G7 Finished - "converted" MXL 2001

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stanz

Well-known member
Joined
Dec 6, 2007
Messages
67
Location
Alameda NAS
I finished it WOO HOO :grin: :grin:

I fired it up tonight. First time up, no sound at all. Crap. OK, found the plate was getting no voltage. Bad connection. Fired it up again, all sorts of hum. Once again, bad connection where I (supposedly) joined 0V for heater and HT. Third time is the charm. Pulled out my acoustic guitar and played through the G7. Sounded very nice. I of course will have to give it a good testing now to see what it really can do. This raises a question. What sort of of SPL can this handle. Peluso CEK-12 with one layer of fairly open grill, probably around 16 x 16. For instance, electric guitar? Vocals, I am definitely putting a pop screen in front of it, at least for moisture. I usually do anyway.

A big thanks to Jakob. Now I have a G7 and a G9 that I have made myself. Very cool. :sam:

Also, thanks Gus, as I pulled a number of points from comments you have posted. Grills, styrene caps, capsule selection, acoustics inside the grill. All of that went into this build and gave me more confidence that I was going to end up with something I would really like.

Jazzy pidjay, your schematic was a big help. Very clear. Thanks. It helped a lot with the layout inside the mic. Your vertical layout is way cool.

I wasn't up for making a body so I opted for a cheap mic I could use for grill, frame, diaphragm mount, and body. Plus, I wanted a U87 shaped grill. Never thought I would hear myself say "Thank god for cheap Chinese stuff." $50 was worht the time saved. I ripped out the two inner grills to open it up. I did buy a Peluso CEK-12 and had to file the two slots on the inner disk at the bottom of the grill in order to get the capsule in as the CEK-12 is wider than the MXL's capsule. Glad it is brass.


I wanted to make it "un MXL-2001ish", so removed all the lettering and I painted the body with some gold metal paint I had left over from another project, and acrylic coated it. At first I thought it was going to look stupid, but I am really starting to like how it looks. The 7 pin xlr hanging out was an ordering mistake, but it is working fine. I am going with it in keeping with the DIY spirit. You can see the tube socket that never got used. Not enough room.

G7-MXL200101big.jpg


G7-MXL200102big.jpg






This was the fun part, figuring out how to wire it all up without any board of any sort. My key criteria was to make sure all solder joints were well insulated. I got it all to fit. I wasn't sure there for a while. I ended up using the frame as a ground buss as my biggest challenge was trying to figure out how to connect the five points around the tube that all needed to go to ground. That made it real easy. OEP transformer as I was trying to keep it a modest budget. The capsule was the one thing I was willing to spend some money on, as I figured the extra money would reap a big pay off. JJ EF806 tube.

Man, it sure looks like crap, but that is not why we use it.


G7-MXL200103big.jpg


G7-MXL200104big.jpg





Power supply. What can I say. It works. They are real important but so un-sexy. I did go with a 9 position capsule voltage selector.



G7powerSupplybig.jpg
 

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