prophei

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #340 on: February 10, 2019, 10:13:31 PM »
Hi All,

Thanks in advance for any help you give me, as I am just about to start my first build.

Some background... I bought the current kit D47 body kit from Danny, and got the power supply housing/pcb. As there are not instructions for the power supply, just a schematic, this is the part I am the most concerned with. I have done a lot of DIY, but not at such high voltages (I usually build stuff thats 9v to 15v).

The pcb board for the power supply is the D-EF47.
Transformer is the BV8 Classic
Capsule is the K7 (beez)
Tube is the Tele EF800

With his current body kit, there is an included polarity switch on the mic, and I am not sure how that does or does not relate to the power supply discussed in this thread, which seems to be based on the older mic pcb design. Am I in the right place, or is there a thread specific to this power supply that might be a better starting point for me given the above?


TillM

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #341 on: February 11, 2019, 03:43:19 AM »
Look at the psu schematic.
I think you must omit R5 and R9 and of course don’t connect OM/CRD/COM.

prophei

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #342 on: February 11, 2019, 10:14:18 PM »
Look at the psu schematic.
I think you must omit R5 and R9 and of course don’t connect OM/CRD/COM.

Good call out, that removes the pattern switching circuitry?

rockinrob86

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #343 on: February 21, 2019, 12:43:46 PM »
My mic has started having an intermittent issue.

It will work great and sound normal as it has since I built it, and then make a tube noise/scratching sound like a bad pot or something and lose about 15db.  I've tried a different XLR to my preamp with no change and manipulating the mic cable with no change.  After a bit, it came back to normal volume, but eventually faded again.

One thing I can think of is a couple weeks back, I was using the mic with a friend and had terrible distorted sounds in my DAW, so I jumped up, opened the mic and switched the tube out.  Only to realize that my interface had just gotten "off" and I needed to shutdown and restart.  The mic worked perfectly before this and afterwards for a while, but when I first heard this problem I switched back to the original tube and reconfirmed the voltage going to the amp.  Everything was good but now I heard the mic do this last night.

The only other thing is that months ago, the back diaphragm on my capsule was punctured (long story, a mounting screw came loose and banged into it in the headbasket.  there is a visible "ding" on the back mylar of the capsule now and omni has noise.
Cardioid was unaffected, but maybe the now open back is causing an issue?

iturnknobs

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #344 on: February 21, 2019, 02:44:33 PM »
Rockinrob86-

You could firstly open the mic and disconnect the rear capsule. I would probably recalibrate the B+ voltage in that case. Secondly, if the diaphragm is shorting to the backplate, this might not "correct" the problem. I am guessing that an "open" is not your issue. Without being an electronics engineer, I would probably purchase the cheapest capsule possible that works in this circuit to begin the good old "guess and check" process, if all else fails.

rockinrob86

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #345 on: February 21, 2019, 03:05:49 PM »
yea, this is what I was thinking too.  It is going to be frustrating to track this one down I'm afraid

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #346 on: February 21, 2019, 04:33:48 PM »
Check the connection in the PSU that powers the relais that switches cardioid/omni.... had some nasty stuff happening when the mic was set to omni but the reed relais switched back to caridoid mode - including lots of distortion and a collapsed membrane because of the rising voltages caused by an off-thrown system.

rockinrob86

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #347 on: February 23, 2019, 08:59:02 PM »
It appears my issues in this mic may have been cable related.  I took a good look at the entire path from the mic to the PSU, and resoldered a few joints here and there.  There was one connection on the cable that looked dodgy, but the rest looked ok.  Finished it up and used it for a couple hours with no hiccups, so knock on wood, I think everything is back to normal!

bigbeaty

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #348 on: March 06, 2019, 03:46:43 AM »
Hi guys,
I was very excited to receive my boards from Dany yesterday, and I'm looking forward to getting going with this super project.
Quick question on the mechanical, has anyone successfully built this into a thomann sct-800? It looks like a likely donor, and there's connectors etc to cannabalize. I just fear it's a bit too narrow!
Cheers,
Rich

TillM

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #349 on: March 06, 2019, 04:25:17 AM »
No, the sct-800 body is too short for the pcb.


bigbeaty

Re: D-EF47 Tribute To Oliver Archut U47 Build Thread.
« Reply #350 on: March 06, 2019, 05:16:42 AM »
Thanks TillM, Phew.. you just saved me blowing 175 Euro  ;)

Think I'll try and get hold of an Alctron long U47.

Cheers,
Rich