Lookin to brighten this thing up. With treble dimed and bass all the way off, it's passable for a good tone with humbuckers, but owner wanted it brightened up. I changed out .
As suspected , a bright cap across the channel vol does nothing
https://audiocircuit.dk/downloads/sunn/ ... ix-sch.pdf
Brighten up this Sunn Alpha 4
Moderators: pompeiisneaks, Colossal
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Smokebreak3
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Brighten up this Sunn Alpha 4
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Re: Brighten up this Sunn Alpha 4
Schematic looks like a four channel PA head.
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Smokebreak3
- Posts: 92
- Joined: Wed Dec 28, 2022 12:45 am
Re: Brighten up this Sunn Alpha 4
Yep that's what it is , shaped like a mixing console also. Some players like the sound they get out of these SUNN units. They have 4 identical channels w/ 1/4" inputs. Only 2 shown own schematic.
I've re-capped the power supply (not shown)
I've re-capped the power supply (not shown)
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Smokebreak3
- Posts: 92
- Joined: Wed Dec 28, 2022 12:45 am
3 others liked this
Re: Brighten up this Sunn Alpha 4
For posterity's sake , I'll finish this thread up for future generations of Sunn PA modders 
An examination of the tone stack revealed a James that was pretty bass heavy and cut treble with the small pots and caps selection.
Merely changing C107 to 470p brought a lot of treble back and even mimicked a Fender midscoop. Sounds great with even humbuckers now.
An examination of the tone stack revealed a James that was pretty bass heavy and cut treble with the small pots and caps selection.
Merely changing C107 to 470p brought a lot of treble back and even mimicked a Fender midscoop. Sounds great with even humbuckers now.