Converting old amp (5c5 build)

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PaulWD
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Converting old amp (5c5 build)

Post by PaulWD »

Hi all

I thought I'd drag an old chassis of the shelf and document a rebuild/conversion into something interesting. Namely, another 5c5 like Molly's.

My starting point is an old bitsa of a cinema amp. It has been hacked about a little, with an aluminium plate screwed to the topside to mount a beacon output transformer.

I suspect that it dates from the 50s and was built up using war surplus material.

Chassis is mostly stripped and ready for the boiling water + persil toothbrush treatment.
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PaulWD
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Re: Converting old amp (5c5 build)

Post by PaulWD »

More pics...
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Baseplate
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Re: Converting old amp (5c5 build)

Post by jeremyb »

Holy moly, lot of work ahead there mate!!
Slowy wrote: That's the problem; everything rewarding is just such hard work. Regret takes much less effort.

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Re: Converting old amp (5c5 build)

Post by Molly »

Watching with interest.

Danny was saying there were a couple of old cinema amps on TradeMe at the moment.

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Re: Converting old amp (5c5 build)

Post by jeremyb »

I really wanna build an old tonemaster troubadour 214, Phil X styles!
Slowy wrote: That's the problem; everything rewarding is just such hard work. Regret takes much less effort.

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Re: Converting old amp (5c5 build)

Post by kdawg2a »

Looking forward to this thread!
1935 Martin D-45, 1942 Gibson Southern Jumbo,1950 Fender Broadcaster, 1954 Fender Strat, 1958 Gibson Moderne prototype, 1959 Gibson Les Paul Standard.
1958 Fender twin, 1965 Vox AC30, 1966 Marshall JTM 45, 1977 Dumble OD Special.
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Re: Converting old amp (5c5 build)

Post by Mini Forklift »

Subbed!

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Re: Converting old amp (5c5 build)

Post by RectifiedAmps »

That must smell amazing! Any idea what the original valve complement was?

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Re: Converting old amp (5c5 build)

Post by AiRdAd »

Molly wrote:Watching with interest.

Danny was saying there were a couple of old cinema amps on TradeMe at the moment.
Here we go :-)
Slowy wrote: To Danny, everyone is either a supplier, customer or a courier.

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Re: Converting old amp (5c5 build)

Post by PaulWD »

RectifiedAmps wrote:That must smell amazing! Any idea what the original valve complement was?
Yes, it is rather musty.

Dunno about the power side but it had 6sc7 and 6sj7 in the pre. It had a couple of old sanken diodes in it rather than a valve rectifier. I suspect the chass has been rebuilt a couple of times.

Unfortunately the pt had no 5v tap so I'll swap it out.

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Re: Converting old amp (5c5 build)

Post by AiRdAd »

AiRdAd wrote:
Molly wrote:Watching with interest.

Danny was saying there were a couple of old cinema amps on TradeMe at the moment.
Here we go :-)
What a dumbass, I didn't attach the link. Will grab it
Slowy wrote: To Danny, everyone is either a supplier, customer or a courier.

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Re: Converting old amp (5c5 build)

Post by RectifiedAmps »

PaulWD wrote: Unfortunately the pt had no 5v tap so I'll swap it out.
You could simulate a valve rectifier with some series resistance in the silicon-rectified power supply. A 47R resistor between the centre tap and ground would imitate a 5Y3GT nicely, for example, and save you the trouble of swapping the PT (or adding an auxiliary 5v transformer). Just an idea anyways.

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Re: Converting old amp (5c5 build)

Post by AiRdAd »

Slowy wrote: To Danny, everyone is either a supplier, customer or a courier.

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Re: Converting old amp (5c5 build)

Post by PaulWD »

Progress pic. Still got pots and power supply to wire. Hopefully be all good to go in another week.
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Re: Converting old amp (5c5 build)

Post by Molly »

Mine has such a sweet spot. I set the volume on half and tone at 1 o'clock then run it through the Fryette to bring the volume down. With a Tele it's just really nice, natural overdrive and it's incredibly dynamic. Was playing along with some Tom Petty on the Tele yesterday and the tone was just perfect.

Watched an interview with Tim Pierce yesterday where he said if you could afford only one amp you should get a Bassman. :-)

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