WAD HD83

For anything about cans, and the amplifiers that drive them
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SimonC
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#1 WAD HD83

Post by 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 :D

Cheers
Simon C
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pre65
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#2 Re: WAD HD83

Post by pre65 »

SimonC wrote: Thu Aug 13, 2020 9:32 am 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 :D

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.
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
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Greg
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#3 Re: WAD HD83

Post by Greg »

PM me your email address and I’ll respond.
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Greg
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#4 Re: WAD HD83

Post by Greg »

Email sent.
SimonC
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#5 Re: WAD HD83

Post by SimonC »

Greg wrote: Thu Aug 13, 2020 9:25 pmEmail sent.
Thanks Greg, you are a star :)
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Greg
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#6 Re: WAD HD83

Post by Greg »

You’re welcome.
SimonC
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#7 Re: WAD HD83

Post by 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...
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Greg
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#8 Re: WAD HD83

Post by Greg »

SimonC
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#9 Re: WAD HD83

Post by SimonC »

Before and after
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DSC_0064.png (212.1 KiB) Viewed 10822 times
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DSC_0084.png (211.4 KiB) Viewed 10822 times
DSC_0085.png
DSC_0085.png (223.5 KiB) Viewed 10822 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)
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