Krell KSA Amps and the Apogee Scintilla, which newer Krell models can drive a 1 ohm load?

[Zero000]

Al max volume for my 4Ohm Duettas occurs around 450-500 Watts. Not that it gives much more volume than 300 Watts but it DOES give noticeably more.

Just saying.

Get some Scinnies and see

 

[darkmatter]

Im looking for an FPB600 CX to play around with so can add more to the convo then ..

Though I do not yet have a pair of Scintillas, I am considering looking for a pair at some point.
I alas sold a possible partner for them in my 700cx, sold to finance my next big loudspeaker build.
I may look for a pair of 750mcx or the later 900 Evo mono amps so am researching suitability.
I happen to like the Krell sound hence my focus on them at the current time.

 

[darkmatter]

Apogee Scintilla - List of Krell Amplifiers that can drive them


Krell KSA50 (Just)
KSA100,
KMA100,
KMA200,
KRS-100
KRS-200
Krell KSA 80 (Just with protection setting adjustment)
KMA 160,
KSA200,
KMA 400
KSA150,
KSA250,
MDA 300,
MDS 500
Krell Audio Standard (KAS)
Possible KSA100s
Possible KSA200s
KSA300s


FPBs possibly?

Evolution series a Possibly?


I am going to investigate the suitability of the following to drive a 1 ohm load

Krell FPB 750mcx and Krell Evolution 900

For my 700cx replacement, I may be considering

Krell KRS-200 too old? serviceable?
Krell KMA400 these run very hot so I question longevity and serviceability
Krell MDA500 again these run hot and question longevity and serviceability

I am most likely to consider the last two amplifiers mentioned above and below, as they are the most recent, and probably superior in audio performance.

Consideration will also be given to them provided they can drive the 1 ohm load of the Apogee Scintilla.

I have specified this parameter, just in case I decide to scratch the itch I have had since the late 1980s (teenage!!) to try out a pair of these loudspeakers in my main system.

Krell FPB750mcx or Krell Evolution 900

Simon

 

[magichifi]

Hi every one I have a been using Scintillas for quite a long time now, the first ones I had I used a Krell KSA250 I bought these from the original owner who had owned them from the early 90's he had new ribbons in the Scintillas and the Krell recapped they sounded great, the Krell could power them to very high levels with ease. I now have a pair of fully refurbished/ modified Scintillas running them with a Gryphon Mephisto stereo power amp, this does get hot but even when listening for a good few hours at silly volume levels the Gryphon just plays with speakers it really is a great combination.

 

[LL21]

Hi every one I have a been using Scintillas for quite a long time now, the first ones I had I used a Krell KSA250 I bought these from the original owner who had owned them from the early 90's he had new ribbons in the Scintillas and the Krell recapped they sounded great, the Krell could power them to very high levels with ease. I now have a pair of fully refurbished/ modified Scintillas running them with a Gryphon Mephisto stereo power amp, this does get hot but even when listening for a good few hours at silly volume levels the Gryphon just plays with speakers it really is a great combination.

Fantastic...great amp! I remember the Apogee Stages and still consider hearing them a seminal experience, truly one of the groundbreaking moments for me of all the various auditions I have done over the years.

When did you get your Mephistos and what else did you perhaps hear before selecting them?

 

[magichifi]

Iv'e had the Mephisto around 3 years maybe 4, I had the Gryphon Antillion before that and quite a few Krells before that. I am a big fan of the earlier Krell amps I had two KSA 80 bi amped, a KSA 250 then a pair of FPB 750 mcx and the best pair of all were my Krell KAS 4 box monos, but the Gryphon is just in another league to anything Iv'e had before

 

[LL21]

Good to know! Thanks for that. I have heard Krell Evo 400, 900...FPB 600 or 700 series...Krell Evo Ones. While I never did a shoot-out per se, I can say that your comments about Mephisto concur with my own impressions. At the time I was listening to some of these Krells, I had the much older Antileon (non-Signature, so much much older). And I was already favoring Gryphon even at that time over most of those though perhaps not the Evo Ones which showed a lot of promise.

 

[magichifi]

I think that the Antileon Signature was a fantastic amp the build quality was amazing, even the speaker binding posts had built in washers so not to damage the spade connectors, a feature that the Mephisto does not have and of course it sounded just beautiful

 

[Gregadd]

I recall we use to say ,"Krell can drive a nail." The KSA line was the beginning of the emasculation of Krell. I liked them nonetheless. I recall liking the Scintilla quite well when driven by the Rowland Research Model5,

 

[darkmatter]

Iv'e had the Mephisto around 3 years maybe 4, I had the Gryphon Antillion before that and quite a few Krells before that. I am a big fan of the earlier Krell amps I had two KSA 80 bi amped, a KSA 250 then a pair of FPB 750 mcx and the best pair of all were my Krell KAS 4 box monos, but the Gryphon is just in another league to anything Iv'e had before

Looking at the specs and having heard them a while back maybe I should consider the Mephisto Monoblocs if I won the lotto!!
Anyway back in the real world
So both the 750mcx and KAS 4 box were able to drive the Scintillas 1 ohm load OK, better than the KSA250?

