
yesterday when my beloved Sumo Andromeda III blew the left channel
rail fuses, and subsequent replacments blew as well. I've been told
that fixing it will be tough, particuarly finding replacment parts.
As such, I think it's time to begin looking for a new amplifier.

Being away for a while, I'm not up on new technologies, but I see that
the Krell's of the world are still peddling $10K amplifiers. Way out
of my price range unfortunately. I'm hoping that those of you who
have remained engaged in the hobby might help me narrow my research.
With that said, I'll let the questions fly!!! 8)

1. What's this new technology called ICEpower that is evidently being
embraced by Rowland, eAR, B&O and others? I remember connecting a
500/wpc Carver amp to some Martin Logan's, and the load choked the
amp. Is this new digital technology capable of driving complex loads?
How can such a small, mid-priced amplifier deliver 1000/wpc with
little heat? Is this for real?

2. What's the deal with "commercial" amplifiers, like those from
Crown? I owned some Crown equipment many moons ago, and at the time,
it was considered "high-end." How does something like this differ
from a Krell or Levinson? There's only a handful of ways to skin a
can so-to-speak, so from a technological perspective, are the designs
similar? What do you get from a Krell besides the exotic exterior?

3. Sumo offered the magic blend of "high-end" for the average Joe;
power, sonic performance and value. Is anyone doing this today, or
has the high-end gone completely high-end?

4. Recommendations for an amplifier in the 200/wpc+ range would be
appreciated.

This will be powering Von Schweikert VR-4's (the original) in a very
large room. I need something to control the low-end of the VR-4's to
make sure everything is tight, and I do want something neutral that
has sufficient current to deliver good power.

Thanks in advance!!!

On Mon, 16 May 2005 12:16:24 -0400, "Robert Morein"
wrote:

Coincidentally, there is a general discussion about amplifiers under "Any
Opinions on an Adcom".

I don't have direct experience with the the original VR-4, but I have helped
a friend of mine select an amp for the current VR-4. Unfortunately, many
"bright" amplifiers synergize poorly with these speakers, while "smooth"
amplifiers provide inadequate definition.

Thanks for the observation.......

I'm not sure the Andromeda brought out the best in the VR-4's, but I
think it was close. I've had a devil of a time with bass control, and
the system never had the impact in the low mid's that I crave. I
really like the punch factor and dynamics, as I believe it brings more
realism to the music. For some reason, the Andromeda lacked in this
department. Interestingly, you'd think if all amps aspired towards
accuracy, they'd all sound identical!!

If tight woofer control is a priority, this mandates either a large bipolar
amp, or a Hafler Transnova MOSFET design. However, such a choice may result
in concommitant nastiness in the lower treble. MOSFET designs work well in
this range. You might consider biamping -- use of a commercial bipolar amp
on the bottom, and a MOSFET choice up top. Hafler P-series amps are cheap
and extremely good. You could start with one full range. If you find the
combination has low treble harshness, you could add a conventional MOSFET
amp in a biamp configuration.

I see that Hafler makes professional amps with the Transnova
circuitry, such as the 2600 and 2300. Should these be considered? I
was told that MOSFET amps are difficult to get repaired, particularly
when it comes to component availability, so is this a concern with the
Hafler products?

The high end of sound reinforcement can be quite rewarding. Beware of the
cheaper stuff. Although I've never heard a modern Crown amp, I would not be
hostile to it. But your speakers are hard to match to.

As for whether a top-notch sound reinforcement amp is the equal of a Krell,
I, too, wonder. The differences are undoubtedly fine. Synergy is probably
more relevant than universal optimality. For this reason, I would beware of
any choice of new technology, such as a switching amp, that you cannot
audition with the speakers.

I see where Jeff Rowland has embraced the digital ICEpower technology,
along with some other notable high-end manufacturers. Furthermore,
I've read some encouraging reviews about the technology. B&O
integrated this technology into their flagship speaker system, and
Rowland has always been technically saavy, so I have to wonder if
future amplifier technology will move towards this digital
architecture.

Thanks very much for the input!!

wrote in message
...
On Mon, 16 May 2005 12:16:24 -0400, "Robert Morein"
wrote:

Coincidentally, there is a general discussion about amplifiers under "Any
Opinions on an Adcom".

