This page is about the IMPACT 1017 100W amplifier head.

The amp on the pictures is my own. I have got a couple of reports about others of these. Some in Sweden, some in the UK. I guess there wasn't many made.

One unusual thing about this one is, that it's cathode biased and have no global negative feedback. In reality it's more of a 70W than a 100W amp. It has four ECC83/12AX7 and four EL34/6CA7 tubes.

The power amp section is very similar to the Vox 80/100 amp, the forerunner for the AC-100. It seems as that amp is known for overheating and following failures, and it was certainly a problem with this one too, when I got it. It's really a bad design, as far as speaking about the biasing of the power tubes. They are running far above there maximum plate dissipation with the original values of the cathode resistors.

Please send me an e-mail if You have any additional information or comments about IMPACT!
(Back to main IMPACT page!) Last updated 2014-01-21
Sixten Forsén, EDGAR Audio. Bollnäs Sweden.

Welcome to  

Schematics:
Original (?): Impact 100
Current revision: Impact 100 rev4