Deep Grooves Mastering - Project Bladerunner

[opcode66]

Hey Mark, what do you think of these??? Eddy Current Sensors

http://www.lionprecision.com/eddy-current-sensors/

[opcode66]

The Waiting...

[opcode66]

I've resolved nearly all of my mounting issues. I only need to print one more part. I have the head otherwise fully assembled at the moment. It is very dense and very heavy now. It certainly has mass. I printed it with 60% fill and I added two cavities where I put stainless steel dowels. 5/8th" x 1.5" cylindrical weights are now in each side of the cutterhead. I can now adjust my tension spring to nearly the point it is at for my SX74 cutterhead. I have everything setup and ready to test. Tomorrow I will print this last part I just tweaked and put it on the head. Fingers Crossed! After that I insert a cutting stylus, mount it on the suspension and cut!

Meanwhile, i ordered an Audio Distortion Meter (20 to 20K). I will be using this in testing feedback as well as transducer performance. And, I dug out my micrometer and dial bore gauge so I can perform some excursion measurements of my transducers.

Tomorrow, I should have a 300W per channel 70V amp as well. So, my test cuts should sound good and will have less distortion than they would using my Sony amp.

I have both VU meters as well as my fused amp meter panel all hooked up and ready to go. Just need one part...

Here are some pictures of version 1.4 of my Dynamic cutterhead.

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[sunkingrecords]

I hope it turns out fine! looks impressive and a hell of a job
Good luck!

Miguel

[opcode66]

It works! Not fabulously at the moment. But, it works!

[opcode66]

The first test cut session with Bladrunner. After fixing mounting issues, I inserted a stylus and hung Bladerunner on my Neumann. I cut a bit of one of my tracks. Followed by Beethoven's 9th, 2nd movement. I completely neglected to process the audio with the RIAA EQ Curve. That is why it sounds so heavy on the low end on playback. There are a number of things to tweak. But, overall, I'd say this is a great first test!

[markrob]

Hi,

Nice first test run! You seem to well on your way.

Mark

[opcode66]

It turns out, my mount in combination with my DSub socket blocks on the back of the cutterhead were causing undue pressure to be exerted on the stylus. The cutterhead was not truly floating over the disc. The tension spring was not able to do its job correctly. Nor the vertical servo motor for depth control.

I'm tweaking parts again and reprinting. This time, I should have better alignment of the vacuum tube as well. So, I should be able to run the vacuum on test #2.

Also, the top of the cutterhead has been trimmed. This will avoid the issue of it touching the bottom of the dashpot.

Finally, I realized that I was not able to cut the inner diameters. The side of my cutterhead was hitting the chuck table vacuum hose. This has also been resolved in my current body design.

Just waiting for parts to print for cutting test #2. Video to follow, of course.

I've been asking folks to help me give an official name to the cutterhead. Suggestions? Something that speaks to the very unique nature of this head. Something that does not include my real name, Opcode66, 66 or anything of the like. My ego is not so big as to name this in such a manner. So far, I like Outlier. Or Nucleus. Lacquer Plow was a funny suggestion from JJG.

Anyway, here are pictures of my current issues.

Here we see the top issue as well as the connector block issue.

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The vacuum tube issue. Now, the head hangs lower relatively speaking. So, this should no longer be an issue. I shortened it a bit too.

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Ooops. Hitting the chuck table vacuum tube with the left side of the cutterhead. Doh!

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I'm unable to move any closer to the center than this.

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[opcode66]

Heating Wire Test

I was able to run the stylus without melting the plastic at between 1/2 to 3/4 the amps I use with my SX74. So, contrary to popular belief.... It turns out, I can actually run with heat! So, my next test cut will include heat and vacuum. I should be able to achieve cuts with far less surface noise. Very cool!

For anyone interested, the heating wire at that length is 3.2 Ohms DC resistance.

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[studiorp]

The second cut will be done with inverse riaa ?

[Babooino]

blackbird

[opcode66]

I will have both heated stylus as well as RIAA for the next test cut session. I'm hoping to be cutting again tomorrow or Monday. I am assembling the fifth version of my head today. All new parts printed!

[EpicenterBryan]

Blade Runner actually works for me. I guess you could give homage by calling it something like Kunststoff V1.0.
German for plastic or some variation.

