Hoppe's Brain

On the heels of the launch of my MT-200 Adapters, these solid copper adapter plates adapt new transistors to old formats. Available soon! I just need to test them, but there’s zero reason they won’t meet expectations. Actually these adapters should offer better thermal performance than the original devices. There’s more copper mass overall, so the heat-spreading action should be superior.

Introductory offer: FREE! (If you can help)

I need some help from my customers! I have not yet tested these adapters in any actual amplifiers or receivers. But I have every reason to believe they’ll work perfectly. If you succeed in installing these adapters in your amp or receiver, and can provide me with clear pictures of your install that I can use on this product page, and some user-experience feedback, you will receive a refund for your purchase, up to $45 (8 adapters). Also, if you find you cannot make them work, you’ll receive a refund. I can provide support though the process; you can call or email me about it. We’ll figure it out. If it doesn’t work, it doesn’t work, and that’s the deal. (But it’s probably gonna work.)

MT-200 to TO-3P / TO-247 Transistor Adapters / Heat-Spreaders

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.

What other upgrades should I make to my amplifier? Here ya go ADCOM BOMs. This is everything I do in spreadsheet form.

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!

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.

An old 1/4″ jack, a little dremelling, shrink wrap and zip ties…