Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Diverted on August 26, 2019, 08:12:44 am
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Hi, I'm wondering if anyone has opinions on finding good low niose shielded cable. This is for a foot switch that will have tremolo, reverb and a raw/gain boost switch (tone stack bypass). I've seen lots of wire on eBay with the thin aluminum sleeve and a bleeder wire. Not sure if it's any good for these applications though and if I should instead be getting something with a nice thick woven sleeve.
Thanks!
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The best has to do with how many conductors generally. Go here:
http://www.canare.com/ProductItemList.aspx?productCategoryID=5
Find what you prefer. This is not cheap, but you can believe me when I say it will work. Normally we do not need a lot, but if you do get some here:
https://www.ebay.com/itm/Shielded-20AWG-Twisted-Pair-PTFE-A-E-PETSCHE-Wire-M27500-20JC2N08-40-Feet/192891621685?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
If you need more than 20 feet, message him and he will discount more. This is PTFE, which is Teflon not branded. I used this on a HIFI build recently and was very pleased,
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Thanks Ed. Got kind of lost looking for three-conductor cable in the first link; didn't know about the various ohm readings and if one would be better than another; second link is only two conductor (one short of what I need). But thanks for the suggestions!
I have seen a bunch of four-conductor shielded cable on eBay; they are in twisted shielded pairs. If anyone can speak of whether that aluminum shielding sleeve is adequate for these purposes or not, i would love to know!
Thanks.
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Yes, it's fine. FAA has hundreds of miles of that stuff in use.
You need to specify exactly what you need. Reverb will likely need a shield. Tremolo usually doesn't need a shield but it's OK to use a shield. If your raw/gain boost switch is just gonna lift the ground of a typical Fender/Marshall type tonestack then you will need a shield for that. However, if you will be using a relay to switch the tonestack and just using the footswitch to control the relay coil, you don't need shielded (probably not your case). So, that looks like a cable with two shielded signals and one unshielded signal. Is this what you need?
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Hi, I'm wondering if anyone has opinions on finding good low niose shielded cable. This is for a foot switch that will have tremolo, reverb and a raw/gain boost switch (tone stack bypass). I've seen lots of wire on eBay with the thin aluminum sleeve and a bleeder wire. Not sure if it's any good for these applications though and if I should instead be getting something with a nice thick woven sleeve.
Thanks!
The foil shield will function as well as a braided shield, but is not as durable. For a foot switch application I would look for braided just because it will take the abuse and last longer.
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Depending on how long you need the cable to be, you might pick up a USB cable and cut the ends off. Being a commercial commodity it can be cheaper than buying an equal length of shielded cable from Mouser or Digi-Key.
USB cables typically have two twisted pairs with a braided shield and tend to be durable (some more than others.) One of the twisted pairs is for power and the other data. The power pair will be thicker wire, but in your application you can use the four wires in any way you want. Having said that, I would use one of the thick wires for ground and connect the shield itself only at the amp end.
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Thanks!
My plan is to have at least three, maybe four, switches on a foot pedal:
1. Tremolo cut
2. Reverb cut
3. Gain boost (raw stack). I wired this in already with a 100K resistor across the foot switch so the boost wouldn't be too crazy loud.
But I would also like to put tremolo there and possibly, if I can do it, move the channel switch to a DPDT foot switch as well. F0r this I would need two conductors (one for the input jack end of the switch and one for the plate out).
So what I'm looking for is three shielded conductors (gain, tremolo and reverb) or five conductors (gain, tremolo, reverb, and two wires for the channel switch). Thank you!
As for now amp is playing great and I can't thank everyone enough for their suggestions and help in setting it up. Pic attached.