Sunn model t red knob version

[mark45]

Hello Sunn experts,

I own 2 model t amps. The first is a silver knob sunn that I bought in 1975. The second is a red knob version 2 super T that I purchased as a project amp last year. I was able to restore it to it's original condition. This question has probably been asked many times and I apologize if I am repeating it. But.... I can not seem to dial this amp in. I am having trouble with the mid range selector switch and the amp does not have the same feel as my original t. I searched the internet and there is a mod that eliminates the mid switch and makes a correction to a master volume problem. My question. Is there a fix that can use the three way mid switch were it will be similar in sound as the silver knob T. It would be great if it could be tweaked a little closer to the original and still have the mid switch usable. Any advise would be appreciated.
mark

[Isaac]

There's no need to eliminate the mid switch. The problem with the second generation (2G) Model T is that the midrange control is a boost only, and even at zero, there is still some boost. The trick, then - and it's an easy one - is to eliminate not the mid switch, nor the mid boost, but the inherent boost, so that the boost goes away when the mid control is set at zero.

Another issue with the 2GT's is with the master volume. As you turn up the master, volume increases until you get to 8, then goes down. I have no idea why they designed it that way, but they did. That's an even easier fix, if you want to do it.

Then there's the other tone controls. On most amps, including the 1GT, the bass and treble controls are boost only, but on the 2GT they are boost and cut. That's not inherently a problem, but some people prefer the classic tone stack to the more hi-fi style of the 2GT. That's a more complex mod, and one I didn't bother with on my 2GT. OTOH, my 2GT has silver knobs, and I'm not sure which tone stack it has. Sounds good, though, after eliminating the mid boost and changing the master volume circuit.

[mark45]

Is there info or instructions on the fix that you have suggested, or is the mod that I spoke of earlier the same.

[Isaac]

There used to be a nice web page describing a series of mods designed to convert a 2GT to a 1GT, along with not eliminating the mid boost and mid select, all done by a guy who used to hang out here quite a bit. The mod you describe doesn't sound the same to me.

Ha! The page still exists! I suggest reading through the whole thing and deciding what you want to do before actually starting.

http://www.angelfire.com/blog/sunnmodelt/

[sunn-tanned]

I know I still need to go in an at least snip that white wire with the blue stripe! Also maybe change the mid range cap.

[Isaac]

I highly recommend performing mods 5 and 7, the master volume and mid boost mods. The gain and tone control mods are more a mater of taste. So far, I haven't chosen to go beyond 5 and 7. But I might.

[mark45]

Isaac,
thanks. that is the mod site that I was talking about. I thought that the mod disconnected the mid selector switch, which I thought may be useful. Maybe I misunderstood, I would like to eliminate the boost only  as you mentioned,  I am not a electronics wizard so I can give the information to a more qualified tech. I really appreciate the feedback from all.

Mark