After thinking about it some more, I still really like my Vox Pathfinder 10 as a clean amp. Probably easiest to build a selector for the dirt pedals and eq i like, most likely the easiest way to go about it. Thanks for the input though, it makes the wheels turn.

Cheers

Leftysquire

Would the attached amp be too much to handle for a guy who's done lots guitar wiring and has a fundamental understanding of electronics (1 year passed of a 2 year community college Electronics Engineering Technology course done 20 years ago) ? I'd be approaching it like building blocks, using known good blocks (like tag boards sites or pcb kits for DIY) to keep it mostly paint by numbers. Simple stomp 2PDT True Bypass switching.  I don't plan to use LEDs for status.

My biggest worries are the power supply. It's strictly for practice use.

Am I crazy?

Leftysquire

Sure.

What would be the normal expectation if I were to make the cab Closed back vs the current open back? How would the frequency response typically shift, generally speaking?

Thanks for the info Roly.

I'll test it out with my Pro JR cab to see how the low end changes.

As for the pedals, thanks for the heads up. I figure to use the Axis fuzz straight into a low gain OD, housed in the same box. The fuzz faces and derivatives seems to work better with slightly distorted amps.

What would you recommend as a DIY pedal for some 80's style dirt (old maiden, Rhoads era Ozzy, etc...)?

Again, thanks for the info Roly.

I think I will end up using the Clean/OD switch to parallel a 100nF cap to the mid cap. I'll try the lower freq for the mid dip, hopefully it'll solve my problem.

Great explanation of the op amp circuit, I'll keep it my back pocket if I do decide to go with LM833's, should the noise start bothering me.

I'll try the string trick, but my assumption is that with this small a cabinet the the amount of bass I ultimately may gain will be negligible. The point of diminishing returns is probably not far from where the amp is now.

The next step will be building my pedal setup, that should be interesting to say the least... I'm thinking an Axis Fuzz http://shop.pedalparts.co.uk/Axis_Fuzz_clone/p847124_6532845.aspx fed into a Peppermill http://www.runoffgroove.com/peppermill.htmlfor my fuzz sound, some sort of 80's metal tone (maybe http://www.runoffgroove.com/grace.html with a tone control) and a slap delay to thicken up my sound. I'll probably buy the delay as they seem to be expensive to build correctly. Trying to build a small, but good sounding setup for quiet home use.

I've now loaded the tone stack in TSC, and it's all starting to make sense. C1 shapes the mid response. Doubling it's values would seemingly shift the mid dip into Fender range, while keeping the rest intact.

I'm tempted to put sockets in for the tonestack caps and resistors to play with it. Or hijack the Clean/OD switch to parallel a 100nF cap with C1. The sound is a bit muddy, probably a combination of my pickup and cabinet design. I use the amp as my clean basic sound as I'm not fond of the OD on the amp. The cleans on the amp are really good for low volume playing (I keep below 5 on the master).

I may just socket the IC's and play with them, just to see. But I have no issues with the noise wit this point, i"m using a Dimarzio Fast Track T in my Tele, so it's good moderate level signal going in. Which resistor is the feedback resistor, R7?

I have an extra 1 to 1.5" on the top of the speaker before I hit the chassis top, could a 8" fit in there?  Probably, right? I'll try plugging into the Pro Jr I'll be selling off to see if a speaker change would help in getting a bit more in the low end.

Thanks for all the info, I'm getting a better understanding of how this amp works. I am proceeding slowly and with caution on these mods. Lest it gets out of control...

Thanks for the info Roly.

So replacing R11 with a 1.5K pot would work then? Log or Linear, what would you recommend? I'll try that first and see if I want to shift the the frequency of the mid dip.

I have the TSC software, but I don't know the input impedance, nor the load.

Why would R12 be needed, the speaker size? I am tempted to try and squeeze and 8' speaker in there...

What would the difference be between the 4558's and the LM833's be? is it just straight swap, or do other components need to change too?

I have some electronics background, but mostly guitar wiring and 1 year college electronics technician course, 20 years ago...

Looking to install a Mid control.

Which one should i replace, and with what Value/taper: R12 or R11?

What values for caps should i put in parallel with the C9 & C11 to do a mid shift down to 400hz like Fender? I've included the tonemender schem to give the idea for the mid shift I want to implement.

Thanks

Leftysquire