Belden 8402 IC

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Steve

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Re: Belden 8402 IC
« Reply #180 on: 27 Jul 2017, 04:32 am »
This is a good discussion, very interesting.  Steve, from an inductive reactance perspective, which cable type is more suitable as interconnects, coax or twisted pair?

I use neither and tough to determine between the two. Pros and cons.

Twisted pair, by definition, means higher inductive reactance of each wire due to the wires being twisted/coiled. That simulates a single layer air core inductor. One then hopes to cancel the inductance by proximity of the two wires.

So does twisting or braiding really help to prevent interference VS non twisted close parallel wires?

Quote
Results show regardless if the loop wires are twisted or untwisted detection is not affected. Furthermore, the test results show that no “canceling of the EMFs” (Electromagnetic Fields) are taking place.

If an amp has a problem with RF, it is designed poorly imo. I live within 6 miles of mega watt TV stations and not a hint.

Coax, like RG58U, typically has some 93pf/meter. However, I should say that inductance may be more or less, depending upon the insulation thickness, size of wire, and how wire is twisted. I like to use superior quality copper wire which one cannot obtain in typical coax. Probably tough call for most. I would say, do a listening comparison.

Personally, I use two 22 gauge unshielded wires inside 1/8" tubing, not twisted. The capacitance is only 39pf for one meter. The inductance is reduced both because of no coiling/twists (straight wire inductance) and because of proximity of the two wires. I even use a pair between my Turntable and MM phono stage with just a hint of hum with the volume control at max.

Cheers
Steve





« Last Edit: 27 Jul 2017, 01:45 pm by Steve »

rotarius

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Re: Belden 8402 IC
« Reply #181 on: 28 Jul 2017, 05:54 pm »
Steve, thanks for the detailed response. 

Steve

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Re: Belden 8402 IC
« Reply #182 on: 28 Jul 2017, 09:37 pm »
Steve, thanks for the detailed response.

Your welcom Rotarius. A couple of decades ago, I assumed all ICs "sounded" the same, except for capacitance. After reading some comments that they "sounded different", I decided to perform my own experiments.
 
That first experiment was to build two identical ICs, one with plugs and one without. They were identical in capacitance, inductance, of course DC resistance. Amp input Z was 100,000 ohms, and capacitance was 39pf.

I plugged the first pair into the cd source and the other end into my preamplifier. The 2nd pair I soldered at the jacks of the source and soldered on a different input of the preamplifier, at the jacks. I had super high quality silver contact selector switch in the preamplifier. I not only checked the resistance of both ICs into the source and preamplifier, I also reversed the ICs into the preamplifiers. All I had to do was flip the selector switch back and forth, or have another individual flip the selector switch.

I was amazed how much different the soldered ICs "sounded" VS the 1st pair that was plugged in. I still test periodically, over the years.

Cheers

Steve
« Last Edit: 30 Jul 2017, 03:40 am by Steve »

rotarius

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Re: Belden 8402 IC
« Reply #183 on: 31 Jul 2017, 10:22 pm »
Your welcom Rotarius. A couple of decades ago, I assumed all ICs "sounded" the same, except for capacitance. After reading some comments that they "sounded different", I decided to perform my own experiments.

Funny you mentioned this because for years I never bothered to play around with cables, never heard much of a difference.  Because of my engineering training (not EE), I knew most of the cable marketing is bs.  For some reason with my current speakers KEF R700, the cable changes are quite audible.  In fact, for the Belden 8402, I did notice a difference using switchcraft vs other connectors.  So, agree with you 100%.
For people interested in 8402/8412, try some solderless connectors as well.  Very nice result in my case.

Speedskater

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Re: Belden 8402 IC
« Reply #184 on: 1 Aug 2017, 12:02 am »
I think you misunderstand. Those links are not all about RF, but shows the impedance rise that occurs when a coax/transmission line deals with audio frequencies vs RF frequencies.
* * * * * * * * * *
Once again those are "Radio Frequency Characteristic Impedance" values and how they go bananas when you get down below 100 kHz.

While a coax maybe be used in a transmission line, the coax is only one third of a transmission line.
A complete well matched transmission line system consists of:
a] Output stage.
b] Line either coax or twisted pair.
c] Input stage.
  Now to be well matched, all three parts need to have the same "Radio Frequency Characteristic Impedance" at the frequency in question. That's a tough trick at audio frequencies with the impedance changing for each frequency.
 Also the transmission line needs to be a good fraction of a wavelength long.
 That's thousands of feet at audio frequencies.

