Noisy G7.

I've patrolled the forums for a long time, but this is my fist post. I searched the META and pretty much every post with "G7" in the title and can't seem to find any posts with my particular problem. I just finished my G7 and am getting no signal at all from the output XLR. I've tested my pre with other mics and it's fine. I was originally getting a whole lot of buzzing until I jumpered the heater to ground in the mic. Now things are very quiet except at very high gain, but I hear nothing from the capsule. Here's the curious thing. Without the mic plugged into the power supply, I get 150+V at Pin 2, 0-76-150V at pin 5. With the mic connected, these values get cut in half. 76V at pin 2, 0-35-76V at pin 5. The heater voltage is calibrated to 6.3V exactly with the mic plugged in, and the tube seems to be fine (glowing and the like). I'm just about out of ideas.

A million thank yous in advance.

More info:

I get no AC or DC voltage across pins 2 and 3 of the output XLR with or without the mic attached. I get a contiguous ground between the mic body, the heater OV, the IEC ground, the PSU chassis, and the boards.

Check your connections and solder joints first, check and make sure all the values are correct and in the right spots.  is the transformer wired in correctly I.e. pri and secondary leads in the right spots. then check your PSU... oh hell just double and triple check everything and make sure you have a good tube.

Isn't the unloaded voltage way too low?

What transformer do you use for the HT, 15v:220v or 12v:220v?

(You should get some signal through also with HT=75V)

Found it. The audio outs are shorted somewhere in the mic. I'm going to desolder the 7 pin XLR, and see if the transformers ok, then resolder and test as I go. I'll see what that does to my loaded values and report back.

I'm using a 15:220 transformer.

Well I feel foolish. Of course I'm going to have continuity on the pins of the xlr, they're on either side of the transformer secondary winding. My voltages are a little low because my wall power only reads 108 or so on a good day. The tube definitely glows when powered and shows no visible signs of failure, is there a test I do do with my multimeter to check it? Is there a particular short I should look for given my symptoms?

Just to be shure:

How did you wire the power transformers?

The primary of the 115v:9v must be in parallell, the secondary of the 15v:220v in series.
(If they have two windings of course)

If you have 6.3 volt for the heater, the first transformer seems to be ok, check the 15:220.

You can also try a 12v:220v to get the voltage up a bit.

As pucho said: check everything, solder joints, solder bridges, resistor values...

I'm at my shop now (with proper power), and without the mic plugged in I'm getting 10v off the 115:9 transformer and 140v off the 15:230. Under load I'm getting 137v out the 15:230v transformer, 170v across the first cap, but only 87v across the second cap and out of the supply PCB (pins 1 and 2). Unloaded, I'm getting 170v out of pins 1&2 of the PCB. So what I've gathered from this is that my transformers are fine. I've poured over the boards and even retouched any joint that looked remotely weaker than the others. I've double checked my jacks and retested my cable. I'm going to resolder all the jumpers going to the jack on the mic because the jackets are weak, but I've tested it and am sure it's not the problem. Fresh out of ideas...

What voltages do you get around the microphone? Some measured voltages are here...
http://www.xaudia.com/xaudia/Documents/Entries/2008/3/5_G7_observations.html
Check yours and post them up.

You have a 10K resistor between caps 1 and 2, which is dropping about half your B+ voltage (170-87)V = 83V. That resistor must be getting hot!

Check component values, particularly the resistors around the pattern switch.  Or look for a short after the 10K resistor in the microphone.

Thanks for the response, and sorry it took me so long to reply. While writing the post to tell you what my voltages are, I discovered that I had not headed the pivotal "k" part of the 470K resistors. My voltages unsurprisingly appear normal now. Going to get myself to a pre to try this sucker out. 

That did it. I can hear audio now. Now I have a whole new plethora of problems:

1. Weak signal.
2. On par with the signal level, I'm getting what sounds like pink noise. No buzzing or humming that I can tell, but a rushing water sort of a thing.
3. My polar pattern switch works, and by works I mean assaults my ears every time I switch it. I've read the posts on that, I'm not sweating it for now. However I'm not getting a meaningful response from the reverse side of the capsule regardless of the position, but there's a nic in the jacket of the lead that probably is to blame. It passed a continuity check, so I wasn't worried about it until now. Every ohm counts up at the capsule from what I'm told.
4. From what I can hear of the signal, it sounds out of phase. I'll have to double check my polarity on that.
5. I can't figure out how to change the title of this thread.

Thanks a bunch to everyone that's replied so far. Even hearing the obvious "double-check everything" mantra is surprisingly helpful. You guys are great!

> 5. I can't figure out how to change the title of this thread.

You must "own" the first message of the thread (or have a Moderator's mop).

You do own the first message. Go to that top-of-thread message, hit the " Modify" button, you can edit the thread Subject there.

That's better, thanks for that PRR. A little info to add:

1. Grounding is as follows: heater, mic chassis, and ground are all connected at the mics 7pin xlr lug. I've done a continuity check between the three elements. The IEC ground, pin 1 of the 7 pin XLR, and pin 1 of the 3 pin xlr are all connected at the 3 pin xlr lug in the PSU.

2. I have two layers of brass mesh for the mic grill and I'm sure I have continuity between it and any other place connected to ground.

3. I'm using toroidal transformers in the psu. They aren't very far from the PCB...

4. I've kept the mic powered for about an hour to let the tube break in.