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Thread: Radford TT100 - the saga begins...?

  1. #61
    Join Date: Mar 2017

    Location: London N2

    Posts: 820
    I'm Edward.

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    Love to see some pictures ....
    Source: Tidal/Roon
    DAC: Metrum HEX NOS

    Amp: Sugden Masterclass 2018 spec, Radford Revival STA25,
    Speakers:, Tannoy Eaton


  2. #62
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 4,227
    I'm Alan.

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    Quote Originally Posted by nickbaba View Post
    So, I finally collected the TT100 from David yesterday, with great excitement. It's now home, hooked up to my Tannoy RFC Cheviots, EAR 834p
    I see you are using an 834P. Now you have a stellar power amp the 834 can be improved quite dramatically as well with some simple mods, see http://theartofsound.net/forum/showt...563#post993563

  3. #63
    Join Date: Mar 2016

    Location: Barnet, london UK

    Posts: 869
    I'm Adam.

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    Quote Originally Posted by nickbaba View Post
    So, I finally collected the TT100 from David yesterday, with great excitement. It's now home, hooked up to my Tannoy RFC Cheviots, EAR 834p and SL-1210.
    I've been waiting to hear this amp since I bought it more than 2 months ago... no idea what to expect, beyond a brief audition at David's with his phone as the source. I was told that Radford's are a great match for Tannoys, but never heard one in action before.

    And what's the verdict? Well, I'm happy to say it sounds phenomenal!
    It is in pretty serious company, as it's on the heels of an EAR 890, my recently sold John Wood KT88 and going head-to-head with my trusty old McIntosh MA7000, but in my opinion the old TT holds its own with ease against those beasts.

    Plenty of headroom with its 100w, and it has that valve-y liquid sound in the mid-range, like pouring velvety paint into my eardrums... vocals sound amazing, real presence and smooth flow in the mids, but lacking nothing in the bottom end. Perhaps not quite as pin-sharp and defined as the solid state MA7000 in the very top and bottom, but more than compensated for by the overall musicality of the sound.

    Still plenty of listening to do, only had a couple of hours with it so far, but it put a big smile on my face for sure. I think its still going to be a while before it comes completely on-song, plenty of new and replaced parts that need to bed-in and get settled, and I think the presentation could get a little 'looser' and more relaxed with time, but even at this point it sounds very very lovely.

    I'd like to thank David for the amazing job he did restoring this amp to its former glory, he went above and beyond the call of duty and really worked some magic on it. He certainly knows his stuff and no mistake, and it was a pleasure to deal with him at every step of the process. He took the amp from being basically a blu-tack'd together 600v deathtrap to a thing of beauty that will give many more years of top quality listening pleasure.
    Very well done! It Takes Nuts to purchase such a poorly conditioned Amp in the first place, no matter it's reputation. David Coe's work, commitment to a project and passion is top notch and I know he wouldn't rest until he'd cracked it and had it seriously singing.
    10/10 all round chaps! Picture please!
    "lack of passion is fatal"
    Gerrard 401, classic hifi hammertone, Russ Collinson plinth / Tenuto Gun Metal Turntable Mat / SME 3012 J7 Rewired / audio-technica ATP-12T - phonomac modified / Ortofon Vintage SPU GE /Shure M3D /DV XX2Mk2 / The Cartridge Man Music Master with isolator / Miyajima Zero B 0.7mil Mono / Vintage GE VRII Mono / WAD 300b Power modded, TJ Mesh Plate Valves / David Coe AD Audio 'Satchmo' Pre & Phono / Hashimoto HM-7 SUT / Tannoy 12" MGs in RFC Custom Rutland Cabinets with RFC Custom Crossovers / Speaker Cables: Duelund DCA16GA Tinned Copper / SW1X Audio Design USB-SPdif / SW1X Audio Design DAC 1 Signature / Interconnects: Duelund DCA20GA home brew /SW1X Audio SPDIF AERO 6 / Synology NAS Drive / Roon / Tidal HiFi / Mains Power Conditioner

  4. #64
    Join Date: Oct 2016

    Location: London

    Posts: 59
    I'm David.

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    Thanks for the compliments Guys. It was a great fun project, and, I too, was surprised by the sound quality produced by this beast. I've got some photos of the insides which I'll post when I get a chance. I'd like to thank Will at Radford Revival for lending a friendly ear for advice along the way! The biggest challenge was actually something stupidly simple: the bias voltage was incorrect on one channel which had had a meltdown previously. It's a simple circuit and despite replacing all the solid states bits it just wouldn't produce the correct bias. It turned out after a detailed comparison between the working and non working channels that it all boiled down to one transistor which was new......I had been supplied a BC213A and not a BC213L. These are essentially identical but with different pin outs And the print is only visible with a magnifying glass!

    Pics to follow

  5. #65
    Join Date: Oct 2016

    Location: London

    Posts: 59
    I'm David.

