Using ancient Straight Wire cable to bi-wire new Cambridge Audio amp with JBL speakers

Amko

Member
Greetings all, new member here, delighted to 'meet' you and looking forward to benefiting from the wisdom of your collective experience!

Way back in the day - 1991, to be precise - I set up my first rig, a Marantz PM 35 Mark II 45W x2 amp with JBL XE 4 3-way speakers 10-100W using Straight Wire cables. This set of cables came with two white and two gray wires, each - each cable consisting of 4 wires in one transparent jacket. My dealer advised me to twist together the white and gray wires per cable, effectively resulting in a pair of wires in one transparent jacket, each, if you catch my drift. I proceeded with installation in (what I now understand) was a single-wired set-up.

Edit: Here are cables ( KnuKonceptz Karma Twisted 12 Gauge Bi-Wire OFC Speaker Cable) quite similar to mine, hope this helps.

Like-Straight-Wire-cables.jpg


29 years later it's time to upgrade (finally!), and I just picked up a Cambridge Audio SR 10 85Wx2 stereo amplifier and a pair of JBL A190 2.5 way 6 ohms floorstanders and in an attempt to save I was thinking of re-purposing them for this installation, in a bi-wired set-up, given that the Cambridge have A and B speaker terminals and the JBL, four binding posts each. The Straight Wires (I have really long cables, by the way) seem to be as fresh and new as the day I bought them, no oxidation that I is pretty thick, as Ican apparently see.

Here's the layout I was considering:

biwire.jpg

Question: Since each cable has 2 white wires (twisted together) + 2 gray wires (twisted together), in one transparent jacket: All I would then need to do is cut each cable once, to result in a total of 4 (naturally, smaller) cables, each cable terminating in L and R (white and gray). Is this correct? Each of the two yellow cables would then be represented by a single Straight Wire bi-wire cable. Again, is this right?

***OR: Do I need to make 8 cables, as per the diagram above?***

I am not certain about the wire gauge *per each wire* (AWG?). It looks like I'll have to buy a cable cutter/wire stripper tool anyway for this project, before purchase, I'll check that any tool should have holes that measure the gauge.

Question: My Cambridge Audio manual recommends the above layout/diagram for bi-wiring, which assumes both System A and System B are wired up as above. Since both A and B are being used, would this place an additional load on the amplifier, and result in any degradation in sound, and/or overheating?

That said, I have seen bi-wiring diagrams where only one set of terminals are used in the amplifier.

(I do not wish to bi-amp at this point, having only a spare Yamaha R-N303 100Wx2 8 ohms.)

The other consideration is whether to use banana plugs or not. I have a sinking feeling the terminals on the Cambridge Audio amp are a tad 'wider' than the banana plugs I've seen. The terminals on the Yamaha seem 'narrower' and more in line with the banana plugs I've seen, too. Which of course, begs the question as to why I don't use the Yamaha in the first place! And the Yamaha is in truth a network amplifier, with all the bells and whistles. But I do prefer the Great British Sound of the Cambridge...

I welcome your thoughts, experience and recommendations, and look forward to resolving my confusion. Thanks, and stay safe.
 
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Ugg10

Distinguished Member
You can check the gauge by measuring the diameter of the copper bit. If they are 12awg as advertised then they should be 2.0mm in diameter which is 3.14sq.mm cross section which is plenty for domestic applications.

These are designed to be run as one cable (4 inner cables) per speaker. Hopefully the two grey/white also have some sort of mark so you can identify each of the four inner cables easily (ridge on the insulation or stripe or words etc.). If so, just use black for the black terminal (one on speaker A and one on B) and white on the red terminals making sure you have speaker A going to the woofer and speaker B going to the tweeter (or vice versa doesn't really matter). Remember to take off any speaker link bar or jumpers. So basically, the yellow wires on your diagram are the four wires inside the single cable you have.

Edit - link to cable which says that each pair are marked with a 1 or 2 on them, this will be on the four individual wire insulations -


However, most on here will probably say that with that size wire bi-wiring will have negligible (and no audible) effect and given that the two speaker terminals on the amp are connected internally to just one poweramp then all you are doing is moving the cable link from one end of the wire to the other. You can always try your current method with bi-wiring and see if you can hear a difference.

