SWAP: 60hz Lyrec Motor SM8/3A for 50hz Lyrec Motor

[pandapolar]

Hi Guys .. not too sure how i'll go but .. i have a 60hz Lyrec motor and i need a 50hz Lyrec motor to run here in Australia... thanks in advance

[gold]

Do you have the 60Hz strobe flywheel as well? I might be able to do a swap but i wouldn't do it without getting a 60Hz flywheel too.

[pandapolar]

Do you have the 60Hz strobe flywheel as well? I might be able to do a swap but i wouldn't do it without getting a 60Hz flywheel too.

i have pm'd you

[pandapolar]

hey guys still looking

[Cutterwoller]

The age old problem...running 60hz motors in a 50hz country.

No one gave me a straight answer on this. Some said, "get an oscillator and a power amp and a step up transformer"........fuck that.

Here is how you do it and it works because I use it in my studio daily and have no speed or wow issues. Switch on and go.

You need what is called a "Pure Sinewave inverter". These are used in cars/caravans and they convert usually either 12Vdc or 24vDC to AC at either 50 or 60hz depending on which one you buy. Or, what i did was have one custom made which was switchable between 50 or 60hz at 120VAC.

There are two parts to it, the inverter (which converters DC to AC) and the DC power supply (or sometimes known as a "charger").

Things you'll need to check....

Buy accordingly to what frequency output, wattage and output voltage you want.
Make sure the sinewave is good and pure.
Make sure the frequency tollerance is TIGHT.

As most are made not for driving precision equipment or motors, you might want to call a manufacturer and give them your specification and have it custom made, thats what I did. I plugged it in and it worked perfectly. Its just basically generating the mains of the country that you need.

Cheers,

[concretecowboy71]

I sold a 50hz motor a few years ago to a fellow lathe owner in Lansing, Michigan, USA. He might still be sitting on it.

Just get the right motor for your machine and be done with it! That was the easiest route for me.

[Cutterwoller]

Yes, I agree. Getting the right motor for your mains is obviously the best thing but, sometimes its not easy to get what you want. Especially with things made 50+ years ago, sometimes there no option but to make do with what you have.

I was just giving my recommendation to anyone who maybe is stuck or thinks they cant use their motor if they have wrong frequency motor for their country.

Cheers

[opcode66]

When I have metal frabricating in house I will be making BLDC platter motos. Design is set. Just need cnc and lathe...

16 coils, 4 phases, 4 coils per phase, optical rotary encoder paired with active feedback from non-pulsed coils, custom motor control with complex pulsing patterns. Trying to maintain the size specs of the lyrec. Power grid inspecific. Accurate and powerful.

[Cutterwoller]

The thing is with the Lyrec motors is that they don't really pair up with a Neumann platter so well when cutting a lot of vertical movement.

They rely on the weight of the turntable to bring it past each pole-piece of the motor with out sticking. So, the turntable can actually slow down or judder slightly with heavy stereo.

Its not a bad design, it was just designed for a heavier turntable to be used with it, like on the Lyrec lathes.

Saying that, I have never experienced that problem with Lyrec/Neumann setup. I know people who have had that problem tho.

I once put a Lyrec motor on a scully and sometimes the speed would not lock in. They were not happy together but you could get away with it.

Cheers

[opcode66]

Those who think they don't have a problem with flutter or speed haven't actually measured the inaccuracy of their turntables. Now that I'm doing Groove Graphics, I have become very familiar with this. I have generated a line test audio file. It should form a straight line from the center pin to the out diameter. Only those with a VMS80 or an SP02 can cut the file and produce a straight line. Most have an S shaped distortion running through the disc. That is the result of the motor speeding up and slowing down between rotations. The rest have a radial distortion in one direction, meaning the motor is consistently running slow or fast. In my experience, it has more to do with the shape of the motor and the regularity of the cycle of the power. I can supply the audio here for anyone who wishes to actually see how bad their platter motor actually is if you dare.

[concretecowboy71]

This is a very interesting thread. Recently, we have had some issues with highly out of phase info sounding as if the pitch is "wavering" slightly. The recording were either piano or vibraphone.

Todd, what is the method you described for checking stability? I am interested in learning more about this issue.

Thanks!

