Junkyard dog RCM underway

I've started working on my RCM after long procrastination. The bearing and platter are from a POS Garrard 301 I got in a huge lot of stereo stuff, the motor is from the tone cabinet of an early solid-state Lowrey organ (that I bought for $5 hoping it was a tube unit), the speed control is for a ceiling fan, and the fuse holder was salvaged from a tube Lowrey - thought I might stop at Rat Shack and pick up something with a lower profile. The motor is a bit odd in that it actually has two motors - a small starter and the big main drive. The starter doesn't start under load, instead it has a slip bearing and the rotor/shaft assembly move up as it picks up speed until it hits the main motor's idler tire. The second switch is an on/off for the starter. I haven't started on the vacuum wand yet, it will be made from a piece of 1" copper tubing.

Here's the top plate with the various bits being test-fitted. The bearing assembly has six evenly-spaced holes around the edge. I'm going to drill and countersink holes in the aluminum platter to engage three of them so the platter doesn't slip while under vacuum. Unlike a lot of designs I've seen, the vacuum won't be internal. There will be a fitting in the case to plug in the hose from a 1 gallon mini Shop-Vac - that way I can still use the vacuum to clean my car.

You worried about water getting into the electrics at all?

JonL said:

You worried about water getting into the electrics at all?

Click to expand...

I'll make a shield for the motor before everything is done, and I might make some sort of divider to go between the platter and the controls. I don't plan to spin the platter very quickly, so it shouldn't be slinging fluid around. It won't take much to protect the motor as the pulley is well underneath the platter, and the angled platter edge should deflect water away from it.

Now that I think of it, one of those plastic folder holders that doctors and hospitals put on doors to hold would make an excellent shield over the controls. Time for a trip to the office-supply store...

Whatcha gonna use for vacuum pick up tube?

Didn't know that the 301 came with an angled strobe pattern platter. Seems a pity to sacrifice it to an RCM, but too late...

Windwalker said:

Whatcha gonna use for vacuum pick up tube?

Click to expand...

1" copper tubing. It will make sense once I start putting that together and get a few pictures made. Eventually I'll make extra tubes for 7" and 10" records.

Nat said:

Didn't know that the 301 came with an angled strobe pattern platter. Seems a pity to sacrifice it to an RCM, but too late...

Click to expand...

I think the number was actually GT-301 (edit - actually GT-350...damned memory). It was a broken-up mess that didn't run right and had no spindle. The bearing, platter and dust cover were the only parts worth salvaging. I'm going to have to cut part of a broken changer spindle from an old Magnavox/Collaro TT to fit the bearing, or this won't work very well at all.

water shouldn't be an issue , I rarely have any go off the the LP and then it's only a drop or 2 . But I only use enough fluid to flood the surface , same with the rinse . But I spin by hand so speed is not an issue . Would be nice to have a motor but I'm not that handy .The sears belt drive I use to clean on can't spin under load of course ,so it's not plugged in . I found even my cheap-o rcm to be a wonderful upgrade .

Looks really good so far! Hope it works well for you!

The box is well underway, I should get the rest of the brackets for the top and bottom plates glued in tonight. Might even get the top plate glued into the box. Once the wood is assembled, I'm going to putty any visible seams and screw holes, sand it smooth, and paint the whole thing black. For now, I think I'm just going to use a heavy rubber band for the belt, though I'll try to find something better as time goes on.

This thread was my inspiration: http://www.audiokarma.org/forums/showthread.php?t=204132 The vacuum wand will be similar to that one, but the block to connect the wand will be inside the box at the right rear, and there will be a hole through the side to plug the mini shop-vac into the wand system.

One nice thing about this platter is that the strobe design on the edge is actually raised blocks. If the suction is too high and it needs some help to spin, that will give an easy gripping surface.

Future plans might include a system to automatically distribute cleaning fluid and distilled rinse water. For now, I'm not going to worry about being that fancy.

Sam Cogley said:

The box is well underway, I should get the rest of the brackets for the top and bottom plates glued in tonight. Might even get the top plate glued into the box. Once the wood is assembled, I'm going to putty any visible seams and screw holes, sand it smooth, and paint the whole thing black. For now, I think I'm just going to use a heavy rubber band for the belt, though I'll try to find something better as time goes on.

This thread was my inspiration: http://www.audiokarma.org/forums/showthread.php?t=204132 The vacuum wand will be similar to that one, but the block to connect the wand will be inside the box at the right rear, and there will be a hole through the side to plug the mini shop-vac into the wand system.

One nice thing about this platter is that the strobe design on the edge is actually raised blocks. If the suction is too high and it needs some help to spin, that will give an easy gripping surface.

Future plans might include a system to automatically distribute cleaning fluid and distilled rinse water. For now, I'm not going to worry about being that fancy.

Click to expand...