I don't have direct experience with the the original VR-4, but I have
helped
a friend of mine select an amp for the current VR-4. Unfortunately, many
"bright" amplifiers synergize poorly with these speakers, while "smooth"
amplifiers provide inadequate definition.

Thanks for the observation.......

I'm not sure the Andromeda brought out the best in the VR-4's, but I
think it was close. I've had a devil of a time with bass control, and
the system never had the impact in the low mid's that I crave.

Then bass control is is great importance to you. You need a big amp on the
bottom.
I
really like the punch factor and dynamics, as I believe it brings more
realism to the music. For some reason, the Andromeda lacked in this
department. Interestingly, you'd think if all amps aspired towards
accuracy, they'd all sound identical!!

I don't recall - is the Andromeda a Class A design?
Another reasonable possibility are the large Parasound amps, the HCA2200mkII
in particular.

If tight woofer control is a priority, this mandates either a large
bipolar
amp, or a Hafler Transnova MOSFET design. However, such a choice may
result
in concommitant nastiness in the lower treble. MOSFET designs work well
in
this range. You might consider biamping -- use of a commercial bipolar
amp
on the bottom, and a MOSFET choice up top. Hafler P-series amps are cheap
and extremely good. You could start with one full range. If you find the
combination has low treble harshness, you could add a conventional MOSFET
amp in a biamp configuration.

I see that Hafler makes professional amps with the Transnova
circuitry, such as the 2600 and 2300. Should these be considered?

Yes. The only caveat would be fan noise, which is slight, but meaningful in
some installations. The P3000, P4000, 9300, and 9500/9505 series are
fanless, with external heatsinks.
I
was told that MOSFET amps are difficult to get repaired, particularly
when it comes to component availability, so is this a concern with the
Hafler products?

No. The availability problems concern older MOSFETs, the Hitachi parts that
were originally used. MOSFETs are currently in wide electronics use,
particularly for power switching. Modern parts are plentiful and cheap.
MOSFET amps are rugged. Supposedly, they can be shorted without damage.
However, spontaneous failures of the old Hitachi MOSFETs have been known to
occur.

The high end of sound reinforcement can be quite rewarding. Beware of the
cheaper stuff. Although I've never heard a modern Crown amp, I would not
be
hostile to it. But your speakers are hard to match to.

As for whether a top-notch sound reinforcement amp is the equal of a
Krell,
I, too, wonder. The differences are undoubtedly fine. Synergy is probably
more relevant than universal optimality. For this reason, I would beware
of
any choice of new technology, such as a switching amp, that you cannot
audition with the speakers.

I see where Jeff Rowland has embraced the digital ICEpower technology,
along with some other notable high-end manufacturers. Furthermore,
I've read some encouraging reviews about the technology. B&O
integrated this technology into their flagship speaker system, and
Rowland has always been technically saavy, so I have to wonder if
future amplifier technology will move towards this digital
architecture.

Thanks very much for the input!!

On Mon, 16 May 2005 13:59:21 -0400, "Robert Morein"
wrote:



Then bass control is is great importance to you. You need a big amp on the
bottom.

Indeed........


I don't recall - is the Andromeda a Class A design?

I believe it's Class A/B

Yes. The only caveat would be fan noise, which is slight, but meaningful in
some installations. The P3000, P4000, 9300, and 9500/9505 series are
fanless, with external heatsinks.

Understood, so the technology remains consistent, however the pro amps
have fan cooling rather than heatsinks

No. The availability problems concern older MOSFETs, the Hitachi parts that
were originally used. MOSFETs are currently in wide electronics use,
particularly for power switching. Modern parts are plentiful and cheap.
MOSFET amps are rugged. Supposedly, they can be shorted without damage.
However, spontaneous failures of the old Hitachi MOSFETs have been known to
occur.

Would it be possible to "upgrade" my Andromeda with the current MOSFET
technology, or would everything get thrown out of whack, so-to-speak,
based on the original design parameters?

said:

No. The availability problems concern older MOSFETs, the Hitachi parts that
were originally used. MOSFETs are currently in wide electronics use,
particularly for power switching. Modern parts are plentiful and cheap.
MOSFET amps are rugged. Supposedly, they can be shorted without damage.
However, spontaneous failures of the old Hitachi MOSFETs have been known to
occur.


