I now have a new Rega derivative tonearm which is terminated at it's base into a Cardas plug which is a minature 5 pin din. I have the Cardas socket into which I'll solder the external leads. Unless otherwise advised, I intend to use WD Sonics ICT Interconnect cable for the external wiring. This is individually insulated twin core with a shield per cable.
I am uncertain on the best way to wire up.
The 5 pin din as expected has an arm ground pin and then a +ve volt and 0 volt pin per channel.
What do I do with the individual shield braided wire at the arm output?
I'm assumming whatever I do, the supply end at the phono plugs into the Phono will have the braid unconnected and the arm ground pin will have a seperate wire which will be directly connected to the chassis earth of the phono stage .
My consideration is what to do at the arm connection. Do I connect the shields for both channels to the independent earth pin or alternatively connect the shield sindividually to the 0 volt pins?
All advise gratefully received.
Best wishes,
Greg
Tonearm wiring...seeking advice please
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cressy
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#2
best way ive found is to ground the shield at the plug end and leave is unconnected at the arm end. cut the braid offand shrink some sleeving over the end so it cant contact anything then simply wire up the signal and earth to the plug and the pillar/ arm tube earth to pin 5. i just took the arm earth from pin 5 in the plug to a flying lead. at t'other end, take the internal wire shields to the phono earth and disregard the main braid that goes around the lot. again shrink some sleeving round it. that way there shouldnt be any earth loops
#3
Thanks Anthony for your reply. I understand what you have done but I'm not sure it really answers my original question and I'm a bit disappointed no one else has responded. Maybe I've been sent to Coventry because I dared to challenge Mr I's approach to this hobby. Whatever, I don't know.
Bottom line is I'm using twin and shield per channel for arm external wiring. I don't know the best option to connect the shield. Should it link in at the tone arm end to the seperate arm/chassis earth wire/pin or to the 0 volts pin per channel originating from the cartridge? I recognise Anthony has suggested connection at the phono end but my understanding is that this is not the best option. I've always understood grounding at the source end is favourite. Please enlighten me!
Best wishes,
Greg
Bottom line is I'm using twin and shield per channel for arm external wiring. I don't know the best option to connect the shield. Should it link in at the tone arm end to the seperate arm/chassis earth wire/pin or to the 0 volts pin per channel originating from the cartridge? I recognise Anthony has suggested connection at the phono end but my understanding is that this is not the best option. I've always understood grounding at the source end is favourite. Please enlighten me!
Best wishes,
Greg
#4
Greg
The only time I've used a shielded lead it was connected as Ant says with a flying lead for the arm ground to chassis earth.
The shield connected at phono socket is not a problem as the shield is not needed for such a low impedanse, I have about 5ft of unshielded tonearm wire from the cartridge to phono amp.
Coventry, if it was Barrow in Cumbria I woud worry as seen on telly tonight.
The only time I've used a shielded lead it was connected as Ant says with a flying lead for the arm ground to chassis earth.
The shield connected at phono socket is not a problem as the shield is not needed for such a low impedanse, I have about 5ft of unshielded tonearm wire from the cartridge to phono amp.
Coventry, if it was Barrow in Cumbria I woud worry as seen on telly tonight.
#5
That nicely answers a question that i was just about to ask.I have about 5ft of unshielded tonearm wire from the cartridge to phono amp.
Greg.
Have you bought one of those RB251s or something similar from Ebay.
My homemade arm is still work in progress and i wondered if these £95 RB251s are worth having anyway, as a sort of benchmark. Comments invited, i'm new to all this.
Much to learn there is.
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Richard Higgins
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#6
Hi Greg
With my 3012 there is a separate earth connection on the bottom of the base, so when I made a lead for it I used 2 lengths of the IPL silver plated copper and connected the braids to the earth connector and at the other end to the phono earth stud.
That left the 2 pair of wires for the signal and returns.
It works for me with no hum issues.
Cheers Richard
With my 3012 there is a separate earth connection on the bottom of the base, so when I made a lead for it I used 2 lengths of the IPL silver plated copper and connected the braids to the earth connector and at the other end to the phono earth stud.
That left the 2 pair of wires for the signal and returns.
It works for me with no hum issues.
Cheers Richard
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shane
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#7
Don't worry Greg, I'm still talking to you 
I assumed there would be loads of answers, so didn't respond initially since the way I rewired my Formula 4 is slightly unconventional, but it works really well, and a variation on the same theme may work for you.
