Another noob graciously asks for Royer/BigUgly help.

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Will F

Member
Joined
Oct 23, 2015
Messages
8
Hi everyone,

I've been enjoying reading this forum for the past few months. Let me give an initial thanks to everyone here who makes this place such a great community to learn from and be around. I'm excited to hopefully become part of it.

I've built a few things from kits, but I'm looking to do point-to-point project. I'm planning on a Royer mod mic with a dual diaphragm capsule, so I'd like to make it multipattern.  I've searched and reviewed the Royer MXL tube mic mod Meta on this topic. It looks like I can fairly simply use the G7 PSU with the Royer headamp to make it multipattern.

I've read and re-read these threads:
http://groupdiy.com/index.php?topic=103
http://groupdiy.com/index.php?topic=26249.0

I've also read up on power supplies here:
http://electronicsclub.info/powersupplies.htm

Ok. What I'm wondering if anyone has the BigUgly schematic they'd be willing to send me. It doesn't seem to be hosted anymore.

If not, my question is this: is it as simple has adjusting power supply resisters to bring the 160V down to 105V to make this work properly?

Thanks in advance, and my apologies if I missed this somewhere in my searching. This is just very new territory for me. 
 

dmp

Well-known member
Joined
Oct 28, 2009
Messages
3,043
Location
Madison, WI
I built some but I can't find the schematic you're asking for - I lost a bunch of files this past year.

If not, my question is this: is it as simple has adjusting power supply resisters to bring the 160V down to 105V to make this work properly?

I have built a few of these so I think I can offer some advice on the best way forward.
You don't need to drop all the way to 105v - that is just the voltage a  U47  used. 
Having a B+ of 120v works very well for most capsules (and this is the voltage used in other mics, like C12)
With 120v B+, the patterns can be accomplished by switching from 0v to 60v to 120v, for the backplane to get the three primary patterns.
Starting with the G7 PSU, and dropping all the way to 120v may require dissipating a lot of heat (ohm's law and Power=VI & you can calculate it). But you can always start with a lower transformer voltage if you don't need to drop as far. The G7 and many other tube mic PSUs create a unregulated B+, which means the B+ voltage is based on the supplied AC voltage, the amount of resistance, and the current draw of the mic. 


 

Will F

Member
Joined
Oct 23, 2015
Messages
8
Wow. Thank you, dmp. That's exactly the kind of thing I was hoping to learn about this topic. I'm still wrapping my head around all of this, but it keeps making more sense.

 
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