Deep Grooves Mastering - Project Bladerunner

[jonoaustin]

awfully, awfully cool. jeez.

[dimi751]

Very cool yes how's the metal design coming along ?

[opcode66]

I won't start on metal until I can afford to purchase about 10K worth of gear for metal fabrication. Until then, I am modifying parts so that they fit in the existing footprint and use screws instead of glue. As you can see from the picture below, the transducers are now 100% screwed together. So is the torque tube configuration. There is very little left that uses glue now.

The cutterhead is ready for feedback, though these transducers are dynamic. The wiring is in place and ready to go. The head sounds fantastic on the bench. Test cut video to follow soon.

The cutterhead is wired for heat and I've now completed a very simple solution for a power supply for a heated stylus. I'm posting a video in a new thread about how to build your own! This is completely open source. Simple to make from spare parts. Quick build. Variable current with constant voltage.

I really can't wait to do test cut with Bladerunner 1.F.1. It is quite literally the finest cutterhead I've ever built.

[opcode66]

The variable heating wire power supply video is now posted. Check it out here. http://lathetrolls.com/viewtopic.php?f=15&t=5998

[mc172]

The variable heating wire power supply video is now posted. Check it out here. http://lathetrolls.com/viewtopic.php?f=15&t=5998

Strange - it has disappeared! How utterly bizarre.

[dimi751]

Hi Todd

Thanks for sharing this !

Love to see the video unfortunately I get a message says I'm not authorised to Read this forum ?

Thanks Dimi

[opcode66]

Strange - it has disappeared! How utterly bizarre.

I had the video pulled. The video was meant to explain simply how to make one of these devices. In a hasty attempt to show other cutters how to make a variable current heating wire power supply, I was myself, reminded of lessons learned long ago by our fellow Troll mc172. In the video explanation of the box I fabricated, I echoed a fundamental misunderstanding several times. Granted, I made the video with zero preparation at 1:30 AM with no intention of the video being an instructional on electronics per se. That doesn't excuse the fact that I was wrong. And, I'm not too small of a person to admit that I was wrong. I was wrong.

By trade I am not an Electrical Engineer. I've created, repaired and modified many electrical devices. But, EE is not my vocation. Some academic lessons have been lost. That being said, I made three glaring errors in the video.

1. I measured the voltage of the output of the device without simulating the real world. I did not add a load resistor of 3 Ohms to simulate the heating wire across the terminals being measured. Typically, one would not measure voltage across a component like this... But, in this case, the output leg of the component is going to ground, and we want to measure the voltage going in, so measuring in parallel is ok.

2. The measurement of voltage going into the component is only accurate if you measure a complete circuit and not just everything leading up to that point with the rest of the circuit disconnected.

3. A while ago, I read someplace that voltage drop across a resistor of low value is nominal in comparison to its effect on current. In essence, the voltage drop would be negligible. I committed that bogus concept to memory and largely it hasn't affected my ability to make devices or fix electronics. However, that is not correct. And, if one applies Ohm's law to all of the resistors in a circuit in an extrapolatory manor, one can calculate the voltage drop per component, which apparently is something I've lost over time. Much like writing geometric proofs... This is no excuse, however.

Another point, which was not actually stated in the video, but could wrongfully be inferred from my incorrect statement, is that the voltage drop across all of the components in a circuit would not add up to the input voltage to the circuit. That would not be correct to assume. Voltage drop across all components is equal to input voltage.

These are all concepts I learned at one point in time, but let slide. And that is embarrassing. Instead of allowing a misleading and incorrect resource live, I terminated it with the assistance of the Steve E. I will be re-shooting the video. I never meant for it to be a lesson in electronics. If that were my intention, I would have prepared a bit better for shooting. Rather, my intentions were only to show other cutters how to make an inexpensive and robust heating wire power supply themselves for less than $40 with the minimum of time invested on my part. A number of new Trolls have asked recently how to make one or source one. Additionally, I would like to keep new cutters from getting fleeced by folks like the person here trying to sell a heating wire power supply for $750. http://www.ebay.com/itm/Fairchild-Recording-Equipment-Corp-30013-Thermo-Stylus-Vintage-Unit-As-Is-/171672219295?pt=LH_DefaultDomain_0&hash=item27f8762e9f

I will re-post a new and accurate video soon. Thank you, mc172 for your corrections, they were appreciated. I will let you know when I have the video created so you can review it and give input.

[dimi751]

Hi Todd,

Sorry I missed your response, yeah agree I would imagine the cost of making stuff in metal is expensive just picturing in my head how nice it will look in aluminium..

Keep up the great work with bladerunner ! Also mate it's okay to make mistakes your only human sometimes I feel you are too hard on yourself.

i really appreciates your contributions and knowledge I have learned a lot.

I would really like if your can repost the diy heating project, as I would like to make one myself at some point.


