Trying to connect some phono leads to my arm, the bracket snapped, causing two of the fine tonearm wires to become undone, so I have a couple of queries as to what to next, there has always been an earthing issue on the tonearm, is it possible to fit a proper Cardas plug into this SMG 212,and would a possible rewire devalue the arm in any way
What is the best phono stage for SPU type cartridges, anyone with experience, knowledge of these pickups
Is the bracket that you mentioned a terminal strip to which the internal leads connect to after exiting the bottom end of the arm pillar?
According to the manual, some variants came fitted with a terminal socket within the arm pillar, vs. others having twisted flying leads out the pillar end. Later in the manual they describe how to best connect to a terminal strip within a deck (i.e. such as those fitted to similar vintage decks).
"In case the arm is furnished with a socket for plug-in cables, the wires are internally connected to the socket as shown in Fig. 7."
As to fitting an aftermarket socket, the pillar would appear to be long enough, however you'd need know the internal diameter. I'd also measure the amount of unobstructed depth too. With a circa Ø22mm pillar the usual
Cardas male DIN5 may not only fit, but require shimming to fit tightly.
Personally, as the SPU is of very low impedance and, therefore, relatively insensitive to hum induction, I'd stick with a terminal strip and make sure that the tonearm wires are kept twisted until they reach it. This would keep the arm stock, and likely preserve its rarity (then again, I am a purist, so take with a pinch of saline).
For amplification, considering the vintage of the tonearm and intended cartridge, the obvious answer is a step-up transformer. Both SPU Classic and Classic E have a 0.2mV output rating and 2 Ohm internal impedance. Therefore, gain should be in the region of 25 to 30dB and recommend input impedance >=10 Ohm. Naturally, Ortofon's most expensive model ST-80 SE is a perfect match, however, looking closer at the specifications reveals that the next model down ST-70 can be ordered in 'Configuration B', ideally matching SPU Classic (or any MC with <10 Ohm coil impedance) and requiring circa 30dB gain.