Hi (again) Erik- Googled the 6505 specs. U have either 120w head or 60w combo- either way you have an amp that is designed to push some pretty serious air (ie "stage" volumes). If ur playing at "bedroom" practice volume it's like driving a Maserati thru a crowded parking lot ... the Maserati is happy on the Autobahn - the big wattage tube amp is happy at stage volumes.
If that is the case - consider a "attenuator" (or also called "power brake")... this will make ur amp think it is "on the Autobahn" :) ... ( u may have wattage control on ur amp? I didn't notice). W/proper wattage control u may not even want/need a distortion pedal - natural tube amp breakup is better (IMHO) than most pedals.
Ur Peavey DOES have an "effects loop" (send/return on the rear panel). Run all ur "time" based effects thru the loop (phasers / reverbs / flangers/ delays etc.) but DON'T run ur DS-1 thru it. Plug guitar into tuner ... then to DS-1... straight to amp input. CLEAN channel. ( if u have a compressor put it between the tuner/DS-1)
With amp eq's at 10-12:00 and pedal(s) off ... set amp to desired volume. Engage pedal and use LEVEL control to match volume to clean volume ( no vol diff when pedal switched on/off). Guitar: Bridge pickup. Volume "10". Tone "10"
Now (finally) ur ready to do some "sound sculpting". (you have good gear - this is completely do-able :) ...) Tune ur A string up to B so you have a nice thick power E going without having to put ur left hand on the neck. Chug away at this E while making adjustments to: DS-1 "tone" and "dist" ....AMP: "mids" and "treble" ... just those 4 knobs.
Pay close attention to what each knob does to the "sound" .... and how the 4 knobs interact. This isn't a 2-3 minute drill. Devote the time to get really familiar with this 4-knob family. With due diligence you'll develop a "recipe" to get practically any (distortion) sound you want. Naturally things get a little hairy when the sound u want requires other effects ( delay, etc) but having a grip on the fundamental "sound" is still the starting point to achieving those sounds also.
Again, I'm no "pro" ... if someone suggests a different approach , by-all-means try it ! This is what works for me and I'm hoping it helps you, even if just a little. Take Care