Thanks Todd

Dimi

[opcode66]

After a couple months of working on an inverted moving magnet transducer I am shelving the research. It was interesting and I feel it has potential. But, for the purposes of a cutterhead, in a miniaturized configuration, I was unable to tweak the variables to get anything acceptable. The weight of the magnet was the main factor to overcome. That in combination with its distance to the coil, coil size, coil field strength, spring tension and overall total moving mass. The system worked technically but had a severe predilection for the low end. That makes sense. Once the mass of the magnet got going, with momentum, tracing low frequencies, all else would get rolled over so to speak. The resulting discs had great low end and mids but very little highs. The cuts looked odd visually. You could see the gradual swoops in the grooves. I could tell things weren't coming out correctly without looking through the scope. Even with EQ'ing, the results were just not what I was looking for. The highs were just muddy sounding and way too low.

I don't think that there is zero potential for this type of transducer. I just don't think it will work in the confines of a cutterhead. And, I was so close to finishing things in a standard moving coil fashion that I just can't see continuing to push the release of Bladerunner due to this R&D curiosity.

The up side is that none of my parts change substantially since I was making the moving magnet transducers with only minimally altered parts. All the work I recently did on making parts use screws instead of glue moves forward. I've lost nothing but a bit of time. But, I felt it necessary to give it a go and I'm glad I did. I learned some new tricks.

So, back to rolling flat enameled coils later today. Back to doing a moving coil design. But, with a few new improvements that should result in the ultra high frequencies that were lacking in the past. I'm now incorporating all magnets into the modular transducer design. So, when both channels are removed from the cutterhead body, there will be no magnets remaining in the body. This enables me to do something I was never able to do in my previous modular design. This was the concession I didn't want to make in the past. But, it ends up being much easier to realize than I previously thought it would. Mostly due to the work I did to make my parts screwed together.

More information and pictures of the new moving coil cutterhead (17th full build) by tomorrow. I will post some pictures of the grooves I cut with the moving magnet cutterhead today.

[Sillitoe]

Good on you for trying. I'm sure you learnt lots along the way.
Research and development is a time and money killer, but it's the only way forward...

[mc172]

No trouble Todd, it's all good mate.

In the next few weeks or so, months maybe as I'm so disorganised, perhaps I can come up with a stable design.

Until then, the LM317 you referenced in your video is an excellent starting point.

[opcode66]

I've been using the box as it was detailed in the video. 10W resistors, normal low wattage pot wired as rheostat, and ammeter. There is really no need to do anything else. I get very stable readings on the ammeter. And, most importantly, much quieter grooves being cut. No need to waste the 317 on this.

[opcode66]

This is the schematic for the box I've been using with success. The only thing not on the schematic is the multithrow single pole switch I used with an LED and 1K resistor to indicate if the box is powered on or not. You must use ceramic 10 Watt resistors before the potentiometer wired as a rheostat.

Heating-Wire-Schematic.png

Box-Pic.png

[opcode66]

Inverted Transducer Groove Images

As I explained in a previous post, I've abandoned the inverted transducer idea for now and have shelved the work. I might revisit it in the future. But, I no longer want to take time to pursue it currently. The results were always very accentuated in the low end. Here are some pictures of test cut. I never shot a video because it just wasn't worth it.

I am back to flat wire moving coil transducers. My new design is working very well so far on the bench. So, I am currently building Bladerunner 1.G (17th full build) with moving coil transducers. The biggest changes are that the magnets are now a part of the modular transducer card. And, all the parts for the transducer are now screwed together. Build pictures to follow soon!

Here you can see that the grooves contain audio that is mostly low frequency data

IMG_7602.png

Same here. All lows. You can see it with the naked eye. That is all music, so it shouldn't appear that way.

IMG_7603.png

The only thing you can plainly see are very casual arcs. So, all low end. High frequencies would be many divisions smaller than these waves at this magnification.

IMG_7607.png

Here you can see some highs are fighting to sneak through. The gradual swoops have some wiggles visible in the edges. But, the momentum of the lower frequencies caused any mids and highs to be basically erased.

IMG_7606.png

[opcode66]

Project Bladerunner Version 1.G Test Cut

Please judge for yourself. I have my own opinions.

I can now build a complete cutterhead from start to finish in less than one day. That includes printing the parts, rolling the coils, making the vacuum tube, assembling the cutterhead, doing the wiring, adding the connector, and doing bench testing.

You'll notice the heated stylus wires are hanging loose. I did not add screw terminals for this feature yet. This test cut is without heat. Dynamic transducers. No feedback. No EQ'ing. Only IRIAA via Markrob's VST plugin is applied to the audio. It is interesting to note that the Resonant Frequency is now 500 hz. Not sure why it decreased to 500 hz from 700 hz in previous moving coil versions. Also, though the spectrum graph resolution doesn't show this well, the severe drop off is terminating at 16K hz. That is nice.

Bladerunner 1.G Spectrum Plot.png

Grooves.png

[dimi751]

Sound great Todd congratulation!
Fantastic work as usual !

[inspector77]

Wow, Great Work, congratulations!

[opcode66]

I've learned some critical lessons the past few days. I will print a couple more parts tomorrow and try cutting again with a newer stylus. This one is too dull and isn't articulating highs very well. I will also run heat with the newer stylus. I expect even cleaner and better results than this rip of 1.G.2 test cut.

[Ciuens]

Hey Todd, your test cut is very good. Did you do any cutting using corrective EQ?

[opcode66]

iRIAA only
No other correction
Totally dynamic
No feedback

Thanks. Means a lot coming from a fellow tinkerer.