Members SnorkelMonkey Posted September 27, 2010 Members Share Posted September 27, 2010 (I posted this mod a while back and recently posted some details about it. I thought it might be of some use to the forum. Sorry for the cross thread pollination but I know the forums have become more segregated in recent years). Someone was inquiring about mods for the Vox Pathfinder 15/15r amps a while back and I had a look see at what could be done to improve the amp a bit. There seems to be a consensus (myself included) that the gain control is, well pretty useless as the distortion is less than favorable a bit 80's hair/prog metal. Also the output is just there and IMO not quite up to task to bring to a gig. I looked at the early schematic that's out on the web and found they used a square wave shunt clipper in the form of two LEDs right in the main signal path. Good in some fuzz circuits, I've never really liked them in amps. They have a high insertion loss (loss in gain = output db's) and I've never liked what they yielded as far as distortion when used in amps, certain fuzzes yes. Super simple mod here. Unsolder the two red LEDs shown in the photo and remove them for a noticeable increase in gain/headroom and a better sounding breakup. I'm not saying that the distortion is going to be just like yer favorite old tube amp but I found it much more pleasing to the ear than the LED sw clipper in this amp. IMO the breakup is smoother and more raw. 60's Stones at med gain levels and Young brothers Plexi like at higher gain levels. It's easily reversible but I don't think you will. Others did not and most found the mod very useful. There was one guy that experimented with other diodes/LEDs but went back to keeping them removed from the circuit. You don't have to worry about getting shocked so long as you unplug the amp. One guy just wiggled the LEDs back and forth until they broke off. If you think you might want to put them back in just mark their polarity (orientation) to put them back in correctly. I've seen these pop up in the used market for approx $50-$60. It's a great grab and go amp for small gigs/rehearsals, home practice, late night headphones, recording. After the mod you would have to pry it from my lifeless body it's that good. Suspects in question... Remove'em Link to comment Share on other sites More sharing options...
Members Saturnine10 Posted September 27, 2010 Members Share Posted September 27, 2010 Nice Link to comment Share on other sites More sharing options...
Members hilikus8 Posted September 27, 2010 Members Share Posted September 27, 2010 unless I find a really cheap one to mod, I guess I'll have to man up and try to mod my pathfinder. Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted September 27, 2010 Author Members Share Posted September 27, 2010 unless I find a really cheap one to mod, I guess I'll have to man up and try to mod my pathfinder. Hilikus, No need to run out to purchase another. It is very easy and very easily reversible. Just quickly hit one leg of the LED with soldering iron, pull gently and then hit the other leg and pull gently. Repeat with the second LED. Out in seconds. Test out the amp. If you don't like it just reverse the procedure with a dab of solder. Link to comment Share on other sites More sharing options...
Members hilikus8 Posted September 27, 2010 Members Share Posted September 27, 2010 Hilikus, No need to run out to purchase another. It is very easy and very easily reversible. Just quickly hit one leg of the LED with soldering iron, pull gently and then hit the other leg and pull gently. Repeat with the second LED. Out in seconds. Test out the amp. If you don't like it just reverse the procedure with a dab of solder. I tend to break and mess everything up, but will definitely give this a try Link to comment Share on other sites More sharing options...
Members walrus1 Posted September 27, 2010 Members Share Posted September 27, 2010 Excellent, this sounds very doable. I don't really mind the gain up to about 12 o'clock, but after that it's a little fizzy. Does it improve the sound when engaging the "boost" switch at all? I find that basically unusable. Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted September 27, 2010 Author Members Share Posted September 27, 2010 Does it improve the sound when engaging the "boost" switch at all? I find that basically unusable. IMO yes, very much so. YMMV Link to comment Share on other sites More sharing options...
Members IamBurnout Posted September 27, 2010 Members Share Posted September 27, 2010 Yes. Solder monkey thread. Nothing else to add here, as I don't know that amp. Link to comment Share on other sites More sharing options...
Members brandass Posted September 27, 2010 Members Share Posted September 27, 2010 Looking forward to giving it a go. Love the cleans and very light hair on my 15R, but any more gain that that sux, as does the boost button. Don't want to muck up the goodness, but sounds like too simple a mod to botch it (famous last words). Total newbie to amp modding, though. Surprised you don't need to worry about maintaining the circuit after pulling out the LEDs - they don't leave behind breaks that need to be filled in (eg, with solder)? Please be kind to the newbie! Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted September 27, 2010 Author Members Share Posted September 27, 2010 Surprised you don't need to worry about maintaining the circuit after pulling out the LEDs - they don't leave behind breaks that need to be filled in (eg, with solder)? No worry, you're just lifting them out of the circuit. The signal continues happily on its merry way. One guy told me he just wiggled them back and forth till they broke out of there leaving the LED legs still soldered in place. Which will work but say you didn't like the mod would leave you with having to get the broken legs out and solder in new LEDs. At the low cost of these amps this is probably the best mod you could do to it because there's really no out of pocket expenses. Link to comment Share on other sites More sharing options...
Members walrus1 Posted September 27, 2010 Members Share Posted September 27, 2010 Looking forward to giving it a go.Love the cleans and very light hair on my 15R, but any more gain that that sux, as does the boost button.Don't want to muck up the goodness, but sounds like too simple a mod to botch it (famous last words). Total newbie to amp modding, though. Surprised you don't need to worry about maintaining the circuit after pulling out the LEDs - they don't leave behind breaks that need to be filled in (eg, with solder)?Please be kind to the newbie! Good question. I hesitate also to mess up something that already works - "if it ain't broke," etc. Although it does seem easily reversible, as long as the LEDs came out clean and weren't damaged. It would be nice to have a couple of clips of what the mod sounds like to decide. Link to comment Share on other sites More sharing options...
