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Thread: My 'other' 300B project

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    Default My 'other' 300B project

    over a year ago I purchased a couple of 300B Chassis and after having them sat doing nothing I've finally bought the remaining bits to complete them. The output transformers arrived last week from Amethyst Designs, and I've got a quad of 300Bs (an eye-watering 276) en route as well. I'm just waiting for the nuts and bolts so I can mount the chokes and OpTx in the chassis. Other than that they are complete and ready to go, so I should be able to have them up and running in a week or so.

    The amps are based on the WAD 300B PSE, but have an EF86 - 5687 front end instead of a 6AU6 - ECC82.

    I may look at converting them back to the original but at the moment I have too many incomplete projects. I've still to get back onto the 2A3, which will be next.
    "It's ok your comments are noted, so if you want a war you've got one. Watch your back, ya !!!!...." in an email from Marco 3/4/09

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    Sounds like you have your hands full there, be good to see some pictures when finished. Mind and watch out for those HT shocks now wont you

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    Some progress



    no sound as yet. getting wild voltage at the input stage. not sure what's causing it. the circuit is based on the glasshouse apparently.
    "It's ok your comments are noted, so if you want a war you've got one. Watch your back, ya !!!!...." in an email from Marco 3/4/09

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    The valve compliment certainly sounds like Andy Groves's design for the Glasshouse. Its a lovely amp, had mine for about 8 -9 years. I have some pdf circuit diagrams somewhere, if you need them give me a shout.
    Garrard 301 with SME 3012, Garrard 401 with PU7 both in slate plinths, Puresound P10, Highphonics SUT, Glasshouse TVC Passive Pre, Bel Canto Set 40 (845 power amp), Tannoy GRF Memory`s

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    Yeah. Though this is a PSE design with two monoblocks. Kind of a cross between the two.
    Looking forward to finally getting it singing.
    "It's ok your comments are noted, so if you want a war you've got one. Watch your back, ya !!!!...." in an email from Marco 3/4/09

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    I bet you are, what sort of output would you expect from them?

    The Glasshouse struggles to get to grips with the low frequency when driving my Tannoys, it could just do with being maybe 18w instead of 9w.
    Garrard 301 with SME 3012, Garrard 401 with PU7 both in slate plinths, Puresound P10, Highphonics SUT, Glasshouse TVC Passive Pre, Bel Canto Set 40 (845 power amp), Tannoy GRF Memory`s

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    should get around 20w from it.

    Have narrowed the fault down to the EF86 grid voltage. it should be 125v but is sitting at 2v. so either faulty capacitor or faulty EF86. have replacements of both on the way...
    "It's ok your comments are noted, so if you want a war you've got one. Watch your back, ya !!!!...." in an email from Marco 3/4/09

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