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    Quote Originally Posted by Firebottle View Post
    I see you are using an 834P. Now you have a stellar power amp the 834 can be improved quite dramatically as well with some simple mods, see http://theartofsound.net/forum/showt...563#post993563
    Certainly agree with this: the 834 is very modable for improved performance!
    Last edited by AD Audio; 12-07-2018 at 17:00.

  6. #66
    Join Date: Sep 2012

    Location: London

    Posts: 295
    I'm Nick.

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    Not much to show pics-wise from my end - it's a big black box! But here's a couple, one round the back showing the 4 NOS GEC KT88s currently singing happily...
    I'm sure David will post some shots of the juicy stuff inside in due course... I don't want to mess with the cover which is screwed into place and quite awkward to remove.

    Thanks for the tip regarding the EAR 834p. As far as I know its un-modded, altho' it does have rolled tubes, which were in it when I bought it from RFC Paul. A Mullard and a couple of triple mica Philips 12AX7s if memory serves. I tried Telefunkens in it but didn't hear much of a change tbh.

    I'll look into the Thorsten mods. David is currently building me a SUT with Hashimoto HM3s which I'll use to bypass the 834 MC input/internal trannies and go through the MM in. I'm keeping him busy this summer!

    IMG_1021.jpgIMG_1023w.jpg

  7. #67
    Join Date: Oct 2016

    Location: London

    Posts: 59
    I'm David.

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    Hi All,
    Some pics attached. The main work undertaken was:

    1. Replace mains lead and plug, inc. lead retention.

    2. Replace mains cable currently used as speaker cable with correct cable from output transformers to sockets.

    3. Replace 4 x main smoothing capacitors.

    4. Install correct mounting brackets for main pus caps

    5. Replace 11 other old electrolytic capacitors

    6. Replace cathode bypass capacitors with Elna Cerafines

    7. Remove and rebuild the driver boards adding correct insulation on 8 coupling caps to make safe and reliable

    8. Re-wire and improve earthing arrangement (currently made through oxidised tag connectors)

    9. Remove and rebuild power supply board with correct mounting on new brackets and stand offs, replacing capacitors and adding insulation where necessary

    10. Replace cathode resistors with Mills audio grade non inductive

    11. Re-wire and insulate mains switch

    12. Re-bias amp for current tubes

    13. Replace broken regulators in driver power supply and rebuild to original specification

    14. Replace indicator light and reconnect power supply inc. mounting power supply board correctly

    15. Reflow all connections on two driver amp boards

    16. Replace bias pots

    17. Trace bias fault on one channel

    18. Replace faulty transistors and op amps in that channel

    19. Repair broken tracks and reflow entire driver board on faulty channel

    20. Upgrade coupling capacitors to Leclanche /Mundorf ZNs

    [IMG]Rad3 by David Coe, on Flickr[/IMG]

    [IMG]
    rad2 by David Coe, on Flickr[/IMG]

    [IMG]rad1 by David Coe, on Flickr[/IMG]

    Happy to answer any questions!
    David

  8. #68
    Join Date: Mar 2017

    Location: London N2

    Posts: 820
    I'm Edward.

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    Good grief - that looks like pretty much like a rebuild.

    Amazing quality David. I've had the pleasure of hearing some of your work and I have no doubt this Radford is similarly out of this world.

    Are you inspired to do a build using similar circuitry to the Radford TT100?

    Edward
    Source: Tidal/Roon
    DAC: Metrum HEX NOS

    Amp: Sugden Masterclass 2018 spec, Radford Revival STA25,
    Speakers:, Tannoy Eaton


  9. #69
    Join Date: Oct 2016

    Location: London

    Posts: 59
    I'm David.

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    Hi Edward, I was very impressed with the sound quality and very low noise of the circuit and in particular there was loads of grunt with my fussy Tannoy Canterburys. But being a valve man I'm thinking of doing something with the all valve STA circuit and seeing what that does with a pair of Tannoy Canterburys!

    It's been really interesting turning some of my holy cows on their udders so to speak. Eg I'd always thought no feedback amps were my favourites and solid state driver stages-who'd want them in a valve amp? So seeing what Radford and others can do with properly implemented feedback and solid state opamp input stages has been a real eye-opener!

  10. #70
    Join Date: Mar 2017

    Location: London N2

    Posts: 820
    I'm Edward.

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    Yes that I believe Arthur Radford was so successful in his design in being able to reduce distortion to to vanishingly small levels via feedback - and oh yeah the iron grip his push pull ideas have on speakers such as Tannoys.

    Edward

    PS: Need to chat sometime with you on the PSU thing (the one Adam brought over) but no rush on that.
    Source: Tidal/Roon
    DAC: Metrum HEX NOS

    Amp: Sugden Masterclass 2018 spec, Radford Revival STA25,
    Speakers:, Tannoy Eaton


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