I have a matched pair of GFA-565 boards in stock! Fully tested. Near aerospace-grade construction. 😸
https://hoppesbrain.com/product/adcom-gfa-565-replacement-circuit-board/
ADCOM GFA-555 MK1 “Vertical” circuit boards are here!
Some early models of the GFA-555 MK1 used these vertically-mounted input boards. My existing horizontal board kits could be adapted to work with these amps, but it required fabricating brackets, drilling holes, and adapting the wiring. It was kind of a pain and a bit confusing.
The biggest design challenge for the vertical board model, is the way the original bridge switch is mounted to a small circuit board that is held in place by the RCA jacks. These are not great RCA jacks, and most people will want to swap them for nice chassis-mount types. So I came up with this “Mezzanine board” arrangement with two PCBs stacked together. The first board holds the bridge switch in place, and houses connections for the RCA jacks, LEDs and thermal breakers. Then the input board stacks on top of the mezzanine board, and uses WAGO cage-clamp terminal blocks to connect to the output modules. The input board can be removed and serviced without soldering!
GFA-555 MK1 “VERTICAL” boards coming soon!
Do you have one of the first batch of ADCOM GFA-555 amps ever made? My GFA-555 MK1 boards work great in these amps, but they must be physically modified to work with the horizontal board.
Until now! I have designed new boards for these early “Vertical” 555’s.
I really like how this layout turned out. Very pleasing symmetry.
This is the original board:
The nicest GFA-555 MK1 I’ve ever built, $1600
Update: *SOLD*
Dang, I kinda want to keep this one, but here it is for sale!
Hoppe’s Brain Refurbished ADCOM GFA-555 MK1
This particular GFA-555 came to me as a customer trade-in, and was very well loved and cared for, so I thought it deserved a new life.
I went all-out on this one. It’s got all the options, including an entirely new input circuit board, and a soft-start power supply with (4) 27,000uF capacitors.
Continue reading The nicest GFA-555 MK1 I’ve ever built, $1600
New Adcom GFA-555 MK1 Input boards!
By popular demand, I have created new input circuit boards for the GFA-555 MK1! These boards integrate all of the improvements I normally make when I refurbish a GFA-555.
The GFA-565 boards keep getting better
Hi everyone,
I’ve just built a batch of eight GFA-565 boards, and they turned out amazing! I wanted to share the improvements I’ve made to the boards, and my build process.
Because I’m terrible at self-promotion, here’s a video I should have posted last month!
YouTube blogger XRayTonyB did a three-part video series on repairing a GFA-585 using my boards!
As usual, he goes into great detail on the restoration process, and gives all kinds of generally helpful electronics troubleshooting advice along the way. Tony’s channel is loaded with videos about restoring some really interesting gear like vintage receivers, amplifiers, test gear, etc.
This was not a paid promotion, and there is no commercial affiliation. Tony just bought boards from me like any other customer.
Fully assembled GFA-565 boards back in stock!
I’ve just finished building this batch of GFA-565 input boards. More are on the way soon!
A Tour of a Hoppe’s Brain Adcom GFA-585 Restoration
Hi everyone,
This is perhaps the nicest amplifier I’ve ever restored! A GFA-585; The first of its kind with newly designed replacement input boards. (To fix the infamous leaking capacitor issue.) And I can’t believe I’m saying this, but…
It’s for sale. $1800. Update: SOLD to previous customer, Bill.
Also, I wanted to share what I know about restoring a GFA-585. I hope this is useful to others who are tweaking their GFA-585’s, or installing a set of my replacement circuit boards.
Continue reading A Tour of a Hoppe’s Brain Adcom GFA-585 Restoration
Adcom GFA-585 replacement circuit boards are here!
Hi Everyone,
At last, GFA-585 input boards! Available at my store.
GFA-585 input circuit board left
GFA-585 input circuit board right
As you may know, the Adcom GFA-585 suffered from the same leaky capacitor issue as the GFA-565.
Continue reading Adcom GFA-585 replacement circuit boards are here!