Author Topic: 1972 Sunn Concert Bass head  (Read 2138 times)

Offline Bob Cruz

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1972 Sunn Concert Bass head
« on: September 05, 2006, 12:20:45 PM »
Over the weekend I acquired a 1972 Sunn Concert Bass head in working condition--free!  It cleaned up well and is fun but I don't think I'll keep it.  It's just begging to be played through a 2x15 in a 70's Zeppelin/Who/Hendrix tribute band, which isn't my style right now.  Anyway, if anyone remembers this amp, what's the story on the distortion circuit?  The head doesn't have the footswitch to turn it on and off, so I bridged across the footswitch inputs with a phono cable, and the amp got a lot (I mean a LOT) louder, but still sounded clean to me.  The trouble is, it was so loud I had to roll off the output on my bass to almost nil.  I suspect it needs to be cranked up to really hear the distortion.  FYI, it's a solid state amp, no tubes.

Bob Cruz
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Offline jmcgliss

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1972 Sunn Concert Bass head
« Reply #1 on: September 05, 2006, 01:43:38 PM »
Hmmmm interesting. My Deep Purple tribute band is calling. I at least need some 2x15 cabinets to put my Eden 12's in [:D]  Do you know if it will run at 4ohms?

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Offline Bob Cruz

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1972 Sunn Concert Bass head
« Reply #2 on: September 05, 2006, 01:50:17 PM »
I'm pretty sure it's good at 4 ohms since it has two parallel speaker out jacks and that usually means it's good for two 8-ohm speakers at least.  I ran it into my 4-ohm 212XLT for a while and it didn't get hot but I was babying it.  I couldn't find a manual for it online, only a schematic.

Bob Cruz
"Live the life you love, love the life you live."
Bob Cruz
"Sun is shining.  The weather is sweet.  Make you want to move your dancing feet." -Bob Marley
WTX260 - GB Streamliner 900 - US Peavey Cirrus 5 strung with TI jazz flats - ESP LTD fretless 5 - Cruz 112 x 2 (20 pound flyweight cabs I built) - Avatar Neo 112 x 2 - Bag End TA12 x 2 - SWR WM12

Offline jmartin

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1972 Sunn Concert Bass head
« Reply #3 on: September 05, 2006, 02:44:19 PM »
One of the reviews here http://reviews.harmony-central.com/reviews/Bass+Amp/product/Sunn/Concert+Bass/10/1 mentions a footswitchable treble boost and gain boost.  Not finding any other info regarding distortion.

Jim

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Offline Bob Cruz

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1972 Sunn Concert Bass head
« Reply #4 on: September 05, 2006, 03:23:25 PM »
I wonder if that "gain boost" is the distortion circuit and the reviewer had the same experience I did--it makes the amp louder but still clean.

Bob Cruz
"Live the life you love, love the life you live."
Bob Cruz
"Sun is shining.  The weather is sweet.  Make you want to move your dancing feet." -Bob Marley
WTX260 - GB Streamliner 900 - US Peavey Cirrus 5 strung with TI jazz flats - ESP LTD fretless 5 - Cruz 112 x 2 (20 pound flyweight cabs I built) - Avatar Neo 112 x 2 - Bag End TA12 x 2 - SWR WM12

Offline pbd

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1972 Sunn Concert Bass head
« Reply #5 on: September 08, 2006, 12:06:09 PM »
Hey Bob Cruz, I "grew up" with Sunn stuff.  
Can you send a link to the schemo?
pbd
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Offline Bob Cruz

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1972 Sunn Concert Bass head
« Reply #6 on: September 08, 2006, 12:38:29 PM »
Here you go: http://www.freeinfosociety.com/electronics/schematics/audio/sunnconcertbass.pdf

Bob Cruz
"Live the life you love, love the life you live."
Bob Cruz
"Sun is shining.  The weather is sweet.  Make you want to move your dancing feet." -Bob Marley
WTX260 - GB Streamliner 900 - US Peavey Cirrus 5 strung with TI jazz flats - ESP LTD fretless 5 - Cruz 112 x 2 (20 pound flyweight cabs I built) - Avatar Neo 112 x 2 - Bag End TA12 x 2 - SWR WM12

Offline pbd

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1972 Sunn Concert Bass head
« Reply #7 on: September 15, 2006, 09:24:48 AM »
Thanks for the link Bob.  I was hoping I could hook up with an electronics friend but I've been out of town.  I was also hoping that there might be an electronics person here that might help.

It looks like there are two footswitches with both labeling "Dual Distortion".  I've been away from electronics for a while so I'm rusty as to differentiating the two circuits.

I should be able to hookup with my friend soon.
pbd
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