I have been working on a solution for suspending a plinth using maglev suspension for two years now to no avail. I never thought of o-rings. Brilliant! Mind if I borrow your idea? Nice work by the way.
The motor in mine is by Hurst and is used by VPI. It vibrates like a chain saw and requires a very heavy case. It's the PB series P/N 3203-001 They still sell them but they don't like to export. Got an American friend?...
I got the platter from ebay. No longer available I would guess the weight at 10 or so kilo. With a heavy platter the table weight can be less. The shaft is 9.97 mm. The rest is in the pic.
Where did you get your platter?
Cheers; Glenn
@dot
I did look at these photos when you posted them and wondered how such small magnets could fully suspend a 10 kilo platter. I presume that the platter is fully supported by magnets ? .
Looking again and more closely I notice that the magnets in the plinth seem to be doubled up. Does that double the repelling strength of the magnets ?
Hi Deadhead;
I'm rereading the thread, looking hard at Adelmo's suspension. With more spare time, I'm ready to make my plinth "float". One gets tired of having to tip toe around the room!
The platter magnets are rather large compared to what's available. As to whether the force is doubled, you would have to study Earnshaw's theorem. It is significantly more than singles. What gets me, is that after a few years, it hasn't sagged any.
I see that platters are available again on ebay.com. Search for...
60T Super Sound Aluminum Platter+Tungsten steel Maglev bearing for Turntables
Cheers; Glenn
I'm rereading the thread, looking hard at Adelmo's suspension. With more spare time, I'm ready to make my plinth "float". One gets tired of having to tip toe around the room!
The platter magnets are rather large compared to what's available. As to whether the force is doubled, you would have to study Earnshaw's theorem. It is significantly more than singles. What gets me, is that after a few years, it hasn't sagged any.
I see that platters are available again on ebay.com. Search for...
60T Super Sound Aluminum Platter+Tungsten steel Maglev bearing for Turntables
Cheers; Glenn
My self designed and self built RIAA amp.
I recently did a couple of these and had the enclosure CNC machined:
Example frequency response deviation (jumps at low frequecies caused by QA software settings). Note the Y-axle span.
I may post a dedicated thread about this one if there's interest.
Risto
- MM & MC
- Adjustable load capacitance for MM and load resistance for MC
- Adjustable gain, 4 steps
- DC servo to eliminate unnecessary coupling capacitors
- Active/passive RIAA network with 0.1 % thin film resistors, 2 % PPS caps
- RIAA accuracy better than +/-0.1 dB
- Mute circuit to eliminate pops at power-up and off
- Low noise and ultra low distortion
- 4-layer PCB with good GND plane for low noise
I recently did a couple of these and had the enclosure CNC machined:
Example frequency response deviation (jumps at low frequecies caused by QA software settings). Note the Y-axle span.
I may post a dedicated thread about this one if there's interest.
Risto
Thanks, I will post a thread with more details in the near future.
Here's my Denon TT with the original 1.0 version that I designed in 1989 as a student. Here I had modified it to use the modern Linear Technology (ADI) power supply circuit which I then used in the new versions.
Here's my Denon TT with the original 1.0 version that I designed in 1989 as a student. Here I had modified it to use the modern Linear Technology (ADI) power supply circuit which I then used in the new versions.