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Thread: modifying and recapping ditton 44's

  1. #21
    Join Date: Oct 2013

    Location: Wrexham

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    I'm Darren.

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    I still think re-spacing the inductors would be worthwhile even if not replacing. How were you thinking of making 72uF from the values HiFi Collective have available?
    Darren.
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  2. #22
    Join Date: Sep 2014

    Location: brighton uk.

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    I'm jamie.

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    to be honest i hadnt gone that far yet,so dont know if i can get the 72 value using mundorf.
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  3. #23
    Join Date: Sep 2014

    Location: brighton uk.

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    I'm jamie.

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    seems using them the closest you can get to 72uf is 71.9 made from a 68uf and a 3.9 i doubt the difference would be audible .
    My System
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    Paradise Phono Stage
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  4. #24
    Join Date: Oct 2013

    Location: Wrexham

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    I'm Darren.

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    Quote Originally Posted by jamie123 View Post
    seems using them the closest you can get to 72uf is 71.9 made from a 68uf and a 3.9 i doubt the difference would be audible .
    That's all I could come up with too, I might give them a try?
    Darren.
    Listening Room.
    UNDER CONSTRUCTION
    Turn Table. Garrard 401, Reso Mat, 2 Tier Slate Plinth, DIY Hadcock GH242, Nick G modded Lentek, Denon DL-103.
    Pre Amp. Croft Super Micro2. Power Amps Quad 405 Mono Blocks.
    Speakers. TBC

    Home Cinema.
    UNDER CONSTRUCTION
    DAC/Pre Amp. Denon AVC X3700H.
    BDP/Streamer. Panasonic DP-UB820EB / Apple TV4K.
    Display. Optoma UHD51 / DIY False Black Window Screen.
    Power Amps. 2 x Nakamichi AVP1.
    Front Speakers. DIY Baby Celestion Ditton 66. Surround Speakers. Celestion Ditton 11. Subwoofer. BK Electronics P12 300SB PR.

    Old Gallery. http://theartofsound.net/forum/showt...-of-the-70%92s

  5. #25
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 6,089
    I'm Alan.

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    The 0.1 difference in value is moot as the tolerance of the larger cap (3%) will give a difference in value of up to 2uF.

    I love Hendrix for so many reasons. He was so much more than just a blues guitarist - he played damn well any kind of guitar he wanted. In fact I'm not sure if he even played the guitar - he played music. - Stevie Ray Vaughan

  6. #26
    Join Date: Oct 2013

    Location: Wrexham

    Posts: 1,058
    I'm Darren.

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    Quote Originally Posted by Firebottle View Post
    The 0.1 difference in value is moot as the tolerance of the larger cap (3%) will give a difference in value of up to 2uF.

    Agreed, however by the same rational a modern single low tolerance 68uF capacitor could be closer to the specified value than the original 72uF Elcap used by Celestion. We have no idea how thorough the manufacturing process was, but judging by the variety of capacitors found in different generation Celestions I'd speculate it wasn't that rigorous and the components were far from hand picked for each pair of speakers. I'm not saying this just to be a dick, but because I'm trying to make improvements to the original construction and (to my ears anyway) have achieved this by improving component quality (e.g. internal wiring) and by following rules Celestion did not adhere to (e.g. inductor placement).

    My concern is not about achieving an absolute 72.00uF but how to do it if not using a single value capacitor. The rules suggest if an absolute value cannot be used the next best option is to use equal values in parallel and I don't know what the rule is if this too is not achievable. Looking at Ken's arrangement for the Mid it would seem he is not concerned about these rules and with all the experimentation he has done with the 66 x-over maybe I'm worrying about nothing, but I do like rules!

    Using a 68uF with a smaller value capacitor has it's appeal. As you said, the 68uF will undoubtedly not be 68uF so with a handful of low value and low cost capacitors 72(.something)uF could be achieved. I still like rules, with limited (and I'm flattering myself here) technical knowledge, it takes the guess work out .
    Darren.
    Listening Room.
    UNDER CONSTRUCTION
    Turn Table. Garrard 401, Reso Mat, 2 Tier Slate Plinth, DIY Hadcock GH242, Nick G modded Lentek, Denon DL-103.
    Pre Amp. Croft Super Micro2. Power Amps Quad 405 Mono Blocks.
    Speakers. TBC

    Home Cinema.
    UNDER CONSTRUCTION
    DAC/Pre Amp. Denon AVC X3700H.
    BDP/Streamer. Panasonic DP-UB820EB / Apple TV4K.
    Display. Optoma UHD51 / DIY False Black Window Screen.
    Power Amps. 2 x Nakamichi AVP1.
    Front Speakers. DIY Baby Celestion Ditton 66. Surround Speakers. Celestion Ditton 11. Subwoofer. BK Electronics P12 300SB PR.

    Old Gallery. http://theartofsound.net/forum/showt...-of-the-70%92s

  7. #27
    Join Date: Sep 2013

    Location: North Island New Zealand

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    I'm Chris.

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    Hi
    Here is a design tip for, that you are unlikely ever to find elsewhere
    think of what a capacitor is - momentarily storing charge and releasing it.

