[Harp-L] Delay pedal and changes in tone

[Jon Vaughan <jon.vaughan@xxxxxxxxx>]

Hi.

I have a Maxon AD-80 analog delay pedal, which I use either with a
shure 545(Hi-Z) or Blues Blaster and Laney LC15 or Gibson Skylark amp.

The tone is quite noticeably different - even with the pedal disabled.
It's a bit louder, and harsher.

Is this an something like an impedance mismatch?  Would the problem
still occur in an effects loop (neither amp has one), and is there any
way around it without an effects loop?

Thanks in advance