Extending the Phono and earth leads of a Pro-ject P1

['LIVEWIRE?']

Is it a good idea to do this? The leads fitted to this turntable ar about 1.3M long, but need to be over 2M. to reach the amplifier from the shelf on which the TT stands. The easiest way, of course, would be to use a high quality combined RCA & Earth extension lead, though a more elegant solution would be to open the deck, remove the originals, and fit longer leads. Besides this, the Pro-Ject distributors quote £40.00 for a 1.2M extension lead, plus £2.50 for a similar length earth lead. Any opinions as to how to proceed welcome!
Incidentally the P1 is a 220vAC deck. Is it likely to suffer from being used on 230/240v UK Mains? It has a UK mains plug.

[PsychMan]

Personally, I wouldn't use extension leads here. Given the signal to noise ratio with a phono signal it's best to avoid any extra interconnects at this stage, as it is also best to limit the length of the lead.

Plugging in an extension lead is easily reversible - why not let your ears be the judge ? Thats ultimately what matters over the science of it

[Edward Huggins]

Providing the extension lead you add is as short as possible, I would have thought that you could use an female to female in-line connector (0.99p) and a piece of thick single core copper wire for the earth connected via a terminal block. There might be some just measurable HF attentuation, but you are unlikely or hear it. Try it and see. If you seem to hear any degradation, then replace the lead as advised above.

[Radio Wrangler]

Get a few phono plugs and sockets and make up a cable yourself. No rocket science is involved and neither is 40 quid. As Psychman says, it's reversible.

Signal to noise ratios and sensitivity to wiring resistance are somewhat significant with moving magnet cartridges. They are a lot more serious with moving coil ones.

Plan B would be to get one of those phono converter preamps with the RIAA characteristic built-in, and locate it with the turntable. It's the right place to amplify the signal from the cartridge and the wiring from the preamp is a lot less sensitive.

A hifi group will tell you to use cult cables at even greater expense and will rib you for mounting your turntable on a shelf or to send your turntable to a craftsman in Seattle to have longer cables fitted.

David

[Nickthedentist]

I would just buy a good quality 3m dual phono-phono lead, chop the plugs off one end, and fit it instead of the original leads. A separate ground wire can be attached with a few rings of heat-shrink every 6" or so, and terminated with a crimped- or soldered-on spade terminal.

In theory, the extra capacitance of the longer lead could alter the frequency response, but in practice, it's unlikely to be noticed.

Nick.

['LIVEWIRE?']

Thanks, all, for your answers. It seems, as I suspected, that 'Audiophoolery' comes into play. The Pro-ject isn't mine,( I have a TeAC PX300 Direct Drive turntable), so the owner will have todecide if he likes the resultant sound quality, though I certainly wouldn't use the cheap RCA leads on such a good quality TT. I'll probably fit longer leads, using, as you suggest, Nick, a good quality RCA Lead, and a new length of Earth lead.

[Radio Wrangler]

Surprisingly, there isn't really a lot wrong with the connections that cheap phono plugs make. The contacts are high-pressure and wiping, so they clean the surfaces which make contact. It would take very good plating indeed to withstand a couple of dozen insertions if you opted for gold. The chief benefit from the better ones is in support for the cable.

It's all too easy to say prices must be matched. It sounds quite reasonable, but it isn't a valid reason unless there is some real engineering behind it. Ten years ago I treated myself to an expensive car. It still gets expensive tyres not because they're expensive but because the ones chosen do make a real difference, but I haven't sought out appropriately overpriced fuel.

David

[paulsherwin]

The problem with very cheap leads is poor screening, which can be particularly important with a magnetic cartridge. Apart from that, there is little advantage in expensive cables, and the gold plating found on most cable plugs has no audible effect.

Anyway, I would say the two realistic solutions are to move the deck closer to the amp or use a male-female extension cable with a wire wrapped round it for the earth. It's up to him how much he chooses to spend on the cable and where he buys it from. Replacing the leads altogether seems OTT to me.

[mhennessy]

It's not just noise/screening...

The screened cable used for this sort of thing measures 100pF/metre, typically.

A magnetic cartridge expects to see some loading capacitance of around 150-300pF, depending on model.

MM pre-amps have 100pF-200pF as their input capacitance. Coupled with 1m of interconnect, that's around 200-300pF.

So adding another 2 or 3m of interconnect will perhaps double the capacitive loading, altering the HF response. So it's something you'd have to check before doing - I wouldn't just make assumptions. Depending on the cartridge, the sound quality might alter more than you might expect.

