Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dude on March 01, 2020, 11:53:32 am
-
If I'm using a buss bar on the pots and all grounds from pots to the bar, do l have to worry about the paint on the chassis interfering with the ground through the nuts? The bar goes all the way to the input jack sleeve then to chassis along with the board preamp grounds.
-
no
-
.... do l have to worry about the paint on the chassis interfering with the ground through the nuts?
I think the possible problem would be the absence of paint and the resulting multiple ground loops through the nuts (if the nut is electrically connected to the body of the pot)
Franco
-
My answer was based on the assumption that the buss is NOT soldered to the back of the pots.
-
The buss wire "is" soldered to the pots but the buss wire stops at the sleeve of the input jack. Then from the sleeve to the chassis right below the input. The board preamp side runs to that chassis ground too.
I was just wondering if the tone stack, master vol, presence grounds being grounded at the input ground would be a problem?
I can easily scrape the paint off but ain't easy.
I think Doug said his buss bar soldered to the pots and grounded at the input, but l'm sure each pot is grounded to the chassis at it's location
-
https://el34world.com/Forum/index.php?topic=25209.0
In this link, Doug says he solders a buss or a wire to the pots and then grounds at the preamp end., Sluckey replies too in the link. I'm ready to wire the pots and attach the faceplates, real hassle if I have a ground issue, tough to get pots out.
I can't see any reason, that soldering a wire to the back of the pots is a problem as long as the wire is grounded at the preamp side of the amp "only" along with the input jack, and preamp side of the board. I believe Sluckey's says run a wire from the sleeve to the preamp ground on chassis too.
Only issue I would have in this amp if it's an issue at all, is there is no ground connection through the paint on the pot nuts, only at the preamp ground. Just wonder if all the pot's grounds attached to the wire and grounded at the preamp, would be be of any concern? I don't think so?
Hopefully, I'll get some feedback, soon.
Read the link .
-
connection through the paint on the pot nuts,
do a quick test;
take the "ground" lug of the pot and ohm to the pots threads, what do you get?
-
Give a look to the layout on this pdf file
http://sluckeyamps.com/18w/18w.pdf (http://sluckeyamps.com/vox/Vox.pdf)
it is the way Sluckey do the pot connection to ground via the bus wire
Franco
-
what do you get?
1.3 ohm, the 3/8" holes drilled through the chassis are grounding the pots, probably a little higher resistance because of the paint. Don't have pots wired up yet.
I'll just run a wire bit on my drill and take a little paint off, probably for nothing though. In another amp, I ran a copper 14 gauge buss bar floating along side of a board but not touching the pots. Wired all the pot's grounds to that bar as it ran down the bd. Grounded the bar at the preamp only, no problem.
The reason for the wire soldered to the pots is I don't have the room for grounding in the narrow AO43 chassis, much easier to take all the grounds from the pots to that wire and ground it at the preamp only. Like Doug did in his 6V6 Plexi.
I don't know maybe another stupid question, I never seem to get much of an answer lately. :icon_biggrin:
-
I don't know maybe another stupid question, I never seem to get much of an answer lately. :icon_biggrin:
You've been doing this long enough that you should be the go-to guy for all AO-43 to Plexi6V6 conversions. Just do it!
-
I don't know maybe another stupid question, I never seem to get much of an answer lately. :icon_biggrin:
Just do it!
That's what she said, :l2:
OK, I did it, I "Just Can't Help It" It's the cabinetmaker in me, my ruler only has 32nds, :icon_biggrin: