Deep Grooves Mastering - Project Bladerunner

[sunkingrecords]

You seem to be making a lot of progress and having fun at the same time

Very cool work

Miguel

[opcode66]

Big progress has been made. I will shoot video soon. I've dramatically compacted my design. It now has more or less the dimensions of an SX cutterhead. My latest spring design is working fantastic. I'm really excited to post the next video! STAY TUNED!

To explain my lack of posts, I've been busy working on a few contract projects. But, I finally had time to revisit almost every part and make the needed tweaks. I reprinted everything. I just need to roll two new transducer coils and perform the final assembly. But, otherwise, things are coming along great!

I should also have my Caruso Preamp built out by next week. So, I can start to focus on feedback. I now have a very ingenious idea for how to create feedback for my cutterhead. So, I'm anxious to experiment with that.

Bladerunner Version 1.6 has a festive seasonal color scheme.

[opcode66]

Pictures of my progress and issues...

Here you can see what turns out to be the 7th build of my Bladerunner project. I counted the heads in my parts graveyard and it turns out I built 6 already. Wow!

I significantly reduced the size of every part. I can now mount the head and roll my suspension all the way to the end of a 45 side. So, I could now cut a full side. To get the head slimmer I had to shift a lot of things around and shrink a number of things. I also spent a lot of time working on the transducer system. Some parts were rubbing in my prior design. That was causing frequency loss. Now, nothing rubs. Each transducer moves freely on its own and also moves free and has no rubbing when coupled to the other transducer via the torque tube. The cutterhead sounded fanstastic in bench tests. Really, really nice. I printed the body with 95% fill this time.

Since my bobbin is now reduced in size it is not only light, but the coil I'm winding turns out to be exactly the same as Neumann SX. 4.7 Ohms DC Resistance. I didn't plan that at all. It is just a consequence of the reduced size of my parts.

Note the festive holiday color scheme.

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[opcode66]

I also spent time rebuilding the boards that drive my meters. They are now much more accurate for my purposes. Also, I've implemented a proper RC Network on my output going to the head. So, I have filtering, protection via fuses and accurate current metering.

[opcode66]

I got very excited and tried mounting it on my lathe. However, I had mounting issues again....

I made everything slimmer. However, I didn't make everything shorter as well. So, I ended up with a very nicely built, mechanically working cutterhead that could be mounted and rolled to the end of a side. However, the stylus could never touch the disc. Damn!

[opcode66]

So, I am now working on Bladerunner 1.8. All parts are printed. The dimensions seem to be right now. I think it will mount and cut correctly. I have a very good feeling about this one! Just building the transducers now.

Note: I've added additional weights as well. Since the head keeps getting smaller, it is also getting lighter. So, I've now incorporated 4 metal dowel pins 5/16" x 2". This adds a lot of weight to the head.

[EpicenterBryan]

Great update Todd! Too bad about the Orange version. It would have been awesome to have that one running for Halloween. I do like the 1.8 black one with the orange highlights though. Nice touch with the 66 insert. Great quality print as well.

Looking forward to your next update. My project is on hold - waiting for parts. But now I have time to address the motor noise so all is not lost.

Oh, and I did download your dgmGrooveGraphics program and checked it out. Very cool! Too bad I'm stylus-less right now. Should have the only 462 long shank Apollo Masters had in stock by the weekend.

Bryan

[opcode66]

Did you get it running with .NET Framework loaded? If so, then I'll get the latest version to you within a few weeks. I added a lot more functionality and tweakable settings.

The most critical aspect about my head design now is the new and improved transducers. I spent a lot of energy working out all of my mechanical issues within the transducers. I had issues with both the bottom of the bobbin rubbing as well as the spring leafs rubbing. It never happened with one transducer on the bench alone. But, when assembled, a transducer is no longer autonomous. For anyone attempting to make a cutterhead, read this carefully. Your transducer must function well on its own, but also when connected to another transducer via the torque tube.

This is a very important consideration. In a stereo configuration, when one transducer moves in and out, it is linked to the other. And, if the other is not moving in and out (i.e. mono content), it can be teetered vertically. This teetering is what was causing rubbing of the bottom of the bobbin on the inside of the transducer wall. I didn't account for enough wiggle room within my transducers because they were developed isolated and independent on my workbench. Once linked to another transducer, these issues became clear and obvious.

