Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: p2pAmps on November 14, 2020, 06:40:18 am
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Hello Team builders,
I wanted to share an idea you may want to give a go. It's nothing new thats for sure but I have found this to work VERY well on Hoffman PR type builds. Instead of grounding to the back of your pots or direct to the chassis on your signaling stuff check out the ground buss. Again, nothing new here. I have started to adopt this for every build now as it really makes grounding trouble free for me. The buss where the pots and cathode grounds go attached to the chassis very near the input jacks. The buss is also a great place to keep your signal wiring neat and away from any B+ headaches. The power section grounds near the PT. Take a peek at the pics and you will see what I mean. Now I know there are many pros on this forum so please chime in if you see a better way and I will certainly listen. As always, Cheers!
note: knob in the back is a mid control in case you are wondering :)
(https://images.squarespace-cdn.com/content/v1/56fbe87462cd94ff6ec9d02c/1605357028577-S51B5NAF4W061GP63W3I/ke17ZwdGBToddI8pDm48kPoswlzjSVMM-SxOp7CV59BZw-zPPgdn4jUwVcJE1ZvWQUxwkmyExglNqGp0IvTJZamWLI2zvYWH8K3-s_4yszcp2ryTI0HqTOaaUohrI8PIeQMKeWYgwh6Mn73n2eZmZLHHpcPIxgL2SArp_rN2M_AKMshLAGzx4R3EDFOm1kBS/Ground+Biss.jpeg?format=2500w)
(https://images.squarespace-cdn.com/content/v1/56fbe87462cd94ff6ec9d02c/1605356993175-F53YWG9IML9BK0CBSR8F/ke17ZwdGBToddI8pDm48kL3VKmwKI3leYB51VJjLFB8UqsxRUqqbr1mOJYKfIPR7LoDQ9mXPOjoJoqy81S2I8N_N4V1vUb5AoIIIbLZhVYxCRW4BPu10St3TBAUQYVKcgK5SGg9Ovb1yloBBOHcruw_mYLfAhRzzgArFCB07Dw0L8n4JypuoE5Tg6Wg5Oyvs/1.JPG?format=2500w)
(https://images.squarespace-cdn.com/content/v1/56fbe87462cd94ff6ec9d02c/1605356995659-PVIWLCVK7L5NMI4IUWLM/ke17ZwdGBToddI8pDm48kL3VKmwKI3leYB51VJjLFB8UqsxRUqqbr1mOJYKfIPR7LoDQ9mXPOjoJoqy81S2I8N_N4V1vUb5AoIIIbLZhVYxCRW4BPu10St3TBAUQYVKcgK5SGg9Ovb1yloBBOHcruw_mYLfAhRzzgArFCB07Dw0L8n4JypuoE5Tg6Wg5Oyvs/4.JPG?format=2500w)
(https://images.squarespace-cdn.com/content/v1/56fbe87462cd94ff6ec9d02c/1605356997638-JG61S8KPM97G0QRA64J1/ke17ZwdGBToddI8pDm48kL3VKmwKI3leYB51VJjLFB8UqsxRUqqbr1mOJYKfIPR7LoDQ9mXPOjoJoqy81S2I8N_N4V1vUb5AoIIIbLZhVYxCRW4BPu10St3TBAUQYVKcgK5SGg9Ovb1yloBBOHcruw_mYLfAhRzzgArFCB07Dw0L8n4JypuoE5Tg6Wg5Oyvs/6.JPG?format=2500w)
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I and many others who contribute here use the same or similar ground buss scheme. I sometimes use a single insulated turret to secure the far end of the buss if it is not well secured by a pot ground. I gave up soldering to the backs of pots years ago as it seemed foolish to put that heat stress on pots, and its the first solder joint to fail as there is no mechanical connection. I do not cable tie any leads to the buss, probably for the same reason I do not organize my sock drawer and never arranged my LPs in alphabetical order. :icon_biggrin: Your work is nice and neat; neater than mine.
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Looks really neat and tidy! Ill certainly consider it. What are you using for the buss bar?
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It looks like 14/16ga solid copper wire stripped from some romex. It's what I have used as well. It's rigidity is usefull.
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I do something similar with #12 square bus wire, which is fairly rigid and pre-tinned. Tubesandmore carries this.
Quit soldering to pots after making mistakes on one of my first builds, and it was a pain to disassemble . . . Now when I goof, or want to experiment, I don't have to take out the entire front panel, or cut the bus itself.
Nice and neat looking work! :happy1:
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Looks really neat and tidy! Ill certainly consider it. What are you using for the buss bar?
I take a piece of cooper from some romex, stick one end in the vise and the other in my drill. Then spin it some and it will be laser straight! Fun little trick :)
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Looks really neat and tidy! Ill certainly consider it. What are you using for the buss bar?
I take a piece of cooper from some romex, stick one end in the vise and the other in my drill. Then spin it some and it will be laser straight! Fun little trick :)
I use the drill trick with the square bus wire. It ends up with a cool looking twist and is very straight and quite stiff. Looks cool.
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I learned to do the preamp ground buss over at 18watt.com
I use 1.2mm silver plated solid copper wire. The non plated appears to require too much heat, so soldering components directly on that will fry them without use of heat sink
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I learned to do the preamp ground buss over at 18watt.com
I use 1.2mm silver plated solid copper wire. The non plated appears to require too much heat, so soldering components directly on that will fry them without use of heat sink
Why not pre-tin the entire length of the ground bus copper wire prior to attaching any components?
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I learned to do the preamp ground buss over at 18watt.com
I use 1.2mm silver plated solid copper wire. The non plated appears to require too much heat, so soldering components directly on that will fry them without use of heat sink
Why not pre-tin the entire length of the ground bus copper wire prior to attaching any components?
Why bother? It's available at Tubetown.. ready to be used
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Why not pre-tin the entire length of the ground bus copper wire prior to attaching any components?
That's what I used to do. What a pain in the ass! Then I switched over to 17AWG electric fence steel wire. Smaller, stiffer, and neater that romex copper. Never going back again. Silver (tin) plated copper 16AWG buss would be my first choice if I wasn't cheap. :icon_biggrin:
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Dang, this stuff is cheap as chips... I'll pick some up. Thanks for the tip.
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And you can use it to keep the kids off your lawn. :cussing:
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I take a piece of cooper from some romex, stick one end in the vise and the other in my drill. Then spin it some and it will be laser straight! Fun little trick :)
Huh?
If both ends are 'pinned' and you spin it wouldn't it twist the wire?
I don't understand. :dontknow:
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I've done it for a few projects and it does twist the wire - but no harm as long as you stop once it is straight.
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I've had a Carolina Overdrive Special with reverb that was reasonably quiet at levels I play at. However, if one really cranked the amp then there was some slight hum. I probably tried 5 or 6 times over a year period to get rid of this last little bit of hum but to no avail.
I decided to try this method of the buss wire floating as illustrated in the first post.
Result is there is absolutely NO hum! Zero! Only hiss white noise. And this is a reasonably high gain amp. Hooray! Not saying this will work for every amp but it resolved the issue on this amp completely.
With respect, Tubenit