New addition to the Baz Cave

[Barry]

I have been toying with the idea of running a balanced cable between my pre and power - both English. Presumably it would not matter matter of the XLR cable was made in US, so long as the two components are wired the same?

Hi Andrei,

Yes any balanced cable fitted with XLRs will do. How far apart are your pre and power amps? If they are near (say only two or three foot apart), then you may not notice much improvement. If however your power amp is located close to your speakers and you use long length interconnects back to your preamp, then the improvement could be considerable. The interconnects running between my pre and power amps are 12m long (nearly 40')!

[Andrei]

Thanks Barry.
The correct length at the moment would be 30 cm! - one components sits on top of the other. They manual recommends balanced cables but a lot of advice in manuals is based on 'one size fits all'.
As for 12m, is you pre hidden under your bed?

[Spectral Morn]

Thanks Barry.
The correct length at the moment would be 30 cm! - one components sits on top of the other. They manual recommends balanced cables but a lot of advice in manuals is based on 'one size fits all'.
As for 12m, is you pre hidden under your bed?

It's worth checking how the XLRs are wired in the electronics. If the same company's then wiring should be the same in the pre and power, if two different companies then I would check just in case one company uses the American way.

I disagree with Barry, yes XLR usually has more voltage than RCA and thus allows easier driving of longer cables but it is the rejection of noise that is the advantage here and lowering the noise floor is regardless of length of cable a big plus and in my view experience audible.

Now the other question is, are the items truly balanced, having dual differential circuit topology. Having XLR outs does not make a design balanced.

Wiki says this................ https://en.wikipedia.org/wiki/XLR_connector

'Pin Function
1 Chassis ground (cable shield)
2 Positive polarity terminal for balanced audio circuits (aka "hot")
3 Negative polarity terminal for balanced circuits (aka "cold")[17]
Prior to the introduction of this standard, the wiring of pins 2 and 3 varied. The pin 2 "hot" and pin 3 "cold" convention was typically used by European and Japanese equipment manufacturers, but American companies used pin 3 "hot" and pin 2 "cold". This caused problems when interconnecting equipment with unbalanced connections. The pin 3 "hot" convention is now obsolete but is still found on vintage equipment.[18] Pin 1 has always been ground and/or shield if the cable is shielded, and many connectors connect it internally to the connector shell or case.

Although covered in industry technical standards,[19][20] there is still some disagreement on the best way to handle the use of pin 1 for grounding (earthing). The main controversy is whether the shell of the connector should be connected to pin 1 or the shield, or left floating. AES standards mentioned above recommend that shells of cable-mounted connectors should never be connected to pin 1 or the shield, because inadvertent contact of the shell with another grounded surface while in use can create unwanted current paths for fault current, potentially causing hum and other noise. On the other hand, equipment containing active circuitry should always have pin 1 connected to the conductive enclosure of the equipment as close as possible to the point where the signal enters the enclosure. The argument centers on the radio frequency shielding provided by the shell of the connector, which may be reduced if it is left floating. An alternative solution is to connect the shell to pin 1 and the shield through a small value capacitor, providing RF shielding but allowing very little audio-frequency current to flow. This capability can be built into a fixed jack or a cable terminated with XLR connectors.'


Regards Neil

[Barry]

Hi Neil,

I've just checked my gear and all of the Levinson equipment (ML-26 and ML-28 preamps and the ML-2 power amps), as well as the Quad 510 and 520f power amps all use XLRs wired following the European (IEC) convention:

pin 1 - earth
pin 2 - +ve (hot, or non-inverting)
pin 3 - -ve (cold, or inverting)

The Revox C221 also follows this convention. Furthermore the Levinson and Quad amps are non-inverting, so no problems there!

I agree that the advantages of balanced line interconnects are two-fold:

(1) external interference, being common mode, will be rejected by cancellation,

(2) since the signal does not share the earth or 0V rail, any mains-bourne interference or power supply noise will not add to the signal.

The advantages are, of course, independent of cable length: it is just that for short cable lengths (~ 1 metre), I doubt if balanced line interconnects would have audible advantages over un-balanced connections. That said, the balanced line interconnects between the CD player and the pre-amp are 50cm long, as I believe in using cables that are as short as necessary (if only for the sake of neatness).

Regards
Barry

[Barry]

Thanks Barry.
The correct length at the moment would be 30 cm! - one components sits on top of the other. They manual recommends balanced cables but a lot of advice in manuals is based on 'one size fits all'.
As for 12m, is you pre hidden under your bed?

No Andrei,

The amps are located directly behind each speaker (so the speaker leads are only ~50cm long) and the speakers are ~7m from my listening position and from the source(s) and pre-amps. However to run a cable round to the left-hand speaker, I need a further 3 - 4m.

Regards
Barry

[Marco]

They manual recommends balanced cables but a lot of advice in manuals is based on 'one size fits all'.

Never trust anything that says 'one size fits all', as your recent escapades with stockings and suspender belts should've taught you...

Marco.

[The Black Adder]

lovely, Barry..

I would love to get my hands on a pair of 510's.

[Barry]

Thanks Joe - I am very pleased with them.