Members Mitchell? Posted September 27, 2010 Members Share Posted September 27, 2010 Surprised you don't need to worry about maintaining the circuit after pulling out the LEDs - they don't leave behind breaks that need to be filled in (eg, with solder)?Please be kind to the newbie! Look at the schematic, the LED's run to ground. Therefore, by removing them, you aren't 'breaking' anything. Link to comment Share on other sites More sharing options...
Members TravvyBear Posted September 27, 2010 Members Share Posted September 27, 2010 I'm really interested in the Pathfinder 15r 100 bucks new, for this? Can't really go wrong. I wish they made a 12 inch model.30Fvmsi7SA0 Link to comment Share on other sites More sharing options...
Members brandass Posted September 27, 2010 Members Share Posted September 27, 2010 I see how the LEDS link the main circuit to ground, yes. My worry is that by pulling them out they'd leave gaps at where they had intersected the main circuit. Sounds like that's not a problem at all, which is great. But for my pitiful education, can you tell me why? If the drawn circuit was interconnected wires, and you pulled out the LEDs, you'd have to tie up the wires again (or at least make sure that the other connections weren't damaged) to maintain the rest of the circuit. Apparently this is not like that at all; you pull out the LEDs and there's no question of gaps or damage, the main circuit is just fine. The LEDs must T off from an always-intact circuit; what is the nature of that circuit? Thanks! Link to comment Share on other sites More sharing options...
Members brandass Posted September 27, 2010 Members Share Posted September 27, 2010 I'm really interested in the Pathfinder 15r100 bucks new, for this? Can't really go wrong. I wish they made a 12 inch model. Even better: $50-60 used! WTF?! Not sure what exactly is under the hood (which must be apparent by now, what with my stupid-ass questions), but it's really, really sweet! Link to comment Share on other sites More sharing options...
Members renula Posted September 27, 2010 Members Share Posted September 27, 2010 wow! just what i need for lo-volume rehearsals... Link to comment Share on other sites More sharing options...
Members Mitchell? Posted September 27, 2010 Members Share Posted September 27, 2010 Because the LED are soldered to a pad on a copper trace. This means if you remove the LED, there is still a connection.. It's kind hard to explain without visuals. Link to comment Share on other sites More sharing options...
Members brandass Posted September 27, 2010 Members Share Posted September 27, 2010 Because the LED are soldered to a pad on a copper trace. This means if you remove the LED, there is still a connection.. It's kind hard to explain without visuals. No, I think I got it: the circuit is maintained because the gaps left behind are essentially holes within a pad that siphons signal from the trace but doesn't interrupt it in any way, is that right? Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted September 27, 2010 Author Members Share Posted September 27, 2010 I wish they made a 12 inch model. You might be pleasantly surprised at how loud and what range the stock speaker has in these things. I don't know who makes these 8" speakers for Korg but if I could find out I would put them in my other 8" combos. They provide a lot of bass and are really loud for their size. No 12" speaker needed. Link to comment Share on other sites More sharing options...
Members chris_d Posted September 27, 2010 Members Share Posted September 27, 2010 I am surprised that people like these amps. I really hated mine. Compared to almost any decent amp, especially one in a correctly-sized cabinet, the Pathfinder just always sounded thin and cheap to me. Also, i didn't find its clean sound particularly "Voxy", either. Also odd, i found that one of the greatest improvements to be had with the thing, was just to run the speaker out into a properly sized 1x12 with a good speaker in it. I thought the little 8" speaker was particularly oddly voiced, hollow sounding and with a strange midrange focus that was not particularly pleasant. It was reasonably loud though, i will give it that... It is just odd how different ones perceptions can be for stuff like this. Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted September 27, 2010 Author Members Share Posted September 27, 2010 It is just odd how different ones perceptions can be for stuff like this. I picked one up because a bandmate used to bring one to practice once and while when they didn't want to grab the big guns because it was so light and they could stuff it in the car and not worry about someone breaking in to steal it. I thought it was cool that it was small, light, cheap and I what they used it for worked. But personally... I was never fond of his tone from it nor did I even really like the amp myself except for cleans and practicing at home. Until I did the LED mod. I have a different perception of this amp now for sure. Link to comment Share on other sites More sharing options...
Members tlbonehead Posted September 27, 2010 Members Share Posted September 27, 2010 In addition to a combo, I have this little mini stack. Someone should buy it from me and do the mod! http://www.voxshowroom.com/uk/amp/p15smr408.html Link to comment Share on other sites More sharing options...
Members TravvyBear Posted September 27, 2010 Members Share Posted September 27, 2010 4, 8 inches? That would be bad ass. Link to comment Share on other sites More sharing options...
Members jdpkeeper Posted September 27, 2010 Members Share Posted September 27, 2010 before and after clips please! Link to comment Share on other sites More sharing options...
Members jacobhf Posted September 27, 2010 Members Share Posted September 27, 2010 In addition to a combo, I have this little mini stack. Someone should buy it from me and do the mod!http://www.voxshowroom.com/uk/amp/p15smr408.html That would be a lot of fun! Link to comment Share on other sites More sharing options...
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