Presto 6N Motor / Speed Controller update options

[JayDC]

Hey guys,

I have been researching different options to control the speed for my presto 6n. So far I have found 2 options, and I wanted to see everyones opinion before I spend any money.

The first one:

The Origin Live Ultimate:
This unit runs a 15W DC motor (included). The manufacture said to me in an email that the DC200 motor option should be enough torque to compare to an SP10mk3, and offered a money back guarantee if it did not work out with the presto. This unit would drive the platter like flo's mod, using a belt. They make the belts and can make a belt for the 6n.
Can run on 220 or 110 mains.





The second:

The Music Hall Cruise Control 2.0

The music hall cruise control permits the electronic speed control of music hall and project turntables between 33.3 and 45 rpm at the simple touch of a button. Removing the platter and moving the belt from one pulley to the next is no longer required. The quartz-locked speed control provides unmatched speed stability to within ±0.0001% deviation. Used with the appropriate pulley and cartridge, it also permits the replay of 78 rpm records. The replay speed can be increased and decreased in twenty steps of 0.1 rpm. The quartz lock provides perfect speed control for all music hall turntables, many project models, and any turntable with 120v AC synchronous motor.




I'm leaning towards the second one since it requires less work, and is slightly less expensive. I'm just not 100% sure that it will handle the power of the motor. I don't want to damage the bodine.

[Steve E.]

How very exciting! But, regarding the first option, doesn't your 6N use rubber drive wheels? Are belt drives feasable with the amount of friction and torque that a cutting head/stylus adds to the system, plus the 16" platter? And where would the belts go?

The music hall system would require that you use a 45 speed adaptor on your Presto...do note!

I'll be very curious as to whether those old motors can handle this sort of thing!!! I'm watching. If it works for you, I'm next in line.

[JayDC]

Flo modded his 6n wit ha sc-99 and vinylium cutting electronics, there is a picture somewhere on here. He also replaced the original bodine motor with a premotec motor, and mounted the motor where the playback tonearm would be mounted. His 6n is belt driven, and I'm sure it works well, but only flo knows.

So the first mod, if the DC motor is strong enough, would get mounted in the same fashion. With the belt going around the out side of the 6n platter.
This mod also has adjustment pots in the back for each speed to make sure that the speed is correct for each switch.


Not really concerned about having to use the 45 adapter or not, I am just looking for push button accurate speed shifting, coz it's a pita to reset up everything all the time.

The idea of quartz lock on the second unit, my laziness, and my wallet are pushing me in that direction. The only down side is, there are no adjustment pots for each speed. So if 33.33 on the read out is not correct when checking with your strobe, you might have to go 33.1 or 29.5 or 34.2. This sort of turns me off.

[markrob]

Hi Jay,

The second opiton is the easiest and what I would suggest. It requires no change to the 6N. However, this unit is way under powered for the Bodine motor. Its 1/25 HP, or 30 watts. The actual drive required is likely more as the 1/25 hp rating is shaft output not motor power consumption. To be safe, I would assume you would need 50 to 100 watts. It would be a good idea to see what type of output this device generates. In the best case, you would like to see a pure sine wave out. Most inverters are modified sine, which is less desireable as it will cause the motor to run a bit hotter. It may also increase the motor noise due to the presence of harmonics in the drive waveform. It might be good to check with the manufacturer to see how this works.

The first option looks way too skimpy in motor size. Both of these are designed for playback turntable applications and are not designed to handle the extra torque required for cutting. The advantage this method would have is that it would get rid of the rim drive and would likely lower the motor vibration noise coupled into the platter. It will require much more work on your part to get running.

What is you issue with the standard motor run off wall AC?

Mark

[JayDC]

Hi Jay,

The second opiton is the easiest and what I would suggest. It requires no change to the 6N. However, this unit is way under powered for the Bodine motor. Its 1/25 HP, or 30 watts. The actual drive required is likely more as the 1/25 hp rating is shaft output not motor power consumption. To be safe, I would assume you would need 50 to 100 watts. It would be a good idea to see what type of output this device generates. In the best case, you would like to see a pure sine wave out. Most inverters are modified sine, which is less desireable as it will cause the motor to run a bit hotter. It may also increase the motor noise due to the presence of harmonics in the drive waveform. It might be good to check with the manufacturer to see how this works.

The first option looks way too skimpy in motor size. Both of these are designed for playback turntable applications and are not designed to handle the extra torque required for cutting. The advantage this method would have is that it would get rid of the rim drive and would likely lower the motor vibration noise coupled into the platter. It will require much more work on your part to get running.

What is you issue with the standard motor run off wall AC?

Mark

I don't really have so many issue, although almost every time I use the machine I have to adjust the speed a little, and from what I'm finding that is not because of the motor, but because of the phase. The phase in the power coming to my house must fluctuate, and I have had it ruin a cut. I watched it the other day while i was cutting, and all of a sudden half way through the cut, I watched the strobe slow, then go back to normal.

