Amp lead dress tips

[Mr. Foxen]

Anyone know of any good guides or pointers to how to lay out the wires in valve amps to minimise hum and suchlike, I have one that has had a few tinkerings with inside, and it is pretty scruffy, and noisy, sure matter can be improved with judicious replacing and re-routing of wires.

[Lfalex v1.1]

Try to keep low-level signal and high-level signal cables apart. If they have to cross, try to do it at right-angles. This also applies to anything carrying power to/from transformers and power supplies. A bit of judicious shielding around the low-level wires might be good, too.
If you're replacing cables, perhaps try and get some screened ones?
Ferrite rings can help suppress RF noise, be it mains-borne or externally induced.
I'm no expert in amps, it's just what I've garnered here and there, plus a bit of hi-fi lore.

[flyfisher]

Ferrite rings will, indeed, help suppress high frequency interference (useful if you're trying to make it compliant with EMC regulations) but I doubt they'll make any audible difference in an bass amp

[obbm]

Harry Joyce was an amp builder extraordinaire. He built all the early Hiwatts to military standards.

[url="http://www.harry-joyce.com/hjmilspc.htm"]http://www.harry-joyce.com/hjmilspc.htm[/url]

[Pentode]

Might be worth a gander -


[url="http://www.geofex.com/Article_Folders/star%20grounding%20amps.pdf"]http://www.geofex.com/Article_Folders/star...ding%20amps.pdf[/url]

[paul_5]

my Ampeg SVP (and probably all valve amps) has two black wires running from the transformer (at the back of the amp) to the front of the amp (power switch) these NEED to be twisted together for their whole length otherwise it buzzes like crazy. Something that's really easy to check and easy to fix. Not sure if it's relevant but I'm replying just in case.

[SS73]

Mine too Ampeg SVT,[attachment=63250:IMG00811...401_1010.jpg]

If the Earth Star has been messed with, I had a very noisy amp years ago and I seem to remember that the central earth post was not actually earthed to the chassis a new spring washer and some emery was all it needed.

[Mr. Foxen]

Wiring in American amps upsets me.

This has a couple of tacked in wires what cross over loads of the board, but its all preamp wiring there, so I dunno if they will be picking up interference, unless it is to do with the heater supplies or something. I was thinking of replacing a re-routing those first as it just looks like a terrible job.

[paul_5]

Hell's teeth! looks like something threw up in there. Mine's an SVP preamp, and to be fair, everything looks a whole lot neater than yours.

[SS73]

[quote name='Mr. Foxen' post='1015341' date='Nov 7 2010, 03:23 PM']Wiring in American amps upsets me.

This has a couple of tacked in wires what cross over loads of the board, but its all preamp wiring there, so I dunno if they will be picking up interference, unless it is to do with the heater supplies or something. I was thinking of replacing a re-routing those first as it just looks like a terrible job.[/quote]

On an SVT the Pre is in an enclosed unit up top with the pot's/ inputs etc. It's a 1970 and this is the power board that runs a 12DW7 and two 12BH7's. Tis a tad messy, but they must have got something right, endurance and one of the best sounding bass amps ever made.