Krell KSL Pre Amp / Phono Board Recap

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  • SCompRacer
    SCompRacer Posts: 8,352
    edited January 2016
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    Greetings and welcome to the forum!

    I got the parts from a friend and Digikey.

    http://www.digikey.com/suppliers/us/united-chemi-con.page?lang=en

    Hope you have a desolder gun. Makes it much easier to remove caps, less chance of messing up the fiberglass circuit board. The vias pull out easily if forced. For folks who never heard the term, vias are the through hole rivet like things in the board.

    91_Figure1.png

    Here is the photobucket link for pics.

    http://s417.photobucket.com/user/scompracer/library/Krell KSL?sort=3&page=1

    attachment2.jpg

    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • agfrost
    agfrost Posts: 2,421
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    That's a nice looking preamp! :wink:
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Oppo BDP-93 * Modded Adcom GDA-600 DAC * Rythmik F8 (x2)
    Micro Seiki DQ-50 * Hagerman Cornet 2 Phono * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
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  • SCompRacer
    SCompRacer Posts: 8,352
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    You're just sayin that cause you're invested... B)
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • soundfreak1
    soundfreak1 Posts: 3,387
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    I can't speak to the Krell brand on the pre but can on "Class A pre's" I picked up a Perreaux "class A " and was blown away with the difference. Would love to listen to a Krell pre on my Krell amp. But will testify to class A pre's sounding so much better. Very nice job BTW.
    Main Rig:
    Krell KAV 250a biamped to mid/highs
    Parasound HCA1500A biamped to lows
    Nakamichi EC100 Active xover
    MIT exp 1 ic's
    Perreaux SA33 class A preamp
    AQ kingcobra ic's
    OPPO 83 CDP
    Lehmann audio black cube SE phono pre, Audioquest phono wire (ITA1/1)
    Denon DP-1200 TT. AToc9ML MC cart.
    Monster HTS 3600 power conditioner
    ADS L1590/2 Biamped
    MIT exps2 speaker cable
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  • SCompRacer
    SCompRacer Posts: 8,352
    edited January 2016
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    Thanks for the kind words! Fresh caps lets the old gear live a lot longer.
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • agfrost
    agfrost Posts: 2,421
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    Listening to Three of a Perfect Pair vinyl through it at this very moment.

    It's goooooood.
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Oppo BDP-93 * Modded Adcom GDA-600 DAC * Rythmik F8 (x2)
    Micro Seiki DQ-50 * Hagerman Cornet 2 Phono * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
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  • SCompRacer
    SCompRacer Posts: 8,352
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    Wish I was there...how about....although MC5's Rob Tyner said it first, but the KLF used it with great enthusiasm!

    And right now... right now... right now it's time to... kick out the jams, moth#f%&%!!!


    klfcollage.jpg
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • soundfreak1
    soundfreak1 Posts: 3,387
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    Did you also do the power supply upgrades????
    Main Rig:
    Krell KAV 250a biamped to mid/highs
    Parasound HCA1500A biamped to lows
    Nakamichi EC100 Active xover
    MIT exp 1 ic's
    Perreaux SA33 class A preamp
    AQ kingcobra ic's
    OPPO 83 CDP
    Lehmann audio black cube SE phono pre, Audioquest phono wire (ITA1/1)
    Denon DP-1200 TT. AToc9ML MC cart.
    Monster HTS 3600 power conditioner
    ADS L1590/2 Biamped
    MIT exps2 speaker cable
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  • SCompRacer
    SCompRacer Posts: 8,352
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    Steven, an ex Krell service dept manager who started his own biz had made me aware of updates but I did not do any. Jay could look into that though. ;)

    http://www.theservicedepartmentct.com/
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • agfrost
    agfrost Posts: 2,421
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    Well now you're just messing with me, Rich.

    Does he have a power supply redesign, or ??

    I'm not unhappy with its current performance. :smile:
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Oppo BDP-93 * Modded Adcom GDA-600 DAC * Rythmik F8 (x2)
    Micro Seiki DQ-50 * Hagerman Cornet 2 Phono * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
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  • SCompRacer
    SCompRacer Posts: 8,352
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    agfrost wrote: »
    Well now you're just messing with me, Rich.

    Does he have a power supply redesign, or ??

