James the first capsule, 25mm most likely is electret, meaning it does not need bias voltage. The second one, 34mm does.
To your comment on the BM-800. Not sure people replace just the board and leave the existing capsule. (Which totally vary depending on manufacturers). Typically we gut the whole thing and use just the mechanical metal part to house a new capsule and PCB.
The second eBay board (with transformer) may have a bias voltage supply in it. Without schematic, can¡¯t say for sure.
Jules
Best Regards,
Jules Ryckebusch
toggle quoted message
Show quoted text
On Jun 25, 2022, at 07:41, Richards <jrichards@...> wrote:
?Good Morning Gentlemen!
To Jules -- I follow the gist of your commentary. Obviously I need to learn more about polarizing voltage versus phantom power. I would appreciate leads to the homework I must perform. I am not averse to reading, as I do not expect you guys to tell me everything on the forum. Much appreciated - I believe there is a LOT of buckshot in that one shell (reply) and this is the tip of the old iceberg. :-)
To Thet -- I am beginning to understand how much I do not yet know here. I attach photos of the two capsules in question.
The 1-inch item is described here:
I understand the difference between FET and FET-less capsules and your proposed working definition of "true condenser" is what I intended by the term.
And, I believe we can now get down to the THE NITTY GRITTY . . . Um ... ahem ... er ... I did not purchase both boards for either the OPA Alice or the eBay boards under scrutiny. And given the trend of the discussion ... ahem ... I now wonder whether I should have purchased both boards. After reading Jules articles on www.Indestructibles.com, and a website by an UK mic maven www.audioimprov.com, I was under the impression the OPA Alice board could be used alone, as a substitute for the ubiquitous BM-800 boards. I extrapolated that presumption and ordered just the one board in question from an eBay seller, "hoping" (blithely presuming, actually) it is the equivalent of the OPA Alice board.
To Henry -- Please see above.
So, I now wonder whether I failed to purchase a complete kit for the larger, 34 mm capsules.
I purchased another board on eBay that seems to work well on its own. See photos - board with yellow transformer.
I successfully paired it with this capsule -- See photo of all brass capsule.
I have, therefor had rather mixed results, but I now wonder whether I have, as one of you put it, mixed my apples with my oranges, because I do not (yet) fully understand how the bias thing works.
Gee - I hope this makes sense. It appears I started swimming before I fully learned how! THANK YOU for any further insight you can provide. Happy trails to all. James
