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Thread: Radford Revival "The PreAmp"

  1. #21
    Join Date: Oct 2012

    Location: NE England

    Posts: 4,647
    I'm Jez.

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    One for Will. I was looking at an old Hi Fi Year Book and came across Radford Ista and Ima power amps.... I don't recall ever seeing reference to these ever before. What was the story with these?

  2. #22
    Join Date: Apr 2012

    Location: South West of England

    Posts: 211
    I'm Will.

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    Quote Originally Posted by Arkless Electronics View Post
    One for Will. I was looking at an old Hi Fi Year Book and came across Radford Ista and Ima power amps.... I don't recall ever seeing reference to these ever before. What was the story with these?
    Personally I'm not sure - I've seen them mentioned too but never seen one myself. My father Steve might know. I believe they were a bit similar to the K25 studio amps and I think we even have a PCB for one somewhere.

    There are a few 'ghost' Radford products you see mentioned but appear to have never existed or are just incredibly rare to the point that no one appears to have ever seen one. They may never have made it to production.

    One example, though it exists, is the 'STA60' which is actually just the original name for the STA100. They found they could get 100W out of the thing so decided to name it that at the last minute (This is hearsay so I can't say if this truly happened or not, though the STA60 and STA100 are identical.)

    There is also an STA20 that is mentioned somewhere. Someone emailed me with pictures of what may have been one - if it was real it seems to be a hybrid of an STA15 and 25 as you might expect. Visually it was identical to the STA15 and had a GZ34 socket.

    There is an STA7 of which I've only ever seen one example of, it was on ebay a year or so ago.
    Radford Revival
    www.radfordrevival.co.uk

  3. #23
    Join Date: Jan 2009

    Location: Essex

    Posts: 16,048
    I'm openingabottleofwine.

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    Quote Originally Posted by Arkless Electronics View Post
    One for Will. I was looking at an old Hi Fi Year Book and came across Radford Ista and Ima power amps.... I don't recall ever seeing reference to these ever before. What was the story with these?
    http://theartofsound.net/forum/showt...rd-Electronics

    I believe they were successors to the MA/STA 15 and MA/STA 25 series of the mid '60s and used ideas employed in video circuitry.
    Have you listened to this month's choice in the Album Club?

    Barry

  4. #24
    Join Date: Apr 2012

    Location: South West of England

    Posts: 211
    I'm Will.

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    In that case we definitely don't have a PCB for one!
    Radford Revival
    www.radfordrevival.co.uk

  5. #25
    Join Date: Oct 2012

    Location: NE England

    Posts: 4,647
    I'm Jez.

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    Quote Originally Posted by Radford Revival View Post
    Personally I'm not sure - I've seen them mentioned too but never seen one myself. My father Steve might know. I believe they were a bit similar to the K25 studio amps and I think we even have a PCB for one somewhere.

    There are a few 'ghost' Radford products you see mentioned but appear to have never existed or are just incredibly rare to the point that no one appears to have ever seen one. They may never have made it to production.

    One example, though it exists, is the 'STA60' which is actually just the original name for the STA100. They found they could get 100W out of the thing so decided to name it that at the last minute (This is hearsay so I can't say if this truly happened or not, though the STA60 and STA100 are identical.)

    There is also an STA20 that is mentioned somewhere. Someone emailed me with pictures of what may have been one - if it was real it seems to be a hybrid of an STA15 and 25 as you might expect. Visually it was identical to the STA15 and had a GZ34 socket.

    There is an STA7 of which I've only ever seen one example of, it was on ebay a year or so ago.
    Interesting info Will They were available for purchase according to the 1965 hi fi year book where they are described as "Reference standard power amplifiers". A "Patented feedback circuit" is claimed as is "provides larger power over frequency range 10c/s to 50Kc/s than is normally available from domestic hi fi amplifiers".

    There is an IMA30 monoblock of 30W which uses KT88's, ISTA30 stereo version at 67 10S (STA25 50) and ISTA60 at 85 and which although rated at 60WPC mentions 80W available 1% distortion.

