Deep Grooves Mastering - Project Bladerunner

[EpicenterBryan]

But, you still don't have the secret knowledge. Has nothing to do with centering the torque tube after sound stops.

Has to do with keeping the tube parallel? Guess a V mounting at the rear rather than a single mount point. Like yours until you glued them in place. I bet you are changing those into slightly compressible springs, and fixed at the body end.

[opcode66]

Actually, the torque tube has nothing to do with it. I'm leaving it as is for now. It is designed after the Neumann SX head. It has a very similar design. The main difference is that where the two leaf springs are clamped down it is two metal pieces that screw together. Mine is one piece that was using friction to keep the feet in. Works well enough, except for when audio is played at 700 hz.... Buzz. Gluing them in place kills the buzz. And, makes it very similar to the Neumann.

What you do not see behind my torque tube, within the rubber damper, is a metal wire. One end is fixed in the torque tube mount. It runs through the rubber damper. And, then into the center of the bottom of the torque tube. Each end of the wire is glued into place. Again, this is exactly as it is in a Neumann SX.

We still haven't hit the secret. Besides, your head has the V at the base of the torque tube anyway. I'm saying this is something that is not present in your design. So, probably best not to guess at things that are present in your design. Best to guess at what is absent.

[EpicenterBryan]

I'm saying this is something that is not present in your design. So, probably best not to guess at things that are present in your design. Best to guess at what is absent.

Todd, this is fun and educational. Thanks for putting up with me.
Your head has several advantages.
1). You are using a press fit stylus (like markrob did in his design). Hobby guys like me have an easier time with presto type shanks with a flat on one face. But, that means we are stuck with the extra mass of a set screw. It also limits where we put the stylus (since we need access to the screw to change it).
2). You have your stylus behind the driver connection point, giving you mechanical advantage in that your drivers do not see the full upward cutting force. Your torque tube at the stylus connection does, and further out, your drivers see much less. This also means that your driver geometry doesn't go as far out of whack from up force from cutting. I noticed in an old westrex patent that the drivers are not mounted exactly at 45 degrees, so my bet is they also accounted for the error in geometry when the specified cutting force was used (based on materials used in the torque tube, and location of the stylus among other variables).

Am I getting closer to the secret sauce?

Share the #SecretKnowledge. Share the #SecretKnowledge. Share the #SecretKnowledge!

Bryan

[studiorp]

Are returned to DDR perhaps ?

I understand that some things are your secrets about the building of cutting head, but I think that this forum is based as many others on web on a sharing of infos, otherwise Internet is dead.

[inspector77]

Are returned to DDR perhaps ?

I understand that some things are your secrets about the building of cutting head, but I think that this forum is based as many others on web on a sharing of infos, otherwise Internet is dead.

He always shares his knowledge, this is like a game to make you think ...

[opcode66]

Are returned to DDR perhaps ?

I understand that some things are your secrets about the building of cutting head, but I think that this forum is based as many others on web on a sharing of infos, otherwise Internet is dead.

He always shares his knowledge, this is like a game to make you think ...

bright this one is!

i think i've been fairly transparent thus far...

patience

and think about it like i've had too

[studiorp]

Yes, you are transparent, but obvious that you have some secrets.

I say only that could be right share all your infos for build the heads, not only a part.

Why don't write a little manual with title " All secrets for build a good stereo diy cutting head " ? Could be a good idea for many people here that want have a simple head for experiments...

[EpicenterBryan]

Why don't write a little manual with title " All secrets for build a good stereo diy cutting head "

I say do it as an E-book and split proceeds with the webmaster of Lathtrolls.com to help keep all this alive! Charge people double if they never post. And yes, it's all about making people think and getting them engaged

Bryan

[opcode66]

Bladerunner 1.A.1 Rip

Improved Transducer design, improved springs, new Torque Tube linkage. The Transducers now have washer Neodymium super magnets in the bottom of the base, and the coils have been increased to 10 Ohms DC Resistance. The coils now sit within a circular maget aligned with the polarity of the magnet stacks beneath the transducer cards in the cutterhead body.

The only processing is Inverse RIAA, Minor HF Limiting and Elliptical EQ at 196hz.

I now know what I need to tweak next. Look forward to major improvements in Bladerunner 1.B!!!

[inspector77]

Looks amazing! waiting for listen new cuts!

[Machina.Pro]

Nice work man!!!

[dimi751]

Cool, can't wait for you to sell this head as a feedback version this will be nice. Great progress opcode66!! Thanks for sharing your journey with us.