I found other options like the music hall device, but they are only schematics. All of them generate 2 phase, and require you to remove the capacitor. So 60hz to the motor gives you 33.3, and 81hz will yield 45, and since the phase is generated from the unit, its more stable then what peco is sending to me atm.

I had a similar problem when I worked at nation, one of the laser systems had a problem firing coz the power was "dirty" sometimes we'd only get 100v @ 55hz.. This killed a ton of bar coolers and things.

With the laser we just hooked it up to dead UPS back up unit, since these generate there own phase as well, it fired right up.

bottom line, I'm trying to get this thing ready to cut masters and great dubplates for myself. I'm hoping the day I get everything sorted out, and my preamp built, will be the day that flo tells me a caruso is waiting for me.

[markrob]

Hi Jay,

Unless you live in some third world conutry with a bad power grid, there should be no issue with line frequency. I don't undertsand how you are making the speed adjustment with a fixed AC line and a synchronus motor. How are you doing this? This type of motor is very stable and the power company keeps a close control of the line frequency. Otherwise, any motor driven clocks would be way off. Interestingly, if you are checking the speed with a stobe disk, you are in fact using the power company AC line frequency as the reference. The strobe works due to the fact that your lighting flickers/flashes at 2 times the AC line frequency. So, if you are seeing a speed change, its not due to the AC. In fact, if there was an issue with your power, using the strobe disk would not show it because any line frequency change would affect both the motor and the lighting in the same way and cancle out. Your problems are most likely due to mechanical issues (e.g. slippage, dimension of the motor shaft, bad idler wheel, or mis-adjustment of the motor). I suppose its possible your motor is bad, but you should check the obvious first. Also, you should make sure the capacitor its the right value and type for the motor. It may have been replaced or perhaps it is bad.

Mark

[petermontg]

could this help you jaydc

http://cgi.ebay.ie/ws/eBayISAPI.dll?ViewItem&item=180638494029&ssPageName=STRK:MEWAX:IT#ht_500wt_1156

could you condition your power on the motors plug or will you still have the same power problem.

[JayDC]

Hi Jay,

Unless you live in some third world conutry with a bad power grid, there should be no issue with line frequency. I don't undertsand how you are making the speed adjustment with a fixed AC line and a synchronus motor. How are you doing this? This type of motor is very stable and the power company keeps a close control of the line frequency. Otherwise, any motor driven clocks would be way off. Interestingly, if you are checking the speed with a stobe disk, you are in fact using the power company AC line frequency as the reference. The strobe works due to the fact that your lighting flickers/flashes at 2 times the AC line frequency. So, if you are seeing a speed change, its not due to the AC. In fact, if there was an issue with your power, using the strobe disk would not show it because any line frequency change would affect both the motor and the lighting in the same way and cancle out. Your problems are most likely due to mechanical issues (e.g. slippage, dimension of the motor shaft, bad idler wheel, or mis-adjustment of the motor). I suppose its possible your motor is bad, but you should check the obvious first. Also, you should make sure the capacitor its the right value and type for the motor. It may have been replaced or perhaps it is bad.

Mark

we had plenty of power problems in washington d.c. at the club and we were less hen a 1//4 mile from the generation station. I am not ruling that out completely.

If what you were saying is completely true, then the companies that manufacture line conditioners would be out of business.

I'm not saying my presto is whack but a device that would allow control of the motor via frequency is in the realm of what i'm looking for. I could easily remove my overhead, and use a technics sp10mk3, or one of the other heavy duty quartz lock turntables out there, but i want to use the nice presto platter.

bottom line, I want 33 or 45 at a flip of a switch, and I want to do that via an upgrade. Not a new turntable, I don't care if a use an original motor or not. I don't care if its idler, belt, or direct drive. I just want it to keep speed, every time i turn it on w/o an adjustment to the idler engage lever.

[markrob]

Hi Jay,

The line conditioners you speak of do nothing to control or correct for line frequency variations. Unless you go for an onlineUPS, which has an on-board inverter, there will be no control of this paramter. I would bet these do not control the frequency as well as the power company as there are very few devices that need this anymore.

Most of the low to mid priced line conditioners are nothing more than surge supressors and may contain some line filtering to eliminate high frequency noise spikes. Thsi si useful as it protects your equipment from damage. If you move up to top of the line units, they will have means to stabilize the AC voltage against browouts and high line conditions.

Again, if you are seeing large speed devations or large amounts of wow and flutter, then you have a problem with your 6N, not the power line.

