- Spinoo
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Custom Méga utilisateur
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When looking at the main board there is a trimmer that sits between two large orange caps. There are two red leads from these orange caps to the PI socket. With the meter grounded to the chassis you check the volts at the eyelet where the leads connect to the caps. You are shooting for around a 6.5 volt difference, with the lead nearest the power transformer end of the board having the lowest voltage. My voltages ended up at about 302.0 and 308.5. The target voltage difference is 6.5 but once you are in that vicinity you fine tune it by playing notes on the B string at the 3rd, 4th and 5th frets (D, D#, E) and listen for the bloom, adjusting to get the bloom as even as possible between the three notes. It is amazing how very slight adjustments make a difference in the bloom and sustain between the three notes, with dramatic differences between adjacent notes when this is not adjusted right. Since you should (Henry recommends) replace the PI with every second power tube replacement, this will need to be reset then. Also when setting this you have to wait at least 15 seconds for things to settle down after adjusting the trimmer to re-measure the voltages. |
