Krell MRA

microstrip

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I was told long ago that Krell used power supply transistors in the output for the bass control, slam and power they are famous for, and these certainly look like TO 220's to me. Power supply transistors in the output section doesn't necessarily imply musicality. True, true and true?

The transistors are metal can TO3 - I drilled many heatsinks for them. ;) They have much better thermal coefficients than any T0220 type of that period. As far as I remember they were custom made to Krell by Motorola - surely optimized for audio purposes.
 

Roysen

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My old system and the same room where Magico Q7 and Dynaudio Arbiter will be playing in about two months time. BTW, I still have the Krell amplifiers. The Audio Physic Cerubin speakers with its outboard active bass crossover/bass amplifier (in the middle of the floor) is now sold. It has a bigger footprint than the Krell MRA.

Roysens_Rede.jpg
 

Elberoth

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Roysen, a bit off topic - how do you liked the Gldmund transport ? Did you have a chance to compare it MBL transport for example ?

I'm asking because of all the controversy surrounding Goldmund transports.
 

Roysen

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Roysen, a bit off topic - how do you liked the Gldmund transport ? Did you have a chance to compare it MBL transport for example ?

I'm asking because of all the controversy surrounding Goldmund transports.

Well, I have not done extensive testing of the transport only in the Goldmund without using its internal DAC. I did some comparisons with it compared to the GNSC statement modified Wadia 270SE into the Wadia Series 9 DAC with the clocklink cable between the Wadia transport and DAC disconnected. During that comparison I slightly preferred the Wadia but not by much.

This Goldmund Eidos Reference is from the first generation made by Goldmund. After this they have released the Goldmund Eidos Reference Blue and the Goldmund Eidos Reference Blue Limited Edition. The differances are quite substantial. The first generation was an all-out assault on designing the best digital music source at that time. It uses a Pioneer transport but this has been heavily modified and the internal DAC is made in-house. It sounds very nice. The later generations are designed more with the video enthusiasts in mind. The Goldmund Eidos Reference Blue is using a Panasonic transport and DAC. The Goldmund Eidos Reference Blue Limited Edition is using an Oppo transport and DAC. The first generation play CD, SACD and DVD-Audio. The Panasonic based model doesn't play SACD and the Oppo based model doesn't play DVD-Audio.

I used my Goldmund as my main source for a couple of years while the Wadia combination was at GNSC for upgrade. I thought it was better than my Zanden 2000P/5000S combination. This was before the Soulution and MBL combinations arrived.

I have the new Goldmund Mimesis 20H DAC arriving soon. I will use it with the transport of the Goldmund Eidos Reference. I can do more comparisons then and let you know.
 
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Roysen

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Wizard,

I am fascinated... how do they sound? Are they fast SS or tube like SS? The largest amps I've had in the system are the big MBLs. And get this! They are coming back for solo review in a couple months. Before I go to that great listening room in the sky I must hear these Krells!!!

The big MBLs sound more tube-like SS than the Krell MRA which has a nice balance between a fast amplifier and great timbre.
 

Jazzhead

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The big MBLs sound more tube-like SS than the Krell MRA which has a nice balance between a fast amplifier and great timbre.

Would you say the MRA is still competitive with the super amps of today, like the Vitus Master Monos , Dart 458 , Boulder 3050 , Gryphon Mephisto Monos to name a few .
 

Roysen

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Would you say the MRA is still competitive with the super amps of today, like the Vitus Master Monos , Dart 458 , Boulder 3050 , Gryphon Mephisto Monos to name a few .

Yes, I definetly would. They all sound different with their own strengths and weaknesses but in the end they all excell in their own way. The Krell MRA has a power like no other amp ever made. This has a special quality of its own. Anyone who has ever upgraded to a more powerful amp will know what I mean.
 
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LL21

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Yes, I definetly would. They all sound different with differances and weaknesses but in the end they all excell in their own way. The Krell MRA has a power like no other amp ever made. This has a special quality of its own. Anyone who has ever upgraded to a more powerful amp will know what I mean.

I can only imagine. Roysen, do u think the extreme power is something one would be able to appreciate with any speaker? Or only moderate to low inefficiency speakers. For example, 95db efficient Wilson X1s or X2s...once we get past 500 watts and enormous current reserves for dynamic transients, etc...do you think the rest of the MRAs incredible power is superfluous...or do u still hear it...ie, even greater sense of ease or ability to deliver orchestra with each instrument remaining with its own musical line and unique dynamics, etc...thanks!
 