[opcode66]

I don't want to be sued. I do intend to market and sell these cutterheads once completed and working well. Also, Bladerunner 2 is due to come out soon. I'm not trying to cash in on their juice. I (maybe you) can come up with an original name that fits.

Mounting issues are relatively resolved for now. I still am unable to cut to the end of a side. I need to reduce the width of my head by another 1/4 inch to be able to cut a 45. To do this, I would have to majorly redesign a number of parts. I will do that in the coming week. So, it will look different yet again. My head keeps getting more and more compact.

The next cutting test will include iRIAA supplied by a VST form Markrob, vacuum chip pickup, Helium, and likely a heated stylus. I'm hoping for much more movement in the grooves and a lot more highs.

The next steps will be to slim it down so I can cut to the end of a 45, fine tune some parts to avoid resonance, fine tune the springs a bit more and finish the feedback version of the transducer. Once I'm at that point, I should have the caruso pre-amp boards from Flo. He was kind enough to sell me two. I should also have all the components and power supply by then as well. I will assemble those and attempt some feedback tests to see if I can get totally flat response.

I traded in some gear for a QSC GX3 300 Watt per channel 70V power amplifier. It is clean, quiet and very powerful. I highly recommend one to anyone looking to build a cutting solution. Or possibly for use with Caruso.

Here is a video of me performing two sweep tests on my cutterhead. One logarithmic and one linear. Check it out. I have a weird buzzing resonance at about 700 hz. But, then I have flat response from 1K to 20K. Pretty good with no feedback.

[opcode66]

I got the vacuum working as well!!! Check it out.

[opcode66]

Picture of the latest version build mounted on my Neumann. This is the 5th head I've assembled now. Each iteration gets so much better.

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[markrob]

Hi,

Looks like you are making good progress. The way you are testing is ok to try and locate the system resonance (700 hz is a nice place to be start). Otherwise, its doesn't really tell you much about the actual cutting performance. You really need to do a test cutting to get a baseline for where you stand. BTW, be very careful if you try a sweep with RIAA in place. You need to keep you levels very low or you might blow the head. Cutting white or pink (white if your analyzer is FFT based, pink if it is an RTA style) noise for about 1 minute at a watt or so will give you a nice feel for the response. Use averaging over a decent time frame (30 seconds) to remove short term fluctuations in the playback. When doing the noise test, pre-process it to add in the RIAA. To set the drive level, just use a true RMS digital voltmeter and set the AC voltage at the head to a 2.8Vrms (1 watt into 8 ohms)and you'll be assured that you won't fry the head. To make sure you are your measurements are above the system noise floor, cut 30 seconds of silence and note this floor. As long as your playback spectrum is above the floor by 5-10db, you can trust you readings.

Another test you should do early on is establish the sensitivity of your head. You are in a great position to do this easily since you have a VMS cutting system. Make a test cut on you VMS at your normal 0 reference level at 1 Khz (5 cm/sec??). Play this back and note the playback level. Whitout changing the playback gain, cut 1 Khz at 1 watt (2.8Vrms) with your head and compare the two levels at playback. This will tell you how much drive you head needs to attain the same level.


Looking forward to seeing where you are as far as response.

Mark

[opcode66]

As a result of this test cut, I'm going to make a number of changes. So, this week will mostly be spent making new drawings and printing new parts. I did make significant changes to my springs. That helped a lot. I'm getting a lot more movement in my grooves now. More to come at the end of this week.

As a side note, I've been working on a couple of other projects which has taken time. Some of the work will be of interest to the community.

[Stevie342000]

Just a couple of questions really what were you cutting with and on what? What material and what type of cutting stylus.

Assume you were using inverse RIAA this time? May there have been some issue with a component or two which you needed to change on the Caruso Board for the head to work optimally with that board?

Where you using feedback or not (I kinda lost track)?

Even so that is still a good result given the amount of time you have spent on it, that is a lot of progress in a short time.

Awaiting like many others the next installment. As for a name how about The Mean Keen Cutting Machine Head No1 or TMKCM Head No 1. Or The Cutter Head.

[opcode66]

I am cutting lacquer with a sapphire.

I am using a VST to handle the RIAA emphasis.

I do not have my Caruso boards built yet. Just ordered parts. Should be done this week.

No feedback yet.

I feel this is good results for the amount of time I've been working on this. I agree.

I'm going to finish designs and build my 6th head this week.