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Hadcock rewire

M

matt j

pfm Member
I'm going to finally make a start on this, I'm ok with the doing side, not so good with the theory.

I've never got my head around arm/cart/TT earthing paths, I've stripped the original wiring out of it (bit of a bodge if you ask me, but that's for another time) and it looks to have two earths a short one and a longer one that runs to the same length as the RCA end. Both of them were twisted together inside the arm pillar and just wedged up against inside face of that by the cable and some kind of gobbo. The short one is probably 6 inches long.

I've forgotten whether I used the short one or not when I last had it fitted, it may have gone to the arm earthing point of the subchassis on an LP12 but it won't be going back on a metal subchassis deck so is this now redundant?
 
The earthing on my 242SE was not great at all. I never redid it, but there was certainly no coherent path from headshell to ground terminal. My assumption was the ground path was intended to be mechanical from the base via the pivot and four balls, but as I say it was very inconsistent. The red plug is only four pin/wire, just signal and return for each channel, so the main ground has to be via the unipivot itself.
 
Thanks, that's as I thought from looking at it. It seems easy enough and I have done others, my only concern is wrecking the little red plug and socket when soldering which I nearly did on a previous Mission 774. For some reason I can never get soldering to work no matter what I try, and I've read and reread soldering how-too guides and watched a million videos, it just never bloody sticks.
 
I’ve never soldered one, but if the solder isn’t flowing try really cleaning the area with isopropyl alcohol, it may just be very mild corrosion or dirt impeding things.
 
Can you post some photos of the socket?
One of the engineers at work who solders lemos etc says you are best using a hot iron quickly. He always tins the receptacle and the wire, then reheat the receptacle and insert the wire, but only just for long enough. You need to hold the damned thing in a vice, otherwise it will move about and you won't solder it. Buy some cheap din plugs and practice.
 
Solder only flows when liquid - if any surface that you are looking to solder isn't comfortably above the melting temperature of the solder, the solder will not flow - it cools and goes solid so you do not get a joint.

For small components you ideally need very thin multicore solder, and a hot iron. Tin both parts seperately, then hold the two parts together, touch with the iron and you should get a joint.

Unless you have had any Hadcock arm from new, I would not trust any of the wiring as being what was intended - I have seen some total nightmare hatchet jobs.

On current arms, there is an earth wire that ends in a small eyelet that is held by one of the bolts of the socket, which is in the pillar/armrest. The earth wire follows the same route as one of the arm leads.

The connectors are long obsolete. One day British Audio Products will run out of stock, if they have any even now, in which case the only "easy" replacement would be 0.1" headers/pins, although I have only ever seen them tinned, not plated. George must have bought literally 1000's as obsolete stock, as the new arm use the same connectors.
 
Tony L said:
I’ve never soldered one, but if the solder isn’t flowing try really cleaning the area with isopropyl alcohol, it may just be very mild corrosion or dirt impeding things.
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I can never get anything to tin- the tip, the wire or whatever I'm soldering it to. I change the temp, try different solder, cleaning things up with a bit of abrasive etc. it's always a disaster.
 
matt j said:
I can never get anything to tin- the tip, the wire or whatever I'm soldering it to. I change the temp, try different solder, cleaning things up with a bit of abrasive etc. it's always a disaster.
Click to expand...

That sounds like either a crap iron or just a learning curve. I use and would highly recommend a simple Antex XS25 iron. I’ve used one for decades and it never lets me down, I have a few different sized tips for it. The other thing I’d recommend is to use a good old-school rosin-core 60/40 lead solder, you can still find it at Farnell, RS etc. The modern lead-free stuff is crap IMHO. Unless you are working with it day in day out I’ll swap a tiny health risk for a nice clean flowing joint. Beyond that practice. Lots of practice. I can’t emphasise that enough. Tonearm wiring is really not the place to start. Get really good on other larger stuff first.

PS You shouldn’t have to use anything abrasive on a soldering iron tip ever.
 
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Tony L said:
That sounds like either a crap iron or just a learning curve. I use and would highly recommend a simple Antex XS25 iron. I’ve used one for decades and it never lets me down, I have a few different sized tips for it. The other thing I’d recommend is to use a good old-school rosin-core 60/40 lead solder, you can still find it at Farnell, RS etc. The modern lead-free stuff is crap IMHO. Unless you are working with it day in day out I’ll swap a tiny health risk for a nice clean flowing joint. Beyond that practice. Lots of practice. I can’t emphasise that enough. Tonearm wiring is really not the place to start. Get really good on other larger stuff first.

