Junkyard dog RCM underway

[Fast_Eddie]

We need more pics man!

Reading other threads on the subject, bleeding off some of the vacuum seems to be a common need. If you can rig some kind of adjustable opening you could dial it in just right.

I just gotta make me one of these...

 

[shimniok]

I am wondering about too much vacuum too... I anticipate the same problem using my micro handheld vac. I can pick a record up off the table with it, no problem. I will probably find it hard not to stop the record while the platter spins. Maybe use shelf liner material, that really grabby stuff, as a turntable mat. Or else use some type of clamp to hold the record down. When cleaning manually I leave a fair amount of the attachment hanging over the edge to keep from sucking too hard. But even so I have to spin the record rather than the platter.

Is it better to bleed off vacuum upstream, use a less powerful vacuum with no bleed, or encourage more airflow across the record surface somehow? :scratch2:

If you can figure a way to affix the velvet more permanently to a pair of long/narrow blocks placed parallel to each other with a gap between where the air flows, and maybe staple gun the velvet to the vertical sides of the blocks, leaving the bottom side free from staples so it can contact the record... ?

 

[Sam Cogley]

I am wondering about too much vacuum too... I anticipate the same problem using my micro handheld vac. I can pick a record up off the table with it, no problem. I will probably find it hard not to stop the record while the platter spins. Maybe use shelf liner material, that really grabby stuff, as a turntable mat. Or else use some type of clamp to hold the record down. When cleaning manually I leave a fair amount of the attachment hanging over the edge to keep from sucking too hard. But even so I have to spin the record rather than the platter.

Is it better to bleed off vacuum upstream, use a less powerful vacuum with no bleed, or encourage more airflow across the record surface somehow? :scratch2:

If you can figure a way to affix the velvet more permanently to a pair of long/narrow blocks placed parallel to each other with a gap between where the air flows, and maybe staple gun the velvet to the vertical sides of the blocks, leaving the bottom side free from staples so it can contact the record... ?

Right now I have the pads directly attached to the copper tube used for the vacuum wand. Gluing some blocks to the wand with foam pads between the blocks and the velvet seems like a good way to go, I'll look into it.

 

[Bluespower]

I've cleaned about 150 LPs with this arrangement and the felt is hanging in there great. A rubber foot works very well as a clamp. It's easy on/off and prevents the vac from getting a death-grip on your record.

 

[dodog]

It won't look pretty but have you considered duck (duct?) taping the velvet onto the tube? You could always remove the tape and change out the velvet when needed. I've done something similar to this on a DIY wand I made and it's held up well.

 

[Sam Cogley]

I've cleaned about 150 LPs with this arrangement and the felt is hanging in there great. A rubber foot works very well as a clamp. It's easy on/off and prevents the vac from getting a death-grip on your record.

Foam mounting tape... :scratch2: I should have some of that around, and it would provide a bit of spacing under the wand that would help create a bit of a vacuum leak.

 

[Bluespower]

I used a razor to cut a slot in the foam tape (not open ended). You can drill a series of holes in your vacuum line and add/remove screws to dial-in the amount of suck you need.

 

[Sam Cogley]

I used a razor to cut a slot in the foam tape (not open ended). You can drill a series of holes in your vacuum line and add/remove screws to dial-in the amount of suck you need.

I was thinking about putting a piece on each side of the slot, leaving the ends open.

 

[Divotdog]

I too would like to see some more pics now that you are a little further along Sam, it sounds like you are doing a great job.

I use the same method as Bluespower to control the "suck" on mine, works quite well. :thmbsp:

 

[elcoholic]

I really like your machine. I've never heard of a pony motor that small, very curious why they went that route for an organ. I don't think you can have too much vacuum, unless it's pulling the liquid into the motor. My DIY RCM uses a vacmotor out of a 2 HP ShopVac. You just need more record clamp. My spindle is a 1/4-20 bolt and I use a plastic wing-knob as the clamp. I use the VPI tube and it goes a little bit crooked contacting the record near the label and it's about an 1/8" off the record at the rim. The suction lifts (bends) the record to the tube, even 180 g. I've been using it for a while now and will be making a few tweeks to it this weekend. http://picasaweb.google.com/teamo65/RCM?feat=directlink

