Connecting Chinese Weishi microphone to computer

[jdm]

58 minutes ago, Luc said:

I'm afraid that computer power supply isn't free of noise by the way.

Try powering the microphone with a 9V battery to find if that's the case. 

[xyzzy]

If you use my newer version of tg, you can use the spectrogram function to see if there is a specific noise that is causing a problem.  Then it might be possible to use an audio filter to eliminate it or at least discover its source.  It's quite possible for the microphone to pick up noise you can't hear, or for something like a USB device to create electrical noise that shows up in the audio signal.

I recently added a BS.1770 style true peak meter to help adjust gain.  That's not released yet.

[Luc]

Modified the schematic.

 

[TimpanogosSlim]

had the right mix of gumption and boredom. 

I'm sure there are different board revisions, but on mine the test point "A" is directly connected to the audio signal from the mic input. 

It has a DC bias of 4v, so i installed an HPF of a 10uf cap and a 10k resistor. In retrospect, this cap could have been 1uf or even 0.1uf and we'd be fine. 

Used one of the numerous ground stitching vias on the board for the other end of the circuit. Threw on some ferrite beads because they were within arms reach. 

Ironically it turns out that the front panel mic jack on this computer may not be connected. I recently upgraded the motherboard. oops? 

It has enough oomph to power an earbud. line-in type inputs should work too. fwiw, when listening to it with earbuds, I heard some 120hz or so power supply noise. this is with no other electronics connected. Perhaps it just has noisy power and they just filter it out either before or during signal processing? 

Some time later i will maybe dig up the right adapters to plug it into my e-mu 1616m and see if that will work with tg. Or run a wire to the line-in for the motherboard sound on the back of the pc, I dunno. 

Possible other option would be installing an audio coupling transformer to prevent ground loops when connected to the computer. Would replace the resistor possibly. I'll have to see what i have in the parts bins. 

Edited February 10, 2022 by TimpanogosSlim

[TimpanogosSlim]

I did eventually find the right combination of adapters to connect to my e-mu system but then i couldn't recall how to map the asio channels to wdm channels and didn't want to look it up, so i connected to the rear panel line-in which works fine.  I'd attach a recording made in audacity but those aren't accepted here. So here's a screen shot. 

The buzz I was hearing through the earbud may have been LED lights or it may have been due to overloading the preamp with such a low impedance. I hear no such power supply noise when it is connected (correctly) to other input devices. 

TG is working just fine connected to the Weishi 1000 this way

[B52]

Thank to TimpanogosSlim idea I slightly move forward his/her. From the test point A you can get quite weak and unfiltered signal...about 40mV. But from pin no.9 IO 074 you can get nicer, stronger and filtered. As sensor is used RC combination 10K x 2u2. TimpanogosSlim thank you once again!

[JohnR725]

Another way I think is very plausible is just tap into the microphone cable. Because the microphone is a built-in preamp it should be easy enough to tap off of that and you do have a power supply on the cable say of power and a single.

[ColdWind]

I bought the Weishi stand alone from China and made this converter box to be able to use the stand with both my PC/laptop and smartphone. It worked exceptionally well! I couldn't be happier for had gone all out for this mod. Definitely recommend this mod if you already have a PC and can effort just the stand alone on Aliexpress. I made a little video showing my result Weishi 1000/1900 Stand plugs into PC

Edited September 10, 2023 by ColdWind
Missing image

[Kalanag]

On 9/10/2023 at 2:28 PM, ColdWind said:

I … made this converter box to be able to use the stand with both my PC/laptop and smartphone.

Would you want sharing what is inside your box?

[Endeavor]

On 9/10/2023 at 2:28 PM, ColdWind said:

made this converter box to be able to use the stand with both my PC/laptop and smartphone. It worked exceptionally well!

Yes, I would be very interested in a schematic too ......

[Endeavor]

On 1/12/2024 at 10:26 AM, Kalanag said:

Would you want sharing what is inside your box?

 

On 1/12/2024 at 3:24 PM, Endeavor said:

Yes, I would be very interested in a schematic too ......

@ColdWind Is the answer going to be a bit of a "Cold Wind"

Edited January 14 by Endeavor

[ColdWind]

Hi,

I'm too lazy to disassemble mine and take a picture for you all. But don't worry, I've got you something even better. This Youtube video covers everything you need, the internal and the circuit diagram. The adapter was used with an Iphone in the video but it works for PC as well. I made mine based off this video. Have fun.

Timegrapher Microphone Adapter for iPhone (DIY)