lead dress

[iknowjohnny]

I'm starting a new amp and i have a question about power wires. I'm using a multi section can for all 3 preamp nodes. So there will be 3 wires, one for each node running from the can under the board to the plate resistors. Can i bundle them together or is that not a good practice in this context? Also, would it be a good idea to twist the AC leads from the PT to the rectifier diodes?

[Structo]

A common technique is to run those type of jumpers under the board from an eyelet near the power supply then over to the plate resistors.
In other words, have a vertical row of eyelets (or turrets) near the PS, then run the jumpers from those eyelets to the various plate loads.
Marshall usually put those on top the board which may be better because if one falls out when soldering it's a bitch to fix when under board.

[iknowjohnny]

I can't do that because i have already used pretty much every hole in the tagboard thats available. So they will run from the cap under the board to each point. But the question is can i tie them together or is that not good for B+ lines ?

[Phil_S]

Twist the HV supply to the rectifier if space and wire length permit. It can't hurt, but it is not essential if there are no other wires nearby.

I take it you want to zip tie B+ supplies together? I can't see the problem with that. Stlll, keep the B+ away from signal wires or cross them at a right angle.

[iknowjohnny]

I take it you want to zip tie B+ supplies together?

Yes. I figured i'd also run them along the bottom of the chassis under the board so that they're an inch away from the components on the board where there is signal. Although my last amp was fine with the B+running under and against the board. Just being careful. Anyways, yes, i just want to zip the B+ wires together.

[Darkbluemurder]

I take it you want to zip tie B+ supplies together?

Yes. I figured i'd also run them along the bottom of the chassis under the board so that they're an inch away from the components on the board where there is signal. Although my last amp was fine with the B+running under and against the board. Just being careful. Anyways, yes, i just want to zip the B+ wires together.

There is no harm in doing this. The B+ line is ground for AC purposes so there is no signal on it.

Personally I do not like to attach jumpers at the bottom of the board. If they get loose for any reason you will have to dismantle the board.

[Firestorm]

While there's "technically" no signal in the B+ lines, the first one (off the main filter) still has a fair amount of ripple on it. Even though that AC component is biased up to the B+ voltage, you don't want it too close to an early stage input. You could shield those wires; in the later silverface Fenders, they did it by wrapping a wire around the bundle and grounding both ends. It actually works.

Since you're using a can cap where all stages share the same ground point, you may want to experiment with where you ground the cap. Some places will be quieter than others.

[iknowjohnny]

Since you're using a can cap where all stages share the same ground point, you may want to experiment with where you ground the cap. Some places will be quieter than others.

Good point. Till now i always had the node on the board next to thier destination, so the caps were grounded at the ground wire i have running down the edge of the board. The wire is grounded at the same point on the chassis where the cans is, so theyre all essentially grounded to the same point, tho that point is a wire about 10" long. I don't know if that will matter, but theres nothing i can do about it with this multi section can. I could however run a wire from the can to say the point on that ground wire thats in the middle of the turret board so the pre nodes are grounded within 2-3" of thier physical location. Thats about the only way i can see aside from grounding the can at the same chassis point as the main can and PT. But all grounds in the amp are grounded there. It's just a matter of the physical location of a ground along that wire i mentioned. That said, i have used this same basic ground scenario in 3 amps and while experimenting had grounds going every which place and all are high gain amps and not yet have i had any noise more than typical. So i'm not too worried.

[Bob-I]

I have a Dumble ODS I built into a Princeton chassis. Because of the small size of the chassis I used a can cap for primary filter and a second for the preamp filters. The screen and preamp filters have all connections bundled and running along the edge of the board branching off to the PI, OD and clean sections. This amp is quiet and sounds great.

I'd keep the primary filters seperate but the rest will be fine bundled. JMO