Mark

[Amp Doc]

Jay siemens make a single phase motor controller which is frequency agile. It would do exactly what you are trying to do....Look in RS online and you will find one...Not too cheep tho but a lot cheeper than buying a sp10

[JayDC]

I'm wondering if this will work.. there is not alot of info, since it hooks into where the capacitor is contneced, it think it might..

http://cgi.ebay.com/AC-Motor-Speed-Controller-AC110V-120W-/160457600435?pt=LH_DefaultDomain_0&hash=item255c04adb3

[JayDC]

Also found a gentleman in germany that will make oscillator-based 2-phase AC motor power supplies custom to your specs.

for a custom unit that will work with the presto bodine: 450euros

contact: Bernhard Fuss DRBFUSS::::::at::::::AOL.COM

[Kris D]

Hi guys- The Bodine motor, being a syncro type, is designed to run at a set speed only. By varying the hz you can change the speed but the motor won't like it. Torque will fall off and heat will build up. To do this "right" one would need to build a variable capacitor that would change with the hz.

A better alternative is to use one of the three grooves on the outside of the platter (sadly only on 6n and 8n console units and 8d/8dg to the best of my knowledge) and drive it with a tape capstan motor from an Ampex type open reel machine. Almost all are 2 speed and can be changed to half speed at the flick of a switch. A custom pulley must be machined to achieve proper speed. If you make a three step pulley you can use one on each groove on the platter - 33-45-78-!! For belts large O-rings can be found at McMaster. We have an 8D set up like this with a 300/600rpm motor and it works great. By mounting the motor on a separate platform all vibration can be eliminated.
- Kris

[JayDC]

ok..

Kris, how much of a DC motor would you need to do this w/o wow and flutter in the cut.

[mossboss]

Interesting thread this one
Not that I am into Presto's
Idea
Early very early Maxtor hard disc drives about 150 meg or so Full height format 5.1/4"
They are blessed with a very powerful brushless dc motor with all the electonics on board Weighs about 1.5 pound
Would be something to look into
At around the $10 bucks each you can always get your money back selling the whole lot to the scrappies as they weigh about 10 lb's each
All the elsctronics are discreet incuding a dc to ac converter chip
At around the 120 watts it should do the trick
They used to give the power supply of the PC a hard time indeed
Just food for thought on the subject for a low cost alternative to the already mentioned options
I am a scrounger oddball goods
Cheers

[Nickou]

https://lathetrolls.com/viewtopic.php?t=1949&mforum=lathetrolls

I did some tests with that , and it was working pretty good ...


it is more than possible than it could be a solution for you

[emidisc]

I recently changed the motor on my BSR cutter
originally it had a 240v 4 pole sync motor but the insulation had broken
down.
I spotted this on ebay for £10 ( the guy as a few of them)
http://cgi.ebay.co.uk/ROTEL-830-FUJIYA-AUDIO-CO-JAPAN-MOTOR-IM-S275-12D-/280644132514?pt=Turntable_Parts_Accessories&hash=item4157b19ea2
I needed to make a new pully but in runs great and super silent
next I plan to make a combined 33 and 45 pully for quick changeover
to moniter the speed I am using a none contact laser tacho of ebay
cost £12 hope this helps......
emidisc

[JayDC]

this motor works well for you with out causing wow and flutter?

if that is the case, then the origin live control should work.

[Joost]

Hi JayDC,

Sorry to bump this thread again, but since i'm living in Europe (230/50Hz) i also like (need) to swap the motor of a 6N.

I'm thinking about buying a controllable brushless DC motor with loads of torgue and just replace that with the current 120v/60hz motor. Not sure if that's possible and/or if such DC motors with high torgue exists, but it seems like a great way to go with. Also the fact that you can 'pick it up' and plug it in everywhere in the world (it needs an adapter) or even use it with solar powered batteries etc sounds superb to me . If not enough torgue exists in DC's maybe they will provide enough together with some gears (e.g. Maxon has a lot of gears available to mount on top of the motors)?! @anyone knows how much torgue is needed at a minimum to drive a Presto 6N?

I also wonder if the promotec that Flo used on his 'portable' 6N can be used as a direct drive instead of belt. Probably not as he would have done that i guess, but maybe he had different reasons for using it this way?!

Anyhow still looking for a way to go and have a lot of questions to be answered .
Did you find a good solution yet?!

Cheers

[markrob]

Hi,

The brushless DC motor idea should work out great. As far as torque, just make sure the motor is capable of 1/25 hp at the shaft speed you will be running (1800 rpm if going with direct drive). If you can find a motor that can be mounted in the same space as the Bodine, that is the easiest solution. You will probably need to machine a new stepped pulley to fit the motor shaft. The disadvantage of this approach is that you will still be running a rim drive system and be suject to the need for the rubber idler pucks. Also, I suspect that you will have much better motor vibration isolation if you use Flo's approach and go with a belt drive. That seems to be a problem with my 6N.

Mark