pre amp out, power amp in -vs- fx loop

[videocat23]

I have an Acoustic g60t. It has a pre-amp output and a power amp input. If I put a cheap fish-n-chips eq pedal in between the preamp out and pwramp in, it works okay. When I use my TC Electronics G major, the volume drops out.

Any ideas why the g major wouldnt' work?

[soundguruman]

The output of one effects unit does not match the impedance of the power amp input, however it might be modified to match.

[joey]

I have an Acoustic g60t. It has a pre-amp output and a power amp input. If I put a cheap fish-n-chips eq pedal in between the preamp out and pwramp in, it works okay. When I use my TC Electronics G major, the volume drops out.

Any ideas why the g major wouldnt' work?

The problem is in that particular amp the preamp out output impedance is about 71K, actually even higher since it is plate driven, and the input impedance of the TC unit is around 20K or so. Right there you cannot properly drive the TC unit because the preamp out impedance will cause too much signal attenuation. you would need to lower output impedance of the pre out, but it will get tricky without buffering it.

It isn't a problem with the stompbex because they generally have higher input impedances - typically between 500K - 1M