 

[MLAS]

Apogee Scintilla - List of Krell Amplifiers that can drive them


Krell KSA50 (Just)
KSA100,
KMA100,
KMA200,
KRS-100
KRS-200
Krell KSA 80 (Just with protection setting adjustment)
KMA 160,
KSA200,
KMA 400
KSA150,
KSA250,
MDA 300,
MDS 500
Krell Audio Standard (KAS)
Possible KSA100s
Possible KSA200s
KSA300s


FPBs possibly?

Evolution series a Possibly?


I am going to investigate the suitability of the following to drive a 1 ohm load

Krell FPB 750mcx and Krell Evolution 900

For my 700cx replacement, I may be considering

Krell KRS-200 too old? serviceable?
Krell KMA400 these run very hot so I question longevity and serviceability
Krell MDA500 again these run hot and question longevity and serviceability

I am most likely to consider the last two amplifiers mentioned above and below, as they are the most recent, and probably superior in audio performance.

Consideration will also be given to them provided they can drive the 1 ohm load of the Apogee Scintilla.

I have specified this parameter, just in case I decide to scratch the itch I have had since the late 1980s (teenage!!) to try out a pair of these loudspeakers in my main system.

Krell FPB750mcx or Krell Evolution 900

Simon

Hi Simon,

I've had the KSA-100 Mk1 and Mk2 versions, KMA-100 Mk2, KMA-200 Mk2 and now the Krell KRS-100.
I can't say much about the other models you've mentioned but from the KSA-250/150 series onwards none of them are real fixed bias Class A amps. Friends of mine operated KMA-160's and a FPB-600 which became very hot to the touch.
The KSA-80/200 and their mono derivates the KMA-160/400 all had problems with too much heat and too little heatsinks.
My Krell KRS-100's use much bigger heatsinks (and six of them per channel instad of three) than the KSA-80/200 for instance and with 600 Watts AC intake they keep relatively "cool" compared to the other two mentioned. The KSA-250 was throttled down with the quiescent current and got even smaller heatsinks that fitted in with the width of the frontplate.
It's my belief that only the Krell KRS series of amplifiers are truly Class A (I measured 180 Watts Class A @ 8 Ohms for my samples) amplifiers that can power those 1 Ohm Apogees like the Fullrange and Scintilla.
The longtime importer of Krell electronics in the Benelux (Belgium, Netherlands and Luxemburg) told me that they had lots of problems with the KSA and KMA from the eighties and early nineties and not with the KRS Series other than replacing old caps (especially the deep red radial Roedersteins and relays). No reliability problems as with the other Krells.
I love them because they sound so wonderful!

 

[darkmatter]

Hi Simon,

I've had the KSA-100 Mk1 and Mk2 versions, KMA-100 Mk2, KMA-200 Mk2 and now the Krell KRS-100.
I can't say much about the other models you've mentioned but from the KSA-250/150 series onwards none of them are real fixed bias Class A amps. Friends of mine operated KMA-160's and a FPB-600 which became very hot to the touch.
The KSA-80/200 and their mono derivates the KMA-160/400 all had problems with too much heat and too little heatsinks.
My Krell KRS-100's use much bigger heatsinks (and six of them per channel instad of three) than the KSA-80/200 for instance and with 600 Watts AC intake they keep relatively "cool" compared to the other two mentioned. The KSA-250 was throttled down with the quiescent current and got even smaller heatsinks that fitted in with the width of the frontplate.
It's my belief that only the Krell KRS series of amplifiers are truly Class A (I measured 180 Watts Class A @ 8 Ohms for my samples) amplifiers that can power those 1 Ohm Apogees like the Fullrange and Scintilla.
The longtime importer of Krell electronics in the Benelux (Belgium, Netherlands and Luxemburg) told me that they had lots of problems with the KSA and KMA from the eighties and early nineties and not with the KRS Series other than replacing old caps (especially the deep red radial Roedersteins and relays). No reliability problems as with the other Krells.
I love them because they sound so wonderful! View attachment 76029

Hi (MLAS)

Thank you for your reply.
I have an old KSA100 fan cooled model which has given me sterling service. One I will be keeping hold of.
I have been looking at the other Krell amps very carefully up to 750mcx and have been conversing with many others regarding them. Answers vary wildly but what I glean from them and what you allude to is the question of heat and heatsink area has to be considered.
My original question related to Apogee Scintilla driving capability of the various Krell models is still pertinent as I have not ruled out owning a pair of these speakers in the future, but the decision to look for such an amplifier is also based upon what my better half would like to listen to as well.
I know you should not buy audio based upon appearance but unbeknownst to me, and before we got together, she did get to hear a pair of KRS-100 or 200s? Some time back and when she saw me researching the KRS-200, she recognised them as similar to what she heard and asked are those the ones the ones you are thinking of looking for?
I got to hear a pair of the KRS-200s at a show and did get an extended listen to them later in the day when the ticketed!! Demonstrations had finished.
She had a real go at me when I sold my FPB700cx to fund other speaker building projects, but when she saw me searching for the KRS-100/200 models she said right I may help you get a pair of those!!.
However they might well in the end be too expensive for us thought even if a pair came up for sale as we will have to factor in the cost of a full re-capping into the equation?
From your experience of the earlier Krell models, I accept that the KMA/MDA 400/500 would likely get too hot which might? Be prejudicial to their long term reliability.