 

[Sam Cogley]

I really like your machine. I've never heard of a pony motor that small, very curious why they went that route for an organ. I don't think you can have too much vacuum, unless it's pulling the liquid into the motor. My DIY RCM uses a vacmotor out of a 2 HP ShopVac. You just need more record clamp. My spindle is a 1/4-20 bolt and I use a plastic wing-knob as the clamp. I use the VPI tube and it goes a little bit crooked contacting the record near the label and it's about an 1/8" off the record at the rim. The suction lifts (bends) the record to the tube, even 180 g. I've been using it for a while now and will be making a few tweeks to it this weekend. http://picasaweb.google.com/teamo65/RCM?feat=directlink

The problem is with the suction lifting the record to the tube - it stops dead at that point, even though the platter keeps turning. I'm using a 1HP shop vac plugged into the side of the tube system.

Thanks for the kind words, I based it on a few DIY machines I've found in older threads here.

The motor is odd - it came from a very early solid-state Lowrey organ's tone cabinet. I don't know why they didn't go with a standard capacitor start. It will normally turn the platter without the starter, though it occasionally needs a bit of a jump. Also, if I get the speed on the main motor correct, the starter will provide a bit of a torque boost.

I love the cabinetry on your RCM, BTW. I would have done something like that if I had room.

 

[elcoholic]

Thanks. It was also a junkyard effort and I wanted it to be quiet enough to use with the wife asleep in the next room. Between baffling the vacmotor, and the size of the other components it ended up pretty huge. If I ever get a vacuum pump on the cheap I may do another much smaller version.

 

[Sam Cogley]

Thanks. It was also a junkyard effort and I wanted it to be quiet enough to use with the wife asleep in the next room. Between baffling the vacmotor, and the size of the other components it ended up pretty huge. If I ever get a vacuum pump on the cheap I may do another much smaller version.

If you look at the pic in my first post, the smaller starter motor is visible on the bottom of the main motor. Its chassis is turned at a 45* angle from everything else.

 

[elcoholic]

That's so strange. Pony motors were an old school method of starting really large industrial motors that could not be started across the line because of inrush current. Seldome done since the advent of reactor and capacitor starters.

 

[Sam Cogley]

That's so strange. Pony motors were an old school method of starting really large industrial motors that could not be started across the line because of inrush current. Seldome done since the advent of reactor and capacitor starters.

Strange doesn't surprise me. The solid-state amp in there was the first one I'd ever seen with an output transformer. It even has a mini tube cage over the output transistors. I've only seen one other SS unit built that way - my Sansui 3000A receiver, which had an identical tube version (the 500A). The whole organ was odd. Full of 100V orange drops and other bits that looked very out of place in a solid-state design. Maybe that big styrofoam wheel needed extra help starting up.

 

[ke4mcl]

kudos to you man! what they charge for RCM's is ridiculous.

 

[Arkay]

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).

Very glad to hear that. It may actually be doing the audio world a service, to take a worthless TT and use it to create an RCM, and thus many much cleaner records.

Congratulations on the progress. Looking forward to your future/final reports.

 

[Sam Cogley]

I'm getting closer to having things balanced to where I get suction on the disc and it still spins. Right now it needs a bit of help to keep going, but even just brushing distilled water on the surface does an impressive job of cleaning a disc. I tried it with my noiser MoFi "Abbey Road," and it eliminated almost all noise.

The mounting tape idea was a good one - some indoor/outdoor mounting tape solved the velvet tape problem.

 

[Sleep]

Looking good. Seems like I might have to dig up some old threads, get some ideas and build something like this myself. I have a junky TEAC TT lying around that would be happy to donate it's platter...

 

[jimbofish]

Canister-type vacuum cleaners usually have a suction bleed device on the handle end of the hose... the part that you hold in your hand where the attachments, pipes, etc. connect. It's just a partial ring of metal that can be pivoted around the pipe to cover/uncover a large hole in the wand.