Hot batteries and volume drop

[ballooneater]

Just finished building my first two pedals!

I made a Big Muff Fuzz ("Stock" version) and an Ibanez FL-301 Flanger.

Unfortunately, both these pedals have a noticeable volume drop when activated.  This makes them almost unplayable because I need to set my amp's gain to a normally deafening level in order to hear them.  Both use DPDT switches wired for true bypass.

In addition to this, the FL-301's batteries (It runs on 18V) seem to be getting very warm.

Any suggestions to fix these problems would be greatly appreciated.  I can also provide schematics if it would be helpful.

[fogwolf]

A hot battery most certainly means a short. Check for solder bridges or other places on the board that might be shorted together that shouldn't be.

[ballooneater]

After looking the circuit over and trying it again, it seems like only one of the batteries is heating up.  Is it possible that I have them connected wrong? 

The batteries are connected in series between the DC jack and the input jack.

[asfastasdark]

Check with a multimeter for continuity from the V+ of the effect to effect ground. If you get a connection, then there's your problem.

[GibsonGM]

+1, short circuit...probably one battery is fresher than the other, so gives more current and that's why it's the hot one...eventually both will get hot!

[ballooneater]

Thanks for your responses, everyone!  I'll check around the board and see what's shorted out.  Hopefully it will fix the volume drop issue as well.