New Monster Audio Research Amplifier

[MylesBAstor]

Guys were you there and doubt what Micro heard? I think we know by now he's pretty meticulous in his set-up and has heard far more equipment than most here in HIS system eg. a known commodity. So rather than casting aspersions, it might be more useful to understand why.

 

[FrantzM]

Guys were you there and doubt what Micro heard? I think we know by now he's pretty meticulous in his set-up and has heard far more equipment than most here in HIS system eg. a known commodity. So rather than casting aspersions, it might be more useful to understand why.

No Apsersion.. His perception could be different from my personal experience... "Preferences" as has become the norm .. I am out of this discussion

 

[MylesBAstor]

No Apsersion.. His perception could be different from my personal experience... "Preferences" as has become the norm .. I am out of this discussion

Frantz:

Preferences are one thing and represents an overall characterization.

Whether or not a soundstage collapses when comparing two amplifiers is a characteristic that we should all be able to agree on.

 

[DonH50]

I have heard the "sound collapse" phenomenon many times over the years when going from tube to SS. There were some good articles about the effect back in the 80's by some top-notch folk; I don't have them now (the articles or the folk ). As best I recall, the main contributors in order were damping factor (tube amps so low that the speakers would ring longer) and distortion (higher amounts of low-order distortion in the tube amps); I think distortion was deemed by far the secondary effect. Damping factor is really too loose a term; it was a function of how the tube amps' impedances interacted with the speakers' impedances over frequency, and perhaps transient response and phase as much as (but not more than) frequency response.

Ultimately, it came down to the big SS amps driving the speakers (B&W 801, Magnepan MG-III and 20, Dahlquist DQ-10, Beveridge, a few others) having measurably lower distortion as measured in the room but the tube sound liked more by some (and less by others). In other words, preference. Which I have no problem with; my D79 did not fare well into most of the speakers, but I loved the sound and it did OK into my Magnepans.

One of many experiments that yielded some interesting results about what we like vs. what measures best, and esxposed me and others to a wider variety of components and insight into how they interacted.

BTW, this was one of the tests that began easing me away from tubes and electrostats; the tube amps sounded awesome in the midrange but did NOT like the low impedance in the HF and I thought the tube amps sounded more harsh in the upper treble. Measurements backed me up, but of course that went against the grain of all the "tubes are smoother" folk.


Edit: I should clarify that some felt the soundstage increased with the SS amps...

 

[mep]

Guys were you there and doubt what Micro heard? I think we know by now he's pretty meticulous in his set-up and has heard far more equipment than most here in HIS system eg. a known commodity. So rather than casting aspersions, it might be more useful to understand why.

Obviously I wasn’t there, but I was just thinking that maybe, just maybe micro was exaggerating just a wee bit when he said the sound “collapsed” when switching from one amp to the other. First of all, you can’t switch between the amps on the fly to get an instant comparison. That means he powered down the ARC, removed the input cables and speaker cables, hooked them up to the Krell, powered the Krell up and listened. Did the Krell even come up to temperature first or was it ‘power on’ and listen? Given that Magico speakers are low efficiency sealed boxes, it stands to reason that good SS designs could stand up to them better and deliver the power and current they need better than a tube amp ever could. No matter how much output power a tube amp has, they are still low current devices comparatively speaking.

So do I believe there was a big difference in how the two amps sounded? Sure I do. I would expect a good SS amp to make the Magico speakers stand up and bark. I wouldn’t expect the soundstage to collapse because the amp is whimpering with the load. It just doesn’t make sense unless the SS amp used always sounds like crap and there is something wrong with the soundstage it throws on every speaker it is used with.

 

[microstrip]

Obviously I wasn’t there, but I was just thinking that maybe, just maybe micro was exaggerating just a wee bit when he said the sound “collapsed” when switching from one amp to the other. First of all, you can’t switch between the amps on the fly to get an instant comparison. That means he powered down the ARC, removed the input cables and speaker cables, hooked them up to the Krell, powered the Krell up and listened. Did the Krell even come up to temperature first or was it ‘power on’ and listen? Given that Magico speakers are low efficiency sealed boxes, it stands to reason that good SS designs could stand up to them better and deliver the power and current they need better than a tube amp ever could. No matter how much output power a tube amp has, they are still low current devices comparatively speaking.

