Our audio shop has closed due to retirement and I would like to share our mod for the HCA-3500. The only person we have ever shared this with was John Curl many years ago. I hope that this will help some of you who would like a little better sound quality but the mod will improve clarity first and foremost.
I appreciate you posting this list! I wish BIG Sky was still at it! Now if someone has an HCA 3500 and can only only do a few of the most impactful upgrades ....what would be the absolute minimum to do to have the most effect? I have an OEM 3500 and just cant do all of these! So far I have read that that the absolute minimum is replacing the R44 with NOS 47K HOLCO .5W 1%H4 metal film. AFTER THAT STEP Which of these would you believe to be absolutely required for any further sound improvements?
I did all these mods,also replaced all bridges with soft recovery ultra fast rectifiers. This is as close as you can get to a BBQ 3500 from the trio led by John Curl, that led to the birth of the JC1. I can do these mods for you, you can email me tsipkin@gmail.com
U absolute legend
I'd been reading about people sending to you for these mods for about 10 years.
I told my father I would have a go at upgrading it for him one day once I make heads or tails of all available info. That day never came.
Unfortunately he has passed and i have inherited the unit.
I will start sourcing the parts soon. Thanks again