This is one hell of a long shot, but i'm getting somewhat desperate, so here goes.
I recently got myself an ancient knockoff of an AKG P820 tube mic from a local store brand, per the service manuals, at least the PSU is a direct 1:1 copy. Now, the PSU appears to be dead, the T125 fuses blow instantly and the light never comes on, this model is basically wholly undocumented but there is one forum post from 2012 that indicated a possible faulty transformer. Upon desoldering the transformer to take some DCR and impedance measurements off the crusty board, i promptly lifted all pads. That, combined with the no-name unspec'd transformer and the generally subpar parts, have given me the idea to just design a brand new PSU basically replacing everything except for the pattern selection section. So my question is, is there anyone that'd be able to help me figure out what kind of voltages i'm looking at so i can get started? I will post pictures and link to the service manual in a couple of hours when i get home from work.
(I have contacted both the store that used to carry them as well as AKG and it would seem i'm SoL as far as getting original parts, despite the AKG variant being a currently available product, i'd frankly prefer an improved self design version anyhow)
Thanks for any help!
I recently got myself an ancient knockoff of an AKG P820 tube mic from a local store brand, per the service manuals, at least the PSU is a direct 1:1 copy. Now, the PSU appears to be dead, the T125 fuses blow instantly and the light never comes on, this model is basically wholly undocumented but there is one forum post from 2012 that indicated a possible faulty transformer. Upon desoldering the transformer to take some DCR and impedance measurements off the crusty board, i promptly lifted all pads. That, combined with the no-name unspec'd transformer and the generally subpar parts, have given me the idea to just design a brand new PSU basically replacing everything except for the pattern selection section. So my question is, is there anyone that'd be able to help me figure out what kind of voltages i'm looking at so i can get started? I will post pictures and link to the service manual in a couple of hours when i get home from work.
(I have contacted both the store that used to carry them as well as AKG and it would seem i'm SoL as far as getting original parts, despite the AKG variant being a currently available product, i'd frankly prefer an improved self design version anyhow)
Thanks for any help!
If it is a very old microphone, Marco van der Hoeven is an expert on those. You can contact him via his site www.witnessesofwords.com
It came out about 2009, but maybe Marco knows his way around a tube design in general, i'll give him a try, thanks for the tip