So, after many rounds of tweaks, prints, testing and learning, I've arrived at what I think is the most fluid moving paired system I've ever made. Without the rubbing (and in some cases locking of the bobbins) within the transducer body, I will have unimpeded movement of the torque tube. In the process of getting here mechanically, I both shank the size of the bobbin as well as moved it as close as possible to the magnet stack. This has significantly increased the efficiency of the system overall as well as brought my coil resistance down to 4.7 ohms magically. Finally, the reduced size means reduced weight and less overall moving mass.

I measured moving mass today. The bobbin with coil, the length of metal pin I use for linkage, and just the part of the spring that moves all clock in at 0.70 grams. My torque tube with X shaped cover is 0.44 grams. So, collectively, my entire moving mass is 1.84 grams. Give or take a few 1/100 of a gram. Not bad!

[markrob]

Hi Todd,

Looking great! I might not be understanding what you are saying, but in mono operation both transducers are driven. The L&R receive the same signal with one of the channels being driven in reverse polarity. That results in lateral motion. If both are drive with the same polarity, you end up with only vertical motion.

Also, note you may be overestimating your moving mass. Since the torque tube moves on a hinge, the effective moving mass of the tube is not its weight. Only the tip ogf the torque tube moves with full travel. As you progress back to the hinge, the movement of each cross section is less and less, reaching zero at the hinge. I think this results in the effective moving mass being 1/2 of the weight.

Mark

[opcode66]

I'm saying if you only drive one channel. Stereo information with nothing on one channel. Then, only one bobbin is being induced to move. And, therefore, pulling the other transducer via the linkage and the torque tube. The pulling or tugging of the other transducer is in a lateral direction and not a vertical direction (relative to the transducer being pulled). If it were being induced to move electrically, that movement would be in and out, or what I would call vertical movement. I can shoot a video to demonstrate what I mean. If I push or pull one of the transducers manually, of course the other moves. The movement in the other transducer is basically a vertical teeter or rocking. Not the in and out movement that I originally designed for and accounted for.

When I construct my transducers, both magnet stacks are built with the same polarity and orientation. When I wire the transducer coils, I connect them in reverse of each other. I tag the beginning of each coil with a piece of masking tape. Then, when I wire them to the DSub pins on my transducer cards, I make sure that the tagged pins are on different pins for each channel. I follow a pattern in case I ever need to replace a transducer. This insures that they are out of phase.

So, it sounds to me like my moving mass is even small than 1.8 grams. That is a good thing. The smaller the better.

[studiorp]

About your transducers, you connect them so : right channel + & - ; left channel - & + ?? Is that right ? If so, why you connect in this mode ?

[opcode66]

The L&R receive the same signal with one of the channels being driven in reverse polarity. That results in lateral motion. If both are drive with the same polarity, you end up with only vertical motion.

Markrob explains this very eloquently.

[opcode66]

Bladerunner Test Cut #3

The third test cut was awesome! Bladerunner Version 1.9 performed admirably this evening. My stylus chipped. And, I need to work on the torque tube hole for the stylus. But, I was able to cut. And, I got nearly the full audio spectrum! This test has given me much more confidence that I'm on the right track. I feel I've learned a enormous amount over the past week about the design considerations regarding the bobbin, spring and torque tube. Each one of these parts has gone through a number of iterations of changes over the past week or so. Look for more serious improvements in the upcoming Bladerunner Version 1.A.

[Bahndahn]

Great update, thanks.

Any elaboration to share on the development of your printed springs, torque tube, etc? Were you pre-processing your audio with RIAA?

Sounding good!

[opcode66]

Printing parts for Bladerunner Version 1.A

CALLING ALL TROLLS!!!!!

BE PREPARED TO BE SHOCKED AND AMAZED.....

You've been warned. Don't say I didn't tell you so. This is going to be a game changer I think. Probably one or two more revisions before I am ready to start selling dynamic stereo cutterheads. DSub connector, Feedback and Presto Mounts to follow.

STAY TUNED

Sincerely,

Your Friendly Neighborhood Opcode66

[Jccc]

awesome! any news on how much they will cost?

[opcode66]

Very reasonably priced. Less than Caruso. But, only because I'm not going to use much metal. I think the torque tube will likely be the only metal machined part. I'm having great results. I see no reason to increase the cost. And, everyone seems ok with a plastic head as long as it works as advertised. It will allow a lot of people wanting to cut to put together a lathe for a reasonable sum.

