Hello,
While sitting here playing with my toys I came up with an idea to build a new toy with some of the toys I already own.....(well most)....kind of like LEGO...but with a Dremel and a hot glue gun....I already have a SP PREAMP ...that little one with the adjustable gain...It sounds nice but it only has one 1/8 input instead of two... I was interested in making a true 3 wire bat box to help with the higher spl's using some AT 853 boxes and mics I have.......I purchased a set of AT853's from a fellow forum member ( thanks again Todd) and he provided me with small custom made heatshrinked together adapter box so I could connect the 853's directly to phantom power..therefore providing their required voltage (9V I believe not 48V) and a signal path (I/O)....The guts of these boxes came out of the stock boxes that AT provides to connect their mics to 48V phantom power.The inputs are 2 1/8 mini connectors (female) and the outputs are two XLR's connectors.......Since I recently purchased another pair of AT853's from SP I obtained the Sampson phantom power adapters I thought I would convert this "box" into a 3 wire battery box for "Jedi Council business".....
My main question is how to power this thing with a 9V bat........The outputs are already laid out but I'm have some difficulty understanding how to provide power to it a get a signal out......I drew a little picture to show my delima....Any advise would be greatly appreciated....I would PM the person I bought them from but I think I already bothered him enough......
I would like to output the signal to my R-09 with hard wired 1/8 connector and provide power from a 9V battery to feed the mics.......From looking at it I believe the bare/shield is negative.....the red positive and the yellow signal...please correct me if I am wrong....I looked at the thread for the 3 wire box for the 943's and found it very helpful......I have "heard" that the circuitry in the AT boxes sounds better than a regular battery box so I thougt I would give this a try.....The original reason I took apart the heat shrink box in the first place was because of intermittent static from the right channel....I found a bit of a bad connection...so since I didn't have any large heatshrink laying around I came up with this idea.....Thanks....I took a few pic to show what I was talking about.....
One more question......how should I wire the 1/8 trs connector for the output signal....and sorry about all of the simple questions....but I just don't want to "smoke test" anything..........
Peace,
jk
Instead of using up TS space and bandwith... here is a link to my photobucket album
http://s96.photobucket.com/albums/l168/joekar/?sc=3?sc=3?sc=3?sc=3
edit:: I found the TRS wiring on Wikipedia...Sleeve ground.....Ring right and Tip left.....please correct me if I'm wrong
There are two ways to power your mics:
1. AT853x adapters. These convert phantom (48V) down to ~9V to power the mics. They also isolate and strenghten the signal, and provide a balanced output with the transformer.
2. Battery box. Supply 9V (or so) to the mics, typcially unbalanced outputs.
*do not* mix the two. There is no sensible way to power your adapter boards from 9V. They are designed to run on phantom power only. So, you can do either 1 above (build the power modues into a box and power with a phantom supply or preamp with XLR connectors), or 2 above (build a *new* batterh box.
Now, for 2 (battery box), you can build either: a) two wire (standard) type, b) three wire type, c) two wire type, with added 4.7k resistor.
The simplest is probably case (c). Connect a 4.7k resistor between yellow (audio) and shield (ground) on each mic. Then supply power from a standard 2-wire battery box on red of each mic. That's it!!!
Richard