Ground Bus

[Gibsonman63]

I have given up on trying to solder the ground bus to the stainles steel backs on my pots. I have made a couple of tweaks to my board layouts, so I don't think any one would mistake my amp for Mr. Fischer's work anyway. Even my big Bertha soldering iron that I use for Fender chassis grounds can't make the solder stick and I really don't want to keep cooking the backs of my potentiometers. After talking to a technical guru friend and a few searches through the forum, I have decided that there are technically better ways to do this. (My apologies to the purists, no disrespect intended.)

My plan B is to mount a ground bus bar close to the rear of the pots. Any thoughts on this or pictures from those who have been here before? Will I get a good enough mechanical connection to the chassis for grounding the pots from the mounting hardware or is something else required?

[M Fowler]

As long as you use a star washer behind the pot and tighten down you don't need to use additional grounding buss.

If you must, then you can use the pot lugs that Mccracer is selling. (see for sale section) https://tubeamparchive.com/viewtopic.php?t=11482

I run a ground buss off the tone board for all the grounding points which has one end to the chassis.

[dynaman]

http://www.c3amps.com/EnlargementPages/ ... oPots.html

Or mount the bar on standoffs to make pot swaps easier.

Or just run pot grounds to board or lug.

[Gibsonman63]

Nice clean work, Dynaman. Lot's of good construction ideas there. I am going to go with the ground bus on standoffs idea. I like the idea of being able to change pots, just in case I overcooked one with my little soldering fiasco.

You guys will probably be the only ones to see the inside of my amp anyway!

[dynaman]

Thanks, but.....it's not my handiwork!

[steviea55]

Hi, If you do a little Forum research, you'll find there are several threads on this subject listed. The ground buss is very important in this amp. I would use pots that have tin backs which can be soldered. Many different brands are available.

[M Fowler]

If your going for the traditional TW look then get pots that you can solder to otherwise there are other ways to do your grounding besides soldering to the back of pots.

Mark

[Gibsonman63]

Thanks for your help gentlemen. I went with the bus bar on standoffs approach last night. I feel that this ground it critical and the solder really wasn't working for me on the stainless steel pots. I learned a trick from another site for wiring the pots. Install them backwards (and upside down) so the shafts are on the inside of the amp, do your wiring, then remount them in the correct orientation. In doing so, I could never get all of the pots to remain attached to the bus bar and when they fell off, ther was absolutely no solder on the pot.

Another advantage I found with the bus bar approach is that the pots don't act as heat sinks, so the solders flows really well on my ground connections.

I know mine won't be an exact copy, but this just seems like a much better ground connection to me based on what I am working with and the results I was getting doing it the traditional way.

I will try to get some pics posted this evening of the bus bar and then start a new thread with my progress as I go along.

[KellyBass]

Do you have a link to that article? I love learning new construction tips.

[Gibsonman63]

As requested

http://aga.rru.com/Events/MM-DRRI-rebuild/

Check out section 10 for that particular trick. I thought the whole artical was a good read, although the author would drive me crazy as a client.

[PCollen]

Thanks for your help gentlemen. I went with the bus bar on standoffs approach last night. (snip...)

.

Just make sure that your buss bar on standoffs is ONLY grounded at one end, preferrably the end closest to the input jack and furthest from the power supply capacitor grounds. Use nylon washer & screws , if using metal standoffs, to isolate the non-grounded end. If you look at a Ceriatone board, Nik often solders the pre-amp buss bar right on the edge of the circuit board and then runs flying leads to it from the pots, input jacks, and pre-amp grounds.The result is a clean, and easily serviceable ground layout, although not official TW layout.

[Gibsonman63]

It seems that I have read this before about just grounding on one end, but I can't think of any amplfiers that follow this convention. Doesn't the traditional TW layout for the bus bar actually ground in five places, one ground on each of the pots? I know my Fenders ground all over the place, but we aren't talking high gain there.

[dynaman]

It seems that I have read this before about just grounding on one end, but I can't think of any amplfiers that follow this convention. Doesn't the traditional TW layout for the bus bar actually ground in five places, one ground on each of the pots? I know my Fenders ground all over the place, but we aren't talking high gain there.

...And that's why I don't solder to the backs of pots but I've done it before and never noticed extra noise, save for a couple of builds. Too tedious for me.

[M Fowler]

I second that motion, only for traditional TW appearance.

[KellyBass]

That WAS a good read. Thanks!

And yeah,...I would not want him as a client...no way!!