This is evident from the amp going to OMG LOUD very fast. This means that the amp has too much gain since the two front stages are more than capable of this. The power stage is a TDA2030a running at +-20V which gives 18W power and 12V peak to peak output on an 8ohm speaker and an input sensitiviy of 900mV (which amounts to ~2.5V needed if you count the attenuation from the tone stack). Changed the last opamp stage into a buffer. R11 - Removed and added a wire from its C11 pad, towards the junction between R12 and P3-pin3 The pots do not track the same, but it's close enough. So here are my changes, using values of parts that I had. I have checked the curves of the classic Vox tone stack using the Tone Stack Calculator application. Changed the tonestack to match the voicing of classic VOX circuits.
#Vox pathfinder mods mods#
Mods that require some more effort with soldering tools This way you can use any cab with the amp, but you can still plug in its own speaker when you need to. And repurposed the old hole to hold the 1/4 socket, which is soldered to the old wire. I have soldered a cable directly to the speaker. This is super easy and very straightforward. Add a 1/4 jack to allow connection to a cab. Perhaps it makes sense to experiment with different values if you have kept the final gain stage (read below), but without it, you get a nice percussive and super-rich sound that is almost JazzChorus-like. Something especially evident in harmonics and pick attack. Without it, when the boost is on, the sound gets a bit harsh. It rounds the sound a lot, and it kills lots of clarity.
This cap acts as a low-pass filter on the final stage. The only issue with it, is that when the boost is on and the gain is set high, the amp is VERY loud. Just snip the LEDs and you immediately get rid of that "bees in a can" sound when the boost is on. This is very common mod, and the first one that anyone should do.
#Vox pathfinder mods plus#
So here is the list of my mods, gathering info from around the internet, plus results so far. My goal is to have a nice platform to use with my pedals, but mostly diy itself since I have other amps. The schematic has been around for almost a decade, but there still might be things that need to be fixed. It's easy to lift pads if you are not careful. Keep in mind that the pcb is crappy though.
#Vox pathfinder mods full#
Plus it's a DIYer's dream, being a full old-school circuit with a transformer PSU and all through-hole parts. With a "few" mods and a cab it sounds great. That's my second ongoing small guitar amp project after the Fender Champion 40.
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