Hitachi V-MOSFETs are of a different construction than most MOSFETs of
today.
Semelab has some "compatible" types of the same technology in
TOP-housing.


Would it be possible to "upgrade" my Andromeda with the current MOSFET
technology, or would everything get thrown out of whack, so-to-speak,
based on the original design parameters?


If your amp uses K135/J50 types, you could replace them with 2SK1058
and 2SJ162. However, be aware that their heatsinks are smaller, so you
might have to do something about the thermal household of your
amplifier.

In a prototype amp, originally equipped with one pair of K135/J50, I
used two pair of these replacements instead with minor adjustments in
the driver circuit.

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

wrote in message
...
On Mon, 16 May 2005 13:59:21 -0400, "Robert Morein"
wrote:



Then bass control is is great importance to you. You need a big amp on
the
bottom.

Indeed........


I don't recall - is the Andromeda a Class A design?

I believe it's Class A/B

Yes. The only caveat would be fan noise, which is slight, but meaningful
in
some installations. The P3000, P4000, 9300, and 9500/9505 series are
fanless, with external heatsinks.

Understood, so the technology remains consistent, however the pro amps
have fan cooling rather than heatsinks

No. The availability problems concern older MOSFETs, the Hitachi parts
that
were originally used. MOSFETs are currently in wide electronics use,
particularly for power switching. Modern parts are plentiful and cheap.
MOSFET amps are rugged. Supposedly, they can be shorted without damage.
However, spontaneous failures of the old Hitachi MOSFETs have been known
to
occur.

Would it be possible to "upgrade" my Andromeda with the current MOSFET
technology, or would everything get thrown out of whack, so-to-speak,
based on the original design parameters?


The newer MOSFETs have slightly different parameters, including Rdc, which
causes me to question whether any of them can be used as drop-in
replacements. It wouldn't burn up, but it probably wouldn't sound right
either. I assume Sander is looking at the spec sheets, so he may be able to
knowledgeably contradict me.

The other problem is that each set of P's have to be matched with each
other, as with each set of N's, or the load distributes poorly between them.
The old Hitachis were graded into three categories by Hafler; I don't know
whether manufacturing process has rendered this unnecessary with the new
ones.

But as the Andromeda is a "traditional" MOSFET design, you can get improved
bass control with a Transnova, or bipolar amp.

wrote:

Being away for a while, I'm not up on new technologies, but I see that
the Krell's of the world are still peddling $10K amplifiers. Way out
of my price range unfortunately. I'm hoping that those of you who
have remained engaged in the hobby might help me narrow my research.
With that said, I'll let the questions fly!!! 8)

Yeah, they still sell the same overpriced crap. The thing, though,
is that prices have plummeted in the last decade or so for the
normal midrange stuff.

1. What's this new technology called ICEpower that is evidently being
embraced by Rowland, eAR, B&O and others? I remember connecting a
500/wpc Carver amp to some Martin Logan's, and the load choked the
amp. Is this new digital technology capable of driving complex loads?
How can such a small, mid-priced amplifier deliver 1000/wpc with
little heat? Is this for real?

Gimmick. There is no substitute for mass. What are your
speakers, btw?

3. Sumo offered the magic blend of "high-end" for the average Joe;
power, sonic performance and value. Is anyone doing this today, or
has the high-end gone completely high-end?

My recommendation based upon this would be something from Bryston.
Used is better yet, as their twenty year warranty is fully
transferrable. It's a mix of high-end engineering while
keeping to the basics. Or you could always get a used McIntosh
power amp. Nothing wrong with that, though they are a bit
overpriced, IMO.

This will be powering Von Schweikert VR-4's (the original) in a very
large room. I need something to control the low-end of the VR-4's to
make sure everything is tight, and I do want something neutral that
has sufficient current to deliver good power.

Yeesh. Nasty to drive, IIRC. The solution is basically a
really big power supply. I'd recommend a couple of 500-1000W
monoblocks as a start.

wrote in message
...
Howdy,

Well, after a 10 year absence from this hobby, I was thrust back in
yesterday when my beloved Sumo Andromeda III blew the left channel
rail fuses, and subsequent replacments blew as well. I've been told
that fixing it will be tough, particuarly finding replacment parts.
As such, I think it's time to begin looking for a new amplifier.

