Check it out! Thanks Tony! I’m excited about this product, this really solves a lot of problems for people trying to fix 70s and 80s amps and receivers.
Validating the performance of my MT-200 transistor adapters
Testing the thermal performance of my transistor adapters. (TO-3P to MT-200 and 2SD746/2SB706 packages for Pioneer receivers.)
UPDATE: 2024.03.03 They’re now available in the Hoppe’s Brain Shop!
Continue reading Validating the performance of my MT-200 transistor adapters
ADCOM BOMs is live!
What other upgrades should I make to my amplifier? Here ya go ADCOM BOMs. This is everything I do in spreadsheet form.
Spectral Audio DMC-10 Restoration (Send me more gear like this please!)
One of my first Hoppe’s Brain customers sent me this beautiful old preamp to work on. Eight years ago I had refurbished for him, a pair of Adcom GFA-565’s to drive a pair of power-hungry Eminent Technology EFT-8 planar speakers. He loved my work, and sent me this preamp to restore.
Continue reading Spectral Audio DMC-10 Restoration (Send me more gear like this please!)
New product teaser; MT-200 to TO-3P output transistor adapters!
UPDATE: 2024.03.03 They’re now available in the Hoppe’s Brain Shop!
Here’s a (literally) cool solution to replace those MT-200 output transistors in your vintage amp or receiver! These adapters equal the excellent thermal performance of MT-200 devices, using commonly available TO-3P or TO-247 transistors.
The entire adapter is solid copper all the way through; there is no insulating layer. The TO-3P transistor is simply surface-mount soldered to the adapter, using solder-paste and hot-air. The backplate (collector) is connected to the copper body of the adapter.
Continue reading New product teaser; MT-200 to TO-3P output transistor adapters!
A new test jig for the BFA-555
I’ve been making new, more reliable test jigs for all the most popular boards I sell. This jig for the BFA-555 MK1 features a replica of the entire output section of a GFA-555, but with only one pair of output transistors. Obviously, you can’t run much power through this, but it’s all I need to prove the board works.
Pogo-pins meet target pads on the underside of the board under test.
How to never lose your 1/4″ to 1/8″ headphone adapter, ever, ever again.
An old 1/4″ jack, a little dremelling, shrink wrap and zip ties…
Replacement 1/4″ phone jacks for DBX compressors, EQs, vocal processors, etc…
I’ll just put this here. My DBX 166A compressor had terribly corroded 1/4″ phone jacks, and I found these exact replacements with gold-plated contacts. Neutrik part number NRJ6HF-1-AU (Gold plated) or NRJ6HF (Silver plated). These jacks are used in many other DBX products.
A few pictures of a GFA-555 MKI without “The Works”
Hey internet, I just finished refurbishing this GFA-555, and the customer opted to go without the BFA-555 Smart Soft-Start Power Supply, so if you’re wondering what you get without this option, here it is! I do install some Capacitor Hats to replace the crusty originals. The original power supply capacitors were replaced with Kemet ALS30, 22,000uF, which is about as big as you can go without a soft-start. (Or the switch will spark too much and the fuse may blow due to the in-rush current.)
Invoice on this one was $1210, which includes new Kemet power supply capacitors. Without the capacitors this is a $930 job.
Interesting phenomena visualized. Electric fields attract dust!
Dust is attracted to electric fields, and sticks to a board in a way that reveals the shape of the electric field in one plane. Dramatically illustrated here on the underside of an Adcom GFA-555. These dusty traces are at only 83V potential, but that’s enough to make them dustier than surrounding traces at lower voltages. Check out how there is a bunch of dust between the grounded mounting bracket and the adjacent trace at 83VDC.