The F4 has the same 5 pin socket as your new arm. I took the arm earth to the centre pin and the four signal leads to each of the others. I then used a piece of Mr Navships' best twin-core screened silver-plated copper PTFE insulated cable for each channel, ( http://cgi.ebay.co.uk/50-22-AWG-Silver- ... _trkparms=| ) with a 5-pin DIN plug on each end. The screen of one of the cables is connected to the centre pin at the arm end, and both screens are connected to centre pin at the other. This allowed me to mount my SUTs in a box with a 5-pin din socket wired for balanced input. If I want to connect to a conventional phono input I have a 5-pin to phono adaptor lead which connects the centre pin and one signal lead from each channel to the screen of the lead to one of the phono plugs. The screen of the lead to the other phono plug is not connected to the 5-pin din socket. Clear as mud? Thought so. I could always draw it for you...
I assumed there would be loads of answers, so didn't respond initially since the way I rewired my Formula 4 is slightly unconventional, but it works really well, and a variation on the same theme may work for you.
The F4 has the same 5 pin socket as your new arm. I took the arm earth to the centre pin and the four signal leads to each of the others. I then used a piece of Mr Navships' best twin-core screened silver-plated copper PTFE insulated cable for each channel, ( http://cgi.ebay.co.uk/50-22-AWG-Silver- ... _trkparms=| ) with a 5-pin DIN plug on each end. The screen of one of the cables is connected to the centre pin at the arm end, and both screens are connected to centre pin at the other. This allowed me to mount my SUTs in a box with a 5-pin din socket wired for balanced input. If I want to connect to a conventional phono input I have a 5-pin to phono adaptor lead which connects the centre pin and one signal lead from each channel to the screen of the lead to one of the phono plugs. The screen of the lead to the other phono plug is not connected to the 5-pin din socket. Clear as mud? Thought so. I could always draw it for you...
#8
Thanks for all your replies which gives me something to work with. I'm using the silver on copper teflon cable supplied by WD which is similar to that used by Richard and Shane.
Al, I've bought one of these.
http://www.audiomods.co.uk/index.htm
Mine has no brass parts. All polished ali and stainless steel. The counter weight is dimensioned specifically for my cartridge weight. I don't have the micrometer VTA adjuster. Even I'm not that pedantic
I managed to get a slightly damaged RB250 on ebay for a nice price. All I've used from it is the armtube, lifting mechanism and arm clamp. Geoff Spall has made everything else new for me. The RB251 is a much poorer model (RB250 is now obsolete) because of the bad three point mounting and no base pillar. However, if you want to order a kit but have no RB250, Geoff will throw in a new RB251 for which he'll construct a base pillar. He offers this arm at the nice price of £60 if you are ordering a full kit.
Best wishes,
Greg
Al, I've bought one of these.
http://www.audiomods.co.uk/index.htm
Mine has no brass parts. All polished ali and stainless steel. The counter weight is dimensioned specifically for my cartridge weight. I don't have the micrometer VTA adjuster. Even I'm not that pedantic
I managed to get a slightly damaged RB250 on ebay for a nice price. All I've used from it is the armtube, lifting mechanism and arm clamp. Geoff Spall has made everything else new for me. The RB251 is a much poorer model (RB250 is now obsolete) because of the bad three point mounting and no base pillar. However, if you want to order a kit but have no RB250, Geoff will throw in a new RB251 for which he'll construct a base pillar. He offers this arm at the nice price of £60 if you are ordering a full kit.
Best wishes,
Greg
#9
Very nice Greg.
I think that's the sort of thing i'll have to study and maybe aspire to, rather than rush out and buy. Depends if i get to like this new vinyl habit. I realise now just how out of touch i've become.
Still you've answered my question about the new arms. Cheers.
Perhaps i'll look out for an older Rega, then i'll have something to compare my homebrew effort with.
Vinyl seems to be increasingly popular at the moment; judging by the prices people are paying for stuff that would have been regarded as undesirable a few years back.
I think that's the sort of thing i'll have to study and maybe aspire to, rather than rush out and buy. Depends if i get to like this new vinyl habit. I realise now just how out of touch i've become.
Still you've answered my question about the new arms. Cheers.
Perhaps i'll look out for an older Rega, then i'll have something to compare my homebrew effort with.
Vinyl seems to be increasingly popular at the moment; judging by the prices people are paying for stuff that would have been regarded as undesirable a few years back.
Much to learn there is.
