tubologic
Well-known member
- Joined
- Mar 29, 2009
- Messages
- 72
I'm looking for informations about the ALTEC 527A tube microphone power supply. It looks it could be used with the M20/M30 lipstick microphones systems but it has a much more elaborate circuit than the original 525A power supply,with adjustable and regulated polarizing voltage and heater current,including two very nice meters. There are many tubes inside (6CG7/6AU6/ (2)5651 and a 1HT4 current regulator ballast tube) My guess is that it was intended to be compatible with either the 29A or 21D capsules by adjusting the polarizing voltage (60 volts for the 29A and 200 volts for the 21D) but why the heater current is adjustable is still unclear to me. Does anybody have more informations about the 527A and for which microphone(s) it was designed ? It looks more like a special purpose (instrumentation,medical,industrial ?) unit and unfortunately has no balancing/matching output transformer built in. A copy of the schematic/manual would be great but I was unable to find any informations about this model so far on the web. Thank you for your help and advices.
