ab0ez
AB0EZ
Well here I go again! This time it's a pair of Eico HF22 monoblocks that are in really nice cosmetic shape.
They had a half-hearted rebuild some time ago, but there are some problems with that. For one, the can caps aren't really soldered to the chassis at all, so any good low impedance ground connection is probably more of a stroke of luck than anything else!
Looks also like most of the original resistors were left in the amp, even though some show signs of thermal stress. They're gonna get round-filed and replaced with components hand matched to less than 1% tolerance.
All the old caps will be replaced with hand-matched items.
The power supply will get a choke added. This looks to be the 22A version that doesn't have a whole lot of filtering on the B+. We'll fix that! Along with a lot more filtering, I'll probably use a bus ground vs the chassis ground.
The "death cap" on these amps are just that. Not rated for this use and will be drop-kicked into the trash can.
With all these being said, does anybody have any hints or suggestions for other improvements, particularly the front end of the HF-22?
More to come as parts arrive.
They had a half-hearted rebuild some time ago, but there are some problems with that. For one, the can caps aren't really soldered to the chassis at all, so any good low impedance ground connection is probably more of a stroke of luck than anything else!
Looks also like most of the original resistors were left in the amp, even though some show signs of thermal stress. They're gonna get round-filed and replaced with components hand matched to less than 1% tolerance.
All the old caps will be replaced with hand-matched items.
The power supply will get a choke added. This looks to be the 22A version that doesn't have a whole lot of filtering on the B+. We'll fix that! Along with a lot more filtering, I'll probably use a bus ground vs the chassis ground.
The "death cap" on these amps are just that. Not rated for this use and will be drop-kicked into the trash can.
With all these being said, does anybody have any hints or suggestions for other improvements, particularly the front end of the HF-22?
More to come as parts arrive.