#10
Hi Al,
Yep, certainly look out for a RB250 but my experience is that second hand examples have been recently selling for near the same price a new one was. As it is no longer available new, this is a bit of an issue. The RB251 is definitely a down grade with no vertical arm fixing pillar and the mounting is three screws through a plastic molded section. I suspect the change is deliberate because of all the other companies that produced very listenable upgrade derivetives. So, in your case I would look out for a RB250 as it is a very functional base to work from. You may have to pay more than you like but it'll be far better than the 251. I think Cressy has already had a bad experience with this newer version. As said, if you want to go for an upgraded derivetive, Audiomod will do a nice price provided you sign up for a kit of some sort. Incidentally, although I've not listened to mine yet, I'm anticipating a major performance upgrade over my current Michell TecnoArm A which will be shortly up for sale.
I completed my external wiring loom this afternoon following all the helpful advise. Many thanks to you all. Fitted with a Cardas 5 pin din socket, I can now use the same cabling both for the Audiomod Rega and my Mayware F4.
Best wishes,
Greg
Yep, certainly look out for a RB250 but my experience is that second hand examples have been recently selling for near the same price a new one was. As it is no longer available new, this is a bit of an issue. The RB251 is definitely a down grade with no vertical arm fixing pillar and the mounting is three screws through a plastic molded section. I suspect the change is deliberate because of all the other companies that produced very listenable upgrade derivetives. So, in your case I would look out for a RB250 as it is a very functional base to work from. You may have to pay more than you like but it'll be far better than the 251. I think Cressy has already had a bad experience with this newer version. As said, if you want to go for an upgraded derivetive, Audiomod will do a nice price provided you sign up for a kit of some sort. Incidentally, although I've not listened to mine yet, I'm anticipating a major performance upgrade over my current Michell TecnoArm A which will be shortly up for sale.
I completed my external wiring loom this afternoon following all the helpful advise. Many thanks to you all. Fitted with a Cardas 5 pin din socket, I can now use the same cabling both for the Audiomod Rega and my Mayware F4.
Best wishes,
Greg
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cressy
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#11
not so much a bad experience, but i feel with the new one that the quality is lacking. the old version feels better to use, and tbh the three point plastic mount is crap. its on phils old td150 at mi old mans, and sounds lovely, but the entire arm looks and feels cheap compared to the 250. i.e tiny spot welds holding on some covers over the lateral bearings, and a hell of a lot of flex in the three point mount. still sounds good, looks and feels rubbish unfortunately. plus the lack of vta adjustment and no easy fix (or product to fix it with) was very very frustrating with a deep cart 
#12
And then there was this.plus the lack of vta adjustment and no easy fix (or product to fix it with) was very very frustrating with a deep cart Rolling Eyes
http://cgi.ebay.co.uk/Rega-VTA-Arm-Heig ... 7C294%3A50
Much to learn there is.
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Mike H
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#14
Greg wrote: The RB251 is definitely a down grade with no vertical arm fixing pillar and the mounting is three screws through a plastic molded section.
cressy wrote:and tbh the three point plastic mount is crap... the entire arm looks and feels cheap compared to the 250. i.e tiny spot welds holding on some covers over the lateral bearings, and a hell of a lot of flex in the three point mount
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
#15
Hmmm, checking the Rega website I see that all their arms are now sans pillar and are three point screw fixing with the VTA adjuster Al has highlighted. I can't help think this will negatively effect their sales especially considering the 250 and 300 were so popular with many other TT manufacturers. The new design particularly on the cheaper models with that VTA plate will look pretty ugly and no where near as aestheticly pleasing to the eye as the old style was. It'll be interesting to see if the likes of Michell will continue to use them and also that the likes of Audiomods are already offering a tweaked pillared version.
It would also seem Rega don't like what the modification firms do.
Posted on their website.......
Important Modification Information
Rega does not approve of any modification or rewiring carried
out on our tonearms by other
companies.
The high rigidity and weight of wires used in many common
modifications will often lead to
excessive bearing wear and restriction on bearing movement.
This shortens the life of the
product and will lower performance.
Any attempt to modify our products will instantly invalidate
your lifetime warranty.
Geoff Spall tells me the new 251 armtube is heavier and thicker walled than the old 250. It'll be interesting to read some reviews in due course. I have a sneaking suspicion the new arms are not going to be so well regarded. We shall see.
It would also seem Rega don't like what the modification firms do.
Posted on their website.......
Important Modification Information
Rega does not approve of any modification or rewiring carried
out on our tonearms by other
companies.
The high rigidity and weight of wires used in many common
modifications will often lead to
excessive bearing wear and restriction on bearing movement.
This shortens the life of the
product and will lower performance.
Any attempt to modify our products will instantly invalidate
your lifetime warranty.
Geoff Spall tells me the new 251 armtube is heavier and thicker walled than the old 250. It'll be interesting to read some reviews in due course. I have a sneaking suspicion the new arms are not going to be so well regarded. We shall see.