Maliq

Re: "U67"-ish microphone
« Reply #40 on: August 09, 2020, 09:24:48 AM »
Wow great thanks for your answer. I still got 2 of those psu's laying around.

Changed the 72V Zener to 62V zeners.

A chance to get the pcb's allready? if you could put up a BOM that would also be nice. Maybe a few more pictures from the mic, if possible. Would love to build one since i'm in need for a different descent tube mic, i'm over here in germany, been to the netherlands pretty often.

Regards


RuudNL

Re: "U67"-ish microphone
« Reply #41 on: August 09, 2020, 11:33:43 AM »
I had a few PCBs made, but they have all been sold now.
And about the bill of materials: there isn't much in the circuit, so the fastest route is to write down the needed components yourself.
The only 'difficult' parts are the high-value (G.ohm) resistors. (Not every electronics store has them.)
There is a solution for every problem!

http://www.vansteenisaudio.nl

abbey road d enfer

Re: "U67"-ish microphone
« Reply #42 on: August 09, 2020, 12:09:42 PM »
The only 'difficult' parts are the high-value (G.ohm) resistors. (Not every electronics store has them.)
Fanell have them at a reasonable price:
https://fr.farnell.com/te-connectivity/rgp0207chk1g0/resistance-couche-epaisse-1g-10/dp/2805261
They also have 10, 100, 1 000 and 10 000 Gohm at unrealistic prices!
https://fr.farnell.com/ohmite/um050e100bke/res-10000g-3w-radial-thick-film/dp/2944974
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

RuudNL

Re: "U67"-ish microphone
« Reply #43 on: August 09, 2020, 02:35:38 PM »
There is a solution for every problem!

http://www.vansteenisaudio.nl

Strick9

Re: "U67"-ish microphone
« Reply #44 on: August 13, 2020, 01:43:55 PM »
This Cascade Elroy power supply I bought for cheap will work, right? I’m pretty sure it’s 120v B+ and 6.3v for the heater. 

RuudNL

Re: "U67"-ish microphone
« Reply #45 on: August 13, 2020, 03:45:09 PM »
I would measure the +HT output, just to be sure.
The polarisation voltage on the capsule is ~½ of the +HT voltage.
More than 60 volts on the capsule is probably a bad idea...
(If the voltage is more than 120 Volts, you can always change the zener diodes in the power supply.)
There is a solution for every problem!

http://www.vansteenisaudio.nl

ubxf

Re: "U67"-ish microphone
« Reply #46 on: December 12, 2020, 08:33:49 AM »
Big Thanks to Ruud for this awesome project. It sounds great. Ruud you are a prince.
Here is a picture before wrapping it up

RuudNL

Re: "U67"-ish microphone
« Reply #47 on: December 12, 2020, 08:51:13 AM »
Good to read that the microphone works (and sounds!) as expected!
Nice capsule by the way!
There is a solution for every problem!

http://www.vansteenisaudio.nl

ubxf

Re: "U67"-ish microphone
« Reply #48 on: December 12, 2020, 05:22:18 PM »
Thank you, that capsule waited 17 years in my mic locker for your project to come along.
Well worth the wait.

Re: "U67"-ish microphone
« Reply #49 on: December 12, 2020, 11:12:25 PM »
What does the plate voltage A run at?  I think it was about 75v for U67.


RuudNL

Re: "U67"-ish microphone
« Reply #50 on: December 13, 2020, 04:46:24 AM »
It depends a bit upon the tube.
HT from the power supply is +120 Volts.
This voltage was chosen so that you can use a standard commercially available power supply.
Plate voltage is usually in the order of 55-60 Volts.
Plenty of headroom anyway!
There is a solution for every problem!

http://www.vansteenisaudio.nl

Re: "U67"-ish microphone
« Reply #51 on: December 13, 2020, 10:43:25 AM »
I want to try one of these as soon as I can free up a suitable donor body.  With the smaller transformer, this should fit into something like an MXL 2010.  The larger SYT-5 bodies have been out of stock for so long (even the budget YT5 now) that an alternative design like this one is a great option to have.


 

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