U87 (Revision A) in BM800 microphone donor body

[Jarbcd]

As a thank-you, here is a link for the BOM (doubled quantities however, but should spare the endless copy and paste off the pdf)

https://pt.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=4930838ebd

Does this BOM still hold up? A few of these are either out of stock or no longer available.
I'm far from an expert, so I'd love some advice! What would make for good replacements for what's missing?

To make it easier, here are the Mouser ID's:
MF1/4DC1503F
60900213421
URZ1J100MDD
USA1H4R7MCA
RGP0207CHK1G0
271-560-RC

 

[Khron]

Does this BOM still hold up? A few of these are either out of stock or no longer available.
I'm far from an expert, so I'd love some advice! What would make for good replacements for what's missing?

To make it easier, here are the Mouser ID's:
MF1/4DC1503F
60900213421
URZ1J100MDD
USA1H4R7MCA
RGP0207CHK1G0
271-560-RC

Resistors - any 1% 1/4W metal film should do fine (hint: sort them by price, and tick the "in stock" box).
Not sure why there are 10uF AND 4.7uF separately in the BOM. They're likely the same physical size, and they'll work just as well as each other in this simple of a circuit, so why not get closer to the quantity-price-breaks? That being said, for electrolytics, stick with the good Japanese brands (Panasonic, Nichicon, Rubycon, Elna, United Chemi-Con).

[Later edit - You can use three 22uF / 63v just fine, one for the source resistor bypass, and the other two in the supply filtering. Same with the 470nF coming off the drain, you can use the same 470nF in the power filtering, instead of the two 330nF ones.]

The Wurth jumper you can replace with a piece of wire on the underside of the board, in a pinch. Unless you plan on routinely replacing and rebiasing JFETs, that is...

Mouser seem to have restocked the 1G resistors - 6709 in stock as of yet, with another 5000 expected in june.

 

[Jarbcd]

Thanks for this! I wasn't sure what qualified as "audio-grade" or not, so I thought it best to ask.
Should all be on the way

 

[Khron]

I wasn't sure what qualified as "audio-grade" or not, so I thought it best to ask.

"Audio grade" is just a BS term to "justify" adding a 100-5000% premium to the price of a component.

[Edit: grammar]

 

[MicMaven]

EDIT -- OOPS!!! POSTED IN THE WRONG THREAD ... DUH! (But I will leave it because Mr. Khron liked it!) Um... ahem... er ... JHR

* Do you have to relieve some of the pressure before replacing the tap?

* Gee. It looks a bit like motor oil. What style is it?

I like a dark beer, Stout, Porter, Dopplebock, Eisbock, Dunkle, etc. Come to think of it, I ALSO like light Lagers, Pilsner, Amber Ale, ... In fact ... maybe, I just like beer!

(Seriously, however, I do NOT like most IPAs or murky sour Weiss styles)

Cheers! James

 

[mihi_fuchs]

EDIT -- OOPS!!! POSTED IN THE WRONG THREAD ... DUH! (But I will leave it because Mr. Khron liked it!) Um... ahem... er ... JHR

* Do you have to relieve some of the pressure before replacing the tap?

* Gee. It looks a bit like motor oil. What style is it?

I like a dark beer, Stout, Porter, Dopplebock, Eisbock, Dunkle, etc. Come to think of it, I ALSO like light Lagers, Pilsner, Amber Ale, ... In fact ... maybe, I just like beer!

(Seriously, however, I do NOT like most IPAs or murky sour Weiss styles)

Cheers! James

Good pint of beer is welcome everywhere.

Cheers and salut,
Michael

 

[mihi_fuchs]

Resistors - any 1% 1/4W metal film should do fine (hint: sort them by price, and tick the "in stock" box).
Not sure why there are 10uF AND 4.7uF separately in the BOM. They're likely the same physical size, and they'll work just as well as each other in this simple of a circuit, so why not get closer to the quantity-price-breaks? That being said, for electrolytics, stick with the good Japanese brands (Panasonic, Nichicon, Rubycon, Elna, United Chemi-Con).

[Later edit - You can use three 22uF / 63v just fine, one for the source resistor bypass, and the other two in the supply filtering. Same with the 470nF coming off the drain, you can use the same 470nF in the power filtering, instead of the two 330nF ones.]

The Wurth jumper you can replace with a piece of wire on the underside of the board, in a pinch. Unless you plan on routinely replacing and rebiasing JFETs, that is...

Mouser seem to have restocked the 1G resistors - 6709 in stock as of yet, with another 5000 expected in june.

Sometimes recently it was hard to find 1/4W resistors for some values with mouser. So just for completeness, higher watt rating is absolutely fine. Just check if the dimensions are fine with the footprints or vertical application is possible.

The values are actually those of the schematics of rev a. Sure the suggestions are fine - but i never tried to alter those (the bom is not too pricy anyways - capsule and transformer will be main points of cost).

The wurth jumpers i found very handy for troubleshooting. If it is your first build you may consider those or at least bit of longer wires so you can easily remove the pcbs in case first powering up gives you troubles. Biasing the FET is working even without opening - you have a 2.54 connector on the board which you can put eg. pins.

Awesome - i wasn‘t aware of the restock as i was busy with 500 gear. Cool, definitly will make it on the next mouser order. Thanks for the info.

Best regards, happy soldering,
Michael

 

[hteo]

@mihi_fuchs if you still have some of the PCB for this mic available, I would preferably like to purchase 2 of this PCB from you to make a pair of microphones. Thanks.