Roysen

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Hi Lloyd,

I have used them to drive the midrange and tweeter only of the Audio Physic Cerubin. The Krell MRA proved to be a nice improvement over the Mark Levinson No.33H in terms of control, micro dynamics, focus and soundstaging. The background noise also became lower so soundstaging was improved with a blacker background. The ML amps are also powerhouses, so one would not expect big improvements with a more powerful amplifier on those speakers, but the improvements were not subtle. The X1 likes big, powerful amps, so I think the Krell MRA would be a very nice match. I do however of course don't think the Krell MRA iis a great match with super sensitive horns with 110db sensitivity etc but that also applies to the other super amps mentioned.
 

Jazzhead

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Yes, I definetly would. They all sound different with their own strengths and weaknesses but in the end they all excell in their own way. The Krell MRA has a power like no other amp ever made. This has a special quality of its own. Anyone who has ever upgraded to a more powerful amp will know what I mean.

Roysen ... If I remember correctly the Krell FPB series had a captive power cord , which I thought strange . I see that is not the case with your MRA, what PC's are you using on them . Transparent ? . How about the power lines feeding them , how have you beefed them up .Would be interesting to know . best Jazzhead
 

LL21

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Hi Lloyd,

I have used them to drive the midrange and tweeter only of the Audio Physic Cerubin. The Krell MRA proved to be a nice improvement over the Mark Levinson No.33H in terms of control, micro dynamics, focus and soundstaging. The background noise also became lower so soundstaging was improved with a blacker background. The ML amps are also powerhouses, so one would not expect big improvements with a more powerful amplifier on those speakers, but the improvements were not subtle. The X1 likes big, powerful amps, so I think the Krell MRA would be a very nice match. I do however of course don't think the Krell MRA iis a great match with super sensitive horns with 110db sensitivity etc but that also applies to the other super amps mentioned.

Ahhhh...thank you. Very helpful, as i have heard those ML amps so that helps me 'calibrate' a bit more. I also have heard the same about X1s...that they are happy to play with more (high quality) power and respond well to it. I think having just carried my Gryphon amp (80kg/176lbs) up the stairs with my wife after i needed a repair after accidentally spilling something inside...ooops...i will leave well enough alone with a 300kg/650lb+ (each) pair of monos!!! ;)
 

LL21

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Jazzhead

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I've oft wondered how these sound. A guy in NYC has 6 of them! .

Crickey !!!!!:eek: 6 of them ... that's a nuclear station . Any idea what's the rest of his chain . Most likely Home Theatre , that would be such a waste .
 

Roysen

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Roysen ... If I remember correctly the Krell FPB series had a captive power cord , which I thought strange . I see that is not the case with your MRA, what PC's are you using on them . Transparent ? . How about the power lines feeding them , how have you beefed them up .Would be interesting to know . best Jazzhead

Well, I noticed that the pictures above show a Krell MRA without captive power cords. That is strange becuase the original Krell MRA actually has a captive power cord. The US version has a pair of power cords feeding the power supply in paralell. The European version has only one power cord. My was imported from Japan. They had to go through the local distributor to have some mechanical and software updates to work here. They are now the Euro version with one captive power cord on each amp. Yes, I have beefed up the power lines. They have been connected to a 230V 32A line each with a 20 square mm conductor size in-wall solid core copper cable all the way from the electricity company's transformer down the street to the wall outlets (which are of the round industrial type).
 

Roysen

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Ahhhh...thank you. Very helpful, as i have heard those ML amps so that helps me 'calibrate' a bit more. I also have heard the same about X1s...that they are happy to play with more (high quality) power and respond well to it. I think having just carried my Gryphon amp (80kg/176lbs) up the stairs with my wife after i needed a repair after accidentally spilling something inside...ooops...i will leave well enough alone with a 300kg/650lb+ (each) pair of monos!!! ;)

Yes, anything involving stairs would rule out the Krell MRA.
 

jadis

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'Hijacking' a few pics from a B&W thread, of a pair of MRA of my ex-neighbor (he is more of neighbor now to Jack) who owned them many years ago but now has moved over to Nelson Pass' big amps and Wilson X2s.




I was told it took 4 people (at least) to carry each of these amps.





This is one of the cleanest and punchiest bass producing system I have heard, playing Sheffield Lab's James Newton Howard and Friends, the kick drum and percussion is one of the best I've heard at almost live levels.
 
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