Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Madkrafter on June 03, 2020, 11:47:51 pm
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On my AB763 Blackface DR build, I am using shielded cable for the four tone circuit runs: inputs > V1, V2 pin 2 and Vol > V1, V2 pin 7. I have some Belden 9396 microphone wire from StewMac for some electric guitars that I made years ago. Does anyone know how this compares to RG174? There are differences in impedance and other electrical characteristics I admit I don’t quite grasp. Should I swap out my 9396 for RG 174?
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> There are differences in impedance and other electrical characteristics I admit I don’t quite grasp.
The ONLY electrical spec that ever matters in small audio is pFd/foot. And this rarely matters because nearly all coax is about 30pFd/ft.
BUT that 9396 is more than twice "normal". You don't want a run of even half normal length. For 6-inch runs it may not matter, unless you are obsessing for ultra-highs. It would be a poor choice for a 30-foot guitar cable for bright lead-riffs.
Are you having a problem or just in a reading-mood?
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Thanks PRR. I am not having a problem... yet. I am waiting on 6 resistors that were missing from my build kit. They should be here Friday from Antique Electronics. I have two of the four runs soldered. The other two need the missing resistors for the input jacks. I just placed another order tonight :dontknow: for more resistors and a SPDT 3-position switch for RobRob's 3-Way NFB Switch mod. I also put some RG174 on my order. Sounds like it might be worth my time to switch it out since it's just a couple quick re-solder joints.
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Sansteeth forum member find what it look a good shielded cable ;
https://el34world.com/Forum/index.php?topic=26059.0
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I just want to say . if you need parts quick Doug has the best and fastest service . Usually I have my order within 2 days and I live on the west coast. I guess a ( Thank You Doug) is in order.Thanks Bill