Gtr. Tech & Amp Builder at CurranTone, and Guitarist for Esperanto!

Member since:
February 2015

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1967 Sunn Spectrum II 60watt KT88 Amp

Posted on February 15, 2015   

I bought it not working and "restored" and added a few useful mods. Pretty cool.


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  • BillCurran

    March 16, 2015 Reply

    Yea kinda, it's basically a Dynaco Hi-Fi power amp with KT88s running ultra linear and a weird pentode/tridoe 6AN8 phase inverter. The pre-amp is like a fat F-der style input stage followed by a regular single stage EQ (backwards to a Blackface, closer to a tweed Bassman I guess, but without the cathode follower for the EQ). I did some mods and tweaks after I got it running so I don't really know what it's supposed to sound like stock. It was really dull and muddy at first so I messed around with the negative feedback and I'm still not 100% happy with it yet, but it sounds pretty good. You pretty much still have to leave the Treble at 10 to get the clarity, but it is very clear with the Treble at 10, Bass at about 3, and Mids(Contour) at 0, sounds kinda Blackface-y. Crank up the volume, mids, and bass and it gets a huge fat fuzzy sweet bluesy sound, great for slide, and doom or w/e people use these things for. Get's a decent Leslie West tone, but doesn't quite nail it, his amp had more gain stages.

  • Ian

    March 8, 2015 Reply

    interesting amp. i've never seen a spectrum in person. is it a hifi bassman-ish type deal?