    I'm not unhappy with its current performance. :smile:

    It's true, there are improvements although what fun is life without messing with your friends? ;) Details were not given, it was a send and pay to get the updates. He had some for the KRC-HR too.
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • soundfreak1
    soundfreak1 Posts: 3,387
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    Can one of those power supplys be built???
    Main Rig:
    Krell KAV 250a biamped to mid/highs
    Parasound HCA1500A biamped to lows
    Nakamichi EC100 Active xover
    MIT exp 1 ic's
    Perreaux SA33 class A preamp
    AQ kingcobra ic's
    OPPO 83 CDP
    Lehmann audio black cube SE phono pre, Audioquest phono wire (ITA1/1)
    Denon DP-1200 TT. AToc9ML MC cart.
    Monster HTS 3600 power conditioner
    ADS L1590/2 Biamped
    MIT exps2 speaker cable
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  • agfrost
    agfrost Posts: 2,421
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    Not 100 % understanding your question, soundfreak. The power supply is part of the chassis; it's a one-box unit. Rich updated the capacitors in the original power supply. I'm sure that the Krell guy's upgrade is proprietary.
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Oppo BDP-93 * Modded Adcom GDA-600 DAC * Rythmik F8 (x2)
    Micro Seiki DQ-50 * Hagerman Cornet 2 Phono * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
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  • SCompRacer
    SCompRacer Posts: 8,352
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    The Krell KRC-HR I had used an external power supply. Be tough to reverse engineer a four layer circuit board without a schematic though. Way, way past my ability.

    krc_hr_pwr_in_hires.jpg

    and they used an external PS for the external KPE phono pre amp...

    178258-krell_kpe_phono_preamp.jpg

    diyaudio store has a power supply kit. One would have to research what voltage/amperage is needed and build to suit.

    http://diyaudiostore.com/collections/frontpage/products/universal-psu

    The thread...

    http://www.diyaudio.com/forums/diyaudio-store/238918-v3-universal-power-supply-circuit-board.html#post3554857
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • soundfreak1
    soundfreak1 Posts: 3,387
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    Yes I had read about recapping the power supply, it's quite sophisticated piwer supply from what I've read.
    Main Rig:
    Krell KAV 250a biamped to mid/highs
    Parasound HCA1500A biamped to lows
    Nakamichi EC100 Active xover
    MIT exp 1 ic's
    Perreaux SA33 class A preamp
    AQ kingcobra ic's
    OPPO 83 CDP
    Lehmann audio black cube SE phono pre, Audioquest phono wire (ITA1/1)
    Denon DP-1200 TT. AToc9ML MC cart.
    Monster HTS 3600 power conditioner
    ADS L1590/2 Biamped
    MIT exps2 speaker cable
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  • husafreak
    husafreak Posts: 2
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    Well this is all very interesting. I have a KSL Preamp/phono board and KST amplifier. Twenty Five years young! I wondered if these components age and seeing this discussion I see they do. I do not have any problems with this equipment but I would like to know that it is operating at its peak. I am handy with soldering and circuit boards. But not electronics cicuit board design. Is it as simple as desoldering the caps and matching part specs? Is it just the caps that deteriorate? I do not know how to adjust the bias on my phono stage. Any advice would be appreciated.
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  • agfrost
    agfrost Posts: 2,421
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    Hi husafreak,

    I'm not the technical expert here, I just just enjoy the fruits of SCompRacer's labors. He hasn't been around too much of late, but I'm sure he'll be by soonish to chat with you a bit.

    Welcome to Club Polk. Feel free to stick around and join in the conversations, it's a nice place to hang.

    Jay
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Oppo BDP-93 * Modded Adcom GDA-600 DAC * Rythmik F8 (x2)
    Micro Seiki DQ-50 * Hagerman Cornet 2 Phono * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
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  • husafreak
    husafreak Posts: 2
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    Thanks! Of course I may choose to hire out the work if someone wants it. I am still working so it may be more reasonable for me to work a few extra days than spend countless ours trying to puzzle this all out for myself.
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  • MassimoConti
    MassimoConti Posts: 2
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    Hi everybody
    thanks for subscribing to your blog
    I am writing to you about the problem you have had with the KSL.
    I am asking you if you would kindly give me information on how to calibrate the bias to the Phono card.
    Precisely where to place the volmeter or oscilloscope probes, and what are the values.
    I have already replaced all the caps on the mother board, I am waiting for the icaps for the phono board to arrive
    Thanks in advance for helping me.
    Massimo Conti
    P.S I live in Florence, Italy
    Le opinioni sono come le palle ,ognuno ha le sue.
    Clint Eastwood
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  • SCompRacer
    SCompRacer Posts: 8,352
    edited January 2022
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    Greetings Massimo! It has been so long (2013) that I cannot recall where I adjusted anything. I'm also older and am not as smart, if I were ever smart...lol. There was no schematic available for the KSL. I probed many areas and may have given pots a very slight turn to see what happened and took notes, but they are long gone. I must have thrown them out.

    I'm sorry I cannot help. You might try searching/posting at diyaudio. I had received some assistance there with the KSA-250 amp and possibly the KSL.

    https://www.diyaudio.com/community/

    EDIT: After translating, love the Eastwood quote...
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • MassimoConti
    MassimoConti Posts: 2
    edited January 2022
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    SCcomRacer thank you all the same for giving me your time o:)
    Greetings from Florence
    Massimo
    Le opinioni sono come le palle ,ognuno ha le sue.
    Clint Eastwood
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