Scott Dorsey's diy direct box

[Seymour]

I put one of these together today according to the March 1998 article
in Recording Magazine.
It is working without phantom power, which doesn't seem right to me.
When I turn the phantom power on, the signal gets hotter, but only a
couple of db. Is it supposed to work this way, and if not, any ideas
what I messed up?

[Scott Dorsey]

Seymour > wrote:
>I put one of these together today according to the March 1998 article
>in Recording Magazine.
>It is working without phantom power, which doesn't seem right to me.
>When I turn the phantom power on, the signal gets hotter, but only a
>couple of db. Is it supposed to work this way, and if not, any ideas
>what I messed up?

My guess is that you have the leads reversed on the lefthand FET and
maybe on both FETs. The gate of the fet basically has no connection at
all to the other pins at any time (which is why the input is so high-Z...
there is effectively no internal leakage) so there should be nothing
passing through it when it's cold. So my guess is the input is not
being applied to the gate but to some other pin.

Look at the schematic and make sure the voltages match... as I recall,
there should be about 35V on the input, and 0.6V on the source of the FET.
Those voltages are listed there to help you find problems.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."