"Old" KRELL Help

[CDLehner]

Wow; I was kind of surprised...there wasn't a Krell sub-forum, in the Manufacture section. So...I'll post here.

I'm a fan, of class-A; and, of course, I find Mr. Pass' designs to be wholly satisfying. Problem is; they ain't cheap. XA is out of my budget...I need balanced in, so that limits my FW choices (and I'm not so sure, they have quite enough grunt...without pretty efficient speakers. While my PMC Twenty5-23s aren't a difficult load...86.5db, but a pretty stable impedance...I think they need, just slightly more push than say a J2 will give).

Old Krells, have caught my eye recently; a KSA-50S to start. I know nothing, of the old Krells; so I started doing my research. It seems, some hated the KSA-S series; I think mostly because they were KSA owners, trying the new thing...and that adaptive bias circuit, made them psycho-acoustically think, they heard less "slam". Other have said, yes...less slam, but better mids and highs. Some have said, the only KSA-S worth a damn...is the 300; but I just don't need the power, nor the 185 lb. weight.

I thought a 100, might be the sweet spot; but then some have said, the baby 50 is sweeter-sounding.

Then...there are FPBs, lol.

Anyone here, a Krell aficionado; and can give me a proper run-down, on these older units?

[Mike]

Is Krell still in business?


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[Elberoth]

I'm not sure I would get the KSA-50S for anything else than collectible / sentimental value right now. It is true it was the sweetest ounding of the entire KSA-S range. The bigger KSA-S models have always made my ears bleed. To my ears, the FPB series was a clear upgrade over the KSA-S - much more natural sounding.

Both KSA-S and FBP series amps are at least 20 years old now and would probably need an expensive recapping.

BTW - what is your budget ? I think you can get a better amp for similar money.

[Mr Peabody]

The KSA are pretty old, if they haven't already had work, one would be ready for updating. I'm not sure what the pecking order is, most of my friends who had them had the 250's

I'm haven't seen pricing for Coda in sometime, you may want to look at their Class A line. You may even get lucky enough to see one used.

Most of the Pass A/B bias fairly high into Class A. I know a few who like the .5 still due to it being the warmer compared to .8 or original. I've seen some good deals used on the .5 Class A monblocks.

[Elberoth]

KSA is an older series than KSA-S. The later debuted in 1993, FPB in 1997/8.

[AJ Soundfield]

I'm a fan, of class-A; and, of course, I find Mr. Pass' designs to be wholly satisfying. Problem is; they ain't cheap. XA is out of my budget...I need balanced in, so that limits my FW choices (and I'm not so sure, they have quite enough grunt...without pretty efficient speakers. While my PMC Twenty5-23s aren't a difficult load...86.5db, but a pretty stable impedance...I think they need, just slightly more push than say a J2 will give).

I would be hesitant to mix Class A and 20+ years old (unless she's really cute )
Have you considered a non-Krell like a Belles SA-30?
Speaking of J2s, if you like that type of champagne sound/beer budget pricing, check out a relative unknown, Abacus. Very similar to FW, transconductance amps. The 60-120B would drive those PMCs well. Don't let the low prices and anti-bling "staid" looks fool you, they sound very good. I have a custom Ampino for use with HE horns on occasion. Good luck!

cheers,

AJ

[CPP]

Is Krell still in business?


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I saw this dated March 8, 2018

"
So…Is Krell in Bankruptcy? We Ask the Owner


Finally, during the storm, we connected with Krell co-founder and current owner Rondi D’Agostino. We asked D’Agostino, is Krell in bankruptcy or planning to file for bankruptcy?
“No, not at all,” said a surprised D’Agostino. “Whoever your source is, don’t use them anymore. They don’t know what they’re talking about.”
In other words, we pressed D’Agostino, you’re saying everything is fine…correct? “Well, it’s not perfect, but we’re not filing for bankruptcy and we’re not going out of business. It’s business as usual…after the storm is over.”
https://www.strata-gee.com/krell-business/

[Mr Peabody]

What relation is Ron to Dan?

[puroagave]

What relation is Ron to Dan?

Rondi is Dan's ex-wife and former co-owner of Krell.

[a.wayne]

Wow; I was kind of surprised...there wasn't a Krell sub-forum, in the Manufacture section. So...I'll post here.

I'm a fan, of class-A; and, of course, I find Mr. Pass' designs to be wholly satisfying. Problem is; they ain't cheap. XA is out of my budget...I need balanced in, so that limits my FW choices (and I'm not so sure, they have quite enough grunt...without pretty efficient speakers. While my PMC Twenty5-23s aren't a difficult load...86.5db, but a pretty stable impedance...I think they need, just slightly more push than say a J2 will give).

