Rega rb251/ol1 rebuild

Love it or hate it, it just won't stop
Post Reply
User avatar
cressy
Shed dweller
Posts: 2906
Joined: Fri Aug 03, 2007 7:07 pm
Location: the great white space
Contact:

#1 Rega rb251/ol1 rebuild

Post by cressy »

Just spent the last few hours on the first part of rebuiding the rega arm. I was just going to rewire it but why not do it properly.
Ive removed all the paint from the arm wand and given it a bit of a polish. Also filed out all the casting marks (of which there were many) with small warding files and reshaped a few areas where it looked decidedly rough around the headshell. cleaned all the crap off the bearing pins, and dry fit it all back together so i dont lose any bits.

Next i need to decide what to do with the arm cable where it comes out of the base of the arm pillar
Image

It'll never be an ekos but perhaps it can be made into something half decent. Jeff spall managed it
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#2 Re: Rega rb251/ol1 rebuild

Post by Mike H »

Rewired mine with Litz, I just let the wires out the bottom and soldered them onto a bit of stripboard that's fastened with a mounting bracket.
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
User avatar
cressy
Shed dweller
Posts: 2906
Joined: Fri Aug 03, 2007 7:07 pm
Location: the great white space
Contact:

#3 Re: Rega rb251/ol1 rebuild

Post by cressy »

Ok, so stage 2, drill holes in the arm tube. I chose to do an alternating size hole pattern in the underside of the arm tube.
Marked it in 10mm increments and piloted the holes with a 0.75mm bit
Image

Then piloted again with a 1.5mm bit
Image

Then added 2.5mm alternating holes
Image

And finally alternate 3.5mm holes.
Image

Then wired it up with the bearings protected
Image

And gave it a respray in aluminium silver
Image

Why the respray? Well i read on't t'interweb that the paint adds some damping to the tube. That might be bollocks, but i also wanted it to look better. The bare ally had the filing and sanding marks in it, and quite frankly i could not be arsed to polish them all out.
So it has had 3 coats of silver and 3 coats of clear coat to protect it. Once cured the clear coat will give a hard finish that wont scratch. You may notice that i also filed off the indicator mark on the top of the pivot section, that indicates the vtf if the tube is in a 300 series rather than a 250 series. Perhaps im getting increasingly anal about little things......
Last edited by cressy on Wed Jul 20, 2016 5:22 pm, edited 1 time in total.
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#4 Re: Rega rb251/ol1 rebuild

Post by Mike H »

Remind me what's the reasoning for the holes?
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
User avatar
cressy
Shed dweller
Posts: 2906
Joined: Fri Aug 03, 2007 7:07 pm
Location: the great white space
Contact:

#5 Re: Rega rb251/ol1 rebuild

Post by cressy »

They are supposed to break up resonances in the arm tube
Audiomods drill their pattern in a spiral around the tube but i didnt do that as i think it would look a bugger if i got any of the holes slightly out. They also put small discs inside the tube to further damp out the resonances which i think is a good logical thing to do. Im trying to figure a way of doing something similar
User avatar
Greg
Social outcast
Posts: 3198
Joined: Wed May 23, 2007 11:14 am
Location: Bristol, UK

#6 Re: Rega rb251/ol1 rebuild

Post by Greg »

cressy wrote:They also put small discs inside the tube to further damp out the resonances which i think is a good logical thing to do. Im trying to figure a way of doing something similar
I think Jeff Spall either reams or drills out the internal of the tube, clearing casting excess to facilitate this. Of course the biggest benefit in his conversion is to remove the bearings from the arm and fit them in the supporting yoke. I'll follow your progress with interest. Good job so far. :thumbright:
User avatar
Greg
Social outcast
Posts: 3198
Joined: Wed May 23, 2007 11:14 am
Location: Bristol, UK

#7 Re: Rega rb251/ol1 rebuild

Post by Greg »

Furthermore, now having seen the underside of the arm, what you have their is definitely not an OL1. The OL1 has a slot cut in it's underside along the length of the tube in the same way you have drilled your holes. It may at some time had some attention from OL, but certainly it's not an OL1.