Best dimi

[Jccc]

Your cutting head is coming along nice. I also love how you have Public Enemy playing in the video!

[opcode66]

Looks amazing! waiting for listen new cuts!

The audio in the video above is a rip of my latest cut. The graph in the video is the frequency response for that clip.

[opcode66]

Just wanted to post an update. I have tweaked a number of parts including some fairly significant changes to the cutterhead body itself. I started to print the parts for version Bladerunner 1.B. However, I ran into some print issue. A part for my 3d printer has worn out. As soon as I get the replacement, I will commence with printing the remaining parts for the 11th full build of my cutterhead project. I am expecting some really good results. I will post more as soon as I can.

Some changes to the body include:
- An indentation for the torque tube holder so it now embeds into the body
- A shorter overall length pushing the transducers and thereby the cutting stylus closer to the back of the cutterhead (more inline with the platter center spindle). This also makes the transducer cards shorter and more compact. That means they are faster to print now.
- The bottom of the cutterhead in back is now flat since the torque tube holder is now inset
- I added 10 mm to the top and made two additional weight chambers. That makes 6 x 2 inch long, 5/16" diameter holes and 4 x 1 inch long, 5/16" diameter holes. The holes are filled with non-magnetic stainless steal dowel, glued and then sealed with a cover. There is no vibration or interference with the magnet flux from the permanent magnets. They significantly increase the overall weight of the cutterhead. I'm doing this to stabilize the head, make is more dense, and get the weight to nearly that of an SX cutterhead. This is important for easy swapping on my lathe so I don't have to change my tension spring in my suspension much.
- The outer diameter of my vacuum tube has been reduced. I also spent a lot of time re-engineering the tube to be very smooth. I also learned that if I want to use plastic, I have to really file and smooth it on the inside. If there are any blemishes, the chip gets snagged, and the tube fills and chip starts dropping on disc. I have been able to cut for about 5 minutes before this starts happening. So, the tube design is good. But, really needs to be metal eventually. But, this is the first tube that has at least worked relatively consistently.
- I made the cable entry on the side of the back of the cutterhead a bit larger for the addition of heating wire leads.
- I made a hole from the back to the front for the heating wires to go through.
- I made two holes in the front of the cutterhead for putting in screw terminals. The heating wire leads will be soldered to the screw terminals. The terminals will then be secured in the holes. So, the stylus wires will screw down on the terminals for heating wire current connection.
- I made the back connector a bit longer so head hangs lower. Again, this is to get it to be closer to the SX cutterhead. That way I don't have to adjust the vertical offset of the suspension box when changing between my head and my SX.
- I moved the helium intake in back a bit higher so it is not so close to the top of the mount. It was too close in 1.A.
- I made the torque tube leaf springs a bit longer and thinner. They were too stiff before. This will loosen them up nicely. I'm going to find softer rubber for the damper in back. Possibly none at all. And, I'm using a much more bendable pin to anchor it to the torque tube holder (not piano wire but very close).
- I made a slight change to the tension of my transducer springs.
- I've reduced the size of the bobbin. This has gone back a forth a number of times as I try different DC resistances for the coils. 10 seemed to be too much for driving. 4.7 was just ok for this configuration, but without the engineering on the level of a Neumann, that just isn't enough EM field for me. 8 seemed to work very nice for both drive package and magnetic configuration.
- I moved the new washer magnet embedded in the transducer cards (that surrounds the bobbin) 1 mm up so it now surrounds the center of the coil instead of just the bottom of the coil.

That is most all of the changes to the parts. Stay tuned for the next build!

[opcode66]

My printer is back online! I am printing the next cutterhead body now. Should be done in 7.5 hours...

[opcode66]

All parts are now printed. I just need to wind coils and do final construction of Bladerunner 1.B. Looking forward to even better results this time!

[EpicenterBryan]

Looking forward to even better results this time!

Great Stuff Todd!
Looking forward to your next results like usual.

Sewing needles? Do you have another hobby we are not aware of?

[opcode66]

I use these instead of piano wire. They are very flexible. Size 10 is the smallest you can buy. Sure did get some odd looks at the Joanne Fabric store.

[opcode66]

Pictures of the 11th full build (version 1.B) of my cutterhead codenamed Project Bladerunner. There are so many improvements in this build. I've learned so much on this journey. I have confidence that this build is going to produce fantastic results!

Bladerunner-1.B-Build.png