Well if your shop vac is like mine ( the little red screaming banshee from WM) I think the belt drive may be an issue ? It requires a fair bit of torque to rotate when the wand is on the lp . mounting it off the surface of the Lp might work but would that not leave residue in the bottom of the grooves ?
I have seen folk on here use bread machine , ice cream makers or cordless drill motors , lots of torque and low rpm but they are direct coupled to the spindle . Again I am no mr fixit guy but belt drive might be an issue ?

ARJohn said:

Well if your shop vac is like mine ( the little red screaming banshee from WM) I think the belt drive may be an issue ? It requires a fair bit of torque to rotate when the wand is on the lp . mounting it off the surface of the Lp might work but would that not leave residue in the bottom of the grooves ?
I have seen folk on here use bread machine , ice cream makers or cordless drill motors , lots of torque and low rpm but they are direct coupled to the spindle . Again I am no mr fixit guy but belt drive might be an issue ?

Click to expand...

I was going to use a bread machine motor until this organ fell into my lap. As long as the belt has good grip, it will turn. Torquey little bugger.

All of the braces are glued into the box. Once it's dry I can get some update pictures, then install the top panel.

Lookin good!

I've been thinking - I might add another switch and an outlet on the side so I can flip the vacuum on and off from the top instead of reaching over to the vacuum body.

I finally tested the motor and bearing, using a heavy rubber band as a belt. It has enough torque that I can barely slow the motor with my fingers, and grabbing the rough edge of that platter will make a good attempt at sanding your fingerprints off. I think I made the right choice on the drive system.

The bottom plate fits without any issues, but I'll have to fire up the table saw and gently buzz a few edges of the top plate. It doesn't quite fit right, but it's very close.

I attached a small vac brush to a tonearm with a couple feet of plastic and rubber tubing. Then an adapter to fit the shopvac hose and it's done. Electronics are safely away for the most part. I slowly move the brush/arm across the spinning record and it sucks everything off. Works great. It's a manual. John

Given that the Garrard 301 --admittedly, after some necessary refurbishment and re-plinth-ing-- is one of the most highly-prized audiophile turntables ever made (at least thought of as such among its cult-like following), and widely sought after by many music aficionados worldwide, I'm surprised to see anyone using parts from one for an RCM. You probably could have sold those parts to a 301 fan in need of them, and had enough money to just buy a VPI 16.5. This is, to my mind, a bit like using parts from a wrecked Rolls Royce to make a cart to haul manure around the fields. It'll work great, but really isn't the best use for those parts.

I don't mean to challenge all the good work you're putting into making a nice DIY RCM; I think it's great. :thmbsp: Just wish you had picked some other parts than those of a 301. There are less-prized TTs out there which could donate perfectly serviceable parts for your purpose.

Arkay said:

Given that the Garrard 301 --admittedly, after some necessary refurbishment and re-plinth-ing-- is one of the most highly-prized audiophile turntables ever made (at least thought of as such among its cult-like following), and widely sought after by many music aficionados worldwide, I'm surprised to see anyone using parts from one for an RCM. You probably could have sold those parts to a 301 fan in need of them, and had enough money to just buy a VPI 16.5. This is, to my mind, a bit like using parts from a wrecked Rolls Royce to make a cart to haul manure around the fields. It'll work great, but really isn't the best use for those parts.

I don't mean to challenge all the good work you're putting into making a nice DIY RCM; I think it's great. :thmbsp: Just wish you had picked some other parts than those of a 301. There are less-prized TTs out there which could donate perfectly serviceable parts for your purpose.

Click to expand...

Post #6 (I think) might allay your fears. I mis-remembered the number, the table was actually a GT-350 - and a pretty sorry example of one at that. Flimsiest plinth I've ever seen, and that includes those 80s "rack system in a box" disasters.

No worries, everyone - no useable audio gear was injured in the making of this useful device. Just a dead organ and a POS changer TT (that happened to somehow have a nice platter and bearing).

Okay -- that answers my puzzlement at the strobe ring on the platter -- its not a 301 after all. And now that you mention it, that's also why the platter looked familiar -- I was given one of those once. Not a terrible table, but its no loss to the planet that you are giving it a different use.

The work is coming along nicely. The box is together, and while I could have done a more smooth job with the finishing, at least it doesn't look terrible. Most of the guts are installed, and I'm working on the wiring now. The bearing assembly had six evenly spaced holes in cast tabs in the plastic, now that I've done a bit of drilling those will work nicely to secure the platter to the bearing top. A bit more wiring, and some assembly work on the vacuum tube, and the beast will be ready to go!

Still have to cut the broken spindle off of the Collaro/Magnavox TT to use it in this project.

OK, I have everything together and had a chance to test it last night.

Some observations:
1) I have too much vacuum. I'm going to try drilling a hole into one of the suction arm blocks to bleed some of it off. Right now it's stopping the record while the platter keeps spinning.

2) The "permanent" double-stick tape I used to attach the velvet pads to the suction arm isn't very permanent. One side of a record and they fell off. Suggestions will be very happily accepted to alleviate this issue.

3) It works very well. I dropped a beat-up thrift-store copy of "Are You Experienced?" on the platter and cleaned side one as my test subject. It went from horrid to quite listenable.