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Thread: Celestion Ditton 66 recap

  1. #31
    Join Date: Oct 2015

    Location: Woodmancote, West Sussex

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    I'm Ian.

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    That is very true, Samsung TV's packing up because the capacitors in the power supply failing...I know this because I had one and Samsung replaced the board free of charge as it was a known problem.
    I guess it's just one of things we have to live with if we want to keep these lovely old pieces of kit alive.
    Turntable
    Toshiba SR-370/Mission 774/Van Damme cable with MS Starline plugs/Ortofon Quintet Black
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  2. #32
    Join Date: Sep 2014

    Location: brighton uk.

    Posts: 4,737
    I'm jamie.

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    just put the original hf2000's back in and BINGO! we are back to normal!they are noticeably louder
    Last edited by karma67; 31-01-2017 at 19:41.
    My System
    John Wood KT88 Amp.
    Paradise Phono Stage
    Sony TTS-8000 Turntable.
    PMAT-1010 MK6 Tonearm.
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    Yamaha NS1000m Speakers

  3. #33
    Join Date: Sep 2014

    Location: brighton uk.

    Posts: 4,737
    I'm jamie.

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    i must say a big thanks to paul at RFC for the advice,many thanks
    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

  4. #34
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

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    Quote Originally Posted by jamie123 View Post
    just put the original hf2000's back in and BINGO! we are back to normal!they are noticeably louder...
    LOL.....

    See what happens when you think you're 'upgrading' something, and you're not?

    Nice one - glad it worked!

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


    Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!

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  5. #35
    Join Date: Nov 2016

    Location: Gozo, Malta

    Posts: 50
    I'm Rod.

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    I think this definitely means I should keep the original crossovers as untouched and have a good listen first then try to change components in stages.
    Sounds like the bass and mid section benefit most from component upgrade or are you hearing better things now from the top end than before changing to the ansar caps?

    What were the ohm's readings on your 'red labels' and on your existing tweeters again, could this make that much of a difference or could it be a different type of coil design perhaps.....

    Glad things are working out well for you, must be a big relief

  6. #36
    Join Date: Mar 2012

    Location: Gloucestershire

    Posts: 3,377
    I'm Paul.

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    Quote Originally Posted by rodthebod View Post
    I think this definitely means I should keep the original crossovers as untouched and have a good listen first then try to change components in stages.
    Sounds like the bass and mid section benefit most from component upgrade or are you hearing better things now from the top end than before changing to the ansar caps?

    What were the ohm's readings on your 'red labels' and on your existing tweeters again, could this make that much of a difference or could it be a different type of coil design perhaps.....

    Glad things are working out well for you, must be a big relief
    Just as a tip to those reading this:

    You cannot go off DC ohms ratings to determine the suitability of a "like for like" tweeter swap. The impedance with frequency is what matters which will determine the impedance value at crossover, along with the matching acoustic response, both of which will determine the crossover values. The tweeter sensitivity also has to be known. Use the tweeter that came with the speakers unless you know how to re-design the crossover to accommodate a tweeter with different T-S parameters (as this may also necessitate altering the low-pass section of the mid bandpass filter).

    As I mentioned to Jamie yesterday, Celestion had it right as they designed these, so like for like values depending on the earlier or later versions, is the way to go. Tolerance on caps matters far more than brand. If you try brand "A" and decide you prefer brand "B", what is the real reason? Often tolerance can be further out on one than the other, affecting crossover point, phase, and audible SQ. The originals probably were not specified to anything better than 10%. KEF often hand picked their caps in their more complex filters to ensure when new that they were to 1% and more typically, 5% but not all companies, Celestion included, went to these lengths.

    For large values in the LF, make up with 2 or 3 caps (electrolytics to match original ESR) as this will even out any variance in tolerance and get you closer to the values needed, ditto for the high pass part of the mid band pass. For the mid low pass with the tweeter and the tweeter values, you are safe using polys for better sound quality and do not have to bridge or bypass any value under 10uF, just pick a modern 3 or 5% tolerance PP capacitor from whatever brand, and this will get you as close as the factory originals. You do not have to worry as much about ESR with the mid or tweeter for lower cap values as the ESR variance at higher frequencies with low values, is far less than with large values, therefore you wont get any appreciable shift in crossover by doing this.

