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repair [message #20472] Sun, 13 April 2014 07:47 Go to next message
stevem is currently offline  stevem
Messages: 4728
Registered: June 2004
Location: NY
Senior Member
Due to the mis fortune of a bass player who had his Sunn 1972 solid state bass head take a 20 ft fall (aluminum chassis can`t take it) I was able tp grab the PI transformer out of it to check if it would work for a replacement as the phase inverter/drive transformer in our Frank heads and it looks like it might work.
The Sunn transformer has near doulble the primary Impeadance of the Kustom part, but the 4 secondarys of the Sunn when wired in serise is near dead on.
Over all it has a 1.5 to 1 turns ratio to the Kustoms 1.3 to 1
so I think it will just push the output stage of the Kustom to clipping a bit sooner and in the end just make the amp a get a bit louder faster.
Also on the good side is that fact that its core mass is a tad larger and the bolt pattern looks to be a match!
Tonight I will strap it into may 66 Frank head and report back in the morning on how it does.
These type of Sunn heads for both guitar and bass where made from 72 to 76 so finding a toasted Sunn to donate its phase transformer should not be impossible.

[Updated on: Sun, 13 April 2014 07:49]

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Re: repair [message #20482 is a reply to message #20472] Mon, 14 April 2014 06:17 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4728
Registered: June 2004
Location: NY
Senior Member
Well its a no go with the Sunn transformer!
The driver circuit of the Kustom as configured can not drive the higher imppeadance of the primary over the Kustom transformer.
Re: repair [message #20483 is a reply to message #20472] Mon, 14 April 2014 07:30 Go to previous messageGo to next message
sunnhead is currently offline  sunnhead
Messages: 221
Registered: June 2010
Location: Minnesota
Senior Member

any other sunn parts???

-S
Re: repair [message #20484 is a reply to message #20472] Mon, 14 April 2014 11:17 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4728
Registered: June 2004
Location: NY
Senior Member
As in what.
Re: repair [message #20485 is a reply to message #20484] Mon, 14 April 2014 13:58 Go to previous messageGo to next message
sunnhead is currently offline  sunnhead
Messages: 221
Registered: June 2010
Location: Minnesota
Senior Member

knobs? power switch.. any Goodies I guess. is it a white or red knob version?
Re: repair [message #20486 is a reply to message #20472] Tue, 15 April 2014 06:22 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4728
Registered: June 2004
Location: NY
Senior Member
Not much, the power switch lamp is dead, and the two knobs that it does have are blank as in no white numbers left on them.
Its without question seen its better days!
Re: repair [message #20487 is a reply to message #20472] Tue, 15 April 2014 14:11 Go to previous message
sunnhead is currently offline  sunnhead
Messages: 221
Registered: June 2010
Location: Minnesota
Senior Member

wow i guess!
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