It would be worth chopping off an inch of the cable at each end to get clean wire before removing the outer insulation and inner insulation. You don't need a wire stripped as craft knife can be used if you are careful.

Hope this helps.
 

Amko

Member
Hello, Ugg10, thanks for responding. However, to clarify:

- You said: "These are designed to be run as one cable (4 inner cables) per speaker."

This means you recommend that I chop 1" off the two ends (to ensure clean wire) of both the two cables in my old (single-wire) set-up, separate the 4 wires per cable, two white and two grey (not black :) ), and use either colour to connect to - and + for System A and System B for Speaker L (say) - and then, the other (also chopped, separated 4 wire) cable to connect to - and + for System A and System B for Speaker R. Doing this means the bi-wiring is complete, yes? I trust I've followed you correctly, else please take a quick minute to weigh in. Thanks again.

- You also say: " However, most on here will probably say that with that size wire bi-wiring will have negligible (and no audible) effect and given that the two speaker terminals on the amp are connected internally to just one poweramp then all you are doing is moving the cable link from one end of the wire to the other. You can always try your current method with bi-wiring and see if you can hear a difference."

OK, I will. Thanks.

Any one have any recommendations on decent banana plugs? I have read chapter and verse as to how they are convenient but not necessarily from a sonic standpoint. I've seen models which cost an arm and a leg, and other dodgy (read - Chinese made) options, and I'm looking for something in between, say Monoprice or Mediabridge, and would appreciate any links. Any thoughts on AmazonBasics?

Any thoughts on if such a set-up -as I've attempted to describe above - would place an extra load on the Cambridge amp?
 

oscroft

Member
Any one have any recommendations on decent banana plugs?
I got a load of cheap ones on eBay labeled "Nakamichi" and they're just fine, though very unlikely to actually be made by Nakamichi. Probably made in China too, but then, so's my MacBook.

I've never read any justification for buying expensive banana plugs that I haven't considered to be pure BS.
 

Amko

Member
I got a load of cheap ones on eBay labeled "Nakamichi" and they're just fine, though very unlikely to actually be made by Nakamichi. Probably made in China too, but then, so's my MacBook.

I've never read any justification for buying expensive banana plugs that I haven't considered to be pure BS.
LOL, you said it, what isn't made in China these days, eh? And +1 on the BS :)
 

oscroft

Member
Any thoughts on if such a set-up -as I've attempted to describe above - would place an extra load on the Cambridge amp?
Firstly, it should be no problem for your amp - whichever way you connect it up, it's still powering the same set of speaker drivers and crossovers.

I agree with Ugg10 that biwiring is unlikely to make any difference - I've certainly heard no difference when I've tried it. All biwiring does is move the connection between the speaker drivers to the other of the cable, which is electrically identical.

But, as you already have doubled-up cables, you're in the ideal situation to try for yourself and compare.
 

Amko

Member
Thanks, Oscroft, but - at the risk of repetition - do I chop 1" off the two ends (to ensure clean wire) of both the two cables in my old (single-wire) set-up, separate the 4 wires per cable, two white and two grey - and use either colour to connect to - and + for System A and System B for Speaker L - and then, use the other (also chopped, separated 4 wire) cable to connect to - and + for System A and System B for Speaker R. Doing this means the bi-wiring is complete? Please do correct me, folks, if I still haven't got it.

You know, I recently read tons of marketing brochures prior to purchasing said new speakers, and they all seemed to advocate the practice (bi-wiring), claiming audible improvement particularly in the midrange. Ironically Cambridge Audio didn't, stating that their speakers have only one pair of terminals.
 

oscroft

Member
Thanks, Oscroft, but - at the risk of repetition - do I chop 1" off the two ends (to ensure clean wire) of both the two cables in my old (single-wire) set-up, separate the 4 wires per cable, two white and two grey - and use either colour to connect to - and + for System A and System B for Speaker L - and then, use the other (also chopped, separated 4 wire) cable to connect to - and + for System A and System B for Speaker R. Doing this means the bi-wiring is complete? Please do correct me, folks, if I still haven't got it.
I'm finding it hard to picture that, so I'll tell you the way I'd do it and see if that makes sense. Referring to just one channel here (left or right)...

