SE KT88 amp pics and clip

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rfgordon
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SE KT88 amp pics and clip

Post by rfgordon »

Here's my summer personal amp project, the Dragon. It's pretty simple, with a nice reverb. In the clip, I start out with the gain at noon and master at 1:00 and the guitar volume rolled back. You can hear it when I open the guitar up!! The second minute of the clip is with the gain dimed.

There's an Eminence Wizard in there right now.

I had the faceplate made at www.designyourowncard.com
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Rich Gordon
www.myspace.com/bigboyamplifiers

"The takers get the honey, the givers get the blues." --Robin Trower
dimitris
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Re: SE KT88 amp pics and clip

Post by dimitris »

Great rock tone,nice cab too.
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Structo
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Re: SE KT88 amp pics and clip

Post by Structo »

Nice!
How about some details on the circuit and possibly some gut shots?
Tom

Don't let that smoke out!
rfgordon
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Re: SE KT88 amp pics and clip

Post by rfgordon »

Thanks for the kind words, guys. I have gut shots in the camera, but I'm on the road right now. I'll post them later this week.

As for the circuit, the first gain stage is both sides of a 12AX7, set up Matchless style-- Ra = 220k w/ Rk/Ck = 1k5/5mF

Then there's a rather ordinary tone stack, kinda 5F6A style, then a gain stage. The signal goes to the reverb in a non-Fender kind of way. The verb circuit is one tube (12AT7). Then there's a mixer stage and a driver for the KT88.

Right now there's a 100mF Ck on the KT88, and there's too much bass, so I think I'll drop that Ck down to 25mF and see if it reigns the bass in a bit. I also want to monkey with the verb to get more depth.

It's a fun amp to play, because it's so responsive. I'm gonna have to find a better brand of KT88, cus the ones I've used are crap. One shorted and one rattles. On the other hand, it sounds great with a 6L6, too. I haven't tried 6550 or KT66 yet.
Rich Gordon
www.myspace.com/bigboyamplifiers

"The takers get the honey, the givers get the blues." --Robin Trower
jimipage
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Location: way out West

Re: SE KT88 amp pics and clip

Post by jimipage »

wow, Rich! -- you always make such cool stuff :D
rfgordon
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Re: SE KT88 amp pics and clip

Post by rfgordon »

jimipage--thank, man. I really like making stuff that the regular companies don't make.

BTW, I forgot to mention that the clips were recorded with the Eminence Wizard, not the WGS ET65 in the picture. I ended up selling the WGS speaker to my #1 beta tester after he had this amp for a week. I just happened to get a good deal on the Wizard, but it is a really nice speaker.

I hope to post gut shots tonight when I get home.
Rich Gordon
www.myspace.com/bigboyamplifiers

"The takers get the honey, the givers get the blues." --Robin Trower
Wayne
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Re: SE KT88 amp pics and clip

Post by Wayne »

Great sounds, man. And a SE KT88 amp is not something just anyone's gonna have!

There's something about those '88s - they even look loud :D

W
rfgordon
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Re: SE KT88 amp pics and clip

Post by rfgordon »

Wayne,

Yeah, there's a lot of loud in this box! At first, there was no NFB in the power section, and I thought I could tighten things up a bit with some. So I ran an NFB line from the 8 ohm tap to the top of the driver Rk via a 22k resistor. I fired it up, and WOW!! was it super dee duper loud! Until, that is, I turned the master up past about 2 oclock, and the NFB, which was really PFB, turned the thing into a squealing siren! My wife came in and said, "why are you making such horrible noises with your amplifiers?" Um, cuz I'm a knothead and I need to reverse the OT primary wires....

Anyway, here's the gut shots. The small internal pot adjusts how much signal gets to the driver, and it lets me exactly dial in the magic spot for the most punch with the least noise and hiss. This thing is phenomenally quiet at full tilt, even without putting a DC reference on the filaments. I'm still not sure it's actually finished.....y'all know how that is, right?
Rich Gordon
www.myspace.com/bigboyamplifiers

"The takers get the honey, the givers get the blues." --Robin Trower
rfgordon
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Re: SE KT88 amp pics and clip

Post by rfgordon »

Sorry, having ISP issues. Pic 1
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Rich Gordon
www.myspace.com/bigboyamplifiers

"The takers get the honey, the givers get the blues." --Robin Trower
rfgordon
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Re: SE KT88 amp pics and clip

Post by rfgordon »

pic 2
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Rich Gordon
www.myspace.com/bigboyamplifiers

"The takers get the honey, the givers get the blues." --Robin Trower
rfgordon
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Re: SE KT88 amp pics and clip

Post by rfgordon »

pic 2
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Rich Gordon
www.myspace.com/bigboyamplifiers

"The takers get the honey, the givers get the blues." --Robin Trower
argonaut
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Re: SE KT88 amp pics and clip

Post by argonaut »

Very cool build, RFG.

What did you use for iron?
rfgordon
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Re: SE KT88 amp pics and clip

Post by rfgordon »

The PT is from a 1961 Harmon Kardon mono receiver. The choke is from CE Dist (the bigger of the two they offer for Fenders). The OT is the big SE one from Ted Weber.
Rich Gordon
www.myspace.com/bigboyamplifiers

"The takers get the honey, the givers get the blues." --Robin Trower
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