Having a clear out and found this teenage project. Its a valve headphone amp based around EL84 but I don't suggest turning it on is safe at all! (and no valves are included). However I thought it might be of interest here as there are some decent parts that could be re-used:
1* 1:1 isolation transformer
1* 15-0-15 shielded toridal transformer
Valve bases
Nutrix RCA and headphone sockets
19" 2u rack mount chassis (some holes obviously already drilled but would patch up)
It looks like some of the capacitors have started bulging in all the years its been stored and the wiring is super suspect been done very cheaply by my young self so please don't apply power to it.
I'm looking for £20 basically to cover postage (UK only sorry wouldn't seem worth sending it elsewhere) or it can be collected from Warrington WA4.
1* 1:1 isolation transformer
1* 15-0-15 shielded toridal transformer
Valve bases
Nutrix RCA and headphone sockets
19" 2u rack mount chassis (some holes obviously already drilled but would patch up)
It looks like some of the capacitors have started bulging in all the years its been stored and the wiring is super suspect been done very cheaply by my young self so please don't apply power to it.
I'm looking for £20 basically to cover postage (UK only sorry wouldn't seem worth sending it elsewhere) or it can be collected from Warrington WA4.
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I'll take it, i need a few parts there. postage will be required though - too far for pick up.
Those gold samwa caps are horrific arent they. I serviced my el84 power amp this weeked, they looked like footballs even though over specced in voltage. 12 years....
Those gold samwa caps are horrific arent they. I serviced my el84 power amp this weeked, they looked like footballs even though over specced in voltage. 12 years....
Great! I have sent you a PM.
Yes I was suprised that un-used caps decided to expire in such a way. Conventional wisdom is that capacitor lifespan is reduced by heat and voltage but these have not been used.
Yes I was suprised that un-used caps decided to expire in such a way. Conventional wisdom is that capacitor lifespan is reduced by heat and voltage but these have not been used.
now sold.
mmm its a long time ago I doubt the website with the project on it is still up but I have found this archived schematic of the power amp. SE EL84 by the looks of it. Not what I would do now and there where lots of issues (I did get it to produce sound at one point).
The complexity is from the regulated HT supply and the regulated heater voltage and power sequencing circuits. So at least when its working there is no hum. The issue I had was that the HT supply was set to a too high voltage with the zenner string so kept going out of regulation. I got a bit turned off from the project though because I realized I had built it quite badly and really needed to start again.
mmm its a long time ago I doubt the website with the project on it is still up but I have found this archived schematic of the power amp. SE EL84 by the looks of it. Not what I would do now and there where lots of issues (I did get it to produce sound at one point).
The complexity is from the regulated HT supply and the regulated heater voltage and power sequencing circuits. So at least when its working there is no hum. The issue I had was that the HT supply was set to a too high voltage with the zenner string so kept going out of regulation. I got a bit turned off from the project though because I realized I had built it quite badly and really needed to start again.
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Hi, instead of EL84 could I suggest you a 6L6 S.E. amp? It works fine also with other equivalent tubes, taking into account max. P(diss) of each and the right cathode bias of the power tube. Schematic isn't too tricky, the only thing needed is a suitable transformer with sec. at least 450V.
I heard it playing and it's very satisfable.
I heard it playing and it's very satisfable.
