Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jly56 on December 14, 2015, 07:58:20 pm
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Hi..
Sorry if this is a dumb question.... I am building a Hoffman 5f6a in a JTM45 chassis - nice having room to work! I usually build them with only two input jacks instead of the usual four. I would like to add a switch to bridge CH1 into both sides of V1 (pins 2 & 7) and remove CH2 from the mix. I'm using RG174 shielded cable and the 33K resistors are at the tube.
Most examples of bridging (paralleling) jacks (TUT1 or on this site) show using the standard Hi/Low jacks for each channel... and I'm not clever enough to adapt it to a single jack configuration.
Would DPDT switch in attachment 1 work?
Where would I attach the shielding ground from the RG174 running between the tube and the switch?
Do I need to use RG174 between the jacks and the switch? It would only be a couple of inches between the jacks and the switch..
Attachment 2 is everything, so far.
Thanks for your input.
Jeff
Sorry the pics flip when you expand them...not sure what I'm doing wrong.
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Your drawing will do what you want. Attach the shields to the ground lugs on the input jacks. No need for shielded cable for the short run between the jacks and switch.
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Thanks Steve...