Old Krells, have caught my eye recently; a KSA-50S to start. I know nothing, of the old Krells; so I started doing my research. It seems, some hated the KSA-S series; I think mostly because they were KSA owners, trying the new thing...and that adaptive bias circuit, made them psycho-acoustically think, they heard less "slam". Other have said, yes...less slam, but better mids and highs. Some have said, the only KSA-S worth a damn...is the 300; but I just don't need the power, nor the 185 lb. weight.

I thought a 100, might be the sweet spot; but then some have said, the baby 50 is sweeter-sounding.

Then...there are FPBs, lol.

Anyone here, a Krell aficionado; and can give me a proper run-down, on these older units?

I would recommend the FPB CX series , much better refinement and sound than the KSA plateau bias series ..


Regards

[puroagave]

Wow; I was kind of surprised...there wasn't a Krell sub-forum, in the Manufacture section. So...I'll post here.

I'm a fan, of class-A; and, of course, I find Mr. Pass' designs to be wholly satisfying. Problem is; they ain't cheap. XA is out of my budget...I need balanced in, so that limits my FW choices (and I'm not so sure, they have quite enough grunt...without pretty efficient speakers. While my PMC Twenty5-23s aren't a difficult load...86.5db, but a pretty stable impedance...I think they need, just slightly more push than say a J2 will give).

Old Krells, have caught my eye recently; a KSA-50S to start. I know nothing, of the old Krells; so I started doing my research. It seems, some hated the KSA-S series; I think mostly because they were KSA owners, trying the new thing...and that adaptive bias circuit, made them psycho-acoustically think, they heard less "slam". Other have said, yes...less slam, but better mids and highs. Some have said, the only KSA-S worth a damn...is the 300; but I just don't need the power, nor the 185 lb. weight.

I thought a 100, might be the sweet spot; but then some have said, the baby 50 is sweeter-sounding.

Then...there are FPBs, lol.

Anyone here, a Krell aficionado; and can give me a proper run-down, on these older units?

I say go for it. You'll get a lot of 'opinions' but from who and how far back to they go with Krell? My first 'super amp' was a Krell KSA-50 mkII I bought new in '87. from there it progressed up the line to the fin-cooled era culminating with MDA-500s (ca 1992 or so). if it were me, Id look for a KSA-80b (balanced input) Its a sweet amp id put up against anything made today. I would have kept it but it was shy on power running my then, Apogee Duetta Sigs. The 50S was a nice amp, I never owned one but heard it in dealer demos. I also think it was the first of the plateau biased series of amps (High Bias A/B).

[Anatta]

I'd contact Reno Hi-fi which has some demo and used Pass XA30.8 units and see if you can get a deal.

[AJ Soundfield]

I saw this dated March 8, 2018

It’s business as usual…after the storm is over.”
https://www.strata-gee.com/krell-business/

There was a follow up on Mar 15th referencing servicing etc https://www.strata-gee.com/sharper-f...cture-emerges/

[Mr Peabody]

The articles indicate Keigan was president of Krell up until late 2015, now Rondi is for the last two years and seems she is in control. I wonder if that means the investment company that made the foolish error of ousting Dan is out of the picture?

I wonder if Krell ever received the cash infusion Rondi was talking about in the article. Could be a coincidence, this is the first year I saw Krell at Axpona and I'm almost certain I saw mention of them in Munich.

Either way it's a crowded market and will be an uphill battle for Krell. It would be interesting to know if any original designers/engineers still worked there. I don't know his name, one of the engineers now works at Levinson.

[Elberoth]

The problem #1 for me is the shitty design. Krell products make Emotiva look hi-end.

[Mr Peabody]

Come onAdam, that's a bit extreme. Krell has had some decent products in their history.

The problem #1 for me is the shitty design. Krell products make Emotiva look hi-end.

[a.wayne]

I say go for it. You'll get a lot of 'opinions' but from who and how far back to they go with Krell? My first 'super amp' was a Krell KSA-50 mkII I bought new in '87. from there it progressed up the line to the fin-cooled era culminating with MDA-500s (ca 1992 or so). if it were me, Id look for a KSA-80b (balanced input) Its a sweet amp id put up against anything made today. I would have kept it but it was shy on power running my then, Apogee Duetta Sigs. The 50S was a nice amp, I never owned one but heard it in dealer demos. I also think it was the first of the plateau biased series of amps (High Bias A/B).

Pretty far back , to the early bad ones and then the later good sounding ones. All the early ones had to be modified, good platform and drive but so so sonics. We eventually built our own amps to Drive apps ...

What about Brent offerings from Bully Sound , no takers ....?

[Mike]

Pretty far back , to the early bad ones and then the later good sounding ones. All the early ones had to be modified, good platform and drive but so so sonics. We eventually built our own amps to Drive apps ...

What about Brent offerings from Bully Sound , no takers ....?

Brent passed away.