You've probably done this already, but have you checked that there's no
short-circuit from the speaker output? (With the amplifier switched off,
check the resistance across the amplifier's speaker outputs for the failed
channel.)

If the resistance is low, the output transistors will deliver full power,
draining the smoothing capacitors and blowing the supply rail fuses.

Tim

On Wed, 18 May 2005 00:30:59 GMT, "Tim Martin"
wrote:


wrote in message
.. .
Howdy,

Well, after a 10 year absence from this hobby, I was thrust back in
yesterday when my beloved Sumo Andromeda III blew the left channel
rail fuses, and subsequent replacments blew as well. I've been told
that fixing it will be tough, particuarly finding replacment parts.
As such, I think it's time to begin looking for a new amplifier.

You've probably done this already, but have you checked that there's no
short-circuit from the speaker output? (With the amplifier switched off,
check the resistance across the amplifier's speaker outputs for the failed
channel.)

If the resistance is low, the output transistors will deliver full power,
draining the smoothing capacitors and blowing the supply rail fuses.

I did check the connections carefully, but interestingly enough, this
occured after I moved the amp, and also changed the wiring
configuration on the speakers...I lightly tightened the binding post
connections with a wrench, so I wonder if they could have twisted
internally...I'll remove the binding posts and look.....

The amp will blow the fuses now whether there's any connections to it
or not, so I wonder if permanent damage was done.....

In article ,
says...
Howdy,
Well, after a 10 year absence from this hobby, I was thrust back in
yesterday when my beloved Sumo Andromeda III blew the left channel
rail fuses, and subsequent replacments blew as well. I've been told
that fixing it will be tough, particuarly finding replacment parts.
As such, I think it's time to begin looking for a new amplifier.

Being away for a while, I'm not up on new technologies, but I see that
the Krell's of the world are still peddling $10K amplifiers. Way out
of my price range unfortunately. I'm hoping that those of you who
have remained engaged in the hobby might help me narrow my research.
With that said, I'll let the questions fly!!! 8)

1. What's this new technology called ICEpower that is evidently being
embraced by Rowland, eAR, B&O and others? I remember connecting a
500/wpc Carver amp to some Martin Logan's, and the load choked the
amp. Is this new digital technology capable of driving complex loads?
How can such a small, mid-priced amplifier deliver 1000/wpc with
little heat? Is this for real?

Methinks something was wrong with your Carver amp. I have a Carver 250w/ch
amp that comfortable drove my Apogee Calipers ( not signature) as well as
my Martin Logans. I was not baby the amp either. I turned it up as load
as the speakers could comfortably handle.

2. What's the deal with "commercial" amplifiers, like those from
Crown? I owned some Crown equipment many moons ago, and at the time,
it was considered "high-end." How does something like this differ
from a Krell or Levinson? There's only a handful of ways to skin a
can so-to-speak, so from a technological perspective, are the designs
similar? What do you get from a Krell besides the exotic exterior?

Some commercial amps use fans, which some folks find noisy.

------------
Alex

"Alex Rodriguez" wrote in message
...
In article ,
says...
Howdy,
Well, after a 10 year absence from this hobby, I was thrust back in
yesterday when my beloved Sumo Andromeda III blew the left channel
rail fuses, and subsequent replacments blew as well. I've been told
that fixing it will be tough, particuarly finding replacment parts.
As such, I think it's time to begin looking for a new amplifier.

Being away for a while, I'm not up on new technologies, but I see that
the Krell's of the world are still peddling $10K amplifiers. Way out
of my price range unfortunately. I'm hoping that those of you who
have remained engaged in the hobby might help me narrow my research.
With that said, I'll let the questions fly!!! 8)

1. What's this new technology called ICEpower that is evidently being
embraced by Rowland, eAR, B&O and others? I remember connecting a
500/wpc Carver amp to some Martin Logan's, and the load choked the
amp. Is this new digital technology capable of driving complex loads?
How can such a small, mid-priced amplifier deliver 1000/wpc with
little heat? Is this for real?

