Over Lockdown I have been picking up bits for a turntable as and when they have popped up on that favourite auction site. Anyway, today I put it all together and it actually sounds very good.
Recipe -
The outcome is pretty good, there are a few inclusions in the moulding but at 5ft it look pretty good. Its very heavy (around 20kg, 45lbs) so stands up to shock well.
I have added a few photos of the finished article. More info in the link below and also a YouTube link to prove it works. All comments welcome.
Frankenstein home made turntable - YouTube
Lockdown #2 Project | AVForums
Recipe -
- Rega RB303 tonearm which I rewired with Litz silver cable and added a Michell VTA mount. I added a AT VM95ML to the arm and aligned using the Vinyl engine Rega Stevenson protractor.
- Lenko L75 Heavy duty bearing and platter, bearing cleaned and ceramic ball bearing inserted.
- Project M303 motor that I mounted in a 75mm diameter x 100mm high aluminium housing, replicated the drive board and added a Speedbox.
- The I encapsulated some 50mm Walnut slab in epoxy resin (Epoxyplast B20, several,layers) for a base and main plinth, the main plinth having cavities for the motor, platter and tonearm.
- Finally added some 30mm diam 20 shore hemispheres on the base and ally spikes for the plinth plus a project rpm junction box underneath.
The outcome is pretty good, there are a few inclusions in the moulding but at 5ft it look pretty good. Its very heavy (around 20kg, 45lbs) so stands up to shock well.
I have added a few photos of the finished article. More info in the link below and also a YouTube link to prove it works. All comments welcome.
Frankenstein home made turntable - YouTube
Lockdown #2 Project | AVForums
Attachments
Looks great!
What's the thinking behind the encapsulation?
What happens if the wood shrinks a bit?
What's the thinking behind the encapsulation?
What happens if the wood shrinks a bit?
Mostly aesthetic but I guess the different densities may help resonance. The wood is fully kiln dried and then left indoor for 6 months so well dried out. The epoxy is pretty thick (minimum 5mm thick) and pretty tough and by encapsulating the wood then there is no way for moisture to enter or escape and indoors it is at pretty much constant temperature so limited method for warping/cracking etc. which tends to be through moisture take up or drying out or temperature changes.
Also, I weighed it today, 23kg from both parts (just over 50lbs), and a quick knuckle wrap on the table it’s on show it is very resistance to vibration/shocks.
Also, I weighed it today, 23kg from both parts (just over 50lbs), and a quick knuckle wrap on the table it’s on show it is very resistance to vibration/shocks.
Thanks for the comments guys and gals, Much Appreciated.
@Analog_sa, in order for me to learn please can you expand on your comment, seems as though you think heaviness is not a desirable trait in a turntable.
My aim was to ensure none of the environmental, motor or bearing vibrations reach the arm and therefore providing a heavy/dense platform sitting on vibration absorbing feet was a method for doing so but I am happy to learn otherwise just in case I go down this route again.
@Analog_sa, in order for me to learn please can you expand on your comment, seems as though you think heaviness is not a desirable trait in a turntable.
My aim was to ensure none of the environmental, motor or bearing vibrations reach the arm and therefore providing a heavy/dense platform sitting on vibration absorbing feet was a method for doing so but I am happy to learn otherwise just in case I go down this route again.
Well, moisture diffuses through epoxy resins, 2% water absorbance is a figure I've seen. But in steady state conditions nothing will change.
The relative ease with which water diffuses into epoxy is why ICs come packaged with silica gel bags so they don't risk pop-corning during reflow soldering.
Epoxy is hydrophilic (moisture loving). Plastic packaged integrated circuits absorb a fair amount of moisture. This is why a pre-assembly bake step is called for for larger plastic packaged leadless ICs. If this step is ignored solder joint reliability can be seriously degraded. ICs with leads fare much better in this respect as the leads act as a strain relief.
In the case of this very nice TT build I don't think the hydrophilic property of epoxy will be much of a problem as I don't expect indoor domestic humidity to change drastically and there is no hard connection that the epoxy must butt up against.
In the case of this very nice TT build I don't think the hydrophilic property of epoxy will be much of a problem as I don't expect indoor domestic humidity to change drastically and there is no hard connection that the epoxy must butt up against.
We watch closely. Below 25% RH we have nose-bleeds; above 60% sticky and musty/allergies. In near-zero weather with the heat on, the house wants to go to 20%RH so we set out water-trays. Summer can bring (in Maine) 84degF and 85%RH outdoors, so we run the air conditioner even down to 75 outside. (The A/C is carefully sized barely-enough so it dries more than chills; normally-sized A/C would chill and shut-off before it dried much.)
Ugg10,
the plinth looks great. Being unique (resin and wood) any chance of listening to vibration by putting stethoscope on plinth ? or by any other method ? Would be interesting to compare.
thanks and Regards.
the plinth looks great. Being unique (resin and wood) any chance of listening to vibration by putting stethoscope on plinth ? or by any other method ? Would be interesting to compare.
thanks and Regards.
Ugg10: not being a native speaker may I ask for some "translation" of the title of this topic? I can feel more than understand of it 
@Icsaszar - Sorry if the Title is a bit obtuse, my strange British sense of humour.
Bitza - in English - short for “Bits and pieces” - often used for describing a cross breed of dogs.
Frankentable - refers to Frankenstein I.e. made from tots of different pats from different places (manufacturers).
Hope this helps.
Bitza - in English - short for “Bits and pieces” - often used for describing a cross breed of dogs.
Frankentable - refers to Frankenstein I.e. made from tots of different pats from different places (manufacturers).
Hope this helps.