    Interestingly though, there is a Radford ad near the back of the book which mentions only the STA15 and 25....

  6. #26
    Join Date: Apr 2012

    Location: South West of England

    Posts: 211
    I'm Will.

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    I have a feeling Radford had a habit of announcing products before they were ready.
    Radford Revival
    www.radfordrevival.co.uk

  7. #27
    Join Date: Oct 2012

    Location: NE England

    Posts: 4,647
    I'm Jez.

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    Ah I see Barry posted before me with much more info

  8. #28
    Join Date: Apr 2012

    Location: South West of England

    Posts: 211
    I'm Will.

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    Interestingly enough I have been developing my own amplifier circuitry with similar ideas, achieving more feedback than is usually possible. Theoretically a ten-fold decrease in distortion!
    Radford Revival
    www.radfordrevival.co.uk

  9. #29
    Join Date: Mar 2017

    Location: London N2

    Posts: 292
    I'm Edward.

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    So I had a preamp shoot out over the weekend here and at a mate's house.

    Preamps tried included Radford Revival, Musical Fidelity PreAmp II (60s vintage), Tisbury passive, Cambridge Audio 851N and 840E, Electrocompaniet and an Audio Note.

    Speakers included: PMC LB1S, XTZ Divine Alpha and Celestion A3. Amps were a Radford Revival STA25 and a pair of Musical Fidelity A308s.


    Essentially all combinations tried were great with lots of musical emotion.

    Here is a brief summary of the preamps (working from memory - I really ought to take notes).

    Radford Revival - wide open, sweet, engaging, very 'musical'.

    Musical Fidelity PreAmp II - great dynamics, open - but now showing its age (+40 years old) as focus not spot on. A recap may cure things.

    Tisbury Passive - engaging, smooth but soft and lacking in dynamics.

    Cambridge Audio 851N - Fast and engaging but somehow not 'organic'.

    Cambridge Audio 840e - similar to above and very slightly veiled.

    Electrocompaniet - super smooth and musical but somewhat soft.

    Audio Note (kit built about 7 years ago and not used until now) - Similar to the Radford - wide open sweet etc. But bass a bit lacking. Higher grade caps may well cure that.

    Anyway all mentioned fwiw.

    My current setup for next few days is: Radford preamp > Radford Revival STA25 > Celestion A3. (next few days only as the A3s lack WAF and I will need to go back to the PMCs).
    Source: Win10 server, Win10 Mini-ITX Renderer running JRiver
    DAC / Preamp: Perreaux DP32
    Amp: Radford Revival STA25, TubeHunter Class D IRS2092
    Speakers:, Kudos Cardea C2 (ex Westlover), Acoustic Research 8BX (modded)
    Power Conditioner: ISOtek Qube 1kw
    Currently resting: Chevron Paradox NDF16 DAC, Radford Revival Prototype preamp, Paul Baldwin 405C amp, Arcam 290P, Sony TA-VA8ES, PMC LB1 Signature, Micromega MyDac

  10. #30
    Join Date: Apr 2012

    Location: Southall, West London

    Posts: 28,426
    I'm Geoff.

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    Hmm. The Musical fidelity PreAmp II can't be forty years old and from the sixties.

    I had one years ago. It dates from the later seventies or early eighties if I'm correct. Didn't rate it much to be honest, it wasn't a patch on the Rappaport Pre 2 I was mainly using.

    Can't comment on the others, as I've not tried them, but I reckon my TVC would give all a run for their money!
    Mr. Tact!

    Main system: MMs/ADCs/Low output MC's/One rare Japanese SUT/One scarce British phono stage/various tonearms/hefty Japanese DD TT and hefty Japanese BD TT and small British BD TT. 4 CD players/2 jitter buster/2 DACs/Valve buffer. TVC stepped attenuator or valve pre-amp or solid state pre-amp. Current dumping power-amp or either of two Class A SS power-amp or Class A EL34 valve monos or big Japanese (part Class A) integrated. Big dual concentric speakers/Smaller dual concentric speakers/Two way British compacts and full range speakers, amongst others. And too much more to list!

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