So do I believe there was a big difference in how the two amps sounded? Sure I do. I would expect a good SS amp to make the Magico speakers stand up and bark. I wouldn’t expect the soundstage to collapse because the amp is whimpering with the load. It just doesn’t make sense unless the SS amp used always sounds like crap and there is something wrong with the soundstage it throws on every speaker it is used with.

Mep,

Happily we have a common reference we have both owned and loved. How would you compare in your own words the soundstage and musical performance of your Krell after four hours playing and thirty seconds after being un-played for two days? Please compare using the same negative order I refer - comparing the cold with the sound of hot.

You have a point that I have not described the big room and ancillaries - but the subject of some mini-monitors performing exceptionally with a particular amplifier system has been addressed several times and I do not consider it a novelty. I see why most people only make vague statements in incognito systems in WBF - every time we refer to direct situations and experiences, specially if we touch a preferred brand the post gets scrutinized by the owners.

 

[microstrip]

(...) BTW, this was one of the tests that began easing me away from tubes and electrostats; the tube amps sounded awesome in the midrange but did NOT like the low impedance in the HF and I thought the tube amps sounded more harsh in the upper treble. Measurements backed me up, but of course that went against the grain of all the "tubes are smoother" folk.

Good point. Early SoundLabs sounded great with tubes and OTLs, but as most users used them with solidstate amplifiers, newer versions with better performance had lower impedances in the treble and could not operate properly with these amplifiers that have typically low current - new monsters being an exception.

 

[still-one]

I was at my Dealer yesterday and the 750 was just delivered. I look forward to going back in a week or so and see how it sounds with the XLF's and Aida's.

Jim

 

[Bill Hart]

Isn't what Micro is describing the very nature of tube amp sound- perhaps a little less analytical but big and open sounding? With a tube amp that powerful, there's no issue about driving an inefficient speaker, or bass control, so I'm guessing it's part of the nature of a tube v. solid state 'sound.'

 

[LL21]

I was at my Dealer yesterday and the 750 was just delivered. I look forward to going back in a week or so and see how it sounds with the XLF's and Aida's.

Jim

Definitely post next week!

 

[Roysen]

The finish and buttons looks very familiar (Wadia). BTW, I started a thread on Audiogon about this amplifier when I frist learnede that AR would release it (about 12 months ago), but it was delete (?).

Thanks,
Roysen

 

[A.wayne]

My cj is wired for 4 ohms and drives my MLs just fine

CLS ..?

They are 1.5 in the high frequency , running on the 4 ohm tap may have an interesting result due to the Impedance mismatch , It May just tame that Logan glare most are sensitive to ..

 

[Frank750]

I have owned Krell Audio Standard, Rowland Model 9TiHC, ARC Ref 600, 210 and Ref 610 with KT120s among others. The Ref 610 was the finest sounding amp I had owned. I will argue with anyone about sound quality of ARC amps. Problem is all of my ARC amps were always on a truck to Minnesota for repair. I owned each of the ARC amps above for about 2 years each. The 210s went back 3x in 2 years and that was the fewest of the 3 amps. They were driving Wilson Grand Slamms and Alexandrias. Not exactly a tough load and I don't drive my amps hard at all. Maybe I was just unlucky but there always seemed to be a problem. Never again.

 

[A.wayne]

No, I have never heard the 610T and doubt I ever will. I am dumb enough to think that the Krell KSA-250 is a monster of an amp. Any amp capable of putting out 4000 watts into a .5 ohm load has a major league power supply. There is a reason why the power transformer weighs 83 lbs. I have never heard this amp break a sweat regardless of the volume level. Somehow I can't see the sound "collapsing" if I switched from a monster ARC tube amp to the Krell. But then, I haven't heard a monster ARC amp in my system. I have heard a bunch of the little ARC monsters in my system though. I still have the VS115 sitting in my room, but I haven't been tempted to swap it out for the Krell though.

What speakers are you running the KSA 250 on ..?