Steve

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Re: Belden 8402 IC
« Reply #185 on: 1 Aug 2017, 04:37 am »
I think you misunderstand. Those links are not all about RF, but shows the impedance rise that occurs when a coax/transmission line deals with audio frequencies vs RF frequencies.
* * * * * * * * * *
Once again those are "Radio Frequency Characteristic Impedance" values and how they go bananas when you get down below 100 kHz.

That is correct Speedskater, the impedance (Z) of the cable rises below 20khz audio frequencies. And how is that reactance determined?

Quote
The LF curves (yellow) use expressions with the fixed limiting values of Rc and Lc and are therefore accurate for f < ~ 20 kHz.

http://www.jensign.com/RG58U/index.html



First, there is not complete cancellation between shield and inner conductor since they would both have to occupy the exact same space, which they do not, so the shield has inductive reactance.

Secondly, the shield is in parallel with both pin 1 and with the other channel's IC shield, thus musical return current will flow through the IC shield, the other IC shield and pin 1 in the power cord. The result is, again, more inductive reactance in the shield. It is definitely not only the DC resistance of the shield.

Cheers
Steve
« Last Edit: 1 Aug 2017, 06:00 am by Steve »

Speedskater

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Re: Belden 8402 IC
« Reply #186 on: 1 Aug 2017, 12:15 pm »
For an unbalanced interconnect, the problem is Common Impedance Coupling noise. CIC noise is all about 60 hZ and it's low harmonics. For all practicable purposes in a coax cable,the  DC resistance, 60 hZ AC resistance and 60 hZ impedance of the shield end-to-end are all the same. The Ohm-meter scale on DMM will give you, way more accuracy than you need.

Steve

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Re: Belden 8402 IC
« Reply #187 on: 1 Aug 2017, 03:25 pm »
For an unbalanced interconnect, the problem is Common Impedance Coupling noise. CIC noise is all about 60 hZ and it's low harmonics. For all practicable purposes in a coax cable,the  DC resistance, 60 hZ AC resistance and 60 hZ impedance of the shield end-to-end are all the same. The Ohm-meter scale on DMM will give you, way more accuracy than you need.

You are suddenly changing directions, now only 60hz CIC problems. If you had read my previous posts, I was addressing problems to 20khz. So why the criticism?

Cheers
Steve

ohenry

Re: Belden 8402 IC
« Reply #188 on: 21 Sep 2017, 05:38 am »
Over the past few months I've made some Belden 8402 and 8412 ICs using the Switchcraft black/gold RCAs and I can't tell a difference in the two cables.  I really do like these ICs and have found them to provide good imaging, detail and frequency extension.  Clarity is a word that comes to mind when I use them.  They seem to sort out complex music passages very well.  They are flexible, robust and quiet. The RCA connectors are well made and fit their respective jacks perfectly.  So far, I can't find a reason to fault them.  :)

I got the Switchcraft connectors at Best-Tronics and have found the Belden 8412 cable at Parts Express by the foot.  The 8402 and 8412 do look identical except for the exterior jacket as mentioned here before.  Best-Tronics still sells the 8402 cable in bulk or assembled into ICs.

I noticed a post here tonight stating that the shield should be connected on both ends to get better lower mid response.  I haven't tried that yet with the homemade cables as the shield on mine are only connected on the upstream end.  I do have an assembled pair from Best-Tronics connected on both ends and will compare the two soon to see if I can tell a difference.

The Belden ICs slightly better the Oyaide PA02 with copper Eichmann connectors IMO... and do it for less money.

wushuliu

Re: Belden 8402 IC
« Reply #189 on: 21 Sep 2017, 01:32 pm »
Over the past few months I've made some Belden 8402 and 8412 ICs using the Switchcraft black/gold RCAs and I can't tell a difference in the two cables.  I really do like these ICs and have found them to provide good imaging, detail and frequency extension.  Clarity is a word that comes to mind when I use them.  They seem to sort out complex music passages very well.  They are flexible, robust and quiet. The RCA connectors are well made and fit their respective jacks perfectly.  So far, I can't find a reason to fault them.  :)

I noticed a post here tonight stating that the shield should be connected on both ends to get better lower mid response.  I haven't tried that yet with the homemade cables as the shield on mine are only connected on the upstream end.  I do have an assembled pair from Best-Tronics connected on both ends and will compare the two soon to see if I can tell a difference.


Yes definitely compare with shields connected. Shouldn't be subtle.

ohenry

Re: Belden 8402 IC
« Reply #190 on: 21 Sep 2017, 03:40 pm »
Yes definitely compare with shields connected. Shouldn't be subtle.

