My Spectrum II

[Spectrum II]

I bought one & I loved it (for about 45 mins). The tone was incredible before it began to crackle. It had kt88's in it with Sunn logos on them (what's up with these?), but they were apparently shot so I had them replaced with Svetlana KT-88s. The transformers were huge Dynaco ones. An entire 1/4 of the amp is a big grey transformer! (similar to this 1200s on Ebay) It's a late '67/early '68 judging from the use of KT-88s & the arrow knobs, correct? I can't really find any info on these on the internet, other than schematics & what's posted on Rich's Sunn Shack. I can't wait to get it back from the shop. I 'm putting 393 dollars into it for new tubes, a three-prong power cord, & some circuitry replacement.

I play a 2004 P-Bass with it into a Ampeg 410HLF cab (the prettier older model).Tell me about this amp (or what I have done to it)...pics coming soon!

[Spectrum II]

So here's the thing:

Spectrum II's are supposed to only have two KT-88's, right? Well, man has four? If anyone has any info on this, let me know.

I'm also trying to find out the deal with this KT-88's that were in the amp when I bought it. They marked with the Sunn logo, have "GT BRITAIN 1022-850" below the logo, & "KT 88 ZC Z MADE IN U.K." within a stamped square.

I'll post pics as soon as I get a hold of a digital camera.

[Spectrum II]

Okay, so in addition to have two more KT88 than it is supposed to have, it also has an extra GZ34?

4-KT88
2-GZ34
1-6AN7
1-mystery metal cylinder (7025?)

Basically, I'm judging from the info provded in the brochures & catalogs on this site that this is not the normal configuration for the Spectrum II. I could be mistaken. I'm really desperate for info on this thing & since I do not have the equipment to take photos at the moment I drew up a diagram of the tube positionings.

[Spectrum II]

After spending hours trying to stop myself, I gave in to temptation & I took the chassis out to have a look. There weren't any initials or dates like I was hoping for, but under a layer of dust on the top of the chassis were labels of which tubes were which in marker. I also discovered a 12ax7 & that it's a 6an8 not 6an7 (I had originally listed 6an7, I think). If you're counting that's:

4-KT88's (Formerly Sunn labeled KT88's, replaced with Svetlana KT88's.)
2-GZ34 (Amperex, left in because they tested fine.)
1-6AN7 (Sylvania, left in as well.)
1-12AX7 (Sylvania, I think. It wasn't replaced. Could have been Amperex? I don't remember & It's too difficult to get to.)

 I took some photos of all of this with a disposable camera that I had around, I just hope they turn out. I refuse to take this thing apart again. It was a bitch getting the chassis out & I don't want to risk fucking anything up if I haven't already. I still have yet to go down to the practice space to hear how this baby sounds now. It was spectacular before, so I'm sure it can't sound worse. We'll see...

I'll get the pictures developed tomorrow & I'll scan them ASAP. I hope someone's reading this that'll be able to help me out with this thing. I feel like there's not much traffic around here.

[Spectrum II]

I mean 6AN8. For some reason I keep saying 6AN7!

Sincerely,

Man Who Talks to Himself Via Messageboards

[Spectrum II]

http://img78.photobucket.com/albums/v292/jamesalvinbarron/

There are the photos. Let me know if you know anything.

[Anonymous]

OK, I'll hazard a guess here. It looks as though some amp tech took a Spectrum II and made a 2000S out of it. The ouput transformer looks like a Dynaco from a Mark VI monoblock amp. The two tubes flanking the bias adjustment pot are the original output tubes, the other two were added. Likewise the extra 5AR4/GZ34 was added. Looks like a second choke was added too. The silver canister is the multi-section filter capacitor. The old-style grille cloth and early style Sunn logo date the amp to 1967. Check the pot code for confirmation. This 120 watt configuration on a 24" chassis reminds me of the original Sunn Coliseum P.A. So.....could this have been a Sunn prototype platform for the Coliseum / 2000S? If Conrad Sundholm is out there, perhaps he could enlighten us!
Good luck!
Ryan

[Spectrum II]

So this head was modded by someone out the to be a 2000s? Interesting. As a joke,I was gonna go around & claim this was one of the juiced up Spectrum II's that Jimi Hendrix used.

Thanks for the info, Ryan!

My search continues...

[Anonymous]

Any interest in selling the old Sunn branded KT88's?  Shoot me an e-mail at vikkinbill@aol.com

[loudthud]

Looks like a prototype that was done at the Sunn factory. For one thing all the octal tube sockets are the Cinch brand with the tention ring like my 1200S. Also the 47 ohm resistors that connect to the output tubes are the same. Four 2 Watt carbon comps and four smaller white ones that I've never seen except in Sunn amps. Also I don't see any scars around the unused transformer mounting holes that you would see if it ever was a stock Spectrum II. The two Illinois Capacitors look newer. They are probably replacements in the bias supply. Lastly it looks like some of the wires that go to one of the added output tubes go into part of the wiring harness which pretty much eliminates the idea that the tubes were added later. I like the extra brackets on the power transformer.

My you never hear Surf Music again ...