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Rebuild of classic Krell KSA50 fan heater

Discussion in 'classic' started by Arkless Electronics, May 5, 2019.

  1. ToTo Man

    ToTo Man the band not the dog

    10 or 15 yrs ago I was close to buying a Crown DC 150A or 300 to partner with my IMF PM mk3's, as forum member DJSR swore by this pairing back in the 70s for really gripping the mk3's underdamped bass driver. He did however caution about pairing it with other loudspeakers that were a bit more lively up top as the Crown's could apparently "strip paint off the walls".
     
  2. Hooch500

    Hooch500 Active Member

    Yep they were not a good match with NS1000 s...
     
  3. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I have a couple of DC300A's and although they do have very impressive grip and slam in the bass the rest is rather more uncouth I think we could say... not to extent of "stripping paint" etc an yes it can be called a hi fi amp but just not a particularly refined one...

    A mate I've not seen in years did use IMF RSPM's driven by a DC300A actually.
     
    ToTo Man likes this.
  4. ToTo Man

    ToTo Man the band not the dog

    That's interesting, the RSPM's are quite a bit more clinical in the upper registers than the PM3's, they're also tauter in the bottom end. Did he use the TILT and SLOPE controls on the crossover to take the sting out of the top end?
     
  5. sq225917

    sq225917 situation engineer

    Which is odd as the yams fall off a cliff after 15k
     
  6. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I really can't remember... I don't recall his system sounding particularly harsh or toppy or anything so maybe... I'm vaguely remembering that he may have had a Klark Teknic pro graphic equaliser in the system actually...
     
  7. ToTo Man

    ToTo Man the band not the dog

    IMO it's generally the 8kHz-16kHz region that's most responsible for giving an etched/steely or fizzy presentation. Anything above 16kHz is mainly 'air' and is seldom objectionable to most ears if it departs (within reason) from linearity.
     
  8. sq225917

    sq225917 situation engineer

    And the yams are ruler flat from 3k to 15k
     
  9. Hooch500

    Hooch500 Active Member

    Nothing to do with it. They are just very transparent to everything upstream. Bot all happening worth mentioning after 15 k anyway..The NS10000 were the same.
     
  10. Barryoke

    Barryoke pfm Member

    Love this thread, and seeing the innards of such a wonderful beast, nice one, Jez. Having read this thread, I mooched the earlier Krells, and the ksa50's and 80's were popular to buy 2 of, and switch them to a mono block form.. wow, how much power does one need? lol. Is that a difficult process to achieve?.. and would it make them less of an animal when reverted back to stereo later in life, if that would be possible, after mono usage?
     
  11. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Easy enough to do but pretty pointless IMO... No need to do anything to it internally.
     
  12. Barryoke

    Barryoke pfm Member

    Ok, that's interesting.. being the luddite that I am, why would that be, Jez, genuinely interested?.. would using one amp per speaker not be of benefit, on a hard to run speaker? I read that the ksa50/80 are better for accepting bridging, but how that is I know not, so would obviously take it with a pinch of salt, until i'd spoken to someone more qualified.
     
  13. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Maybe if you were wanting to drive Apogee Scintillas then paralleling them may be worthwhile (bridging would be the last thing you would want!). The "monoblocks are loads better" thing is largely an old wives tale... but with plenty of if's and but's and exceptions that prove the rule!
     
    Barryoke likes this.
  14. Barryoke

    Barryoke pfm Member

    Yep, I see where you're coming from now. Bridging.. hahaha, see, that's why i'd check with someone that knows better, and as the old saying goes.. don't believe everything you read on the net. ;) .. Cheers, Jez.
     

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