What did you think about my KSA100s bigger brother the fan cooled KMA200 you owned? These might be more affordable?

I am guessing that the KRS-200 is my favourite though and is the amplifier I am really after but do the KRS-100 run cooler?

Thanks,

Simon

 

[MLAS]

Hi Simon,

The KRS-200 & 100 do probably run equally hot but as stated their coolingcapacity is enormous especially compared with the deratives the KSA-80/200 amps that are clearly under dimensioned.
The KRS-100 is the better amp of the two ergonomically (you can just handle them at your own with 59 kilograms) and the chassisintegrity is better due to the shorter depth. As said I measured 180 Watts of pure Class A @ 8 Ohms which is great.
Of course you can run the Apogee The Apogee and Scintilla directly as a Mark Levinson ML-2 and the Classe Audio DR-3's can by the way.
See the as super ML-2's (which I had twice also) they will drive anything and it was the best solidstate I had.
They cost a nickle to run of course....

KMA-200 was the amp the Dutch importer switched on with the end of a broomstick just in case it would explode...
Not kidding that's what he said but I had no problems with my KMA-200 Mk-2's though and liked them too on my Acoustat 2 + 2's.
I would advice you to go for a pair of KRS-100's and a good service adress.

Kind Regards,

Robert

 

[darkmatter]

Hi Simon,

The KRS-200 & 100 do probably run equally hot but as stated their coolingcapacity is enormous especially compared with the deratives the KSA-80/200 amps that are clearly under dimensioned.
The KRS-100 is the better amp of the two ergonomically (you can just handle them at your own with 59 kilograms) and the chassisintegrity is better due to the shorter depth. As said I measured 180 Watts of pure Class A @ 8 Ohms which is great.
Of course you can run the Apogee The Apogee and Scintilla directly as a Mark Levinson ML-2 and the Classe Audio DR-3's can by the way.
See the as super ML-2's (which I had twice also) they will drive anything and it was the best solidstate I had.
They cost a nickle to run of course....

KMA-200 was the amp the Dutch importer switched on with the end of a broomstick just in case it would explode...
Not kidding that's what he said but I had no problems with my KMA-200 Mk-2's though and liked them too on my Acoustat 2 + 2's.
I would advice you to go for a pair of KRS-100's and a good service adress.

Kind Regards,

Robert

Hi Robert,

Thank you for your reply and the information.
Certainly plenty for me to ponder but this confirms what I wanted to do just after selling my FPB700cx. Probably a couple of years off when I will be in a position to be able to start looking for a pair of KRS-200 or 100 amps.
Thanks again
Simon

 

[MLAS]

Hi Robert,

Thank you for your reply and the information.
Certainly plenty for me to ponder but this confirms what I wanted to do just after selling my FPB700cx. Probably a couple of years off when I will be in a position to be able to start looking for a pair of KRS-200 or 100 amps.
Thanks again
Simon

KRS Balanced plus KRS-200 in Madrid: https://comoficho.com/for-sale/krell-krs-balanced-krell-krs-200_25326
Do not know if it is real or what the price is.

 

[christoph]

KRS Balanced plus KRS-200 in Madrid: https://comoficho.com/for-sale/krell-krs-balanced-krell-krs-200_25326
Do not know if it is real or what the price is.

The price is on the right side...
7k Euro

 

[MLAS]

For both the KRS Balanced and the KRS-200's?

 

[darkmatter]

Looks like it, shame these have come up now and not in a couple of years time.
My Wife and I are prioritising a house purchase in the next 2 years or so, after then I can begin my search.

 

[christoph]

Looks like it, shame these have come up now and not in a couple of years time.
My Wife and I are prioritising a house purchase in the next 2 years or so, after then I can begin my search.

You really think 7k will put your house plans in serious distress?
Such a chance might never again pop up
I have no idea if this ad is legit but if you are looking for those amps for such a long time and the price seems very tempting, I would definitely investigate further

 

[MLAS]

You really think 7k will put your house plans in serious distress?
Such a chance might never again pop up
I have no idea if this ad is legit but if you are looking for those amps for such a long time and the price seems very tempting, I would definitely investigate further

Hi Simon,

I think Christoph is right. This combination is unique, the KRS-1 true balanced version with stereo Spectrol Model 100 (the best sounding it seems) per channel so the signal trough the potmeters stays balanced.
7k for the whole lot is a bargain. I would ask at least 10k for this Reference set.