Cartridge/tonearm wiring problem

dromunds

I just finished putting a Grace 707 arm on a Denon DP72L, (together with making a new armboard out of Corian.) However, when I went to connecting the tonearm wires to the cartridge (Denon 110), I found the wires coming out of the arm by the cart are colored yellow, blue, orange and blue. The manual says they should be green, red, blue and white, like on the back of the Denon cart. Looks like somebody "Frankened" the wires on the tonearm. Does anybody have any ideas on how I can figure out which wires from the arm would correspond with the green, red, blue and white on the cart? The Grace arm has a five-prong plug in the bottom of the arm base. I've never seen anything like this and not sure why anybody would install wires with these colors...what would happen if I gambled on the colors and was wrong? Thanks much. Will post photos of the mods later....

SCompRacer

Congrats on your mod! I would use an ohm meter/continuity tester and match your RCA's (R, L, center and GND) to the color code on back of the Denon. Write it down.

SCompRacer

Left Channel: White (Center pin of RCA)
Left Channel Ground: Blue (Outer barrel of RCA)
Right Channel: Red
Right Channel Ground: Green

So with ohm meter, connect one lead to left channel center pin of the black or left channel RCA. (Make sure you don't touch both the center pin and outer barrel for accurate results). Touch the other ohm meter lead to each of the four wires out of tone arm. Write the color down that had continuity (like yellow = left hot or yellow = white), then move to left channel RCA ground, then right hot and ground. Tape your arm color code to the bottom of table so you know in the future. E on the cart is earth or ground, outer barrel of RCA.

The five pin plug is a common DIN plug used to connect to the base of tone arms. You can purchase a rewire kit that is continuous wire to the phono pre amp and get your color code back, but they cost a few bucks. Or rewire using correct colors. My advice, if it works and sounds good, leave it.

What could happen depends on how you wired it, but nothing would explode. No sound, inverted phase, hum, etc. Some meters have a sound feature so you can watch what you are connecting to and listen for the sound. If not you have to watch the meter.

dromunds

SCompRacer, thanks much, I very much appreciate the help. I will give it a shot. I'm getting an error when I try to download photos of the mod. It turned out pretty nice, the Grace arm is very elegant. Some little bugs along the way but got them all worked out except this one, I think. Will keep trying to download pics.

schwarcw

dromunds wrote: »

SCompRacer, thanks much, I very much appreciate the help. I will give it a shot. I'm getting an error when I try to download photos of the mod. It turned out pretty nice, the Grace arm is very elegant. Some little bugs along the way but got them all worked out except this one, I think. Will keep trying to download pics.

You want want to use one of those photo sharing site, then you could copy and past the image link. I would create an account at photobucket.com

Rich, what is the fifth pin for?

dromunds

Alright, let's give this a shot:

<a href="http://s1284.beta.photobucket.com/user/dromunds/media/Denon - Grace Mod/2013TurntableDenon-GracearmFriJan250357_zps2ee983ed.jpg.html&quot; target="_blank"><img src="http://i1284.photobucket.com/albums/a561/dromunds/Denon+-+Grace+Mod/2013TurntableDenon-GracearmFriJan250357_zps2ee983ed.jpg&quot; border="0" alt=" photo 2013TurntableDenon-GracearmFriJan250357_zps2ee983ed.jpg"/></a>

dromunds

Eek.

dromunds

Ok let's see if this works

SCompRacer

Glad to be of help dromunds! I see a pic! Small, but at least we see something.

schwarcw wrote: »

Rich, what is the fifth pin for?

Ground wire. You remember Dipole Dan's LP12? That had a 5 pin DIN plug IC with ground terminal. My Moerch DP-6 has the 5 pin DIN as well.

dromunds

SCompRacer: I am pretty limited with computer skills but I will attempt sometime this weekend hopefully to post some better pics of the armboard mod. It was a fun project, my buddy suggested we use a scrap piece of Corian for the armboard, so we hogged down a 1/2" piece to 1/4" with a router, then made a paper pattern of our new armboard and a die board pattern from that and attached the corian to the die board pattern. Used a router and a bearing to cut out the corian to the pattern and rounded the edges. Calculated the distance for the mounting hole, etc. The arm rest, of all things, was problematic because it fell beyond the outline of the previous Denon armboard, so we had to extend the new armboard towards the front quite a bit but there was a circuit board under the spot where the new arm rest would go so we had to tap threads in the corian and attach the arm rest only to the corian. I will try to get my technological shite together and post some pics later. Thanks again for your help, very much appreciated, I'm going to attack the wires coming from the arm with an ohm meter tomorrow when I have some time and hopefully get 'er spinning again.

del44

I'm going to be making another armboard for my VPI, and I think I'll be using Corian also. I have many scrap colors at my shop. I'm just worried that the 1/2 thickness would post a problem.

del44

Edit: looks like 1/2 inch would be the right size.

dromunds

I'm no expert on material for armboards, that's for sure. I took the corian down to 1/4" because of the height measurements with the Denon platter. (Was going to go 3/8" but decided on 1/4" and I'm glad we did in the end because of the platter.) Also made an extra board that is 1/8" for a cherry wood arm I have just in case I decide to switch some day. The quarter inch actually seems pretty sturdy. Even the 1/8" one seems sturdy enough but I wouldn't go too nuts on that one. My buddy and I were actually pretty surprised on how hard it was to break the scrap pieces of the 1/4" one. Maybe somebody with more experience can chime in. The stuff is remarkably easy to work with on both Router and band saw, and sanded easy. Took it down to 600 grit. I thought maybe the edges would chip rounding them, but nothing. It came off more like plastic shavings. I had no experience with Corian. Drilled and tapped easy too. Used nylon washers on top and bottom of board plus the metal ones. All in all it was pretty nice to work with. 1/2" Corian is actually pretty damn hard, so not sure what you mean by 1/2" would be a problem but if you're worried about strength all I can tell is its twice as thick as the 1/4" and that seems plenty strong.

del44

I was just worried that 1/2 inch would put my tonearm too high. But after measuring the acrylic armboard that sits in the plinth, half inch is perfect and probably better damping than something thinner.

SCompRacer

dromunds wrote: »

SCompRacer: I am pretty limited with computer skills but I will attempt sometime this weekend hopefully to post some better pics of the armboard mod.

Thats OK. If you need some help there are folks here real sharp with 'puties that can help. Don't be afraid to ask.

You done real good with your arm board! There are folks that use Corian for plinths. It is known as the poor mans slate. Slate makes a good plinth but is more difficult to DIY and can be pricey to have done. You have a nice platform for that arm too!

I know this fellow Peter from the Lenco forum. He was one of the first to make a thick stainless top plate available for the Lenco turntable to replace the OEM stamped one. He uses Corian for his plinths.

http://www.ptpaudio.com/solid12.html

dromunds

Very interesting. Thanks.