I was using a nice Lenco PTP (pics here where I sold: https://avx.hu/forum/viewtopic.php?p=2669729#p2669729 ) with Fidelity Research 24 tonearm, till the owner/designer/diyer of 72 audio – Zsolt Bodnár – showed me that there is way of improvement at my frontend. He brought a DIY turntable with Dual 1219 roots and his tonearm built in small series with some MC and MC trafo (72 audio).
The tonearm is a miracle, which just works due to its simplicity. This blog entry shows in pictures what to do with the Dual 1219 to improve sound quality to finally be on the same page or better as Garrard, EMT, SP10, or my PTP. (I know just the PTP with proper experience, so handle this now as my strong belief) So ideas are not from me, I just try to have the same sound again in my chain that I got demonstrated by Zsolt:
(yes this is an Dual 1219!)
Compare sound to a Garrard 401 with Audio note: https://www.youtube.com/watch?v=HmleXoPgT2U
Step 1 Remove everything from the chassis. Part you have to keep is the chassis(14), spring leg (78-82) the turntable (3-6, 16, 17) speed setting components (8-12, 101-115) and the motor (116-125), the motor switch is not mandatory, but feel free to keep it (parts 130-135, but you need to cut and bend the switch lever to make it constantly on). User manual to see assy and identify part numbers, motor electronic schematic is here.
Step 2. Close the holes with car body repair filler (is epoxy based) and sand it down with water proof sandpaper (water helps to not fill up the pores while sanding ) 200-400 sandpaper is fine. At the speed setting knob, add a 29mm coin exactly centered to the middle shaft hole (the 2 slot is not centered! Do not worry. if one seems to be more away than the other. You can see this in the bottom right of the next pic)
Step 3 Paint or add leather to look nice (The one in the picture is used by Porsche).
Step 4 Assy it back. Do not forget to clean and oil with sewing oil all bearings and moving parts. I see the debates to use single 40W or multi 5W20… probably all works, but self need to test which the best, maybe the tackier 40W. (inside the motor there is one hidden bearing, you will need to take it apart) The height of the driver motor wheel helps to set the speed knob to the middle(side screw-118 fixes, top screw -116 aligns height) Add bitumen-based sound absorber (car HiFi shop, 2mm with a thin aluminum carrier), to compensate for weight loss and eliminate vibrations (add double on the tonearm side to compensate asymmetric plate weight) Oh and you will need a hook to fix part 103 (spring of the idler arm) somewhere. I fix the hook with the the bitumen plate, I simply put it under it, while hook comes out.
Step 5, Polish the running surface till it mirrors. (the top of the left pic is a mirror)
Step 6 Add a heavy wooden plinth. The aim is that there is no feedback from the loudspeaker, while resonances are well suppressed. Think about using a wall console!
Step 7 Get 50Hz 230V clean power source. Less, than 60 Watt type, so something built for turntables . Should be with the precise clock to eliminate wow, flutter, or speed deviation. Should operate with LOW THT Sinus. Should drop the voltage to minimize motor vibration. 110Volt is enough. That will help that motor gets not hot. Ensure that chassis has protection earth!
Step8: Plinth. 5 layer CNC formed 6pcs 18mm plywood.
Can give you not painted one for 180Eur+ship cost. Mail me at r.bakos.gyorgy at gmail.
Note: Dual 1219 has a really bad bearing. PTP or Lenco is way more advanced. Motor vibration is enorm, but it gets very well suppressed with the motor holder. The plate has also audible noise while rotating as the motor. I think the side idler helps a lot with the direction to eliminate this. Overall: Very hard to believe this is better than my PTP, but listening confirms it. What comes from the loudspeaker is not bearing the listed flaws.
Interesting links:
Warsaw critic, search for 72 audio: https://soundrebels.com/audio-video-show-2022-cz-2/
“And now it’s time for … no, not for Telesfor, but for probably the biggest sensation of this year’s exhibition, i.e. the Hungarian Popori Acoustics electrostatics, which, together with the 72 Audio electronics, caused such a stir in the lobby that most of the interlocutors were unanimously inclined to consider them the best sound in the Sobieski, with which I do not intend to argue, because it was indeed a phenomenal musical feast. Maybe the bass did not go very low, but it was energetic and tight enough not to show signs of slimming, while the rest of the band stunned with its resolution and speed. Big and well deserved applause!”
Stereophile mentioning
https://www.stereophile.com/content/warsaw-day-2-exotica
Michael Fremer:
“SOUNDED REALLY GREAT”
I recently upgraded with magnet bearing. Bought an 20mm-10mm/3mm N35 magnet from Aliexpress. Drilled up one with 11.6mm in lathe with using Dremel.(dust is cancer! Avoid it while work.) For bottom you need 4-5mm (if smaler, then take N48 or bigger) I sourced this: https://neomagnet.hu/Neodimium-gyuru-magnes-23x10x5-mm-N35
https://www.aliexpress.com/item/1005004709258043.html?spm=a2g0n.order_detail.order_detail_item.3.206cf19cN2SCJb , funny that they sent 3mm, while says it is 2.5mm When I ordered later an 3mm, then got a 2.5mm… So you need to deal with this…
Found it usefull forces: https://www.kjmagnetics.com/calculator.repel.asp?calcType=ring
Warsawa 2023, from time 15:40, 72 Audiio introduces this, but, is in Hungarian: https://youtu.be/yzpy-SiPzDU?si=KMBfjN9WLeZCs-lJ
Philips AG9015 