24-02-2016, 09:32 PM
I also realised that I'd wrongly connected the leads from the pickup to the volume control. Having fitted a 5-way tagstrip to which, with some difficulty I soldered the very fine wires from the pickup arm, I then connected said tagstrip to the i/p points on the control panel, using a 'figure of eight' twin screened lead terminated in small 'spade' connectors (the twin brown lead visible in some of the pictures) However, I connected the inners of the two screened leads to either side of the volume control via 2n2 Class 'Y' caps. So far, so good, but I then connected one of the inner cores of the screened lead to the 'spare' tag (i.e. that which would have the second channel of a stereo cartridge attached) of the tagstrip. This meant that one side of the X5H mono cartridge was connected to the 'hot' side of the V/C, but the other was, via the screens of the twin brown lead, connected to the control panel chassis. Having corrected that error by connecting the inner core of the screened lead to the other side of the cartridge, I was rewarded with decent quality sound, or at least as good as I'd expect to get from a one-valve amplifier, but the hum level, although reduced, is still, to my ears, too high. It varies with the setting of the volume control, but is still noticeable with a record playing. I'll replace the unscreened leads in the PU arm with a length of miniature twin screened wire, and may also reroute the mains lead so that less of it is in the cabinet. BTW, originally there was no isolating cap. between the Live mains lead & chassis, only one on the neutral side, so I fitted a 2n2 from the Live side to chassis as well. Ws that a good idea?
