The Dual 1219 Likes the Stock Mat
Recorded on April 4th, 2016
After the inner-rim polishing experiment last night, I was able to do more listening today. Without a doubt, the noise floor is vastly lower with the polished inner rim. I’ve finally nearly achieved the same inky-black background with the Dual 1219 that I loved with the Thorens TD-165. When I crank up the volume, I can faintly hear the rubber idler driving the inner rim, but it’s way quieter than it was in the past. And when I put my ear up to the platter to listen to it “airborne”, the only thing I can hear anymore is the motor. No whirring/turning from the idler + rim interface.
With that improvement in the bag, the other big a-ha moment today was going back to the stock Dual mat. Until now, I had a thin strip of drawer-liner mesh from Target lining one of the voids in the mat, to deaden the space underneath a record and give it some buffer from the metal platter. With everything quieter in the first place, I thought I’d remove that strip of mesh. Immediately, everything got brighter and more alive. It was like night and day. A vinyl record must want to have the solid, hard foundation of the the stock Dual rubber mat. Even better than that, as shown in the photo above, I made a “clamp” from a wine bottle cork, a small sheet of mesh, and a circular scrap of leather. I put that on the spindle and it pushes the disc down to the mat. The important thing to remember is that stereo grooves are not just lateral. Half of the groove wall information is contained in an up-and-down axis, so you really want a hard surface supporting the record. It might have been quieter having a more squishy mat underneath, but I’ll take a hint more rumble if it means crystal-clear highs come with it.
You may want to say, “But why don’t you just put a hockey puck or a weight on the record if you want to press it against the mat?” Ah, yes, I have a hockey puck. But it’s a little too heavy, and anything with enough mass to use gravity to press the record down is also going to drag the platter. I’ve done it, but the sound loses its life, and sometimes I can even hear it slow down. The trick with the cork + mesh scrap + leather scrap is that it weighs almost nothing, but it hugs the spindle cap and pulls the record down close to the mat, so there’s no air gap, no give, and no resonance. The vinyl stays coupled to the mat radially, and up and down.
I also fixed the tonearm wire so that the side forces on the arm were more equal from either side of the pivot. It’s not perfect – I need to get some more lightweight Litz wire from England to replace the relatively stiff, shielded, cannibalized FireWire arm wire – but it’s better.
The result for now: The Doobie Brothers sound like they’re in the room. Totally hallucinatory.