Longer instrument cable (synth) sounds audibly worse than shorter one - why?

Or check the cable for the prescence of a conductive layer on the outside of the center insulator,
Shorting/resistive path to gnd,?
Jus sayin ?

JohnRoberts said:

...
Perhaps discard the cable that sounds bad
...

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yes+no

put it in a drawer and label it as "LO-FI MOJO SPECIAL". use it as a special effect once in a while

who knows, it may just provide some special mojo on a special occasion

It is worth understanding why, and then throw it away.  ;D

JR

JohnRoberts said:

It is worth understanding why, and then throw it away.  ;D

JR

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I've been wondering when I'd find a proper quote to use as a signature. May I? Pretty please?

Well, one possible explanation would be that a cable could be represented as a distributed parasitic capacitance (and other unwanted parasitics)

so instead of a RLC low pass filter, it would look more like RLCLCRLC...RLC... - and that would be much more detrimental to any transients trying to pass that cable

In other words, it is like you have a wire, choke full of Blue Meanies,
http://en.wikipedia.org/wiki/Blue_Meanies_(Yellow_Submarine)
... each one bitting away some piece of your music, and at the other end, only the leftovers could be heard

Since 7 meters is a relatively short distance at audio frequencies, doesn't the lumped element model still suffice?

dfuruta said:

Since 7 meters is a relatively short distance at audio frequencies, doesn't the lumped element model still suffice?

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that's "officially"...

...but when your tone gets mushy when passing across a 7-metre long coaxial capacitor, you start to question the official science truisms.

I've replaced that cable (no visibible damage, thickly insulated drilled coaxial cable) with a couple old and very thin cinch cables connected via cinch couplings I had lying around. Sounds good now.

How do you measure capacitance with the resistance being that low? I tried it with my multimeter, but it doesn't show reliable readings...

tv said:

dfuruta said:

Since 7 meters is a relatively short distance at audio frequencies, doesn't the lumped element model still suffice?

Click to expand...

that's "officially"...

...but when your tone gets mushy when passing across a 7-metre long coaxial capacitor, you start to question the official science truisms.

Click to expand...

The established science of electricity flowing in metallic conductors is mature and well understood. The official science has withstood many challenges from the audiophool community, as long as there have been audiophools (as long as I can remember).

Have you ruled out that there isn't something wrong with the cable, or the circuitry on both ends. There could be some subtle flaw in the cable or interaction with circuitry that isn't apparent.

I would look somewhere else other than the fundamental science of conductors. It you hear it, it is real. figure it out, without rewriting the physics.

Measure, isolate, identify.

JR

PS: You could measure the capacitance by creating a one pole LPF. Simply drive the center of the grounded cable through a 100k resistor and look for the -3dB point with a scope.

For the cable guess about 39pf a foot but I would guess yours is higher.  Is the cable cable high or low capacitance.  you can sometime find an alphanumeric marking on a cable and search for the specs.

What brand is the cable?

Have you tried it with the stock opamps and the longer cable?  maybe the "better" one is oscillating.  I would doubt you can hear a x3 741 buffer sound different than newer chip opamps.  Just because a chip is older tech does not mean a new one will work "better"

You could up the output resistance value and/or check how well the "upgraded" 3 opamps "share" with the 4.7 ohm resistors

Look into what C13 is doing.

A tele is a passive device and a guitar electronics will interact with the cable capacitance.

Followers can look simple but they can be a challenge to get to work well sometimes

I had a lenghty duel with guitar cables some 20-25 yr ago. I couldn't match the tone of a (standard length) cable(s) to that of a short cable(s) into the same "input", no matter the loading I emulated (with RC passives).

iow, with a shorter cable (50cm or 1m), I was unable to replicate the same tonal response as it was when using longer cables (selected "standard" studio instr. cables, klotz, proel etc), no matter how "close" to the measured cable capacitance I approximated the "artificial loading". The resulting tone was obviously different, and I ran so much tests that confirmed what I was hearing (also used some of these gadgetry on "less critical" recordings, fe jingles etc, on more serious sessions producers wouldn't let me use it).

My conclusion is that there must be something more to the story.

Now waiting for the lab cats for a scientific breakdown and analysis.

It's definitively the cable, results were the same with my Juno-60. So the schematic of the Polaris ouput or the op amp are not relevant.

There are no further markings on it. It's a cheap instrument cable, I wasn't expecting it to make a difference. The other cheap instrument cables here, regardless of length, are all fine.

I'll try measuring the capacitance per John's suggestion.

Thanks everyone!

Gus said:

I would doubt you can hear a x3 741 buffer sound different than newer chip opamps.  Just because a chip is older tech does not mean a new one will work "better"

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In this case it sounds a lot better, subjectively.

tv said:

My conclusion is that there must be something more to the story.

Now waiting for the lab cats for a scientific breakdown and analysis.

Click to expand...

If you can hear something reliably, you should be able to measure it. If we can measure it we can fix it.

I don't expect a cable to be a perfect capacitor, inductor, resistor.

Cable capacitance could also interact with driver electronics in subtle ways.  Suppose your high output source was trying to put out a loud high frequency signal, but the driver was challenged for drive current. It might slew limit in the presence of transients causing IM distortion or more.

There is always a scientific explanation for any real phenomenon.  Note: my slew limiting is just a hypothetical.  If you had a stereo path you could put one of each cable in a leg and null them to help isolate the error.

JR

No.. well, I heard the difference repeatedly with multiple cables, over a couple of years span, compared and debated then with other instrument players (for some reason, studio owners and techs/producers tried to completelly evade/ignore/downplay this issue). This was not an isolated incident.

Also I don't believe there was slewing involved - it sounds different (I know how it sounds, I "designed" slewing into some of my circuits, speaking of my experience)


But now there is a known cable with known effect so hey, why not dissect it?

I mean there must be something more to the story - why would fe audiophiles spend fortunes on cables - or else? I don't think it's as one-dimensional as to proclaim "this cable has capacitance so-and-so, resistance so, and inductivity so-so".. but what do I know?

s2udio said:

Or check the cable for the prescence of a conductive layer on the outside of the center insulator,
Shorting/resistive path to gnd,?
Jus sayin ?

Click to expand...

Hello. Was this checked (if there is one present)? Sometimes people aren't aware that the conductive plastic layer (which I understand is to deal with the noise when the cable is moved around) needs to be dressed (cut) so it isn't contacting hot (otherwise the signal is loaded down).