Fender 5a3 Deluxe service?

[Tom Phillips]

Thanks Tom! What about the neutral wire?

The neutral (white) wire connects directly to the power transformer primary lead left over after the other primary lead is connected to the fuse/switch side.
In an amp such as yours there is no handy terminal to do this. In that case I do a neat inline splice covered with a couple of layers of heat shrink.

[dchang0]

Yeah, basically, Tom starts with the scheme I described and moves the power switch from the white side to the black side, leaving nothing on the white side except one of the two black wires on the PT.

I find it very difficult to get a good solder joint between the green safety ground and the chassis, so I just use locking nuts on the PT bolt.

[Mike62Jazz]

The neutral (white) wire connects directly to the power transformer primary lead left over after the other primary lead is connected to the fuse/switch side.
In an amp such as yours there is no handy terminal to do this. In that case I do a neat inline splice covered with a couple of layers of heat shrink.

On a Mission 5E3 I built, The white (neutral) was was combined with the other PT transformer wire and connected to an unused Pin (1,3,5, or 7) on the Rectifier tube socket and heatshrinked well. I believe this would work the same as your splice, but with something to attach to, correct?

[dchang0]

I'd recommend against that. There is always a chance that someone might accidentally insert an incorrect tube OR insert the tube turned a pin or two over. I've done that by accident, thinking the index in the socket would prevent me from inserting the tube incorrectly. But the socket's center hole was so wide that the tube could be inserted in any orientation. Blew out a capacitor.

Go with Tom's inline splice. I do it this way: twist the wires together, solder them, then twist an oversized wire nut down onto them. Heat shrink or hot glue to keep the nut from falling off. Overkill, really.

[Bruce / Mission Amps]

I'd recommend against that. There is always a chance that someone might accidentally insert an incorrect tube OR insert the tube turned a pin or two over. I've done that by accident, thinking the index in the socket would prevent me from inserting the tube incorrectly. But the socket's center hole was so wide that the tube could be inserted in any orientation. Blew out a capacitor.

Go with Tom's inline splice. I do it this way: twist the wires together, solder them, then twist an oversized wire nut down onto them. Heat shrink or hot glue to keep the nut from falling off. Overkill, really.

Wire nuts are ugly and amateurish looking in vintage amps.
Slip a piece of shrink tubing over the end of one wire, twist the bare ends together, solder them, cool it off, slide the shrink tubing down to the solder joint and heat it up.
Do it anyway you want but if you use my method it works well and is neat looking.

Plug the wrong tube into an octal rectifier socket and you might have more to worry about then if the odd number 1-3-5-7 lugs are at neutral, or Earth ground in your fuse or circuit breaker panel.
Regardless.... common octal based rectifiers have their heater elements on odd number lugs and other octal tubes use even ones.
There is nothing connected to the 1,3, 5 and 7 lugs anyhow.

[dchang0]

...you might have more to worry about...

Why add risk for the sake of convenience? Yes, if the user inserts the wrong tube or the right tube the wrong way, he's got X amount of problems. With that as a "floor," using the unused tabs add Y amount of potential problems (we don't know how the user might screw up; an unused tab is very likely safer than a connected one except in the happy accident that the neutral ground grounds dangerous currents).

Better to use Tom's (or your) inline splice, which, agreed, looks very neat and tidy. After all, if Mike's going to conform to commercial wiring codes whose intent are to mitigate risk as much as possible, might as well go all the way.

---
I use wire nuts because I am concerned about the low melting point of heat shrink tubing. It'd suck to have the heat shrink melt, exposing the joint and opening up the risk of shorting out something nearby. Yes, if the wire is hot enough to melt heat shrink, there are other problems; again, this is just an additional protection to mitigate risk.

[Mike62Jazz]

Here is what I ended up doing. Please critique and tell me if I'm correct. Connected hot from the power cord to end of fuse holder. Connected a hot jumper from side of fuseholder to On/off switch. Reconnected PT black wire from PT to on/off switch. Removed Cap and other black PT wire from side of fuseholder and reconnected black PT wire to white neutral. Picture shows all connections done and ready to shrink wrap the PT/neutral connection.

[Mike62Jazz]

Here's the final result before putting it all back together and testing! Still would appreciate a look at the power cord wiring before I fire it up.

Thanks in advance, Mike

[Tom Phillips]

You take good photos Mike.

From what I can see the black lead (hot) and the white lead (neutral) wiring appears to be correct. However, I can't see any earth ground connection (Green lead).

Did you end up enlarging the chassis hole and fitting a strain relief? I can't tell for sure from the photo.

Tom

[Mike62Jazz]

You take good photos Mike.

From what I can see the black lead (hot) and the white lead (neutral) wiring appears to be correct. However, I can't see any earth ground connection (Green lead).

Did you end up enlarging the chassis hole and fitting a strain relief? I can't tell for sure from the photo.

Tom

The ground is routed to the outside and connected to the PT bolts. Unfortunately, it is bolted from the outside with no nut on the inside. I dont have a powerful soldering iron to melt or afix chassis grounds so I had to go this way. BTW, for the board grounds I used Bruces' (Mission Amps) way of grounding by drilling small holes in the brass plate for the pots/inputs and using a wire to make the grounds from the eyelet to the plate. Next purchase is a powerful iron for chassis grounds. I think I will "Locktite" the screws holding the pt for extra security.

[Tom Phillips]

... grounding by drilling small holes in the brass plate for the pots/inputs and using a wire to make the grounds from the eyelet to the plate. ....

Understood but keep in mind that there are customers and collectors out there who would be upset if such changes were done to their vintage amp.

[Mike62Jazz]

Understood but keep in mind that there are customers and collectors out there who would be upset if such changes were done to their vintage amp.

I understand. It is totally reversible except for (3) 1/16 holes in the plate. But, point taken. Thanks for your help.

[ThermionicScott]

Why not connect your signal grounds to the chassis tab on the input jacks? I've started doing it on my builds when I can't get the solder to stick to the stupid brass plate.

- Scott

[Mike62Jazz]

The grounds are done, but that's another idea! I fired it up and it's mostly good. I either have a microphonic preamp tube or a parasitic of some form. It seems to move when I swap preamp tubes (V2 for V1 for instance). It manifests itself at the tube (ringing) and also the bypass cap of the grids of V1 when tapped with a chopstick. I, unfortunately, don't have a known good 6SL7 spare. I am going to clean and retension the tube sockets. I did that a couple of years ago to this amp and I bet it hasn't been turned on since but I have to rule it out. Any suggestions on 6SL7 tubes? Anybody making new versions that are decent?

[Mike62Jazz]

The grounds are done, but that's another idea! I fired it up and it's mostly good. I either have a microphonic preamp tube or a parasitic of some form. It seems to move when I swap preamp tubes (V2 for V1 for instance). It manifests itself at the tube (ringing) and also the bypass cap of the grids of V1 when tapped with a chopstick. I, unfortunately, don't have a known good 6SL7 spare. I am going to clean and retension the tube sockets. I did that a couple of years ago to this amp and I bet it hasn't been turned on since but I have to rule it out. Any suggestions on 6SL7 tubes? Anybody making new versions that are decent?

Sorry, not Bypass caps, Coupling caps. I have ordered some Tung Sol reissue 6SL7's. We will see if that fixes the problem.