I used from another very cheap Chinese microphone. But it can also be bought separately from Ali
Anyway, we all have this problem with bodies bought separately, surely there are different solutions, links
OPEN SOURCE DIY Mic Project - ORS 87 - Stripped Down u87
- Thread starter Wordsushi
- Start date
Help Support GroupDIY Audio Forum:
Anyway, we all have this problem with bodies bought separately, surely there are different solutions, links
You can get the cheapest Cliff UK panel-mount XLR connectors from TME in Poland - they look like the discontinued Neutrik NC3MP.
You can also stock up on passive components and whatever, likely a bit cheaper than the US-based distributors. Just too bad they don't have any free shipping threshold, but on the other hand, the 9,90e UPS Express Saver can do next-business-day delivery to at least Finland
Later edit: Either the Cliff UK FC6105, or the even cheaper Ninigi equivalent
Last edited:
AdamFrisen
Member
This looks tempting. Anybody have experience?
https://www.aliexpress.com/item/100...=scene:pcDetailTopMoreOtherSeller|query_from:
https://www.aliexpress.com/item/100...=scene:pcDetailTopMoreOtherSeller|query_from:
This looks very good, the outer diameter should fit the microphone perfectly.
In general they fit to Chinese microphones
I'd like to ask your opinion about my BIAS calibration procedure (using 24V zener).
No hardware oscilloscope is used, only DAW.
1. Disconnect both capsules wires from the PCB (FD and BP)
2. Connect mic XLR to preamp INPUT and phantom +48V powered on. Connect preamp output XLR to your DAW and use some kind of scope / frequency analizer.
3. Adjust trim pot to get 11Vdc in JFET drain as a starting point (assuming 24V zener)
4. Inject a 100mVac signal from your DAW signal generator to the PCB (use a two wires unbalanced cable with (+) terminal connected to JFET gate and (-) terminal connected to GND). You should have something like this.
5. Raise signal to 200mVac and you should have a little more distorsion (harmonics)
6. Raise signal to 300mVac and you will have this (even more distorsion)
7. Now adjust trim pot to decrease this harmonic distorsion as much as possible (you won't be able to remove distorsion completely). Something like this
8. My final reading in JFET drain is 9,2Vdc.
9. Remove calibration 2 wires cable and solder capsule wires.
10. It's done. Congratulations !!!
What do you think? Do you find it correct?
I wanted to confirm using this detailed explanation.
No hardware oscilloscope is used, only DAW.
1. Disconnect both capsules wires from the PCB (FD and BP)
2. Connect mic XLR to preamp INPUT and phantom +48V powered on. Connect preamp output XLR to your DAW and use some kind of scope / frequency analizer.
3. Adjust trim pot to get 11Vdc in JFET drain as a starting point (assuming 24V zener)
4. Inject a 100mVac signal from your DAW signal generator to the PCB (use a two wires unbalanced cable with (+) terminal connected to JFET gate and (-) terminal connected to GND). You should have something like this.
5. Raise signal to 200mVac and you should have a little more distorsion (harmonics)
6. Raise signal to 300mVac and you will have this (even more distorsion)
7. Now adjust trim pot to decrease this harmonic distorsion as much as possible (you won't be able to remove distorsion completely). Something like this
8. My final reading in JFET drain is 9,2Vdc.
9. Remove calibration 2 wires cable and solder capsule wires.
10. It's done. Congratulations !!!
What do you think? Do you find it correct?
I wanted to confirm using this detailed explanation.
Were the tests, viewing, measurements, BIAS, etc. done with the signal going through the transformer?
The procedure, yes. Not sure the exact signal amplitudes are crucial or relevant, but that is indeed the way to go.
Pretty sure "DAW" means "audio interface", so there's your answer
Yes, the procedure was done including PCB+transformer (complete mic circuit excepting capsule). All screenshots from DAW analyzer was taken from preamp output at minimal gain. Probably the signal amplitudes are not crucial, I just wanted to have reference values
The only caveat is that you're not able to see the effects of the feedback network on the frequency response, but that's only relevant if you know (or care about) the "raw" response of the capsule itself
I disconnect the primary of the transformer from the 1uF capacitor.
Instead, at this point I connect a sound card input (in 1)
I feed the microphone with Uphantom via XLR from another channel (in 2).
Otherwise, I would follow the procedure described by you, using the DAW on the channel (in 1).
So I make the BIAS of the jFET without the influence (harmonics) of the transformer.
Finally, when everything is adjusted, I connect the transformer.
Which parts are included in the feedback network ?? Remember I made my own PCB and I included R6 1G, C4 470pF and R7 1G from the original schematic.The only caveat is that you're not able to see the effects of the feedback network on the frequency response, but that's only relevant if you know (or care about) the "raw" response of the capsule itself
I actually inject the signal before this C4 470pF, not directly in JFET gate. But I wanted to share this procedure assuming we are in ORS87 thread.
Last edited:
Referring to the original U87 (non-A schematic), it's C9, C6, R8, C5, R9, R10.
peterc
Well-known member
This was an earlier post from Khron:
Just measure the resistance between all four wires. Larger resistance side goes towards the circuit, lower resistance side goes towards the XLR. If it turns out to be out of phase with a standard mic, swap the two wires going to the XLR. No need to assume or wonder or anything...
Just measure the resistance between all four wires. Larger resistance side goes towards the circuit, lower resistance side goes towards the XLR. If it turns out to be out of phase with a standard mic, swap the two wires going to the XLR. No need to assume or wonder or anything...
Last edited:
667-ECE-A1VKS4R7 16VDC
667-ECE-A1VKS4R7 35 VDC Hello, can you tell me if I can also take the 35 VDC or is that bad? 16VDC are indicated, what can be destroyed?
16V rating is the MINIMUM voltage rating to use there. Anything above that is good; less than that is "no". As long as the capacitor still physically fits, of course...
Will it be possible to have pcbway build the circuit? That looks to cost $30 + parts for 5.
Yes, with Chinese components.
jFET Toshiba, Wima and Nichicon capacitors etc, Made in China.
What would be the difference? At $30/circuit I'd be willing to give it a try vs. not being able to build my own circuit.Yes, with Chinese components.
jFET Toshiba, Wima and Nichicon capacitors etc, Made in China.