I plan to supply the cutterhead with one set of spare transducers cards and an instructional video on how to change them out. So, in case you blow a coil, you are back up and running in no time. Easy to do. Then you just order replacement transducers from me. You would have to make a critical error twice in a row to put yourself out of service. And, even then, it would just be a matter of a couple weeks to get a replacement transducer from me. I feel that the ability to repair your own head easily is the most functional part of my particular design.

So, somewhere in the neighborhood of 1K I think should be reasonable. I feel confident in my results to ask this. In fact, I think people are going to see a real value to be honest. If I had a mono suitcase cutter, I'd be happy with v 1.9.... Version 1.A will surprise everyone is my prediction. I will be ripping cuts this time. I didn't really feel it was worth the time to do up until now. And, I've been shooting such detailed video I figured why bother. But, the 1.A cuts will be ripped, analyzed and posted.

Thanks for your interest!

[EpicenterBryan]

Very reasonably priced. Less than Caruso.
...I plan to supply the cutterhead with one set of spare transducers cards and an instructional video on how to change them out.

Todd, please elaborate: Head, plus spare transducers, and are you providing populated Caruso cards, or unpopulated with the option to have them populated? Not nit picking - just need to know costs...

So is this head you will be offering a full feedback unit (I assume since you mention boards). How about some non-feedback response curves? Sure would like to see what we are talking about.

Bryan

[opcode66]

Sorry, don't mean to be confusing. What I'm referring to is not the Caruso pre-amp boards. What I'm referring to are the card assemblies that I've created that contain the bobbin, coil, linkage and dsub pin connectors of my cutterhead. Think of them as the equivalent of the speakers that you are using for your head. Except, the magnets are embedded in the cutterhead body and not a part of the transducer card.

The biggest fear for most cutters aside from trashing a stylus would be blowing their cutterhead (i.e. smoking a coil). Cutterhead repair can be costly. And, you never know how long it will take. And, in some cases, you get your head back with a message saying it can't be repaired. This is a nightmare. You out of commission for an indeterminate amount of time. And, you are probably under pressure to finish pending cutting jobs. I decided to follow a design strategy that allows for simple and quick repair by the end user. No special tools or skills required. Not even soldering. My transducers slider right out after disconnecting the linkage from the torque tube.

The first cutterheads I'll be selling will be dynamic. No feedback. I will be adding feedback very soon. It is still in development. I have created a unique way to generate feedback from a secondary shielded coil. I am using only one set of magnets for both drive and feedback. More to come on this topic later. But, suffice it to say, with an EQ curve, this head can produce better results than any mono head I've heard.

Since I've been continuing to tweak and improve parts, I really didn't feel that I was at a place where spending the time to rip my test cuts was worthwhile. It's been more important to spend time doing the r&d for the next version than proving what the older ones are doing. My ear is pretty good. I've done a lot of cutting over the past 4+ years. I know when things are right and when they aren't. And, aside from my ear, my scope has been invaluable in knowing when things are right or wrong and why.

But, I feel confident that Bladerunner 1.A will be cutting well enough for me to justify ripping my test cuts. I will be cutting white noise, pink noise and sweeps. I will rip the cuts and use frequency analysis to determine what my response actually is. Everything will be documented in a nice edited video as is my routine.

To be completely clear, my cutterhead will come with the head, a mount of your choice, color scheme of your choice, customizable logo or text on the sides, a stylus insertion and orientation tool, and a cable with connector. That is all.

FYI, I will be offering upgraded versions of the Caruso pre-amp soon. I'm doing mine first then will show everyone. Additions are: pre-amp for phono that uses the same riaa as caruso feedback, 3 position selector for phono/feedback/input and the feedback monitor jack now becomes a selectable monitor, addition of VU meters and board with trimmer for calibration. Also, I will have additional jacks for you to route the output of your power amp back into the pre-amp so it runs through fuses and an RC network and also splits to Ammeters so you can see the current on each channel. Then out jacks to the cutterhead. The face will then have 4 meters (2 VU and 2 amps).

Here is what my transducer cards look like. You can see how I've easily pulled them out of the cutterhead.

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[opcode66]

Forcing my latest video to the top of the next page....