69 Deluxe Reverb wiring

[sonicmojo]

I have a Silverface drip edge '69 Deluxe Reverb on my bench and I am perplexed by the wiring in it. I was expecting something different, maybe cloth wire, but there is none and it is very messy and colorful. Is this stock wiring or was this amp fully rewired at some point? I can't imagine why someone would go through the trouble.

[M Fowler]

Looks stock to me.

Mark

[Gibsonman63]

When they got away from the cloth covered wire the lead dress suffered. Still a great amp though.

[RWood]

I got a '72 Twin on the bench for a buyer's inspection. Fender must have gone through miles of that wire, as each one was at least half again longer than necessary. I also couldn't believe how wavy the board was and how much electrolysis was on the chassis in an amp that was always in the closet of an air conditioned bedroom (I personally knew the deceased owner). I was also amazed at how quiet it was for such a rat's nest.

[sonicmojo]

Looks stock to me.

Mark

Thanks! First time I've seen that type wire. The blackfaces from a couple years before are way more consistent and tidy.

[M Fowler]

Yes the older ones seem to be a lot better.

I actually like that green or white wire from the board to the tube sockets, it stays in place and easy to use.

[Stevem]

Once again the CBS guys wanted to save some penny's, so to make the amps faster for there employees to wire they use multi colors to distinguish plates from grids and cathodes and or other circuit sections!

Some of these amps have a low level 120 hz hum even when all is well and if your turn up the controls on the channel you are not plugged into you can lower this due to phase canceling .

Also you may need to move the filter node ground for the output tube screen grid from the front brass grounding buss over to the center tap of B+ secondary where it belongs!

[Teleguy61]

That wiring in the SFs is indicative of production having been moved to Mexico, and away from the little ladies in Fullerton, who did such beautiful and permanent wiring work.
As the post above says, CBS wanted to increase production and cut costs.
What's the line?
"Good, cheap, and fast-you can have two."

[Firestorm]

Yeah, but this is a '69, so it's still from Fullerton and probably still wired by the ladies (and maybe even the day laborers populating boards in the back of pickup trucks). What killed the more elegant lead dress was UL's insistence that cloth insulation was not safe for high voltage leads (they were probably right), so Fender lost the push-back wire that was fast and easy to work with. At first, they used plastic insulated solid core wire with cloth covering and followed the old style dress. The wire was expensive and didn't offer any speed benefit, so the switch was made to standard insulation (and stranded wire). Early attempts to route wire early '60s style failed because the later wire doesn't stay put and if it's routed under the board, melts and shorts if a lead is soldered to an eyelet above it. So it's not just the CBS bean counters, it's UL too.

[sonicmojo]

Early attempts to route wire early '60s style failed because the later wire doesn't stay put and if it's routed under the board, melts and shorts if a lead is soldered to an eyelet above it.

That makes sense as this board has all the holes in it but no wires through them - another reason I was thinking something weird when I first saw it. Great history lesson!

[rfgordon]

The lead dress in some of these amps is so bad that you can move around one lead and interfere with the tremolo function and even kill the signal altogether with phase interference.

If you were to tighten up the leads by taking out the slack, I'd bet you'd take over a foot of wire out there, easy.

An easy fix for reverb noise in these amps is to take the V4a coupling cap off of the plate resistor on the board and solder it to the tab on the reverb pot. Then solder a lead from the cap back to the plate resistor. This converts that long lead from high to low impedance and gets rid of about 8 inches of unshielded grid lead.

Far too many of these CBS era Fenders are disregarded because of noise and other lead-dress related issues. That's a shame, because when they're cleaned up they are fantastic amps!

For my money, a well-tuned Deluxe with a Tone Tubby is hard to beat for almost anything.

[Structo]

Yep, when CBS took over this is the result.

If it sounds ok and is unaltered, consider only doing maintenance updates (Filters and maybe cathode caps).
And a three prong power cord.

[Firestorm]

I will usually shorten the leads and re-route them to conform to pre-CBS dress. Time consuming and not really economically viable, but I'm stupid that way. When players get them back, I want them to say "Wow."

[sonicmojo]

Yep, when CBS took over this is the result.

If it sounds ok and is unaltered, consider only doing maintenance updates (Filters and maybe cathode caps).
And a three prong power cord.

Agreed. The main reason this amp needed fixing was simply a bad power tube. It already had a three prong so just a few new tubes and bias. I convinced the customer to get a full cap job since it was his main gigging amp and one of the filter caps had a blowout.

[Firestorm]

+1. Never a bad idea in a gigging amp of this age.