WAD HD83

[SimonC]

Hi folks,

Its been a quiet summer on the hifi front for me, but I couldn't pass up a bargain and picked up an HD83 for a sensible price as the metalwork has a bad case of the pox.

Lifting the lid it looks to have been loved at some point in its past as it has a pair of Jensen coupling caps grafted in, and some Philips UK ECL83's.

Does anyone have a circuit diagram and the build notes for one of these in their archives? Mine has obviously been tweaked during its life and I want to figure out which bits are std and which bits are later additions. I also need to figure out the output impedance connections to suit my HD650.

Also any upgrade hints would be welcome.
Number 1 on the list has to be an IEC socket as the mains cable grommet thing is rubbish, and I've got some soft recovery diodes in the parts box so they can go in, but after that I can play

Cheers
Simon C

[pre65]

Hi folks,


Does anyone have a circuit diagram and the build notes for one of these in their archives? Mine has obviously been tweaked during its life and I want to figure out which bits are std and which bits are later additions. I also need to figure out the output impedance connections to suit my HD650.

Also any upgrade hints would be welcome.
Number 1 on the list has to be an IEC socket as the mains cable grommet thing is rubbish, and I've got some soft recovery diodes in the parts box so they can go in, but after that I can play

Cheers
Simon C

Greg is your man for these Simon, he's the archive man for World Designs. If he doesn't spot this send him a PM.

[Greg]

PM me your email address and I’ll respond.

[Greg]

Email sent.

[SimonC]

Email sent.

Thanks Greg, you are a star

[Greg]

You’re welcome.

[SimonC]

Filtered vs non-filtered IEC sockets for audio equipment, what are the thoughts from the internet?

I've got both in my spares box, just wondering if there is any practical effect of filtered ones as the electrons are going to be squeezed through a transformer, some diodes and an assortment of caps anyway...

[Greg]

You could do this.

http://www.world-designs.co.uk/forum/sh ... .php?t=149

[SimonC]

Before and after

DSC_0064.png (212.1 KiB) Viewed 7040 times

DSC_0084.png (211.4 KiB) Viewed 7040 times

DSC_0085.png (223.5 KiB) Viewed 7040 times

" it's alive! Alive! Arrrhhhh, now I know it is really possible! "

Got a bit carried away while I was adding the IEC socket and squeezed in a Pi + MamboDac and a regulated power supply for it, plus some change over switches to flip between the onboard dac and the external inputs. Still got a couple of mods to go with a nice silver plated headphone socket, shunt-modding the pot with a couple of fancy resistors from HiFi Collective, some extra holes to let the smoke out and a then lick of paint.

Onwards..

(Post edited to add the before pic)