Condenser Mic Innards???

[ashcat_lt]

Anybody know if/where I might find a fully assembled circuit board for a condenser mic at a reasonable price. It seems like the kind of thing I'd be able to find on amazon for like $5, but I can't seem to find the right search terms. Everything I come up with is for electret elements expecting like 5V power. I don't actually need to polarize an element, but I do need a small amplifier that can power from 48V phantom without exploding and preferably with a balanced output. It is for a DIY project, but I really don't want to DIY the circuit itself. Any hints or help would be appreciated.

[Scodiddly]

What's the capsule? Lots of stuff available these days if it's for a common part.

One of the common DIY condensor mic designs that doesn't need capsule polarizing voltage is the "Alice" and a few people are making PCB boards for that now.

[ashcat_lt]

Well, the "capsule" is a speaker. The one I tried actually works pretty well, sounds suprisingly good, but it could use some gain. I figure it would be best to get that gain as close to the capsule as possible and an actual balanced output would also be nice for S/N reasons. I've got a couple of broken condensers and was going to mess with their guts to see if it helps at all, but I'd like to make a few. Don't want to mess with transformers and don't really love the idea of DIYing the circuit itself. There are sooo many cheap boards for electrets!

[A.David.MacKinnon]

I don’t know a ton about circuit design but if the capsule is a speaker then the mic is by its nature a dynamic. A condenser mic functions on a different principle and it seems unlikely to me that a pre-amp circuit from condenser would work on a dynamic element.
You’d be better of with something like a cloud lifter type pre-amp or something like what’s used in active ribbon mics. The right transformer could also increase the gain and balance the output.

Just my totally non-technical two cents. I’m sure someone with more technical knowledge can advise in more detail or correct my hazy thinking.

[floid]

I would tend to agree with the above. A condenser capsule is connected to an input in the GigaOhm type range. Subbing in a speaker in the ones to tens of ohms range seems problematic. A transformer with say an 8ohm to 200ohm ratio might work better. Maybe one from a ribbon mic?

[ashcat_lt]

I appreciate the responses, but I disagree. Higher load impedance is always better. 1G is way more than necessary for this purpose, but it sure ain't gonna hurt anything unless it adds more noise than necessary, but that's usually not a big issue in this kind of circuits.

Whether the circuits meant for condensers will give enough quiet gain is another question. If it doesn't significantly increase S/N over just adding gain at the mic pre, it won't really be worth it.