I did compare and noticed a subtle change for the better.  I made the comparison connecting a Hornshoppe Truth preamp to an Audiosector Patek clone amp that are both brutally revealing pieces.  I didn't perceive a change in noise or clarity (a good thing).

One minor point I forgot to mention regarding rolling your own.  If you want to mimic the Best-Tronics use of a small length of heat shrink tubing at the RCA plugs for strain relief (not really necessary, but nice), use the 3M 3/8" thin walled 2:1 heat shrink tubing.  The usual 3:1 tubing is a little too thick walled to allow the plug covers to slide over them when using the Switchcraft RCAs.  Again, good ol' PE sells the stuff in 4' lengths.

Happy cobbling and listening...

bacobits1

Re: Belden 8402 IC
« Reply #191 on: 21 Sep 2017, 05:03 pm »
I do like the 8402 cables. I made my own and did connect the shielding at both ends.



After nicly soldered I take a 6" piece of Teflon plumbers tape doubled over. Insert between the soldered connections and wrap.
Then use a short piece of shrink to cover. Isolates the connection and dampens the plug a bit. After that the plug ain't going nowhere!

ohenry

Re: Belden 8402 IC
« Reply #192 on: 24 Sep 2017, 01:08 am »
I made another set today.  These ICs remind me of Occam's "Sarah Lee" power cords.  They just do a great job for little money and effort, and get out of the way.  It's always nice to find little bargains along the way that make life better.  And, they allow me to tinker a bit as well.

Next up: Bob Crump's Belden 19364 power cables.  Just waiting for the IECs to arrive.  :)

srb

Re: Belden 8402 IC
« Reply #193 on: 24 Sep 2017, 01:55 am »
I made my own and did connect the shielding at both ends.

According to the spec sheet using the shield in parallel with the signal return wire doubles the capacitance value compared to conductor to conductor capacitance, so in a grounded (non-floating) audio circuit it would seem to somewhat nullify the promise of the 8402 being a "low capacitance cable".

I would probably connect the shield at one end and hope that it might provide a small measure of EMI/RFI supression ala Faraday shield.

bacobits1

Re: Belden 8402 IC
« Reply #194 on: 24 Sep 2017, 02:03 am »
I followed the Jeff Day
Yazaki-san formula.
I agree all my others are floating at one end always made them that way.

ohenry

Re: Belden 8402 IC
« Reply #195 on: 24 Sep 2017, 02:53 am »
I'm following the leaders as well.  They must have an experience to prefer it that way.  I did make a pair with one shield connected and didn't perceive an advantage (and they were oriented correctly). 

Though it is cool to have directional arrows on the outer jacket.  :D

rotarius

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Re: Belden 8402 IC
« Reply #196 on: 27 Sep 2017, 01:39 am »
FYI, I found the Belden 8422 to be a great alternative to the 8402/8412 wire.  Lower capacitance, PE insulation and a tad tighter in the bass in my system.

wushuliu

Re: Belden 8402 IC
« Reply #197 on: 27 Sep 2017, 02:14 am »
FYI, I found the Belden 8422 to be a great alternative to the 8402/8412 wire.  Lower capacitance, PE insulation and a tad tighter in the bass in my system.

Interesting. Certainly lots of Belden wires to try out. The tighter bass could be due to the smaller gauge - 22awg vs 20awg of the 8402/8412.

thanks for the feedback

Wind Chaser

Re: Belden 8402 IC
« Reply #198 on: 6 Oct 2017, 06:35 pm »
So I just ordered a 12' pair of these balanced cables with "High Clarity G&H XLR Connectors" through Best-Tronics Professional Audio. A few days ago I also ordered some shorter (2M/6.5') wireless single ended Game Changer liquid IC cables from TEO.

It will take a while for everything to break in ... new amps, DAC and cables ... but it should make for a very interesting comparison. I won't be comparing measurements, technical merits and all of that other stuff that seems to matter so much to some. No, there's only one thing that ultimately matters to me as a music lover; that is, how does it sound?

So a big thank you to all those contributors in this thread who recognize that. And for those of you with so much to say about a cable you haven't heard - really?? Haven't you anything better to do??   :nono:


WireNut

Re: Belden 8402 IC
« Reply #199 on: 6 Oct 2017, 08:30 pm »
Fwiw, the best inexpensive RCA male plug IMO is the Amphenol ACPL series for $2.14 each at Mouser.
It could be a little longer but you'll get used to soldering it.

Take a look.





See how thick it is, it grips like a beast.









And here's a couple pics of my Belden 8412.













This RCA is the Amphenol ACPR series. Not as good as the ACPL series IMO, just longer.





To Thin IMO.

No split center pin.