Convert line level circuit to high impedance

[armdnrdy]

I worked out a project for a Sonic Maximizer that is designed to work with -10dBu line level.

The input impedance of the stock circuit is 47K....not good for guitar.

The original circuit is built around a proprietary IC (NJM2153) which includes the input buffer and the resistor that sets the input impedance. This configuration can't be changed.

I was wondering if including a JFET buffer in front of the existing circuit will solve the impedance problem.

Here is the input of the existing circuit. The components in the yellow box are included within the IC.

[ashcat_lt]

I was wondering if including a JFET buffer in front of the existing circuit will solve the impedance problem.

Yep!

I personally would use an opamp, but either will work.  You might want to give it a little bit of variable gain.  Guitars range in output levels from a pretty low to maybe a bit high compared to -10dbu.

[armdnrdy]

Thanks Ash,

I would have rather used an op amp but...I am limited on board space. This was sort of an afterthought.