Long time, no blog! I’ve been super busy with Adcom amp and preamp refurbishings, and obsessing over new circuit board designs.
Here are completely new versions of the GFA-565 input boards, and for the first time, I am offering fully assembled and tested boards for $380. (Please allow up to a 15-day lead time. They are hand-made, by me in my shop.) Click here to buy.
Coming soon: (These items are all available by request, just not yet in the store.)
GFA-535 MK1 Power Supply board
GFA-535 MK2 Power Supply board
GFA-545 MK1/MK2 Power Supply board
Unbalanced stereo line driver. One stereo input, four stereo outputs, buffered and driven by OPA2134 op-amps. (For running long unbalanced patch cords, or adding buffered tape outputs to a preamp, among other uses.)
Bipolar audio power supply, +/-15V. Super low noise, low impedance and high speed. Based on TI LP38798.
Thanks to all my customers for the continued success of Hoppe’s Brain. I am so happy to be doing this for a living.
Hoppe’s Brain is thriving, but demand for my services has been overwhelming! My waiting list has grown to more than a year,so I’m sorry, but I must declare a temporary hiatus on accepting new clients for repairs and refurbishings.
I need concentrate on my existing customers. Thanks for understanding.
I still sell circuit boards and kits, and this area of Hoppe’s Brain will continue to expand. Look for my store to go online in the next few weeks. In the meantime, contact me with the form below and let me know what you want. (Power supply boards for GFA-535, 545 and GFA-555 amplifiers, GFA-565 input boards, etc.)
If you’ve emailed me and not heard back, I will get back to you within the next few weeks.
Thanks to my awesome customers for making Hoppe’s Brain a success!
Hey there people! Here’s a sneak preview of some new circuit boards that just arrived, in preparation for my web store grand opening. All but two of the boards shown will be available for purchase by DIY’ers. (Along with existing boards like the GFA-555 soft-start power supply and GFA-565 input boards.)
Hi everyone! One of my customers sent me a particularly nice GFA-555 MKI to be refurbished. It’s never been tampered with, and has very few scratches on the case… just beautiful. So I thought I would take lots of pictures along the way as I refurbish it, and show you the latest iteration of my GFA-555 rebuild process. This is the full monty upgrade package including the Hoppe’s Brain soft-start power supply board, with all sound quality and reliability improvements. $1025 in total.
Hey folks, I hope this will be useful to anyone attempting to clean an ALPS sliding listen/record selector switch like those used in the Adcom GFP-555 and GFP-565. These are common in many brands of preamps and receivers.
It’s an “Earth loop breaker”; A common method of providing some resistive isolation between star ground and chassis, lowering noise in an amplifier. I designed it for the GFA-555, but it will also work in many amps.
My sincerest apologies; My communications have been terribly slow, and my turn-around time for refurbished equipment is getting out of hand. I have customers waiting up to four months for their equipment, and that’s no good. I wouldn’t want to wait that long!
I never anticipated such a level of interest! Many thanks to all of my customers; it’s a pleasure to help you build your music systems, and I love hearing people’s comments after they get their gear back.
I like to say “YES!” to everyone’s projects, but I have taken on more work than I can possibly keep up with. I am buried in emails, and it’s getting hard to find time to work at the bench. Things are snow-balling on me.
It’s a good problem to have. It means I’m succeeding, but I won’t be for long if I don’t limit the scope of what I do.
Adcom GFA-535 owners; Has it always bugged you, how the right channel of your amp buzzes through your speakers more than the left channel? Yeah, me too. The buzz is a buzz-kill… so I killed the buzz! With this thing I made.
Now, the GFA-535 is a legendary little amplifier, deserving plenty of buzz, but it’s too bad so much of it comes out the speakers. Oddly, the GFA-535’s bigger sibling—the GFA-545—using the exact same amplifier boards as the 535, is nearly silent as a stone. What’s going on?