[gold]

The proper term for this is wow + flutter. You can check it by playing the W+F tone on the NAB record and looking at a W+F meter. The specs for the Lyrec motor are published. Not many of the Lyrec motors I've seen have met spec. I recently saw one apart for the first time. I can't see a reason they shouldn't perform to spec with careful restoration, unless there is physical damage.

[Simon]

I have done this power conversation to loads of lathes in the UK

12v to 110v inverter, type you get for campers from US eBay

2500 pure sign wave should do.

Then buy a 50amp power supply 12v and just wire it up and off you go.

If you want to go the other way, just reverse the process.

[Voxster1965]

Hi all - check out the equipment supplied by REDARC based in South Australia. One of their sinewave inverter units will definitely do the job.

http://www.redarc.com.au/

[concretecowboy71]

Thanks Paul!

[tubefan]

Just a note, if you end up with a mismatched flywheel I have LED quartz-lock strobes that fit in the bulb base in the AM32b and can modify the strobotron to quartz lock.

[Greg Reierson]

I can supply the audio here for anyone who wishes to actually see how bad their platter motor actually is if you dare.

Post a link. I'd like to try it.

[chris-zwarg]

The proper term for this is wow + flutter. You can check it by playing the W+F tone on the NAB record and looking at a W+F meter.

If you have a digital audio workstation that includes a decent-resolution spectrograph, you don't even need a W+F meter: Cut an 1kHz tone (or for that matter any midrange frequency that registers loud and clear) and digitize the playback of it. It should look a perfectly straight horizontal line in the spectrogram. An off-center disc will turn the line into a sine wave, while a poor motor will produce irregular jiggles.

But check your playback turntable first by using such a tone from a pressed, professionally-recorded test record, to make sure you are not introducing wow & flutter at the playback stage!

Among "real-life music", the piano (both the classical and the Fender e-piano variant) is among the most difficult subjects to record in terms of wow & flutter. Variations as small as +/- 0.2% become obvious with such material to the trained ear. The reason is that the instrument has a very "pure" sound with well-defined pitches and no natural vibrato at all, unlike strings, brass, or vocalists. So if a piano recording does sound perfectly steady and in tune on your equipment - no matter if disc-cutting or analog tape - everything is fine and you are well within Hi-Fi specifications.

In German, audiophile equipment able to give a satisfactory piano reproduction is often called "klavierfest", literally "piano-steady"

[opcode66]

Using a NAB disc and a Wow and Flutter meter is a great way to measure the eccentricity of a motor. However, not a lot of folks want to spend $250 on a W+F Meter for something they may use once. Especially if they aren't planning on tuning the motor. I don't think a lot of cutters really care if there are minor variations.

However, with the Groove Graphics, it really makes a big difference because any minor variations in speed will cause very obvious visual distortions. The wow and flutter meter will only tell you what the current drift is. Unless you devise and build a means to capture the flutter data across the diameters of a disc, there is no way of telling what the drift was like over time. Especially if the motor is inconsistent in its drift, which a lot are.

Therefore, I used my Groove Graphics software to create audio files with timed chirps. The image I used is below. It is just two lines which meet at a 90 degree angle. When you cut the cross to disc, it encapsulates the flutter data visually in a log that you can read from outer to inner diameter. You can see if the motor is consistently fast (lines slope toward you), consistently slow (lines slope away from you), or wavering inconsistent slowing and speeding up (S pattern in the lines). A digitally controlled platter motor will cut this and it will look exactly like the image.

Four files. Varying lengths for no particular reason (just didn't feel like taking the time to fully render each one for the full side).

- 33.3 at 200 LPI test
- 33.3 at 350 LPI test
- 45 at 200 LPI test
- 45 at 350 LPI test

Enjoy! I think a lot of you might find this extremely interesting to cut. It will very clearly show you how bad your motor really is. The question.... Are you prepared to know???

[gold]

Unless you devise and build a means to capture the flutter data across the diameters of a disc, there is no way of telling what the drift was like over time. Especially if the motor is inconsistent in its drift, which a lot are.

Long term drift (within reason) is essentially unimportant for music reproduction. That's why it is not accounted for in the specification. The W+F measurement is somewhat crude. You can run an FFT if you want to see frequency signatures of individual parts. For long term drift you just record the tone and look at the frequency variation. Assuming you want to quantify the measurements. I assume the flutter component is unimportant for drawing pictures.