PS You shouldn’t have to use anything abrasive on a soldering iron tip ever.
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This is it

https://www.amazon.co.uk/dp/B099ZLWQCP/?tag=pinkfishmedia-21

I do have some 60/40 but it doesn't seem to make any difference, it flows but it just rolls off in balls instead of sticking to whatever. I always seem to manage eventually but it is purely luck. I've wired a dozen arms probably and various other things, but I've never been happy with a single solder joint and it has never "just worked", it's always a pigs ear.
 
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Try buying the Antex I linked to. The one you have looks like Chinese junk and whilst it looks to offer a lot the quality has to be awful as you simply can’t make that much at that price without serious corner-cutting. The same functionality made by a credible company, e.g. Hakko, would be a couple of hundred. The little Antex couldn’t be simpler but it is decent quality and pretty much every electronics engineer will have one somewhere. I’d also buy a small needle-tip for fiddly stuff like tonearm wires. Solder ‘balling’ can certainly be down to a shit quality tip. It just shouldn’t do that, especially a nice 60/40 lead solder. It should flow easily and neatly assuming you are heating the joint correctly.
 

Here’s part one of a tutorial with Dave Jones of EEBlog. I’m sure I’ve watched it years ago, but I don’t need to in order to link it, I know whatever he says/recommends will be exactly right. He knows his stuff inside out and is always good at explaining it. Practice, practice, practice. I’ve been doing this for over 40 years now, I started with guitar leads and gradually grew from there. You’d never spot my work now, it looks factory done, especially as I always clean up the flux etc. No magic, it’s just practice.
 
Maybe I've just been unlucky and only had junk tips. I'll watch that and see if anything jumps out at me.
 
Thanks for that video Tony, cleared a few things up that might explain why I'm having a bit of trouble.

He isn't a fan of those single temp plug in irons though! Probably using the wrong tip and solder, will get a couple of the other bits he suggests as well. I've managed it anyway for now with perseverance and blind luck as usual.
 
matt j said:
He isn't a fan of those single temp plug in irons though! Probably using the wrong tip and solder, will get a couple of the other bits he suggests as well.
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I’m sure he’s right. I have to admit I’ve never used a proper soldering station, I’ve had the Antex for 40 years (I’m on my second one) and I’m so used to it I’ve never changed. I can do anything from speaker leads to through-hole computer chips with it perfectly neatly. I should really get a nice Hakko at some point. I’ve got a Hakko FR301 desoldering gun which is great for old computer RAM chips etc.

My point is I bet yours is very low quality as it is impossible to make a decent quality variable temp soldering station for £29 and I’m certain the simple Antex will have a far better tip. It certainly never ‘balls’ the solder.
 
If it's just the tip that's the problem, then you might be able to find a different brand that would fit that same iron. That's how I'd start anyway.
 
Obviously I've heatshrinked some of the joints now so you can't really see, but it's done.

You can just see the earth trapped between the cable gland I made for the arm pillar, it is a much tighter fit than the original. I was working with 36AWG wire which wasn't helping, compared to the stuff that was in it it's like strands of hair. The original stuff had gone a bit stiff/brittle so I am not convinced it wasn't affecting the arm movement where it loops out of the wand and into the plug.







 
Matt, when you say the solder was balling up, do you mean it wasn't flowing or the tip wasn't tinning properly? If you've sanded your tip, you've probably removed the iron coating, exposing the copper which will have blackened/oxidised. If so you just won't be able to solder with it. Get some new tips and a little pot of tip tinner. You also need a dampened pad (usually made of natural sponge) to wipe your bit on occasionally. Each time you use your iron, before soldering wipe the tip on the pad and dip it into the tinning pot, and when you've finished, clean the tip and tin it immediately before turning it off. You don't need a variable temp iron, but it's nice to have. A simple, decent 25 to 30W iron will do all small stuff.
As @Vinny said, you can make a variable temp iron using a dimmer switch. I have one which I use with my big 100W iron for big stuff.
 
a.palfreyman said:
As @Vinny said, you can make a variable temp iron using a dimmer switch. I have one which I use with my big 100W iron for big stuff.
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To a degree. The proper soldering stations monitor and load-balance so if you set it to say 400C you get that whether soldering a tiny lead or a big heatsink. If I ever upgrade my humble Antex it would only be to that grade of station.

PS As we are on soldering stuff another recommendation is this Japanese Engineer brand solder-sucker. I really can’t recommend this thing highly enough. Even though I have an expensive Hakko FR301 desoldering gun I use this one most of the time (I just dig the Hakko out for any computer chips I want to get out intact). It is just so much better than the cheap ones with plastic tips as the silicone end can be held right against the iron tip and it really sucks well. An absolute bargain.
 
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