Author Topic: 1971 Sunn Sonaro Amp Tubes..?  (Read 148 times)

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Offline staceyz

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1971 Sunn Sonaro Amp Tubes..?
« on: April 14, 2018, 07:05:21 pm »
Hi, I have an old Sunn Sonaro amp (missing all the tubes) I opened it up, and it has a date stamp on the side of the chassis as 1971. I've read there are a couple configurations of tubes needed, depending if it is a 40 /60 or 80 watt amp. How do I find this out. I've attached photos of the amp. Thanks! Stacey
« Last Edit: April 14, 2018, 07:26:47 pm by staceyz »

Offline EdBass

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Re: 1971 Sunn Sonaro Amp Tubes..?
« Reply #1 on: April 14, 2018, 09:55:49 pm »
That '71 should be a 60/80 watt amp, the '71s I've had were 60 watters with tube rectifiers but I don't see the hole for the rectifier tube socket on yours.

12AX7
6AN8
6550 or KT88 X 2

There are a bunch of things I don't see in your pics. You need much more than just tubes in that amp, it's pretty hacked up. Looks like that old girl may have been pillaged for parts. That power transformer is gigantic, and while generally bigger is better in the world of transformer, it ain't right for your amp.

I suspect you could buy another functioning 60 watt Sunn for about the same or maybe even less money than it would take to rebuild that one to OE spec. My suggestion would be to take it to a qualified tech along with a schematic for a 6550/KT88 Sunn amp and get a estimate to revive it.
I can post or send you a schematic, but they are available all over the web.

Offline staceyz

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Re: 1971 Sunn Sonaro Amp Tubes..?
« Reply #2 on: April 15, 2018, 07:59:32 am »
Thanks for the reply & advice..!

Offline EdBass

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Re: 1971 Sunn Sonaro Amp Tubes..?
« Reply #3 on: April 15, 2018, 11:20:01 am »
No problem, nice old amp if you can get it squared away. This is a gut shot of a 6/4/71 inspection date 200S, pretty much all of the stuff that isn't in your amp's chassis will need to be there for it to work.


Offline BC Gearhead

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Re: 1971 Sunn Sonaro Amp Tubes..?
« Reply #4 on: April 16, 2018, 09:00:33 pm »
Hello fellow Sunn worshipers. I picked up this very amp yesterday, and thanks again for the great deal. Itís missing the bridge, filter caps,one input jack,fuse holder,power cord and the power transformer is definitely not original. Iím hoping the correct voltages are present when I have a chance to test. I probably wonít have time to look at it for a while but that amp has found a good home. I have owned a 2000s for 12 years as well as several small wattage vintage tube amps. I think the Sonaro is going to be perfect for the smaller rooms where I occasionally gig. As well as a 1974 Pre Bass I own a 4003 Ric so it might be fun to use both amps for the ric-o-sound output but I probably have to get in shape first to lift all a that gear :-D. Iíll post about the progress as it happens, might be a few months before I get to it and since itís in very good shape cosmetically for a 47 year old amp Iím going to take my time and do a nice job with the repairs.
Cheers