Hi!
In the preamp section of my guitar amp there are several wires running from preamp tubes to gain pots and tone stacks, and back. The tubes are located at the back of the chassis and the pots are at the front panel, so some of these wires are relatively long and thus I’ve decided to replace them with shielded ones. The amp is star grounded and has local grounds for each preamp section. Most parts are point to point wired and are clustered around either the tubes or the tone stacks. I know that only one side of the shield is to be grounded and that the input wire’s shield should be connected to the isolated input jack’s ground which is then wired to the first stage local ground. How about the following stages thought?
Where is best to connect the shields of these long wires to:
1. the local star ground (which is usually closer to the tubes), or
2. the ground of a volume pot which is then run separately to the local star ground, or
3. the main preamp section local star ground, or
4. the main preamp section local star ground by a wire connected to say the middle (rather than the end) of the shielded wire, where part of the insulation could be stripped, or
5. the chassis?
Thanks and apologies for the newb questions. I did search but was unable to find anything specific enough on this.
V.
In the preamp section of my guitar amp there are several wires running from preamp tubes to gain pots and tone stacks, and back. The tubes are located at the back of the chassis and the pots are at the front panel, so some of these wires are relatively long and thus I’ve decided to replace them with shielded ones. The amp is star grounded and has local grounds for each preamp section. Most parts are point to point wired and are clustered around either the tubes or the tone stacks. I know that only one side of the shield is to be grounded and that the input wire’s shield should be connected to the isolated input jack’s ground which is then wired to the first stage local ground. How about the following stages thought?
Where is best to connect the shields of these long wires to:
1. the local star ground (which is usually closer to the tubes), or
2. the ground of a volume pot which is then run separately to the local star ground, or
3. the main preamp section local star ground, or
4. the main preamp section local star ground by a wire connected to say the middle (rather than the end) of the shielded wire, where part of the insulation could be stripped, or
5. the chassis?
Thanks and apologies for the newb questions. I did search but was unable to find anything specific enough on this.
V.
Generally, these wires are by design far away from the output transformer & power supply, and in their own corner, shielding won't make a great deal of improvement.
If you do go that route, I would connect them to a bus or grounding scheme at the side where the pots are, rather than the tube end.
If you do go that route, I would connect them to a bus or grounding scheme at the side where the pots are, rather than the tube end.
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