Acoustic preamp no output except with headphone amp

[Sunnydayrider]

Hello I've already spent many hours on forums looking for solutions with no luck. I have an Ibanez sst preamp. The tuner works fine but no output. I have tried multiple amps and cables. The weird thing is... With my little Vox headphone Amp it works. I get sound output. I have also tried another battery operated Amp and that did not work again. Also tried phase shift button but no difference and tried stereo and mono cables. Any ideas what the problem could be and why it still works with my headphone Amp? Any help would be hugely appreciated as a replacement is expensive and hard to find.

[TomCarlos]

For reference and a hand drawn schematic, visit thread 36972 and 846078.

Just curious.... if you were to use the XLR output and go into a mixer, do you have signal there?

[Sunnydayrider]

Hey thanks for the reply. I did look through those posts previously and tried some of the solutions. My electronics knowledge is a bit lacking but I tried what I could. I don't have a mixer but I did try the XLR and 1/4" into an audio interface with no luck. I basically gave up on fixing this but when I saw that the headphone amp works I revived my quest. Not sure what would be different about the headphone amp...

[Sunnydayrider]

I did just notice when it works with the headphone amp the volume knob does nothing. Same volume at all positions. Looking at the schematic maybe the phase reverse button is bypassing volume when it works....? Also the volume output of the headphones when they work is low.