 

[A.wayne]

I have owned Krell Audio Standard, Rowland Model 9TiHC, ARC Ref 600, 210 and Ref 610 with KT120s among others. The Ref 610 was the finest sounding amp I had owned. I will argue with anyone about sound quality of ARC amps. Problem is all of my ARC amps were always on a truck to Minnesota for repair. I owned each of the ARC amps above for about 2 years each. The 210s went back 3x in 2 years and that was the fewest of the 3 amps. They were driving Wilson Grand Slamms and Alexandrias. Not exactly a tough load and I don't drive my amps hard at all. Maybe I was just unlucky but there always seemed to be a problem. Never again.

ARC does have an issue , tubes in general do , one of the reason I have stayed away from them ....(tubes)

 

[microstrip]

CLS ..?

They are 1.5 in the high frequency , running on the 4 ohm tap may have an interesting result due to the Impedance mismatch , It May just tame that Logan glare most are sensitive to ..

Happily Myles amps are quite powerful, the speakers are efficient and the power of music is much lower at high frequencies. AFAIK the impedance only becomes so low after 10KHz.

I have owned Martin Logan Prodigy's long ago and do not remember any glare - they sounded pristine with really good treble using an Electrocompaniet AW250. An acquaintance owned them with the Nemo's in a larger room and they were even more impressive. They were critical on cables - the Transparent Reference XL helped them to sound great.

 

[dafos]

I have owned Krell Audio Standard, Rowland Model 9TiHC, ARC Ref 600, 210 and Ref 610 with KT120s among others. The Ref 610 was the finest sounding amp I had owned. I will argue with anyone about sound quality of ARC amps. Problem is all of my ARC amps were always on a truck to Minnesota for repair. I owned each of the ARC amps above for about 2 years each. The 210s went back 3x in 2 years and that was the fewest of the 3 amps. They were driving Wilson Grand Slamms and Alexandrias. Not exactly a tough load and I don't drive my amps hard at all. Maybe I was just unlucky but there always seemed to be a problem. Never again.

ditto. Ref 110 buzzing transformer, blown bias resistors, the latter a very common problem with ARC amps that the the local dealer keeps a handful in stock. REF 5 blown diodes and bypass caps. Ref 150 blown diodes after a month. Ref 250 tube failure taking with it the white Teflon output coupling caps after TWO WEEKS. I'm still using the latter, 8 months with nary a hiccup but barely broken in with just 250 hours. Keeping my fingers crossed but another failure and I'm taking your lead, Frank.

 

[microstrip]

ditto. Ref 110 buzzing transformer, blown bias resistors, the latter a very common problem with ARC amps that the the local dealer keeps a handful in stock. REF 5 blown diodes and bypass caps. Ref 150 blown diodes after a month. Ref 250 tube failure taking with it the white Teflon output coupling caps after TWO WEEKS. I'm still using the latter, 8 months with nary a hiccup but barely broken in with just 250 hours. Keeping my fingers crossed but another failure and I'm taking your lead, Frank.

You were really unlucky. I must knock the wood before writing, but I have more than ten thousands hours of cumulative time in the last few years with ARC equipment (their digital hour counters in the REF3, REF5 and REF40 say so) and only had to replace tubes - most at the end of their life, a very few free of cost in the initial hours because they became noisy. Most of the gear that I dispose of ends in acquaintance systems, and AFAIK the only needed service was replacing a cathode resistor in a REF110, that I did myself in 15 minutes.

Perhaps one important point is that I leave near a power distribution station and the mains in my system is stable +/- 2% every time.

 

[Bill Hart]

It's been a while since I owned ARC stuff, but almost all of it was in the lower powered range 60-70 watt stereo amps, and nary an issue. I still have a Dual 75a that I bought new. Of course, I've had it recapped and retubed over the years, but maybe the issue is higher power and tubes?
I did have something go awry with the Lamm ML2s at one point- my wife, kind soul that she is, dropped them off at Vlad's and a day later, they were ready. Total charge was a few hundred bucks, for some on/off switches, a tube socket and some power tubes.
I have been using tube amps since around 1973.
I thought the Russians continued to use tubes in missile guidance precisely because of their 'low tech' field serviceability.
Not sure all tube based devices are problematic by nature.

 

[jadis]

From what I know, there are already 2 owners in these islands. One of them is a very close friend and I hope to be invited within these few months and not during summer.

Our local dealer is a ardent ARC collector, he has virtually all ARC products that were ever made, even an SP-1 pre-amp which he ultimately sold to another friend of mine.