    The main issue I see with Celestion factory crossovers (board mounted) is the spacing and orientation of inductors. They are too close together and will likely couple.

    Following a re-cap of the boards as described above, re-spacing of the inductors and orienting them more appropriately should improve SQ by reducing the effects of coupling the EM fields on the air cores.

    Hope this helps.

  7. #37
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

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    Quote Originally Posted by Reffc View Post
    The main issue I see with Celestion factory crossovers (board mounted) is the spacing and orientation of inductors. They are too close together and will likely couple.
    Hi Paul,

    Just trying to learn here... In this context, what do you mean by "couple", and why would that be a bad thing? Also, what then, in your view, would be the best way to mount inductors on a crossover board?

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


    Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!

    Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!


  8. #38
    Join Date: Mar 2012

    Location: Gloucestershire

    Posts: 3,377
    I'm Paul.

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    Quote Originally Posted by Marco View Post
    Hi Paul,

    Just trying to learn here... In this context, what do you mean by "couple", and why would that be a bad thing? Also, what then, in your view, would be the best way to mount inductors on a crossover board?

    Marco.

    Hi Marco,

    The thing, especially with air cored inductors, is that when you apply a voltage (signal) through them, they emit an electromagnetic field which can induce a current into nearby wires (or other coils!) causing distortion, and the greater the voltage, and larger the air core (generalisation #1!) the greater the electromagnetic field, as the strength increases This couples (induces current into) with close-by inductors, and apart from cross-talk issues, can lead to inductive leakage, actually altering effective inductance values.

    Anyone who has an inductance meter can try a little experiment. Hold the inductor near to (touching) a metallic surface and take a reading. Now move it away (at least 200mm away) and take a reading. The first reading, I'll bet, is a far bit lower than the second. That is why if you design a crossover on a wooden board then place it in an aluminium orother metal box, chanves are, the crossover points change causing gross distortion. It's a no-no.

    To combat the coupling issues with inductors, there are ways to orient them such that the electromagntic fields don't create as much problems.

    Troels has published some of his experiments and produced a useful little guide which you can read HERE

    The gist of it results in a useful cheat sheet which I have copied and pasted below:



    I have a little experiment which I sometimes demonstrate to customers here, where I use a Tannoy DC drive unit, take a coil of the same type and value as used in their GRF Memory speaker design, whereby the LF coil was placed very close to the back of the drive unit magnet within one of the speakers I worked on.

    I then send a signal generated from the PC consisting of some music and apply that signal voltage through a resistor to provide a load, with the large air coil connected in series and placed close to the back of the drive unit.

    What happens is that the music then clearly emits from the horn! This is a hint that crossovers (inductors) should not be placed so close to drive units!

    Where ferrite, Permite or E&I steel cored inductors are concerned, the spacing can be much closer as they emit a much smaller EM field around them, so a few inches spacing is usually more than adequate for those.

    Hope this explains things more fully.

  9. #39
    Join Date: Nov 2016

    Location: Gozo, Malta

    Posts: 50
    I'm Rod.

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    Thanks for the comments Paul

    I'll try to implement those tips when I eventually recap the 66's by moving the orientation of some of the inductors so they interact better and, of course, when I make up a 'centre speaker' version of a 66 without the ABR. Just a thought, do you think Celestion took the possible interaction into account when they designed the crossover so adjusted the values to suit - after all, the speakers are renowned for their sound and the inductors aren't affected by age.

    Moving the 66 crossover board to the base of the cabinet so it lies flat - would that be a good idea in terms of achieving the greatest distance from the bass driver or is it best to keep it vertical at the base of the cabinet behind the ABR?

  10. #40
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

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    Thanks for the detailed explanation, Paul, and taking the time to post what you did. Much appreciated, and I understand now what you mean. I hadn't considered the electromagnetic field angle

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

    Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.


    Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!

    Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!


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