Firstly, chop an inch off the ends of all four wires in the cable. I'd then allocate one colour to + (the red terminals) and the other colour to - (the black terminals). Let's say use grey for + and white for - . You then have two pairs of wires in each cable, one grey and one white in each pair, with the two pairs marked for identification I believe. I'll refer to them as pair 1 and pair 2.

Make sure the HF to LF bridge is removed from the speaker and connect wire pair 1 from the Speaker A terminals on the amp to the HF connections on the speaker, grey to + (red) and white to - (black). Then connect pair 2 from the Speaker B terminals to the LF speaker connections the same way.

Then do the same with the other channel, and you have a biwiring setup.

To switch to standard wiring for comparison, disconnect the wires and twist the two greys together and the two whites together at the speaker end and the amp end (so that you're comparing with the same overall thickness of wire). Reinsert the HL to LF bridges on the speakers, and then it doesn't matter whether you use HF or LF (I've heard some people say it matters, but it really can't).

Oh, and I suggest waiting for someone else to confirm this in case I've messed up somewhere.

You know, I recently read tons of marketing brochures prior to purchasing said new speakers, and they all seemed to advocate the practice (bi-wiring), claiming audible improvement particularly in the midrange. Ironically Cambridge Audio didn't, stating that their speakers have only one pair of terminals.
I think the key word there might be "marketing" ;)
 

Amko

Member
Thanks again for your patience and step-by-step explanation, Oscroft. I think the light is beginning to dawn. But how would I tell which of the white (or grey) wires is which, at the amp end and the speaker end? The chances of me goofing this up seem high. Any foolproof way to mark the whites and grey's: say grey +, white -, for each 4-wire cable.

And seriously, much gratitude once more.
 

Ugg10

Distinguished Member
As per the amazon link it says they should have a 1 or 2 printed on the wires. Once you have chopped of an inch of f the whole wire, remove two or three inches of the outer insulation and see if you can see the marks.

looking at the picture you can just about see the marks through the outer insulation. Have a look and see if you can still see them.
 

oscroft

Member
I'd use a multimeter to check which connects to which at each end myself, but I'm guessing you don't have one of those. So if there aren't any marks visible, connect one grey and one white wire at the amp end. Then try different combinations at the speaker end until it plays music. Then mark the connected wires (with a sharpie, or sticky tape, or something).

If you do it like this, be sure to turn the volume right down in between trying different connections, and make sure no wires are touching each other before you turn the volume up again. That's because some amps can be damaged if you short the speaker connections while it's playing - and even it yours has protection relays, it can still give you a brief scare if they cut in.
 

Amko

Member
As per the amazon link it says they should have a 1 or 2 printed on the wires. Once you have chopped of an inch of f the whole wire, remove two or three inches of the outer insulation and see if you can see the marks.

looking at the picture you can just about see the marks through the outer insulation. Have a look and see if you can still see them.
Actually, Ugg10, I said the cables in the photo in my very first post was 'similar' to mine. You're referring to the KnuKonceptz, the cables I have are Straight Wire. Still, I will chop an inch off and check. Thanks!
 

Amko

Member
Alas, no multimeter, I'm afraid, Oscroft. Trial and error it is for now, and point noted on the volume. Thanks again.

All, I think I have enough to go on, so I'll update you here.

Speaking of scares, Oscroft, I heard earlier today that speaker delivery to my address is delayed owing to the imposition of a 2 week curfew in Mumbai (Bombay), India, owing to the COVID-19 situation. I'll work on those cables in the meantime.

Is it absolutely imperative that each cable is identical in length? Or does it matter only over long runs? For the simple reason that my daughter's digital piano is situated next to my audio rack, one of the cables is currently longer than the other, but this is easily remedied if required.
 

oscroft

Member
Ach, delivery delays are frustrating. If it's any consolation, I had an order from Manchester to me in Liverpool take three weeks here, and that's only 25 miles! (And something I bought from Australia got here in less time.)

Matching length cables? Nah, it's one of those common myths - a difference in length makes no difference to the sound (as long as we're not talking of very long cables and very big differences).

