OPCODE 1-E Mono Cutterhead (Presto 1-D Clone)

[opcode66]

Interesting. Well, I can say these sound f-ing nice.

Another thing to consider. Unlike a spring in a stereo 45/45 style transducer wherein sound transmission is through the spring more or less directly, these only supply tension. Shot springs or springs made of thinner wire will be more bass centric because they will supply less damping.

All mono cutterheads are comprised of: voice coil, pivot, tensioning mechanism, damper, armature, frame and cover.

[opcode66]

FYI I've posted a 5C head for sale. Details here https://www.lathetrolls.com/viewtopic.php?f=4&t=8226

[opcode66]

OPCODE 1-E Mono Cutterhead Cost Breakdown

This may not be final. But, this is what things are looking like right now. I just made a bunch of springs. And, I'll be posting a video about the brass armature I just machined soon.

Machining and Materials
- Armature
5 hr machine time = $300
2 parts in Nickel Plated Brass with Steel Crossbar
- Springs
0.5 hr machine time = $30
Formed Music Wire
- Stylus Screw
1 hr machine time = $60
2 parts in Nickel Plated Brass and Knurled Aluminum Cuff
- Terminal Block
0.75 hr machine time = $45
3 parts in Space Age Plastic and Nickel Plated Copper
- Steel Pole Piece Inserts
0.5 hr machine time = $30
- Fasteners
6 set screws, 15 screws, Threaded Mounting Sockets = $8
- 3d Printed Plastic Body
1.5 hr Print Time = $75
8 parts in PLA
- Magnets
Neodymium Magnets = $8
- Twisted Wire
It takes time to make it nice… $4

Subtotal = $560

Assembly, Calibration, Profit
- Need to pay bills…. $240

Grand Total = $800

[opcode66]

Presto Armature in Brass
OR...
Bob Hates When I Do Machining

[SueDenim]

Very very nice Todd - fantastic work as always
I mentioned this before but are you able to offer this head with a VR mounting post please?
I'm guessing that there'll be additional costs involved as you'll need to measure where the post should be so that the 1-E stylus lands in the same place as the standard VR head.

Thanks

[opcode66]

You know this is a Presto 1-D clone right? It is modernized. But, a dynamic mono cutterhead nonetheless. Are you confusing this with Mantra V2???

Either way, I had access to a VR cutterhead. I took measurements with a caliper and created a CAD drawing of the body. This includes measurements for where the stylus holder hole is and where a typical stylus tip would be in relation to the body. Therefore, I can overlap that onto any other design and make a mount that will align my work to the VR overhead.

Short answer yes for all my work.

[SueDenim]

Thanks for the quick reply Todd - I'll drop you quick PM to explain my rather specialised reasons for asking you!
PM sent (in a few minutes)

[opcode66]

Making a Helical Tension Spring for the switchblade head popping mechanism in my lathe overhead suspension box. I machined a Mandrel from Aluminum Round Bar. Axial 2.5mm hole drilled on the lathe with the bit in the headstock and the part in a v slot tool holder. Moved the tool holder to a vice and tapped the 4-40 threads with a tapping rig and cutting fluid. It worked fantastic. I added a ground flat spot under the screw not seen in this video. The screw holds the music wire. Chuck it in the headstock. Use vise grips to hold the other end. Turn the chuck by hand.

Note: mandrel diameter is calculated based on the requirements for the spring. There is math for it. There are online calculators for springs as well as Machinery's Handbook section.

[opcode66]

Presto Armature Brass Part 2
Looks great on the bench. Can't wait to put the spring holes in and install this in the next OPCODE 1-E Presto Clone!

[opcode66]

C2 Mini Lathe Maintenance

New Precision Bearings and a new Spindle installed in the headstock. Extremely minimal runout now!

[fredbissnette]

been following your youtube

what you are doing is pretty darn impressive

big up!

fred

[opcode66]

I'll have a new OPCODE 1-E clone fully built Sunday evening and bench test posted here. I've had to make a couple tweaks to some parts to accommodate the armature design I've created. As of now, the build seems like its going to be very impressive. I can't wait to actually electrify the voice coils. More very soon!

[opcode66]

Here's what I've been doing....

OPCODE S66 Suspension Box. Made for RCA Portables, Presto's, nearly any other portable or Frankenlathe. Currently made in plastic. All or selected parts can now be machined in metal with zero changes. Vertical adjustment, lateral adjustment, infinite analog depth control via a self designed solenoid, switchblade head release mechanism with manual and custom solenoid control, head up/down custom read switch indicator, flanged bearings, neumann mount, counterweight spring (I made the springs too!), finishing the viscous fluid dashpot now. The internal space is a mere 10.8 cubic inches. The box is on a sled that can rid on a leadscrew, and has a linear bearing embedded in back. It is essentially a mini Neumann suspension. I can build these parts into a larger professional suspension later.

OPCODE 1-E Advanced Mono Cutterhead with Heating wire terminals and mini connectors. Wiring changes are now a breeze. The heating wire terminal attachment is compatible with original Presto 1-C and 1-D cutterheads as well.

Photo Jun 06, 2 05 51 AM.jpg

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PLS19 Portable Lathe System - First platter motor test. Needs tweaks. Also, a different motor. But, successful! Running at 33.3 RPM

[opcode66]

PLS19 Platter Motor Feedback Control Logic Test

I've added eight magnets to the gear reduction wheel. I also added a magnetic sensor to the plinth. Using an Arduino Uno I'm able to take the magnetic input as feedback and determine an accurate rolling average for rotational speed. I'm also generating PWM to control a standard Motor Controller. All told, this creates a nice realtime locked platter motor that can generate output for a pitch computer. Not bad for one night's work. FYI the middle band is 33.3 RPM. And, all I need to do is set the value of a floating point variable to get 45 or 78 RPM. Both also tested!!!

[Ritter]

Here's what I've been doing....

Lovely work opcode66.

Just out of interest, how much does your head weigh?

[opcode66]

It is extremely light in plastic. I can machine the base plate and back sections from brass which would add a lot of weight, but also add to the overall cost. The covers front and back will always be plastic. I've made a weight attachment for the front of the case as seen in the pictures above.

and now....

PLS19 Motor Control Stable!!!!!
After a couple of days/nights of r&d I finally have very stable, efficiently and cleanly written platter motor control logic. The results are phenomenal. Have a look for yourself!

[opcode66]

PLS19 Custom Tonearm Design
Only thing missing is the spring, wiring, and connector pins.

[opcode66]

PLS19 Motor Control V14 - WOW, WOW and More WOW!!!!!!
I think I've cracked the secrets to precision BLDC motor control. I'll be tweaking some values which will allow for even better control than this. But, this is not too bad.... Moving this code to a real PIC32MX processor will allow me at least one additional order of magnitude of precision with better timer interrupts. Arduino is sort of for kids and has a lot of overhead to run. Getting real, non-preempted, quartz accurate interrupts is just not possible in Arduino. Anyone who uses this platform for doing any DSP or Motor Control is immediately at a disadvantage. However, this works for now.

[opcode66]

PLS19 Tonearm V1
Needs some tweaks for sure. But, very close to what I want.

Photo Jun 17, 6 18 35 AM.jpg

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Photo Jun 17, 5 23 25 AM.jpg

Photo Jun 17, 5 23 12 AM.jpg

[opcode66]

PLS19 Moto Control Enhancements

- Switch Inputs for start/stop and speed change 33 to 45
- Serial Remote Control
- 33/45/78 demonstration