Sillitoe Lathes

[Sillitoe]

Cheers Kev!

Ballscrews.jpg

A box of Japanese precision ballscrews arrived today.
They are a C3 rated screw, nut and floating support, with a C5 rated fixed support unit (to keep cost down a little), giving the linear motion of the arm an accuracy/repeatability of 0.7mils or better.

Maybe not aerospace stuff but they are quite nice...

Cheers
James

[Sillitoe]

I smoothed out the head drop.
Watch in HD so you can see the mm scale clearly, (it looks even smother with the sound off...)
It lifts/ drops about 10mm in total, the last 5mm is very smooth now.

You can see that there is some eccentricity in the bearing that the bar pivots on, (the head moves laterally slightly when lifting and dropping).
This is because I'm using a Track Roller Stud Bearing to develop the suspension box. It enables me to mount the whole thing to one side of the housing, leaving three sides open so that I can tweak things and make changes easily.

This bearing type will not be used in the final design. It will be a sealed suspension box with two thrust bearings giving a true and level pivot.

Cheers
James

[dimi751]

Nice job as always James keep up the good work !

[tragwag]

awesome as usual, great to see the progress and initiative to create the auto head drop!

[Sillitoe]

Here's a video of my 5th cut with the Caruso!

My chain for this is- Ableton Live 9 (with M4L automation for the lathe), everything below 250Hz summed to mono, 30Hz high pass, 17kHz lowpass, Sonnox Supresser lightly touching everything above 7k, NI Z2 mixer, Caruso preamps with 28dB of feedback, QSC G3 power amp, rc network and fuses, Caruso, Shank 320P diamond, Shank black 12 inch.

The diamond was mounted without using a microscope...

No corrective EQ yet, needs a little, very happy!

Playback is Sure M44-7, Technics 1200, NI Z2 mixer, Ableton.

I adjusted the volume to be similar to the original, the tracks are made from samples and synths so you can hear some crackle from the samples, but there is quite a bit of background noise in the cut too (probably from my brush haha).

There is no plinth on the lathe at the moment, the pitch motor is quite loud. You can also hear the fans in the amp.
This lathe and suspension box setup is very different from what the production models will be.

Here's the spectral analysis, Original on the left, Cut on the right. You can see the resonance around 12kHz. Also the background noise.

Original (left) Cut (right).png

The audio in the video goes- Cut, original audio, video sound.

Groove pics and lots more to come soon.

Big thanks to Flo and Shank!!!

[Ciuens]

Very good. congratulations. great quality

[Sillitoe]

Thanks Ciuens!

Here are the files.

Also, I used a heat lamp to get the disk surface to around 40 degrees celsius. No stylus heat.

Cut


Original

[Sillitoe]

Hi Bryan,
Yes I thought the same thing, checked multiple times haha.
You can actually see (and hear) the background noise at points in the files.

Look at the very end of the top soundcloud file, you can see that there is signal at the very end of the cut and at around 1.04, this is not present in the original file.

I was surprised too!

Cheers

Haha, your post disappeared... It seems you checked?

[dimi751]

Hi Sillitoe,

Your doing a great job ! Thank you for sharing this video.

you are awesome !

Dimi

[Bahndahn]

Great work!! I'm motivated by this.

I am interested in seeing a picture of the suspension to get a better understanding of how its working, if you are willing to share.

Sounds really nice! Are you cutting lacquer or plastic?

[Bahndahn]

Ahh nevermind.. "shank 12" black"

[Sillitoe]

Thanks guys!

Bahndahn, check out the "Auto head drop/ lift" video on page 3 of this thread, the current design is just a slightly refined version of that clunky setup, exactly the same principals. It will change again soon.

Cheers

[Sillitoe]

Here's the same thing with some basic corrective eq applied, it's starting to sound similar...

[Sillitoe]

Here it is again haha.

Better EQ on this, closer to the original.

I cut across another groove on the disk at the end, so it skips.
The stereo image is still narrower than the original.
I should probably try to match volume levels better, but you know how it is...

I'll cut some different stuff tomorrow. I promise!

Cheers
James

[opcode66]

Nice one! Great results. Caruso sounds crisp. Nice to see you diligently execute on this build up.

[analoghifi]

James All I gotta say is the sound quality of that head with that lathe you made is strictly WINNING!!!
I Want One haha!

Great job man, I am very impressed, which preamp were you using? Looks solid regardless man.

[Sillitoe]

Cheers guys!

Yes Flo has done an amazing job with the head... of course!

Hey Kev, I'm using the Caruso preamps mate, EDIT- or do you mean playback... Just a little 2 channel Native Instruments DJ mixer at the moment.

The six months I gave myself to be selling have come and gone haha, sorry about that...

Things are going well...

[DjMikiRia]

For enough audio level, I use a very powerful automobile audio amplifier powered by a homemade 100 amp 12 volt power supply. The transformer is a modified high voltage microwave transformer (the HV secondary was removed and rewound using 10 gauge conductor with the output going to a 100 amp bridge rectifier). The filter is two 1 farad caps with a large choke between. Heavy filter is required to remove any line hum.
NOTE: The transformer is very lossy and does get hot, not due to load but because of the flux needed to produce the high amperage in the secondary.
Also, the reason I use this amp is it has its own audio crossover that removes bass that isn't wanted.

[Ciuens]

Hi James, good job.
Have you made any amplitude and phase test? I'd like to see how this beautiful cutting head works.
How much equalization curve you used?

Cheers

Ciuens

[Sillitoe]

Hi Ciuens,

Yes indeed a beautiful head!

My priorities aren't with the head/ audio at the moment as I know it's solid.

I just hooked up the final pitch motor and control yesterday, it is amazing.
You can faintly hear it in the faster track spacing grooves, (the lathe probably shouldn't be sitting on an empty hollow steel tool cabinet haha).
I know how I'm going to fully isolate the motor from the rest of the structure, so don't worry
At the moment LPI at 33rpm ranges from 800 to 8!
I will speed up the ball screw for best peformance by changing the ratio of the pulleys slightly.

Then I will get the microscope out and cut test frequencies.
Then I will have a play with an electromagnet on the pivot bar opposite to the head... (didn't bother with the servo idea).

Soon I'll get a nice tonearm and cartridge on the lathe to do meaningful tests, my 1200s are heavy in the right channel.
So I'm kinda just refining stuff and the cuts are sounding nicer and nicer.

I've removed the plugin that was summing everything below 250Hz to mono. It was doing something else that I didn't like.
Still have the de-esser.
Still using a brush to catch swarf, dropped a big bunch at the end of the first track.
Stereo image sounds good, check the last track.



Tomorrow I'll post a video showing the lathe automated by Ableton, I just drop and lift the head.
I'll also do one showing the corrective eq procedure I did using Fab Filter Pro Q2. (BIG UPS SARDI!!! )

Here it is as of this cut, was a little different for those previous cuts, I'll probably continue to tweak it with my ears.

Screen shot 2015-11-21 at 3.20.45 AM.png

A few other exciting things in the works too!!!

Cheers
James