Simple DI for 1272 / 1290

Hi all.

I understand that the BAE-modded 1272 modules employed a DI that basically fed the unbalanced guitar signal directly to the stepped attenuator - bypassing the input transformer.

I'd like to attempt something like this. Does anyone know how to set this up? Are there any additional passive components needed for the circuit?

Thanks!

to add some info, the secondary of the Neve input trany is wired for 4.8k ohms. But I'm not sure if this means the input to the BA283 preamp section has a similar (matching) impedance or higher (bridging) impedance.

Here's a couple pics of a BAE-modded unit I took a while ago...




It looks simple enough!

I believe the resistor mounted on the 1/4" jack is a 100K and it's a switching jack.

Anyone have a schematic on something like this?

Thanks!

the 100k res is probably connected at DI input and at the attenuator, to have an input impedance so high to be drived by a guitar, because the attenuator probably has a total resistance < 10k that it's too low for a di input.

However, I council you to put a resistor of 100k between the attenuator and the DI input, even if the BAE schematic is different with I've written here

or if you want a more complex circuit you can use a fet DI module , using a switch to select the mic or di inputs.

the 100k res is probably connected at DI input and at the attenuator, to have an input impedance so high to be drived by a guitar, because the attenuator probably has a total resistance < 10k that it's too low for a di input.

Click to expand...

I think you are right. The 100k resistor appears to be connected to the tip of the DI jack. BAE is using a Switchraft 13E jack (isolated break circuit). When the plug is inserted, the guitar signal is fed through the resistor to the input attenuator.

or if you want a more complex circuit you can use a fet DI module , using a switch to select the mic or di inputs.

Click to expand...

This is a good alternative. I found a schematic for this on an old post...
http://sethglassman.com/KennedySchemo.pdf


Thanks for your help!!!

I will send you a more simple DI schmatic for neve 1272 , PM an email address to send you the schematic, if you want.

I used the DK schem and it fit in a pretty small space. You could do it even smaller if you skip the relay switching feature I also tried to implement. This would allow you to go through the input tx, and is still dead simple.