Replacing the CAT5 with your choice of solid core wire instructions.

[ssssly]

Having previously experimented with using CAT5 in the signal path of preamps (FPII and III) I know I don't like the way is sounds. So I never planned to use it in my Beepre.

Since I have plenty of Mundorf Silver/Gold solid core wire and cotton tubing, that was selected for the input and output wiring.

This also required redoing the directions for point to point vs. color coding. So here are the directions I wrote up for myself to wire the input and output.

Ground tab R1 to rotary switch 9
Center pin R1 to rotary switch 12

Ground Tab L1 to rotary switch 6
Center pin L1 to rotary switch 3

Ground tab of R2 to rotary switch 8
Center pin R2 to rotary switch 11

Ground tab L2 to rotary switch 5
Center pi L2 to rotary switch 2

Ground tab R3 to rotary switch 7
Center pin R3 to rotary switch 10

Ground tab L3 to rotary switch 4
Center Pin L3 to rotary switch 1


(Attach don't solder) Ground tab LO1 to 13U
(Attach don't solder) Center pin LO1 to 12U 
12U-13U 475K 14W metal film (4753F) Solder 7&8U

(Attach don't solder) Ground tab RO1 to 8U
(Attach don't solder) Center pin RO1 to 7U
7U-8U 475K 14W metal film (4753F) Solder 7&8U

I have not wired this yet so I can't say that I didn't botch the directions somewhere. Once I wire it I will post back with if it worked correctly the or revise with any corrections that were needed. Or if you notice that I made a mistake somewhere, please correct me.

And hopefully before I wire it wrong myself. 

Enjoy

 

[ssssly]

Some progress. Decided that I needed some shielding. Looking at the bare cotton wires running between two power transformers set off some bells. So i decided on a copper tape wrap. Works pretty good for RCAs so I figured I'd give it a shot.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8253%2F8618988830_b8798ec403_c.jpg&hash=4dddedc2ee75d26e65d3c708cbc604c55f5aa75e)

Then some cloth tape.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8533%2F8617881697_ffc3017034_c.jpg&hash=4b543f3711592471ef969852cd462e6c3ef0d287)

And a second layer.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8386%2F8618989230_e40687befc_c.jpg&hash=bb84ea62d0459c14b67e45d7382118529ff5e60f)

And a bit of techflex for safe measure.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8244%2F8617882113_5c234372a8_c.jpg&hash=6dd3b949e62bd9bdcaf0bfbf3d59d4c8c299f42f)

Hopefully it will keep the gremlins out.

[Grainger49]

Ok, kind of sadly, I think about these things.  Since there are two transformers and they are opposite hand, shouldn't the magnetic fields cancel each other out?  No, I'm serious.

[ssssly]

Electromagnetic fields in practicality, don't cancel each other. They only interfere with each other.

I find it easier to absorb them than attempt to decrease their amplitude via off phase interference. That and because of their size, the only place that there would even be an appreciable effect, would be an area the distance of half a cycle of the wave. So fractions of a millimeter in either direction from exactly in-between the two sources. And that would only be if they were exactly 180 degrees out of phase and directly propagated at one another.

Otherwise you just get a neat lattice of peaks and troughs of various amplitudes. Which is easily manageable in 2D. But in 3d and for this purpose, a bit unruly for me. It does look super cool though.

If you had a sensitive enough meter, you could turn the amp on and then move a wire through the field to see the best place to re-rout the wires. But I neither have sensitive enough equipment nor the patience to do it. Hence the brute force method.

[Doc B.]

I suspect that method of shielding will be most effective for electrostatic interference. Twisted pairs would be a good idea to help cancel the the influence of the magnetic fields, or very symmetrical and evenly spaced coax style shielding.

[johnsonad]

Attached are a few pics of how I did it.  First I twisted all of the wire.  Second, soldered it to the jacks and labled the other end of the twisted pair.  Third I wrapped the bundle in aluminum foil and wrapped it in a drain wire.  Lastly I covered it in tech flex.

[ssssly]

I did loosely square braid the wires through the middle. Can kind of see it in the pic with the first layer of copper tape.

Think I may do the other two inputs with different wires for experimental purposes. See what works better with what source.

Debating doing input 2 with Belden 89259 and 3 with some milspec 75ohm coax I picked up from work.

Will see how it sounds. If it is still picking up noise or EM interference I may try some active shielding.

[ssssly]

Modified the original post, there was a typo that had two wires going to terminal 10. Fixed now.

[kaleb]

Hi- I'm thinking of doing similar. Can you estimate the total length you needed? Thanks!