HELP just bought a SUNN spectrum 1

[worldsnake]

just won a sunn spectrum 1 off of ebay. i cant find hardly any info on this amp head except that it pushes 125 watts and has either a 16 or 8 ohm option...

does this mean I cant use it for my ampeg 810 as a mono for all 8 speakers?

Im kind of new at the bass world so I know this is a newb question. I just dont want anything to catch fire. also, I want to get the best sound I can get from this thing. I might be re-listing it on ebay if I cant use it for this rig. thanks!

[anderbass]

If your speaker outputs are wired for 16 and 8 ohm, chances are there's also an additional 4-ohm output transformer tap inside your amp that's not connected. An amp tech could confirm this, and then disconnect your 16 ohm tap and conect that 4 ohm tap in its place.

[rickdog]

Originally Posted by worldsnake

just won a sunn spectrum 1 off of ebay. i cant find hardly any info on this amp head except that it pushes 125 watts and has either a 16 or 8 ohm option...

does this mean I cant use it for my ampeg 810 as a mono for all 8 speakers?

Im kind of new at the bass world so I know this is a newb question. I just dont want anything to catch fire. also, I want to get the best sound I can get from this thing. I might be re-listing it on ebay if I cant use it for this rig. thanks!

I recently found a schematic for a Sunn Spectrum 2, I wonder how similar it is? That has a pair of KT88s for output tubes, what's in yours?

Note that the schematic shows the 4 and 8 ohm taps used for the output - but there's a 16 ohm tap (which is just used for feedback).

[edbass]

The Spectrum I is a 2 X EL34 output, Dynaco Mk IV based guitar amp rated for 40 watts. Low powered but should work just dandy for bass.
It came paired with a 38" X 24" X 11.5" bass reflex cabinet loaded with a single JBL D130.
Only offered in late 1966 & 1967 as a 1967 model as far as I know.

If it has the OEM output transformer it has taps for 4, 8, and 16 ohms, and the outputs were factory configured for either 4 & 8 or 8 & 16 ohms with switching jacks that default to the lower impedance tap when both jacks are used. It's pretty simple to switch the taps from one configuration to the other.

The Spectrum II is a different circuit; 60 watts out of a pair of KT88's and much bigger "iron".


This is where you can get pretty much any Sunn questions answered. Not a real high traffic or "instant response" site, but a whole bunch of knowledgable and helpful Sunn-o-philes hang out there.

[someparts]

Yeah, the 60 watt KT88 versions sound like 100 watts.

[worldsnake]

Yeah I decided to sell it to my buddy...I'm going with 2 ampeg svt200t's for the full 8x10 power I want. Thanks for the input though. I'm loving the sunn line up. I'm looking into tracking down 2 concert bass amps. I'm pretty sure that would be plenty loud and tone driven.