Bought another SLO Clone...

[Twisteramps]

...friend of mine built a kit. Amp sounds great! Has a horrible noise problem though - and he couldn't figure it out. So I bought it from him at a really good price, and have started debugging it.

First thing I had to do was disconnect every wire from the tagboard - he got 'tricky' and decided to run every wire under the board. Sure it looks neater, but it means you have to take the entire thing apart for troubleshooting.

What I found after digging around in it for an hour:

1) His grounding scheme was a little off. He had grounds from the power/filter caps going to the same point as his preamp grounds. This makes for a noisy amp.

2) he wired some of his preamp tube heaters backwards - which makes them non-humbucking, or noisier. This is probably where a lot of the hum is coming from.

3) He wired EVERYTHING with the same color wire. Folks, if you build an amp, color code your signal wire, high voltage, cathodes and grounds! This way you can troubleshoot it much more easily. I'm going to rewire most of the amp because of this - I like being able to tell at a glance where my power and signal wires are crossing and how.

So, looks like I'm rewiring an entire amp this weekend. Funny thing is, it looks a lot like the other one. Snakeskin tolex and all. I may put a better fx loop in it though.

Pete

[Dreamland_Rebel]

Killer

[Robert Burns]

I has no idea you were Michael Soldano! Mr Tech... hopefully we
can hear it when its done? Looking forward to it! Most i ever did
was re solder a 1/4" plug once.

[Twisteramps]

Oh yeah, I'll post clips. It's kinda weird reworking someone else's amp - he did some things I didn't like, some things he did really well. I got a good enough deal on it that I couldn't resist...

Pete

[fritzreiser]

He wired EVERYTHING with the same color wire.

:ROTF: :ROTF: :ROTF:

I don't know a watt from an ohm, but even I would know better than that.

[jgcable]

Pete... keep me in mind for this one too!

JG

[Firebird V]

Cool! Snap some pics when you are done Pete.

[Twisteramps]

Man, it's a mess. I've pulled 99% of the wiring, and the stuff that he already did I'm doing some changes for reliability and tone's sake. One example - to make it look neater, he routed three wires to be grounded across the bottom of the amp, then they go into a lug, from there BACK ACROSS THE AMP to a ground point. Wasted about 2 feet of wire. It worked, just wasn't what I would do - my big mantra for building amps is to use the least amount of wire possible. I have about 6 hours in this thing so far and basically have the grounds set up for the power and output tubes, all the filaments/heaters rewired, and started doing the tube sockets.

*whew* I'm going to have a bazillion hours in this thing when I'm done

Pete

[RacerX]

I'm imitating that goofball Special K today....

[slo100]

Pete if you need any pics of SLO internals let me know...though I'm sure you'll be able to route and wire everything on your own. I think I sent you schematics I had from Bill, right?

What are you going to do with the loop?

Hey at least it was not on fire like the 1970 Marshall Super Bass I had to rebuild was!!!

[Twisteramps]

Pete if you need any pics of SLO internals let me know...though I'm sure you'll be able to route and wire everything on your own. I think I sent you schematics I had from Bill, right?

What are you going to do with the loop?

Hey at least it was not on fire like the 1970 Marshall Super Bass I had to rebuild was!!!

Thanks Bret. It's a weber kit, so it uses a different board entirely but the same basic schematic. I still have those schematics from Bill, very cool and helpful.

Regarding the loop, I'll probably put in a (close your ears, tube purists) op amp loop out of one of Kevin O'Connor's books. He has several different designs that would work great. I'm almost thinking of building it in a box like a pedal, but if I did I'd have to have a seperate power supply for it.

Pete

[Souldigger]

If you haven't seen this site yet it's full of info. I've been thinking of building a 50 watt slo myself.

http://sloclone.yesterdaysrevolt.com/index.php

-Jason

[rstites]

Pete,

When you get it all cleaned up, let us know how it sounds. I just noticed the Weber kits for the SLO chassis today and wondered what they sound like. The Weber kits certainly are friendly from a $ point of view!

[Twisteramps]

Pete,

When you get it all cleaned up, let us know how it sounds. I just noticed the Weber kits for the SLO chassis today and wondered what they sound like. The Weber kits certainly are friendly from a $ point of view!

Yeah, but they aren't accurate as far as the boards. Then again, I'm sure Ted doesn't want to get sued either. I'm tempted to just say "screw it" and make a set of SLO clone boards and start over from scratch. We'll see how it goes.

FYI, when I was playing through it, noise and all, it did sound really good. Reminded me of the clone I built, which was better to my ears than a hot rod but not quite up to SLO tones. For the $ though, I think it's a killer deal.

Pete

[Twisteramps]

If you haven't seen this site yet it's full of info. I've been thinking of building a 50 watt slo myself.

http://sloclone.yesterdaysrevolt.com/index.php

-Jason

Been there. If it's your first amp, good luck. Guys have trouble building much simpler one channel amps... it's like a caveman building a gyroscope instead of a wheel to start off with, imho.

Pete