• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Pye HF25 Tube Monoblocks: Restoring Legends

Hi Guys

I've asked a few questions elsewhere on diyforums about these amplifiers and one of the most vexing questions was how to re-apply/restore legends after repainting.

I've finally settled on laser-printed waterslide film and silver foil overlays on the original corroded legend plates.

Having never worked with waterslide film until now, I made a test today, using all the etch primer paint, light blue base coat and finally acrylic clearcoat I'm going to use for the actual restore.

I have the matching Pye tube pre-amp and sanded down to bare aluminium one of its cover plates for my try-out as I wanted to see if all goes according to plan. The first paint application (painted with my airbrush) was the grey etch primer for aluminium, then the matched light blue paint.

I let these two coats dry overnight and then applied a random-choice laser printed text.

When all the moisture had been expelled underneath the sticker, I applied acrylic automotive-type clearcoat over the entire surface.

I think this looks OK as one cannot really see the type's cutting edges unless observed from closer than about 3".

I'm also showing the refurbished legendplates. These were aluminium foil applied over the corroded originals. I cut away the sticker over the stamped serial numbers so that's what you see there.

I will soon start with the work proper as I have obtained all of the absent bits such as an original Bulgin on/off switch, one Bulgin power plug and two tubes which I needed.

bulgin
 

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Thanks for the interest, Kevin. After today, I'm a step closer to starting with the Pyes. Only three more jobs to complete - repairs to two EMT TSD15 cartridges and making a new control panel cover plate for a Thorens Reference turntable. The weather here in Cape Town during March/April is now ideal for airbrush painting with warm weather, no wind.

I'm going to have to make some kind of temporary spraybooth to keep out bugs and airborne debris. Or maybe just a large beach umbrella will do.

Cheers

bulgin
 
I know this thread is a few years old, but I have a question about rebuilding the power supply of a Pye HF25. The filter capacitors are rated for very high voltage (8uf at 700v and series 64uf at 350v for an effective working voltage of 700v). This seems very high. Even the high power Mcintoshes use 500v filter caps. Am I safe in using 500v caps for the power supply rebuild?
 
I know this thread is a few years old, but I have a question about rebuilding the power supply of a Pye HF25. The filter capacitors are rated for very high voltage (8uf at 700v and series 64uf at 350v for an effective working voltage of 700v). This seems very high. Even the high power Mcintoshes use 500v filter caps. Am I safe in using 500v caps for the power supply rebuild?

Go for higher voltages. The transformer is 400 -0- 400 volts so you could see 560 to 580 volts dc on the first 8uF and second 32uF caps as the amplifier warms up or you have the KT66s out for some reason...
 
RIP bulgin

Sad to see this thread come up - bulgin a.k.a. Andre Hanekom passed away earlier this year after a long illness. He was a legend in the South African audio community, and his famous Blue Angel cartridges ended up all over the world. See Re: RIP

Here is his thread on Lenco Heaven, showing the complete restoration: Restoring a 50's British Valve Amplifier