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Thread: Anyone remember JDI pre / monoblocks?

  1. #1
    Join Date: Aug 2008

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    I'm Nat-andthat'swhyIdrink.

    Default Anyone remember JDI pre / monoblocks?

    Anyone remember JDI pre amps and monoblocks?

    They're from around '89 and an English brand, amybe from Cambridge and distributed by Castle Acoustics. Quite expensive gear too.

    Have opportunity to buy the pre and finding it hard to find any info other than a quoted Gramaphone magazine reference (Gramaphone Archive has been taken behind a paywall now... )

  2. #2
    Join Date: Apr 2012

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    One was on eBay last week or the week before. It was quite a high feedback design with fast power supplies which were housed in a separate encloseure. Both pre and power supply were bolted to an integral stand. Alvin Gold, I think, reviewed it for The Audiophile and quite liked it. I have it somewhere, if I can find it.

  3. #3
    Join Date: Jul 2011

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    I'm Dean.

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    Hi,

    I remember these from the late 80s. To my ears, they were a very fine sounding combo. It had good resolution and detail. I remember being very impressed at the time.

    Here is a quote from a query I have seen on Hifi Wigwam from a few years ago.

    JDI amp review from Gramophone (1989)..

    "The Skipton company Castle Acoustics have for some time been liaising with a new British amplifier manufacturer, JDI Amplification, also based in Yorkshire at nearby Ilkley. Castle are now handling all UK and overseas marketing for JDI and at Penta were showing for the first time a two-box preamplifier (signal circuitry in one, power supply in the other) and a monoblock power amplifier. Wide bandwidth, high speed (i.e. transient response) and low noise were the design prerequisites and to this end a novel power supply is used for the preamplifier which has a kind of balanced mode operation which apparently does away with the usual reservoir capacitors and maintains a constant source impedance throughout the audio band. A high accuracy moving-coil only phono stage is fitted which has a claimed dynamic range of 107dB. The power amplifier uses Class A circuits up to the output stage, which then reverts to high accuracy Class AB operation. I was by no means alone in admiring the extremely elegant presentation and cabinet design of these new units. The combination of preamplifier and two mono power amplifiers retails for £3,300."

    Rated output power is 60w RMS into 8 ohm
    Dean

    There are only two types of music. Music I own and music I don't.

  4. #4
    Join Date: Dec 2008

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    Yup i remember them with their shiney facias, looked really nice, my local Hi-Fi dealer at the time had some JDI stuck on a rack for quite some time, this would be the time Castle Acoustics Ltd dealt with Jeklin Float headphones too.. ( i remeber them clearly as it was the same time i bought an old Townshend 600 Pre/Monoblocks from him 2nd hand)..

  5. #5
    Join Date: Aug 2008

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    Quote Originally Posted by Rare Bird View Post
    Yup i remember them with their shiney facias, looked really nice, my local Hi-Fi dealer at the time had some JDI stuck on a rack for quite some time, this would be the time Castle Acoustics Ltd dealt with Jeklin Float headphones too.. ( i remeber them clearly as it was the same time i bought an old Townshend 600 Pre/Monoblocks from him 2nd hand)..
    Oo, fine taste Sir - always fancied trying the Townshend 600 system but feel I've missed my chance as they used to sell for £200 on ebay, an unknown set. Now too many people on there pushing up prices so would expect nearer £500.

    What were they like?

  6. #6
    Join Date: Aug 2008

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    Quote Originally Posted by Mr Kipling View Post
    One was on eBay last week or the week before. It was quite a high feedback design with fast power supplies which were housed in a separate encloseure. Both pre and power supply were bolted to an integral stand. Alvin Gold, I think, reviewed it for The Audiophile and quite liked it. I have it somewhere, if I can find it.
    That's the one - hoping to sort something out off eby as it didn't sell.

    If you could find the Audiophile review I would be very greatful. i've some Audiophiles around so will have a look too. Old magazines are very handy, although always the brief reviews of non-mainstream stuff that are more interesting but you never know what reviews are in them when picking them up secondhand.

    I'm on a bit of a pre-amp trip at the moment, so looking out for rare 80s 90s gear (the era I seem to like - kind of a time for cottage industry high end without all the bling of the '00s)

    Surprised and pleased to get so many responses

  7. #7
    Join Date: Aug 2008

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    Quote Originally Posted by SCIDB View Post
    Hi,

    I remember these from the late 80s. To my ears, they were a very fine sounding combo. It had good resolution and detail. I remember being very impressed at the time.

    Here is a quote from a query I have seen on Hifi Wigwam from a few years ago.

    JDI amp review from Gramophone (1989)..

    "The Skipton company Castle Acoustics have for some time been liaising with a new British amplifier manufacturer, JDI Amplification, also based in Yorkshire at nearby Ilkley. Castle are now handling all UK and overseas marketing for JDI and at Penta were showing for the first time a two-box preamplifier (signal circuitry in one, power supply in the other) and a monoblock power amplifier. Wide bandwidth, high speed (i.e. transient response) and low noise were the design prerequisites and to this end a novel power supply is used for the preamplifier which has a kind of balanced mode operation which apparently does away with the usual reservoir capacitors and maintains a constant source impedance throughout the audio band. A high accuracy moving-coil only phono stage is fitted which has a claimed dynamic range of 107dB. The power amplifier uses Class A circuits up to the output stage, which then reverts to high accuracy Class AB operation. I was by no means alone in admiring the extremely elegant presentation and cabinet design of these new units. The combination of preamplifier and two mono power amplifiers retails for £3,300."

    Rated output power is 60w RMS into 8 ohm
    The guy selling it (the pre) said it replaced and bettered his PT PiP2 which is high praise indeed. In research, I noticed an Audio Note 3 pre for sale with JDI amps so perhaps a way of getting detail and resolution with AudioNote lushness.

    Phono stage with a claimed 107dB dynamic range.. certainly that reads impressively.

  8. #8
    Join Date: Apr 2012

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    I'm Stephen.

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    The review was in the Aug '90 of The Audiophile and was indeed by Alvin Gold. Thought it was two pages but it's just one. It was £2,500 at the time.

    If you want to give an address I'll get it copied on Monday.
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  9. #9
    Join Date: Aug 2008

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    I'm Nat-andthat'swhyIdrink.

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    ooo, thanks Stephen! I tell you what, I'll have a search through my Audiophiles and see if I have it and then PM with my address if not.

    I think I've some from around 92/93 or so though, not 90.

    Interesting magazine Audiophile in that it often has some rarity reviewed that you can't find info on anywhere else. Might have to collect a few more from ebay or whereever.

  10. #10
    Join Date: Apr 2012

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    I did intend to say more but I lost my first reply and was too aggravated as it's been happening a number of times today.

    It has 3 main blocks which are the m.c., R.I.A.A, and line level. The signal circuitry is said to be quite simple with the power supply being complex for providing a suitable environment for the signal side, and this is where the high levels of feedback are employed. A star-earth wasn't used as the designer thought it resulted in unequal path lengths and complexity. There's also no reservoir capacitor on the transformer. A result of the complex power supplies is that it's immune from mains effects. The case was acrylic and frame aluminium.
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