VOX Pathfinder FX Loop building

[Snyder80]

Well hi there folks!
Ive been through all the pages in the web and have found nothing that fits my question!
First of all, is there someone who has a schematic for that pathfinder? and second one, i want to add a serial fx loop (cause it would be the easiest, right). I feel the need of getting some crunchy reverb sounds out of it and reverb to the input in OD channel sucks. This is how it all started:

After playing around with the idea of diy´in a spring reverb ( yes it works: old G-String twisted round an aluminum coat-hanger and u get the spring. Then u need an walkman phones and glue the "spring" to the cones of the phones. Some plug adapter and there u go!) i needed an amplifier for my reverb input, cause its too silent in the guitar jack input. My conclusion was: I need an stereo jack as a combined send-return plug in my tiny Vox amp similar to the one in my Crate GX65 right between the preamp and poweramp... So i need infos on where i have to solder the stuff !?!
I cant imagine that its just like daisychaining a two cables between the preamp signal out and the poweramp in? I saw some specs for adding a tube driven fxloop, but i realy want just a simple as possible SOLIDSTATE fxloop.MAYBE (if it aint that hard) in parallel with a trimpot.
So any help out there?
Greets,
Snyder80

PS: are there some known mods (speaker change doesnt count ) for the OD channel to get it more Matchless DC30 or VOX AC30 britpop like??

[teemuk]

The arrangement of combining send and return into same jack is known as "insert". I din't quite figure out what you are trying to do; make an FX loop (in "insert" configuration) or an reverb send/recovery stage. They are two completely different circuits and work differently. The other one (usually) breaks the signal path, the other one is in parallel with it.

I assume you'r reverb circuit is just a spring glued between right and left earpieces. Since it's based on dynamic earphones you need more than just a gain stage: You need a semi power amplifier stage that can push enough current to the moderately low impedance of the headphones. What is their impedance and can they be driven for example with an ordinary opamp? A dynamic speaker has a very poor efficiency when it works as a microphone so you need a recovery stage that amplifies the output from the mic to a suitable level.

Now, if you connect this circuit in conventional FX loop configuration the outcome will be horrible since the output is basically just the reverberated signal. You need to mix the wet (reverberated) signal together with the dry signal (no reverb) somewhere in the circuit so practically this is means the reverb circuit is in parallel with the signal path, not in series. If the reverb circuit already does all this then you can place it in a conventional FX loop.

[Snyder80]

Well, well i must say you were right,teemuk!

So what i want is one Send and one Return jack for Reverbunits, delays and such Post FX.
And right after my post i found a site, which tell me how to do exactly this in a VOX AD30VT.
(http://valvetronix.net/forum/tweaks-for-the-ad15-30vt-vt785.html
and the instruction on
http://briefcase.yahoo.com/tdunn014@sbcglobal.net)

BUT thats a different amp compared to my ss pathfinder 10 cause it has a valvetronic thing (but still has a ss-preamp). But from what you wrote it seems to be a serial Loop in the .pdf, and so i just can break/split up the signal paths. That means i have to break the circuit at the Lineout path (worked) and now im stuck in getting the return "spot" for my amp since i dont have a Valvereactor (caled VR in the .pdf). Should i easily connect it between my op-amp (its a TDA2030A (CZODE VW / 4H )) and the Volume pot output (it goes directly to the op-amp) with another mono jack (including the switch function to bypass the jackinput if nothing is plugged in)?
But if i would do so, wouldnt the SEND be AFTER my RETURN, so it would end in a feedback loop right?

So right know i feel lost in electronics...

PS: I did some more research and edited my "weird" and nooby post