    Inside a speaker crossover the capacitor is either coupling or rolling off frequency
    without seeing the schematic 72uf is more than likely rolling off frequency for the
    bass driver, or more precisely for the benefit of frequency shelving of other drivers.

    Now instead of trying to make a 72uf cap from other values, use 2x 150uf caps in series
    thereby obtaining 75uf or thereabouts given capacitor tolerances usually is 10%
    here is the interesting part, the midway junction of capacitor terminals + - + - make
    this a inductor of suitable power handling, and I would suggest a very small toroid
    winding about 20 turns.

    Let me know how it goes.

    Cheers / Chris

  8. #28
    Join Date: Oct 2013

    Location: Wrexham

    Posts: 1,058
    I'm Darren.

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    Quote Originally Posted by Light Dependant Resistor View Post
    Inside a speaker crossover the capacitor is either coupling or rolling off frequency
    without seeing the schematic 72uf is more than likely rolling off frequency for the
    bass driver, or more precisely for the benefit of frequency shelving of other drivers.
    Hi Chris,

    I think your assumption is correct, C8 & C6 being the capacitors in question:

    ditton44p1.jpg

    Quote Originally Posted by Light Dependant Resistor View Post
    Now instead of trying to make a 72uf cap from other values, use 2x 150uf caps in series
    thereby obtaining 75uf or thereabouts given capacitor tolerances usually is 10%
    Unfortunately the Mundorf E Cap Plain only seem to go up to 100uF.

    Quote Originally Posted by Light Dependant Resistor View Post
    here is the interesting part, the midway junction of capacitor terminals + - + - make
    this a inductor of suitable power handling, and I would suggest a very small toroid
    winding about 20 turns.
    What's the advantage to this?
    Darren.
    Listening Room.
    UNDER CONSTRUCTION
    Turn Table. Garrard 401, Reso Mat, 2 Tier Slate Plinth, DIY Hadcock GH242, Nick G modded Lentek, Denon DL-103.
    Pre Amp. Croft Super Micro2. Power Amps Quad 405 Mono Blocks.
    Speakers. TBC

    Home Cinema.
    UNDER CONSTRUCTION
    DAC/Pre Amp. Denon AVC X3700H.
    BDP/Streamer. Panasonic DP-UB820EB / Apple TV4K.
    Display. Optoma UHD51 / DIY False Black Window Screen.
    Power Amps. 2 x Nakamichi AVP1.
    Front Speakers. DIY Baby Celestion Ditton 66. Surround Speakers. Celestion Ditton 11. Subwoofer. BK Electronics P12 300SB PR.

    Old Gallery. http://theartofsound.net/forum/showt...-of-the-70%92s

  9. #29
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,757
    I'm Chris.

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    Quote Originally Posted by DarrenHW View Post
    Hi Chris,

    What's the advantage to this?
    So C1xC2 / C1+C2 using 150uf caps is 75uf

    Really needs a scope to see change of one circuit
    with an inductor and one without.

    In a DC circuit one would be right in saying there is not much a inductor is doing
    tucked between two capacitors, as the inductor opposes current changing
    and there is in theory no current, as the capacitor blocks DC

    Then again when first starting a capacitor very momentarily appears as a short

    Also very few DC power supply circuits are DC as there is always some 50-60hz
    AC residue from rectifiers, hence a series cap and inductor midway combination has much promise

    But a capacitor in a speaker is handling a music AC signal , so frequency is involved
    Inductors offer low impedance with low frequency and high impedance with high frequency
    the opposite of capacitors - so combining the properties of each has merit. The inductor
    coming to the rescue of the capacitor, and the capacitor assisting the inductor to a degree.

    If I can find some time I will breadboard each and run through a scope with say 100hz
    and see what occurs with waveforms.

    Cheers / Chris

  10. #30
    Join Date: Sep 2014

    Location: brighton uk.

    Posts: 4,737
    I'm jamie.

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    Quote Originally Posted by Light Dependant Resistor View Post
    So C1xC2 / C1+C2 using 150uf caps is 75uf

    Really needs a scope to see change of one circuit
    with an inductor and one without.

    In a DC circuit one would be right in saying there is not much a inductor is doing
    tucked between two capacitors, as the inductor opposes current changing
    and there is in theory no current, as the capacitor blocks DC

    Then again when first starting a capacitor very momentarily appears as a short

    Also very few DC power supply circuits are DC as there is always some 50-60hz
    AC residue from rectifiers, hence a series cap and inductor midway combination has much promise

    But a capacitor in a speaker is handling a music AC signal , so frequency is involved
    Inductors offer low impedance with low frequency and high impedance with high frequency
    the opposite of capacitors - so combining the properties of each has merit. The inductor
    coming to the rescue of the capacitor, and the capacitor assisting the inductor to a degree.

    If I can find some time I will breadboard each and run through a scope with say 100hz
    and see what occurs with waveforms.

    Cheers / Chris
    well that went right over my head ! in laymans terms please for me
    My System
    John Wood KT88 Amp.
    Paradise Phono Stage
    Sony TTS-8000 Turntable.
    PMAT-1010 MK6 Tonearm.
    Ortofon Cadenza Bronze
    Sony X555ES Cd Player
    Yamaha NS1000m Speakers

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