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Thread: Gary's A&R A60.

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    Default Gary's A&R A60.

    I thought as I have Gary's amp in for some tender loving care I might as well document it here. This is an early one Gary, ser.no.0070 so I think I'll leave it pretty much as it is and simply change components like for like. There are a couple of electrolytic caps that I'll replace with films, and maybe I'll upgrade the rectifiers. I'm wondering if it has been back to the factory at some point because the main smoothing caps have been replaced with later factory items, 10,000uf Rubicons. They look to be in good nick but they'll be replaced anyway. A couple of other caps look like they've been replaced too but there's no date stickers apart from the original build stickers from 1977. There are two decoupling caps that are in a terrible state and they appear underrated to me. One of them has bulged and the end connection has blown out, the other cap isn't far behind. These will be replaced with uprated items. The replacement capacitor count is around 34 atm.
    I'll post a few pics later.
    Si.

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    Sounds good Si. Remember to let the caps burn in

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    Looking forward to this Si.

    I have an Audiolab 8000a from from the late 80's that I've always fancied tinkering with/updating. Hint hint!!!

    Euan
    20 years ago we had Johnny Cash, Bob Hope and Steve Jobs. Now we have no Cash, no Hope and no Jobs. Please God, don't take Kevin Bacon

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    Just caught up with this. Thanks for the update Si, I knew it was an early unit due to the low serial number and the all DIN type connections on the rear. As I said I'm more than happy with how it performs so it shouldn't need too much doing to it in terms of significant upgrades. I wouldn't want it to lose its character.

    Who knows what its history is. It's been around since I was 17!

    The phono stage seems to work ok. I won't be using it when it comes back as after Henry offered me a loan of one of his spare MC carts, I asked him if he wanted to sell one and I'm picking up an AT33PTG at the weekend, so its back to using the Slee Fanfare phono amp. I'll keep the Shure MM as a spare.

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    First things first, I won't be doing any serious modding. Most of the caps will be replaced with better items because we're forty years down the line and things are that much better anyway. There are a couple of electrolytics that are better replaced with films as they tend to roll off the bottom end as they age. I'll try my best to make sure replacement parts are as near to the original spec wise so the amp retains its flavour.

    It's quite a coincidence that last night I was thinking about you and your cartridge choice after the comments you made on the birthday thread Gary. I was going to tell you to get another Eroica as you had a good MC stage that needed using and then I thought of suggesting the AT33 as I've had one and quite liked it. I hope you like it too.

    Ok, I need to get an order into Farnell whilst I'm in the mood. I've never seen as many caps on one board
    Si.

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    This is almost certainly nothing to do with the choice of caps but I did read this amp was designed to roll off sooner at both ends because they thought there's no point amplifying signals we cannot hear.

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    I think you need to read it again Gary.
    Si.

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    What? lol.

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    Does it have the optional MC60 pre-amplifier board fitted for LOMCs? This is a good review of the amp:

    http://zstereo.co.uk/2013/05/04/ar-a60/

    I can't find the write-up about its design now but I definitely read something about it being purposely designed to not amplify signals we cannot hear, or rather they thought there's little point in amplifying signals we cannot hear.
    Last edited by TIU; 20th February 2015 at 12:58.

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    Replacing the two particular electrolytics I mentioned with film caps will not alter the roll off. If I put electrolytics back in there's a chance that as they age the roll off characteristic will change. Fitting film caps should prevent this. After having a search around this morning the minimum order for the films is ten so we may very well end up with two high quality electrolytics in there anyway. We'll see. I've ordered bog standard Panasonics for everything else.
    Si.

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    No MC option I'm afraid, not even a socket for it.
    Si.

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    No worries. In those days the phono stage was an important and integral part so it's a good one. Obviously it will run HOMCs no problem. It does sound very good with the Shure M75. The amp was also designed to cater for quality recording to cassette and reel-to-reel. I'd like to be able to record; it would mean unplugging other components as it's limited to four inputs and I'd need to get a cable with a DIN plug with different pins connected. I can order one from ebay I believe.

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    It's easy to make a switch box ( an extender) that has an output lead with din plug and gives you say four rca phono inputs. You plug it into the auxiliary socket and the job's done. I made one for my lad a few years ago because of a lack of inputs on his preamp.
    Si.

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    A quick pic to whet your whistle



    The other cap back near the rectifiers doesn't look like it's got long for this world either
    Si.

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    Si, are you doing any audio-tom-foolery in there or merely replacing like for like?

    Euan
    20 years ago we had Johnny Cash, Bob Hope and Steve Jobs. Now we have no Cash, no Hope and no Jobs. Please God, don't take Kevin Bacon

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    It's really just a service Eaun so I'm replacing like for like except for a couple of critical caps. I'm uprating all the cap max working voltages though. Those green caps are up from 25 volts to 50 and the smoothing caps are up from 50 volts to 63 volts. The small grey caps ( there's 24 of them) are all rated at 35 volts yet the drawings say 40 volts so they're going up to 50 volts max. It's a pretty fair assumption that after thirty eight years most of them will be past it now though I must admit they've done well.
    Si.

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    Found it. The comments about limiting the bandwidth. http://www.pinkfishmedia.net/forum/s...ad.php?t=53785

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    Also spotted a note about the early models having axial caps fitted, whatever that means
    http://www.pinkfishmedia.net/forum/s...d.php?t=123730

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    bet you can't wait Gary?

    great work Chops, how's your knee?

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    I've read all those write ups Gary. Unfortunately Robert's "how to" is for the later model which is quite a bit different to your early model. Retro HiFi site has all the diagrams etc but even with x3 gogs on I can hardly read the damn things

    Knee's are ok thanks Paul. It's my left hip that's giving me grief atm. I'm off for a scan on Monday and with a bit of luck I might find out what's wrong with me.
    Si.

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