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Copyright 2022 by Wayne Stegall
Created
July 5, 2022.  See Document History at end for details.

DIY Mogami Speaker Cables

Coaxial speaker cables improve the sound of my stereo.

Introduction

I had been studying the cable issue and particularly the idea that pro audio cables could give improvements on a budget when I read in an AES paper that speaker cables made of untwisted parallel wire were inadequate because they did not deal with radio frequency interference.  Having read that Mogami coaxial speaker cables sounded better and were cheaper than their twisted pair type (both of which resist RFI on different principles), I decided to build my own.  I ordered 12 foot of Mogami 3082 wire for $14.88 and some banana plugs from Amazon (approx $8-9) and proceeded with a build.  By comparison, World's Best Cables sells these premade for approximately $70.

Assembly

Wanting to have as little unshielded wire exposed at the ends as possible, I examined the geometry of the wires relative to the expected connector spacings and decided that my end wires would be 3 inches.  I then proceeded as in the following pictures.

Figure 1:  Some tools used.
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Figure 2:  Place two 11/4" lengths of 3/8" shrink wrap sections on wire
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Figure 3:  Lightly score insulation with wire strippers 3" from end of wire..
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Figure 4:  Pull off detached section of insulation to reveal shield.
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Figure 5:  Pull shield to side and twist into a wire.
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Figure 6:  Starting from position on insulation next to joint wrap electrical tape around joint to cover all three valleys between pairs of the legs of the Y then up the bare wire 1/2" short of the end.
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Figure 7:  Trim 3/16" shrink wrap to cover electrical tape wound on bare wire to cover all but last 1/2" inch of wire at end.
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Figure 8:  Apply heat from blow dryer on hot setting to shrink wrap until it fit snugly over wire.  Then strip 1/2" of the insulation from the center wire.
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Figure 9:  Place banana plug boots on wire, attach plugs with set screws, and pull boots back onto the banana plugs to their final position.
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Figure 10:   Pull up 3/8" shrink wrap previous placed on wire to cover junction and shrink with blow dryer.
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Figure 11:  Performs previous steps to all wire ends to get a complete set of cables.
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Text

Sound

After initially connecting the new wires, I was disappointed that the sound seemed worse than the Monster type cable previously installed.  So I left my stereo running and pursued other activities.  I came back to find the Mogami cables sounded better.  After a few days, the sound had changed and was now better than the previous cable set.  The sound was smooth and easy with the Christian rock that I was playing.  In order to verify that this was not just rolled off treble I played some music I knew to have a lot of high frequency energy.  In particular, when I played the Celtic song "Into the Light" by Eden's Bridge, the tinkling bells or chimes and cymbals played showed fully extended treble clean of distortion so that you might call it sweet.  Indeed the entire sound was clean.  Limited open-mindedness to cable differences expected a subtle difference.  To my ears these improvements were not subtle.

Someone else who made a set of the cables commented on a diyAudio blog entitled "So I decided to try Mogami speaker cable."  Thunau writes

Anyway, when I first switched from the factory 10' cable to my 7' Mogami home-brew I thought that something was not right. The cable seemed to attenuate the signal by a dB or so. If anything the music should get louder. The Mogami is a 15AWG-14AWG cable and the factory is at most 18AWG, plus it's about 3' longer. The series resistance has to be higher. Also, the low end seemed to be more pronounced with the thin factory wire. Some investigation was in order. First I checked my connections at the amp. The factory cable (which came with bare ends) was tightened using the binding posts, for the Mogami I used Banana plugs. The amp is an older Adcom. I don't know when the binding posts were used last with banana plugs, so I decided to spray them with Caig Deoxit. That took care of the low end. It was now on par with either cable, or at least very close. The treble still was more pronounced with the factory cable making it seem a bit louder. I started to listen for the particulars. When I put on some big band jazz with prominent drums and a lot of cymbal splashes, the difference became obvious. The factory cable is mushing the treble making it harder and noisier sounding, which I at first perceived as "louder". The Mogami cable is resolving the detail in the treble much better. The cymbals sound like cymbals even when hit hard and fighting for aural space with a brass section at the same time. The factory cable has trouble handling it making these passages lose detail.

This was a worthwhile activity.  Worth doing again.





1Jim Brown, "New Understandings of the Use of Ferrites in the Prevention and Suppression of RF Interference to Audio Systems," October 2005, AES Electronic Library, http://www.aes.org/e-lib/
2"So I decided to try Mogami speaker cable," August 7, 2004, diyAudio, https://www.diyaudio.com/

Document History
July 5, 2022  Created.