Ovo je originalan Ralph-ov text preuzet sa Audio Asylum sajta koji se tice implementacije Atmasphere M60 OTL Amp-a na Westrex masinu za rezanje vinilskih ploca :
`` Those of you who have been watching the blog on our website may have noticed that we mentioned using a set of M-60s for LP mastering with our mastering lathe. I thought I would post this for those interested. We chose a Westerx cutterhead, as it has a nominal 10 ohm impedance and the stock transistor cutteramps for it only make 125 watts. So it seemed like we would have no worries with a set of MA-1s to drive it. However saying that the cutterhead is 10 ohms really glosses over the subject. It starts on the low end at about 8 ohms, has a peak of impedance due to mechanical resonance in the midrange, then continues up from about 9 ohms to about 25 ohms at 25KHz. Now in an LP mastering situation you have to apply the RIAA pre-emphasis; this means that you have to make a fair amount of power at high frequencies because so much emphasis is added. That is why the transistor amps are rated for so much power (the cutterhead itself cannot handle anything near that power level) because the transistor amps lose power as frequency increases due to the load, being capable of only about 40 watts into this load at 20KHz. So as a result our M-60 works out to be an ideal amplifier, as it actually is capable of more power/less distortion into the higher impedances. The cutter system employs a feedback module that adds about 30 db of feedback around the head and amplifier. This is required; without it there would be no channel seperation due to the mechanical suspenions in the head itself. It also controls head resonance. So we set up a set of M-60s without feedback, and a speaker protection fuse, since you can toast the head pretty good with only 20 watts or maybe a little less. So far the results have been excellent and the operation is keeping quite busy! The cutting system is capable of cutting grooves without distortion that no cartridge or arm combination could ever track! In addition, the lathe cuts are considerably quieter than the best vinyl, rivaling digital in terms of dead silence. The bandwith is amazing, good from about 5 Hz to well over 40KHz without effort; with some mods to the electronics and a different needle installed on the cutterhead we could cut a 50KHz subcarrier in the groove with FM stereo modulated on the carrier! I can't say how well an OTL would work on other cutterheads like the Neumann, but for the Westerex its ideal. ``