Do let us know how you get on.

PS: I spent a week in Mumbai in 1991 on a two-month trip across India. To this day I can still remember the masala dosas I had every morning for breakfast - and I've still not had one as good since.
 
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Amko

Member
Then, sir, it may just be time for another Passage to India. Consider yourself invited. I'm a couple of hours away from Mumbai, in Pune (formerly, Poona), once known as the Oxford of the East, now more for its automotive and IT industries, the world-renowned Iyengar Yoga Ashram, the Osho International Commune and more such.

images (43).jpeg


And yes, the finest Mysore Masala Dosas this side of South India, served with piping hot 'sambhar' and green chutney, green as grasshoppers, as Salman Rushdie would put it!

I've visited your beautiful country several times - stopovers in London en route to the US on business, and long leisurely holidays in the UK as well; my brother still has a nice apartment in Central London and I look forward to visiting again. Fingers crossed. The Beatles Museum in Liverpool is on my bucket list.

Thanks for the support. I will most definitely let you know how I'm getting on! Cheers!
 
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Khankat

Active Member
You know, I recently read tons of marketing brochures prior to purchasing said new speakers, and they all seemed to advocate the practice (bi-wiring), claiming audible improvement particularly in the midrange. Ironically Cambridge Audio didn't, stating that their speakers have only one pair of terminals.
That's essentially a wheeze to persuade the reader-in this instance, you- to buy more cable.
 

Amko

Member
Indeed, Khankat. Indeed.

The more I think about it, the more sense it seems to make: sparing myself the time, hassle. The sheer futility of what I'm doing here. Particularly since the type of cable is unlikely to result in an audible improvement, according to a couple of you. And using just the one amp.

It's true I've had stellar results with the cables in a conventional set-up. Why fix it if it ain't broke, and so forth.

Lastly, how about that business with banana plugs, folks? Apart from the convenience/neatness factor, do they in some cases/brands actually diminish the sound quality, soundstage, open-ness, volume etc. Currently I'm running bare naked wire, in case I didn't mention it.
 

oscroft

Member
Lastly, how about that business with banana plugs, folks? Apart from the convenience/neatness factor, do they in some cases/brands actually diminish the sound quality, soundstage, open-ness, volume etc. Currently I'm running bare naked wire, in case I didn't mention it.
Banana plugs won't improve the sound at all, and bare wire is fine. I use banana plugs purely for convenience, because I regularly switch between speakers and amps.
 

gibbsy

Moderator
Lastly, how about that business with banana plugs, folks? Apart from the convenience/neatness factor, do they in some cases/brands actually diminish the sound quality, soundstage, open-ness, volume etc. Currently I'm running bare naked wire, in case I didn't mention it.
Bare wire will give the best connection. Personally I use banana plugs because I'm an old fart and push is easier than a twist.
 

Amko

Member
I may just have attempted to run - before learning to walk.

All talk about bi-wiring and banana plugs apart, I took a closer look at the amplifier terminals of my Cambridge Audio SR 10 stereo receiver (yes, apparently that's what it's officially called).

And going by the look of them, here's when a worrying prospect presents itself: are these terminals compatible with banana plugs/BFAs/spade connectors, or do they just take bare wire?

Here's a photo (apologies for the image quality, my camera phone isn't the best).

IMG_20200705_173510.jpg



For what it's worth, I dropped a line to Cambridge Audio support as well, but apparently they will probably answer only after 48 hours+. So I thought of asking here.

Oh yes, it is possible to remove the centre plug (if that's the word?) of the red/black terminals.

Thanks!
 

gibbsy

Moderator
Oh yes, it is possible to remove the centre plug (if that's the word?) of the red/black terminals.
Just tease them put with a straightened paper clip, once started they'll come out easy.
 

Amko

Member
Thanks Gibbsy, removing a plug posed no hurdle, largely because of this bad boy: my trusty Smith and Wesson Border Guard survival knife.
1593956587351_0_IMG_20200705_190520.jpg


Still unsure if the now exposed hole is the right dimension to accommodate a banana plug/bfa. Please excuse my ignorance, this is all rather foreign to me. 😐
 

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