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Audiomods Tonearm Build


shaky

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A proper build thread, my first, for the tonearm of choice for my 'still in construction' modified Lenco L75.

Instead of purchasing a completed arm, I picked the arm kit from audiomods.co.uk, along with the Rega parts kit consisting of RB251 armtube, arm lift and arm rest. A couple of extras added on as well.

First up, I have to say dealing with Jeff Spall from Audiomods, through the whole process of ordering, buying and even help with construction, has been an absolute pleasure.

The kit turned up, lots of pieces individually bagged, each with a card with the part name on it. A comprehensive set of clear, easy to understand instructions and photos were included, along with a write up of a great selection of carts previously tried with these arms. First impressions were pretty good.

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Should have taken photos of the arm tube before I started but too eager to get cracking. First step was to file any odd castings off the arm. Most were around the bearing end with the arm lift having a few as well. Then to sanding. Recommended in the instructions to sand with wet and dry from 320 through to 1200grit. I went to 2000 just because I had it. This is at 800:

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Once the arm was sanded polishing was next:

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The next step was to drill the arm. Benefits of drilling using the pattern template in the instructions include a reduction in arm mass, the arm tube is allowed to expand a little when internal braces are installed creating tension that controls resonance in the arm amongst others.

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Once drilled the next step was to install the internal braces. A couple of washer shaped pieces of aluminium were slid down inside the arm to about 1/3 and 2/3 length using a long thin rod.

At this stage because I had gotten my armtube from Audiomods, I could skip a couple of steps, drilling a hole to mount an earth point on the arm tube and elongating the hole under vertical bearing housing that wiring comes through. The original hole gets blocked by new bearing assembly.

On to the bearing, installing the bearing carrier turned out to be one of the harder parts I have had to do. I set it up as directed in instructions using a couple of sockets, one against bearing end of arm and one against carrier in my portable vice and started compressing it all together. Became altogether very hard to move after a while and was concerned I was going to break the arm. At this point it seemed me tightening the vice had no effect on moving the carrier into the arm. It was then that I noticed I'd broken one of the cast aluminium jaws on my vice! No wonder I found it so hard. Change of vice brought a complete change of difficulty in getting the carrier into the arm. It just popped in. Yay.

Next step, the already put together arm lift mechanism was installed on the base as well as the arm tube and it was starting to look like a proper tonearm. Don't have a pic of just the tonearm so these ones mounted to Alu arm board and in place on the plinth will have to do, makes the arm look even more at home:

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Still to do, apart from the wiring, I have to mount the antiskate setup plus the stainless counterweight.

Edited by shaky
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Great work there Tim ... it's come up a treat!

I didn't realise that you had to drill the arm yourself when buying it in kit form.

Did you drill it with a vise and pedestal drill or hand drill?

Totally agree ... Jeff is great to deal with and so helpful with any issues or questions.

The instructions are first class and how good is that cartridge guide included.

Bummer you wern't able to get any pics of installing the bearings.

Looking forward to seeing it all finished :)

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Thanks guys. Linc, it'll be great when it's running, once the arm is wired and mounted, I'll pull motor and idler out of Lenco and stick it in the new plinth. It'll be good to have a functional tirntable again, haven't had one in a few weeks, but then again it is my only TT. ;-P

Al, drilling the arm was very daunting. But shouldn't have been in hindsight. Brilliant instructions in that regard (no surprise really, the whole thing is of the same quality. Jeff is really thorough in that regard as you'd know) in how to set up the template on the arm and pattern of sizes and actual drilling. I did it in a pedestal drill in the vice, wouldn't attempt it with a hand drill. I was scared the smaller bits (smallest holes are 1.5mm) may have bent on the curved surface and scratched the arm. But thankfully it never happened.

Yeah seems a little light on for pics. I was sure I took some as I inserted the bearing carrier into the arm but can't find them. Must have been too caught up in the build. If I do I'll add them here along with pics of the finished product.

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Great job on the AudioMods arm, Shaky! I got the arm fully built as I just don't have the DIY skills for something like this. You get the benefit of an outstanding arm (it really is very very good) and the satisfaction of doing the build yourself - kudos to you!

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Guys, thanks. The way the instructions are written pretty much builds the arm itself!! Plus, and I considered this many times in the hours of sanding and polishing I put into the armtube, you can buy a ready prepared armtube, polished and drilled ready to bolt in as an option in the kit. Cuts out most of the hard work and is just assembly from there.

It's a shiny bugger as you can see. Hoping it performs half as good as it has come up looking.

@@bebop, I had a brainfart when I it to mounting the arm and couldn't get enough clearance from the arm lift mechanism for the arm to sit level. An email to Jeff had this sorted. And he even sent me some shorter arm lift sleeves to try out at no cost. Great service.

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I have seen the arm drilling before for RB300 type arms. Has there ever been an A\B with two, say, RB300 arms, one drilled one not, on similar TT setup to determine if the drilling does anything.

I understand changes in mass and resonance but are those changes good or perceivable? The RB300 (one of which I have had from new, purchased1985) was and is hailed as the best value arm available and an outstanding performer. Does making it look like Swiss chess and scrapping off the ultra thin layer of "black stuff" make it sound better?

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On my table, the audiomods does give a lift in performance from a standard RB301. The main thing for me is the better adjustibility this arms provides in VTA, anti-skate, and VTF. The cart tracks much better witht he audiomods, and there was less IGD. 

 

Sound wise, it is nice subtle improvement over the RB301. I think its hard now to comment as its all just memory. But I remembered when I took the RB301 off and put the audiomods on, I was happier ;).

 

Again, Jeff is fantastic. He's so enthused about what he does, it gives added confidence in his product.

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I have seen the arm drilling before for RB300 type arms. Has there ever been an AB with two, say, RB300 arms, one drilled one not, on similar TT setup to determine if the drilling does anything.

I understand changes in mass and resonance but are those changes good or perceivable? The RB300 (one of which I have had from new, purchased1985) was and is hailed as the best value arm available and an outstanding performer. Does making it look like Swiss chess and scrapping off the ultra thin layer of "black stuff" make it sound better?

With the AudioMods arm, by the end of the mods, there's so little of the original RB300 (or in my example, the RB250) left that it's difficult to pin down the differences specifically attributable to the arm drilling. I can only assume that Geoff did much testing before settling on the drilled and internally braced approach for the arm.

From a more holistic perspective, I found the AudioMods a fairly dramatic improvement over the stock Rega with greater transparency and much tighter bass the two most obvious changes.

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  • 3 weeks later...

 

From a more holistic perspective, I found the AudioMods a fairly dramatic improvement over the stock Rega with greater transparency and much tighter bass

 

having just listened to my new Audiomods series 5 arm with Audio Technica oc9/3 cart which was previously hanging at the end of a tecnodec 1 arm  ( essentially Rega 250 with some weight mods etc? )  the differences were

absolutely dramatic and mirrors the above comment plus i will add that the greater transparency really is noticeable! :)

 

 

 

 

 

 

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My arm has been wired today finally, with the Cardas kit I have. Terminated at headshell end so far and earth connection to arm at pivot end. Just need to mount to plinth and terminate the other end at connection plate at rear of plinth and done.

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EDIT: Obviously planning to play my records on the ceiling.

Edited by shaky
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