My usual recommendation for situations where the amp can't be moved is something like this (for example): https://www.cambridgeaudio.com/produ...nema/azur-551p

(Many others available at all price points)

Once the signal is up at line level, it'll go many metres with no worries down cheap lap-screened interconnects, and there's no need to extend the earth lead.

[paulsherwin]

Yes, using an external preamp is another possible solution. It also allows people so inclined to use an 'audiophile' preamp rather than the TL072 class preamp that's probably built into the amp.

[Welsh Anorak]

I might get shot down in flames for this, but I would imagine moving the turntable onto a solid base rather than a shelf will make a more significant difference to the sound than extending the cables.
Glyn

[paulsherwin]

Wall mounted shelves are often preferable because they isolate the deck from the wooden floor.

[mhennessy]

There are countless explanations of cartridge loading out there. This is a good one: http://sound.whsites.net/articles/ca...e-loading.html

The graph about a 3rd of the way down the page shows that increasing the loading from 100pF to 500pf introduces a 4dB peak at 12-15kHz. That extra 400pF could easily come from an extension cable, especially some of the better screened types that you might automatically assume would be better for this.

As I say, it might make more difference that you expect

['LIVEWIRE?']

I plan to listen to the TT in it's original stae first(I have a test record somewhere!), but, having spoken to the owner, he's quite happy to have the exsisting cables replaced with longer ones, then listen again after fitting the new cables, and possibly scope the 'before and after' results.

[ToneArm]

I agree, I think you'd hear a detriment with a plug-in extension.

Using low capacitance cable and the "more elegant solution" you suggest, replacing the cable from the tonearm, that should do it. Vandamme starquad is 50pF/m so the length you want is not a problem.

[mhennessy]

Careful - star-quad is balanced cable! It's intended for microphones.

The phase-to-phase capacitance is 50pF/m, but phase-screen is 95pF/m. So how are you going to wire this up?

I think you'd hear a detriment with a plug-in extension.

I very much doubt it, there may well be a difference who says it's better or worse? I go to the odd classical concert, I think my hi-fi sounds better, am I wrong?. And the ear is fickle, only a proper blind A/B test will do, no good saying "I changed the (whatever) and it sounds better (or worse)", that would only be down to expectation. Try an experiment... listen to music with a friend, friend goes for a pee, turn one (or both) of the tone controls just enough for you to hear a difference. I bet that they upon return won't notice.

[mhennessy]

Regarding what we can/can't detect, for a cut or boost at 10kHz, we assume the following:

With a reference:
"Lay person": +/- 2dB
"Studio Manager": +/-1dB

Without a reference:
"Lay person": +/-4dB
"Studio Manager": +/-2dB

Obviously simplified, but these have been tested over many decades. Knowing these numbers feeds in to the tolerances of an overall broadcast chain, where many amplifiers, etc, are cascaded. Obviously a bit easier in these digital days...

So if a long cable causes a 4dB lift at 12-15kHz, I'd definitely expect to hear it either side of having a pee. But I'm still troubled by line whistle

Straying OT perhaps, but whenever I go to a concert, I come away with such mixed emotions. There's no getting away from it - a full orchestra in a big concert hall makes even the best hi-fi sound rather silly. A recording played at home is only a representation - created by the recording engineer in a studio to sound OK in a wide range of different replay contexts. It simply can not be anything like the original. The Proms concerts are about as good as I've heard, but still just a representation.

['LIVEWIRE?']

Since my original post, I've removed the pickup arm assembly, purely to confirm what I was almost certainly the case, which is that the RCA Leads and Earth wire are terminated inside the arm base, reqiring further dismantling in order to be able to remove the cables. In so doing I discovered another problem, which is that the arm base is secured to the baseboard with two M3 screws held in place by orsdinary M3 nuts. Since the metal plate on the bottom of the baseboard isn't easily removable, due to a 'spire', if that's the right word, clip securing a pivot for the on/off switch operating lever, being present on the underside, and the aforesaid nuts cannot be refitted, the arm base will either have to be fastened using suirtable self-tapping screws, or via captive nuts of some kind. I also realised that the antiskate cord is missing, so I'll have to make up one using some drive cord, and guess the length needed. Briefly testing the player, it seems to track records OK without the A.S cord, but it would still be good to have one fitted.The deck is elsewhere, but on Monday, when I next am there, I'll take some photos to illustrate the above points.

[paulsherwin]

You really are causing yourself grief here. As Mark said, extension cables may cause a bit of lift right at the top end, but if the extension is only 1m then it's unlikely to be audible. Cartridges aren't very linear anyway, with lots of variations in HF response (Ortofon cartridges are notoriously bright sounding, while Shures are notoriously mellow).