Methinks something was wrong with your Carver amp. I have a Carver
250w/ch
amp that comfortable drove my Apogee Calipers ( not signature) as well as
my Martin Logans. I was not baby the amp either. I turned it up as load
as the speakers could comfortably handle.

2. What's the deal with "commercial" amplifiers, like those from
Crown? I owned some Crown equipment many moons ago, and at the time,
it was considered "high-end." How does something like this differ
from a Krell or Levinson? There's only a handful of ways to skin a
can so-to-speak, so from a technological perspective, are the designs
similar? What do you get from a Krell besides the exotic exterior?

Some commercial amps use fans, which some folks find noisy.

It's true. Personally, I am extremely intolerant of fan noise.
However, a fan can provide flexibility in placing the amp "elsewhere". A
fanned amp can be shoved in the bottom of an equipment stack hidden in a
closet, without the danger of overheating that plagues passively cooled
equipment.

wrote in message
...

2. What's the deal with "commercial" amplifiers, like
those from
Crown?

Modern Crown equipment is just fine - what you may call
"commercial" amps are more commonly known as pro audio amps.
I know of a number of audiophiles with Crown amps in
large-scale systems. Also, some audiophiles myself included
use QSC amps. The big gotcha with pro audio power amps
involve the ones with forced-air cooling, the dreaded
cooling fans.

I owned some Crown equipment many moons ago, and at the
time,
it was considered "high-end." How does something like
this differ
from a Krell or Levinson?

Lots more bang for the buck.

There's only a handful of ways to skin a
can so-to-speak, so from a technological perspective, are
the designs
similar? What do you get from a Krell besides the exotic
exterior?

Bragging rights.

"Arny Krueger" wrote in message
...

wrote in message
...

2. What's the deal with "commercial" amplifiers, like
those from
Crown?

Modern Crown equipment is just fine - what you may call
"commercial" amps are more commonly known as pro audio amps.
I know of a number of audiophiles with Crown amps in
large-scale systems. Also, some audiophiles myself included
use QSC amps.

QSC is terrible: objective proof that Arny Krueger has impaired hearing.

On Wed, 18 May 2005 22:51:12 -0400, "Arny Krueger"
wrote:


Modern Crown equipment is just fine - what you may call
"commercial" amps are more commonly known as pro audio amps.
I know of a number of audiophiles with Crown amps in
large-scale systems. Also, some audiophiles myself included
use QSC amps. The big gotcha with pro audio power amps
involve the ones with forced-air cooling, the dreaded
cooling fans.

What about the class of operation? I understand the Crown amp runs in
A/B+B, so does this impact the sound quality, or the amps ability to
handle complex loads?

wrote in message
...
On Wed, 18 May 2005 22:51:12 -0400, "Arny Krueger"
wrote:


Modern Crown equipment is just fine - what you may call
"commercial" amps are more commonly known as pro audio amps.
I know of a number of audiophiles with Crown amps in
large-scale systems. Also, some audiophiles myself included
use QSC amps. The big gotcha with pro audio power amps
involve the ones with forced-air cooling, the dreaded
cooling fans.

What about the class of operation? I understand the Crown amp runs in
A/B+B, so does this impact the sound quality, or the amps ability to
handle complex loads?

These amps have no problem with difficult loads.
However, sound quality may or may not be to your preference. Some people,
myself included, find this class of amplification to be characterized by
"grainy" sound.

wrote in message
...
On Wed, 18 May 2005 22:51:12 -0400, "Arny Krueger"

wrote:


Modern Crown equipment is just fine - what you may call
"commercial" amps are more commonly known as pro audio
amps.
I know of a number of audiophiles with Crown amps in
large-scale systems. Also, some audiophiles myself
included
use QSC amps. The big gotcha with pro audio power amps
involve the ones with forced-air cooling, the dreaded
cooling fans.

What about the class of operation? I understand the Crown
amp runs in
A/B+B, so does this impact the sound quality,

Nothing wrong with class AB operation.

Here's a demo of the sound quality of a Crown amp:

http://www.pcabx.com/product/macrot-5000VZ/index.htm

Can you hear any degradation when you compare music, before
and after passing through this amp?

or the amps ability to handle complex loads?

Class A operation actually decreases the reactive load
handling capability of an output device.