Having hung it for painting, did you do the knock test to see how it rang? The original arm tube hung like this rings like a bell. After treatment, the knock effect should produce a dull sounding result. Michell demonstrated this to me when I visited their factory, but recognise they also inserted foam into the tube to further damp after hole drilling.
Last edited by Greg on Thu Jul 21, 2016 8:07 pm, edited 1 time in total.
User avatar
cressy
Shed dweller
Posts: 2906
Joined: Fri Aug 03, 2007 7:07 pm
Location: the great white space
Contact:

#8 Re: Rega rb251/ol1 rebuild

Post by cressy »

Tbh im not quite sure what it is having taken it to bits, all it has is the origin live badge where the rega one usually is. Theres nothing else other than a hand etched serial number under the bias/ arm rest outrigger

It doesnt ring like it did before, the frequency is different and it stops ringing quite quickly now
User avatar
cressy
Shed dweller
Posts: 2906
Joined: Fri Aug 03, 2007 7:07 pm
Location: the great white space
Contact:

#9 Re: Rega rb251/ol1 rebuild

Post by cressy »

Ok, so we now have a rewired arm. I went to use the planer/thicknesser earlier today to start another chassis build and discovered a chipped blade. No good. So having ordered another one i turned my attention back to the arm.

Firstly, rather than paying through the nose for a din plug and socket specifically for a tonearm, i got hold of a neutrik 5 pin din plug and socket. These are the opposite way around on an arm, the pins are usually up the arm pillar. These are in the cable plug instead. Sod paying loads out for the 'right' bits when i can work around it.

So the socket was modified to fit in the base of the arm pillar. A couple of layers of black nasty to sleeve it up to make a resistance fit, and a couple of o rings space it from the bottom to clear the nut in the top of the pillar
Image

It then pushes in and is secured by the retaining grub screw
Image

Next we thread the solid silver wiring through the arm tube bung. This wiring was supplied by greg with the collection of parts for the mayware, unfortunately it was not flexible enough for that arm but it is ok for this one. So thanks to greg, there are 2 rejuvinated arms!
Cheers greg
Image

Then manhandle the wiring through the tube.
Image

I tapped a thread into the closest large hole to the bearing end and added a proper arm earth using a small ring tag and a 4mm bolt. No stupid sprung bit of steel in the counterweight stub thread any more.

I also inserted some special audiophile green sponge into the arm tube to further damp it, it sits half way along and tapping the tube now results in sod all ringing.

You must use the audiophile sponge, it is impregnated with snake oil and under no circumstances cut it out of an unused bath sponge. If you do the world will cease to be. It must be green, any other colour will result in the arm disappearing into another dimension :lol:

Having added the cart tags and wiring the din socket, the arm part is now done. Need to make a cable now.

I am going to drill a hole in the side of the plug so the cable comes out at a right angle to ensure i have enough clearance under the jbe.

I have some thicker solid silver wire that i use in preamps for the cable so it will be completely silver wired
Image

Hopefully this effort will polish the turd........
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#10 Re: Rega rb251/ol1 rebuild

Post by Mike H »

cressy wrote: You must use the audiophile sponge, it is impregnated with snake oil and under no circumstances cut it out of an unused bath sponge. If you do the world will cease to be. It must be green, any other colour will result in the arm disappearing into another dimension :lol:
... and a unicorn dies :lol:
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
User avatar
cressy
Shed dweller
Posts: 2906
Joined: Fri Aug 03, 2007 7:07 pm
Location: the great white space
Contact:

#11 Re: Rega rb251/ol1 rebuild

Post by cressy »

I made the new cable up out of one of the new cables i ordered rather than making a silver wired one for now. I bought 2 plugs so i can make another up when i get chance.
Its now all mounted on the jbe and playing with the mc10 in the headshell.
Image

Initial impressions are that it is much improved. Much more even handed which i think is down to the arm tube modifications. The silver wiring sounds like silver wiring. Using it quite often in my preamps i can tell the difference in the mid and top. This is much improved over the standard wiring.
The counterweight stub has been altered, it has had a piece of ally rod bashed into it to remove the odd harmonics the plasic one exhibits.
The thing sounds so much more open and that grey sort of squashed sound it had isnt there.

So a summary of that i have done to it
1. Full strip, clean and rebuild
2. Modified drilled arm tube, casting marks removed and general tidy
3. Silver respray 3 coats silver 3 coats clear
4. Silver solid core rewire
5. Improved arm tube earthing
6. Fitted din socket to arm pillar
7. Made new cable.
8. Damped arm tube with foam
9. Modified counterweight stub

So alot of work to get it up to scratch

I bet the audiomods one is superb
Post Reply