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[a.wayne]

Yes , sadly aware of that , but i see his amps being sold used from time to time anyone here tried them .. ?

[CDLehner]

I was going to ask, about BSC!

Singer has a 60 up.

[CDLehner]

I say go for it. You'll get a lot of 'opinions' but from who and how far back to they go with Krell? My first 'super amp' was a Krell KSA-50 mkII I bought new in '87. from there it progressed up the line to the fin-cooled era culminating with MDA-500s (ca 1992 or so). if it were me, Id look for a KSA-80b (balanced input) Its a sweet amp id put up against anything made today. I would have kept it but it was shy on power running my then, Apogee Duetta Sigs. The 50S was a nice amp, I never owned one but heard it in dealer demos. I also think it was the first of the plateau biased series of amps (High Bias A/B).

Thanks Rob. I think I may have seen, a KSA-80B. I'll have a Google...and on the KST series too.

But I figured I'd go straight to the horse as well. KST-100?

[puroagave]

Thanks Rob. I think I may have seen, a KSA-80B. I'll have a Google...and on the KST series too.

But I figured I'd go straight to the horse as well. KST-100?

the KST 100 was part of their 'budget' line, built to the same standard but did not operate in Class A up to its rated power. The other amp I liked a lot was the KSA-150 from that era, it was a lower powered version of tke KSA-250/MDA-500 and, IMHO the sonics were a high water mark for Krell.

I heard the D'Agostino momentum monos last week driving the YG Sonjas and wondered out loud how much better these were from Dan's Krells of the early 90s. me thinks not much, if at all.

Didn't you already have a Pass XA30 in the house?? dont take this the wrong way, but you gotta get off the box-swap[ping merry go round

[CDLehner]

the KST 100 was part of their 'budget' line, built to the same standard but did not operate in Class A up to its rated power. The other amp I liked a lot was the KSA-150 from that era, it was a lower powered version of tke KSA-250/MDA-500 and, IMHO the sonics were a high water mark for Krell.

I heard the D'Agostino momentum monos last week driving the YG Sonjas and wondered out loud how much better these were from Dan's Krells of the early 90s. me thinks not much, if at all.

Didn't you already have a Pass XA30 in the house?? dont take this the wrong way, but you gotta get off the box-swap[ping merry go round

I don't take it the wrong way Rob; you're damn right...and I'm trying.

Trying to simplify too. That's why I tried the PSA DsJ; 3 boxes, down to one. Sure...I've been having discussions, over in the PSA forums; about how the DsJ, just isn't going to live up to say, an ARC Ref 3, as pre-amp. But I'm hoping with the right amp; I can live with the results, and have just a 2-box system.

Yes; I had a 30.8, at a once-in-a-lifetime price. I regret letting it go, immensely I'd look, at the XA-25; but I really do think, I need the extra attenuation of Balanced in, with this DsJ.

[CDLehner]

Have you considered a non-Krell like a Belles SA-30?

I always wanted, an SA-30. Looks like David, only makes them...by special order now; and...I really need Balanced in.

[AJ Soundfield]

I always wanted, an SA-30. Looks like David, only makes them...by special order now; and...I really need Balanced in.

Hmmm, if special order only, wonder if he could do a balanced input stage?
Btw, not obvious from the links, but the other First Wattish amp I recommended, the Abacus, does come in balanced https://www.abacus-electronics.de/60-120d-dolifet.html

[Mr Peabody]

Rob, any idea where the KMA came in?

the KST 100 was part of their 'budget' line, built to the same standard but did not operate in Class A up to its rated power. The other amp I liked a lot was the KSA-150 from that era, it was a lower powered version of tke KSA-250/MDA-500 and, IMHO the sonics were a high water mark for Krell.

I heard the D'Agostino momentum monos last week driving the YG Sonjas and wondered out loud how much better these were from Dan's Krells of the early 90s. me thinks not much, if at all.

Didn't you already have a Pass XA30 in the house?? dont take this the wrong way, but you gotta get off the box-swap[ping merry go round

[puroagave]

KMAs were concurrent with the original KSA series. The KMA 100 shared the same chassis with the stereo 50 and the KMA-200 shared the same chassis with stereo 100. Those amps go back to the early '80s up to around '88, this was before Krell abandoned fan-cooled internal heatsinks. If you're looking to acquire one of these hold out for the Mk II vers. they were better built and sound better.

[Anatta]

Looking at the FR and impedance of your PMCs I think they would work better with a tube amp; they are easy to drive with a 5.6 Ohm minimum impedance and have a scooped presence region coupled with an impedance rise; a tube amp will compensate the PMCs scooped FR as its FR will follow more the impedance of the speaker giving you a boost in that region.

It will also compensate that midbass notch.

