Hacking The Teenage Engineering PO-80

[musicprodcentre]

Has anyone cut on 7" PETG blanks w/ these mods yet?

[Joe90]

Hi all,
I didn’t know whether to post here or to start a new thread.

Anyhow, I’m planning to make a mono cutting head based on the design of the Teenage Engineering PO-80 for a lathe specifically designed to cut 7” PETG disks.
This seems a good place to enter this hobby as the designs are simple and straight forward.

I plan using a Dayton EX25FHE2-4 Exciter 24W @ 4 Ohm
https://www.audiophonics.fr/en/exciters/dayton-audio-ex25fhe2-4-p-20531.html
Driven by a 100w car audio amp and a 12V / 63A Dell Server PSU. I also plan on putting a 1 farad Car Audio capacitor in the amp supply line.

What I’m after from you good people are some dimensions. Specifically dimensions, of the cutter head torque tube ????

The dimensions I need are as follows.
1) Distance from tip of cutting stylus to fulcrum point.
2) Distance from fulcrum point to exciter attachment / driver pivot point.

Dimension can be in metric or Imperial as I’m happy working with either.

I’ve spent many hours on this forum but only reading threads rather than posing. I have nothing but admiration for the skill and knowledge that lies in these web pages. It’s a credit to you all. Anyway, now feel I have a good enough understanding to start building something for myself.

Thanks in advance.

Warm wishes
Paula.

[markrob]

Hi,

You probably should measure and verify, but from my Fusion 360 model of the stock stylus, I read 7.5mm from the tip of the stylus to the pivot point. I never modeled the entire stock arm to locate the distance to the driver center. The overall length of the stylus from my model is 45mm. You have quite a bit of leeway there if you are building a from scratch lathe. Below is a zip file with a Fusion 360 and Step file of my model.

Mark

PO80 Stylus v9.zip

[Robjkl]

Not checking first, I made a 7” adaptor. I’ll share the files if anyone’s interested. I integrated the clip so you can quickly switch between 5” and 7” by sliding the head mount off. Recommend Markrob’s modified cutting head so you can change the cutter angle and length.
I’ve also found that cheap vinyl Tungsten cutting bits already have a conical end which can be sharpened to use as embossers. You’ll need an extension sleeve (use a long split pin for example). I just drilled a 1.5mm hole alongside the existing Gakken mount and installed the embosser there.
Also, I made a 3D printable 42 degree guide block to help with embosser sharpening. It allows you to use knife sharpening blocks (cheap on Amazon) and finally 3000 grit paper etc to get a nice 84 degree cone as per the original Presto spec. Just using a dremel with the stylus in the chuck mounted vertically and slide the guide block into place.

This is 3d printed no? If so may I have the STL?

[PlasticParty]

Wonderful work Mark. I bought a gakken many years ago but shelved it for a later date to dive down that worm hole. Im an engineer and mostly work at sea and abroad which means I'm not at home much to have time to continually work on things like this. Im more interested in cutting due to wanting greater tracking. Have you tried your modified setup for cutting to original blanks?

[markrob]

Hi,

I have not tried to cut using any type of blank. The stock blanks are quite expensive, so I quickly dropped them from any consideration. Spere supplies (e.g. styli and blanks) seem expensive and not so readily available.

I don't see why you couldn't use a diamond stylus and do some cutting, but the cost of that is too high for my budget. So, I specifically whet the embossing route. The supplied motor is quite torque limited for cutting. Lots of wow and flutter in use when cutting with he stock setup.

My stepper upgrade has plenty of torque for cutting. The weak link is the thin belt. There is probably a simpler motor upgrade to be discovered. If I were you, I'd start out embossing to get the hang of things and then move on to cutting. The Gakken/PO-80 is a surprisingly good design for a toy and makes a great base to experiment with.

Nark

[spinnertownblanks]

We recently got one, will look into styli and blanks for it. If PETG does the job then we are good to go. Our 5” discs are £1 already. If it’s 1.5mm we will get them sorted soon.

Look forward to giving it a go and seeing what we can get out of it!

[PlasticParty]

Hi,

I have not tried to cut using any type of blank. The stock blanks are quite expensive, so I quickly dropped them from any consideration. Spere supplies (e.g. styli and blanks) seem expensive and not so readily available.

I don't see why you couldn't use a diamond stylus and do some cutting, but the cost of that is too high for my budget. So, I specifically whet the embossing route. The supplied motor is quite torque limited for cutting. Lots of wow and flutter in use when cutting with he stock setup.

My stepper upgrade has plenty of torque for cutting. The weak link is the thin belt. There is probably a simpler motor upgrade to be discovered. If I were you, I'd start out embossing to get the hang of things and then move on to cutting. The Gakken/PO-80 is a surprisingly good design for a toy and makes a great base to experiment with.

Nark

Thank you for quick reply. It’s nice to see this topic still active.

I recently preordered a Reloop RP 7 (pro DJ 7” turntable) to add to my setup with the intention to mix in 45s more comfortably. I have mixed strictly vinyl for 20+ years so any new vinyl tech always catches my interest. The reloop RP7 reignited my interest in the gakken record maker that I had stored away for many years. I have the idea that if I can get it to sound reasonable then I can use it to occasional add in spoken word, possibly in the style of 1940s news broadcast as that would be more fitting with the lo-if sound. But what is important to me is tracking and possibly gain. I Dont intend on scratching or mixing the 5” record but will be back cuing it to get it timed right. I have tried some embossed records that someone made for me but with mixed results. On my straight arm decks I was able to back cue them but on technics s arm I could not. Fortunately the reloop RP7 has a straight arm so maybe it will be more forgiving to embossed records.

Features that are of importance
- lead out
- decent gain to avoid feedback. 50-60% of normal record volume could be ok
- not skipping when I back cue
- not too noisey
- maybe reduced flutter and wow


Equipment I have:
- soldering station, heat station…(I’m good at soldering)
- FDM 3d printer (I’m good with CAD)
- all the other expected electrical tools and instruments
- access to a lathe if I’m away at work (I can turn)


From what I heard from your embossing example, this is wayyy better quality than I need. If I can do a few of the mods you have successfully done then maybe I can achieve something suitable. Replacement cutting styluses seem to be rare. That is my main concern. Have you found a suitable replacement or mod?. Ideally I wouldn’t want each cut record to cost me more than £4, which could making cutting feasible.

What mods would you suggest for my needs?

[PlasticParty]

We recently got one, will look into styli and blanks for it. If PETG does the job then we are good to go. Our 5” discs are £1 already. If it’s 1.5mm we will get them sorted soon.

Look forward to giving it a go and seeing what we can get out of it!

Excellent. I just checked out your website and your blanks are great price for 5”. That should be attractive for this machine. Yeah the cutting styluses are an issue… if there was some sort of mod or alternative replacement that would be awesome.

[PlasticParty]

I find it so hard to believe with this decade long vinyl hype that no company has made a sub £500 7” cutter that gives reasonable results out of the box. An upgrade of the gakken cutter is what phonocut should have went for instead.

[Leever]

Hi everyone,

I just got my PO80 and stumbled across this forum. It's truly amazing what's possible here. I'm so happy to see how creative people can be and share their skills. Thanks so much for everything. I'll be getting around to hacking this thing soon

Any updates in the meantime?

Leever