midwayfair
Well-known member
I decided to move the oscillators for the "generic" microphone PCBs to their own thread.
These are oscillators to provide an adjustable polarization voltage to condenser microphone capsules. You will need these if you are building one of the projects with no on-board polarization voltage. These are also an "upgrade" of sorts for a mic that uses only the phantom-power voltage for polarizing the capsule, though I think it's rare for a microphone that the PCBs fit to have only one circuitboard.
Project background:
As MXL and other manufacturers selling basically the same product move to SMD, it's harder and harder to find a mic that can just be straight-up modded, and for the most part I don't think the PCB sellers on here are going to be very interested in making a project for sale that's a copy of a dirt-cheap mic.
These PCBs are fitted to the body that's used in the V63/V67 (and the numerous similar mics by Thomann etc), Aurycle (IMO the best completely blank bodies you can get for this size - unpainted but heavy brass), BM800 (I believe that's the same body shape and size), etc.
Standard warning:
******These documents may change until they are verified by both me and at least one other user!******
This is a work in progress -- I am going to make the PCB order this weekend, though, so I'll be able to test all the open source project PCBs at once.
Schematics and layouts:
This one's for single-pattern mics where you want a single polarization voltage that's higher than what you get from the phantom power alone. Usually it's set to +60V, but you can make it higher if you want.
OshPark share link: https://oshpark.com/projects/4gPWNMAc
Mouser cart: http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=5a0be69ef3
There are some notes on the bill of materials that matter depending on your exact needs. Typically this will be paired with the Schoeps-style transformerless project PCB (https://groupdiy.com/index.php?topic=65033.msg824052), in which case your supply voltage will be 12V, but if you want to use it with one of the transformer-coupled mics, the oscillator connection point source voltage is higher (usually closer to 35V), so you'll need the higher-value trimpot (25K). You can also pick between a multi-turn or single-turn trimmer (which is slightly cheaper).
This one's for multipattern mics. It creates adjustable +/- capsule polarization voltages for multipattern condenser microphones. Of course, you could build the multipattern board with only a single voltage if you like. It's identical except that one of the rectifier diodes goes to ground instead of the supply voltage (six of one and a halfdozen of the other).
OshPark share link: https://oshpark.com/shared_projects/4HwGZIpj
Mouser cart: http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=b0c39c326c
Like the single-pattern, there are some notes on parts depending on exactly what mic you want to use it with.
I'll do a full build document once I've had a chance to verify the PCBs. If anyone wants an extra OshPark PCB -- because I won't be building three of each of these! -- let me know.
Thanks to the forum members who helped me out with the oscillators in this thread, the members who have PMed me (you know who you are!), and AudioImprov.
The oscillators are based directly on the one found in the Schoeps microphone and the one found on Audio Improv (which is the same except a slightly different position of the 27pF cap --- and I don't know why it's different in his but it works either way).
These are oscillators to provide an adjustable polarization voltage to condenser microphone capsules. You will need these if you are building one of the projects with no on-board polarization voltage. These are also an "upgrade" of sorts for a mic that uses only the phantom-power voltage for polarizing the capsule, though I think it's rare for a microphone that the PCBs fit to have only one circuitboard.
Project background:
As MXL and other manufacturers selling basically the same product move to SMD, it's harder and harder to find a mic that can just be straight-up modded, and for the most part I don't think the PCB sellers on here are going to be very interested in making a project for sale that's a copy of a dirt-cheap mic.
These PCBs are fitted to the body that's used in the V63/V67 (and the numerous similar mics by Thomann etc), Aurycle (IMO the best completely blank bodies you can get for this size - unpainted but heavy brass)
Standard warning:
******These documents may change until they are verified by both me and at least one other user!******
This is a work in progress -- I am going to make the PCB order this weekend, though, so I'll be able to test all the open source project PCBs at once.
Schematics and layouts:
This one's for single-pattern mics where you want a single polarization voltage that's higher than what you get from the phantom power alone. Usually it's set to +60V, but you can make it higher if you want.
OshPark share link: https://oshpark.com/projects/4gPWNMAc
Mouser cart: http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=5a0be69ef3
There are some notes on the bill of materials that matter depending on your exact needs. Typically this will be paired with the Schoeps-style transformerless project PCB (https://groupdiy.com/index.php?topic=65033.msg824052), in which case your supply voltage will be 12V, but if you want to use it with one of the transformer-coupled mics, the oscillator connection point source voltage is higher (usually closer to 35V), so you'll need the higher-value trimpot (25K). You can also pick between a multi-turn or single-turn trimmer (which is slightly cheaper).
This one's for multipattern mics. It creates adjustable +/- capsule polarization voltages for multipattern condenser microphones. Of course, you could build the multipattern board with only a single voltage if you like. It's identical except that one of the rectifier diodes goes to ground instead of the supply voltage (six of one and a halfdozen of the other).
OshPark share link: https://oshpark.com/shared_projects/4HwGZIpj
Mouser cart: http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=b0c39c326c
Like the single-pattern, there are some notes on parts depending on exactly what mic you want to use it with.
I'll do a full build document once I've had a chance to verify the PCBs. If anyone wants an extra OshPark PCB -- because I won't be building three of each of these! -- let me know.
Thanks to the forum members who helped me out with the oscillators in this thread, the members who have PMed me (you know who you are!), and AudioImprov.
The oscillators are based directly on the one found in the Schoeps microphone and the one found on Audio Improv (which is the same except a slightly different position of the 27pF cap --- and I don't know why it's different in his but it works either way).