[a.wayne]

Looking at the FR and impedance of your PMCs I think they would work better with a tube amp; they are easy to drive with a 5.6 Ohm minimum impedance and have a scooped presence region coupled with an impedance rise; a tube amp will compensate the PMCs scooped FR as its FR will follow more the impedance of the speaker giving you a boost in that region.

It will also compensate that midbass notch.

Sounds like an EQ with power .....

[a.wayne]

KMAs were concurrent with the original KSA series. The KMA 100 shared the same chassis with the stereo 50 and the KMA-200 shared the same chassis with stereo 100. Those amps go back to the early '80s up to around '88, this was before Krell abandoned fan-cooled internal heatsinks. If you're looking to acquire one of these hold out for the Mk II vers. they were better built and sound better.

What about KAS, First time i saw one of those was in 94 , his first 4 box attempt ...

[CDLehner]

^^ Yeah; again...I've always had great joy, with my class-A excursions. Cayin A-265ai, FW M2, Pass XA-30.8.

A 'phile friend and I were talking...about how class-A, is hardly the circuit-du-jour. If it hasn't changed...and in fact, may have had its heyday 20 years ago; why not try and get some old muscle, on the cheap.

But...probably too many variables; not understanding the line, and "Vintage" gear period.

The Rogue ST-100, was kinda the end-game anyway; and now...with this graph. How can I not?

[AJ Soundfield]

The Rogue ST-100, was kinda the end-game anyway; and now...with this graph. How can I not?

Anatta is correct that a tube amp might correct the FR because the impedance peaks line up with the FR dips...but there is a caveat, the amp must have high output impedance. This is not true for all tube amps, especially those with some form of feedback.

cheers,

AJ

[CDLehner]

Anatta is correct that a tube amp might correct the FR because the impedance peaks line up with the FR dips...but there is a caveat, the amp must have high output impedance. This is not true for all tube amps, especially those with some form of feedback.

cheers,

AJ

I cannot find, an output impedance...for the Rogue ST-100.

[Anatta]

No tube amp can match the low output impedance of SS amps, even if they use some feedback.

The Rogue ST-100 seems like a fine amplifier and very good value, I'd go with it over other SS options.

[AJ Soundfield]

See below

[AJ Soundfield]

I cannot find, an output impedance...for the Rogue ST-100.

You would have to ask Rogue. Maybe email them?
Unless the output impedance is high, you won't get much, if any, modification of the FR. The FR could end up being the same as with a typical SS (with feedback).
The Atlas output impedance was relatively low and thus had only a very slight mod to the FR https://www.stereophile.com/content/...r-measurements

[octadyndude]

I cannot find, an output impedance...for the Rogue ST-100.

Hey Chris haven't seen you for a while. My kit has changed quite a bit since then

[Jozua]

Hi

If you can find a KSA 50 mk2 or KSA100 mk2, I suggest you buy it !

It will require a pcb (two 1000 uf at 25V caps per pcb) and four PSU cap and most likely new fans.

I have done a full recap on a KSA100 and replaced the cheap internal speaker wire with Van Den Hul The Wind. The results are more than satisfying.

Regards

Jozua

[CDLehner]

You would have to ask Rogue. Maybe email them?
Unless the output impedance is high, you won't get much, if any, modification of the FR. The FR could end up being the same as with a typical SS (with feedback).
The Atlas output impedance was relatively low and thus had only a very slight mod to the FR https://www.stereophile.com/content/...r-measurements

OK; not sure if this makes sense...and certainly doesn't seem "high". But Rogue says the output impedance os the ST-100; is < 1 ohm.

[AJ Soundfield]

OK; not sure if this makes sense...and certainly doesn't seem "high". But Rogue says the output impedance os the ST-100; is < 1 ohm.

Relative to your speakers impedance its low enough, probably similar to Atlas in that there will be only a slight deviation, <1db. You'd be better off with a real EQ .
Of course there are other aspects of tubes like the ST-100 that might have some allure also. These are all very personal preferences. I have speakers with similar sensitivity/impedance and my 35 watt Triode Labs drives them quite loud with good dynamics (the largely benign soft clipping of tubes helps here). They also respond well to 400 rms class D. YMMV.

cheers,

AJ

[CPP]

OK; not sure if this makes sense...and certainly doesn't seem "high". But Rogue says the output impedance os the ST-100; is < 1 ohm.

Not to take this thread any further away from Krell, But I've been looking at the new Quicksilver Integrated. I spoke to Mike at Quicksilver regarding the impedance. The input sensitivity is 500 mv and output impedance is about 0.8 ohms. I've always liked Rogue and Quicksilver products. I still use a Quicksilver LS on another system.

[deangale123]

That made me laugh, but yeah , I don't know either !

Is Krell still in business?


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[a.wayne]

Nothing like a toob amp instead of a Krell huh guys ..