Members walrus1 Posted October 3, 2010 Members Share Posted October 3, 2010 It's one of those YMMV things. For me I welcomed the increase in output volume and headroom (boost engaged), and the distortion is less fizzy and "metal" sounding, smoother and more raw like a good tube amp? A toggle would be the ultimate. Then you could switch back and forth as desired. I'm going to try mine with a fuzz and see if that dirties it up more again. I don't think it's "tubey" as opposed to "non-tubey" - the 15R is pretty tubey sounding for a cheap SS amp as it is - but more of a fuzz/ non-fuzz thing, even if the fuzz was kind of "fizzy" when there was too much. Link to comment Share on other sites More sharing options...
Members wanderoo222 Posted October 3, 2010 Members Share Posted October 3, 2010 It's what I'm thinkin'.. Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted October 3, 2010 Author Members Share Posted October 3, 2010 Your right the LEDs make it sound more of a fuzz effect than tube distortion. I've compared it without them up against some small tube combos and I think it's pretty tube like without them. The breakup was very similar IMO. I would bet that if I made a recording with it up against some other combos a lot of people would have a hard time picking out which one is the SS amp. But again it's subjective. Link to comment Share on other sites More sharing options...
Members walrus1 Posted October 3, 2010 Members Share Posted October 3, 2010 Your right the LEDs make it sound more of a fuzz effect than tube distortion. I've compared it without them up against some small tube combos and I think it's pretty tube like without them. The breakup was very similar IMO. I would bet that if I made a recording with it up against some other combos a lot of people would have a hard time picking out which one is the SS amp. But again it's subjective. There's something different about the highs, too. I used to run treble about 11 o'clock, now I have to turn it down to 9 o'clock at the most. It's almost more ice picky, the diodes must have bled off a little of that or covered it up somehow, maybe because it was fizzier. Link to comment Share on other sites More sharing options...
Members companyman Posted October 3, 2010 Members Share Posted October 3, 2010 There's something different about the highs, too. I used to run treble about 11 o'clock, now I have to turn it down to 9 o'clock at the most. It's almost more ice picky, the diodes must have bled off a little of that or covered it up somehow, maybe because it was fizzier. hmmm...I really don't want more treble content at all, there is already too much! Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted October 3, 2010 Author Members Share Posted October 3, 2010 I didn't notice any change in EQ. I used to run it with the treble at about 2 o'clock for rock stuff and at about 10 o'clock or so for jazzier stuff. I'm still using the same settings. Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted October 3, 2010 Author Members Share Posted October 3, 2010 Those diodes were definitely some kind of fuzz circuit. They call it a shunt clipper circuit. A cheap way to make a square wave out of of a sine wave aka distortion. There's been a number of fuzz's and overdrive's that have used it with good success but I've never been fond of them in MI amps. They have a high insertion loss (volume loss) and I've never really liked the distortion they produce in the context of MI amps. Link to comment Share on other sites More sharing options...
Members walrus1 Posted October 3, 2010 Members Share Posted October 3, 2010 They call it a shunt clipper circuit. A cheap way to make a square wave out of of a sine wave aka distortion. There's been a number of fuzz's and overdrive's that have used it with good success but I've never been fond of them in MI amps. They have a high insertion loss (volume loss) and I've never really liked the distortion they produce in the context of MI amps. Yeah, the amp has way more volume now after the mod. What's "MI?" Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted October 3, 2010 Author Members Share Posted October 3, 2010 Yeah, the amp has way more volume now after the mod. What's "MI?" Musical Instrument Link to comment Share on other sites More sharing options...
Members walrus1 Posted October 3, 2010 Members Share Posted October 3, 2010 Musical Instrument Link to comment Share on other sites More sharing options...
Members Reaganomics! Posted October 4, 2010 Members Share Posted October 4, 2010 Is there any way to make this mod switchable? That is , to install a switch so you could go from modded to unmodded? Get a DPDT switch, maybe from Radioshack, and wire it like this Imagine that the resistors with the purple lines coming off of the one end are your LEDs, and the ones with the orange end are plain wires. Then you can switch between LEDs and no LEDs. You could also buy two SPST switches and be able to switch one one and off at a time. If you are enterprising you could also buy a rotary switch and switch in different diodes - germanium, silicon, LED's, Mosfet transistors, etc... either in pairs or in any combination of each other either symmetrically or asymmetrically (i.e. their polarity either both run in the same direction or opposite of each other.) It's not really hard, it just takes some planning. Also, anyone afraid of soldering, don't be. It's very, very, very easy. If you can hold a pencil and write your name with it, then you have more than enough skills to solder something. There's youtube tutorials on how to do it. Link to comment Share on other sites More sharing options...
Members wanderoo222 Posted October 4, 2010 Members Share Posted October 4, 2010 That's Freakin' awswome! I'll get it done this week and let you know how it goes. Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted October 4, 2010 Author Members Share Posted October 4, 2010 If you are enterprising you could also buy a rotary switch and switch in different diodes - germanium, silicon, LED's, Mosfet transistors, etc... YMMV, but the problem you will face is due to the nature of the shunt clipper circuit what ever diodes/LEDs you use will cause an insertion (volume) loss. A decent volume drop at that because these lay directly in the signal path. There was a guy on another forum who tested a number of diodes and LEDs using a switch to a/b them in the circuit and his conclusion was it was best without them in the circuit. I pretty much figured that this would be the case myself having worked with them in amp designs in the past. In the context of this amp the distortion this type of circuit produces is not very desirable and the increase in headroom/output volume is a welcomed upgrade. Again YMMV? Link to comment Share on other sites More sharing options...
Members wanderoo222 Posted October 5, 2010 Members Share Posted October 5, 2010 SnorkelMonkey, would there be any drawbacks when adding a DPDT switch as shown in Reaganomics! post? Link to comment Share on other sites More sharing options...
Members gorebuc Posted October 5, 2010 Members Share Posted October 5, 2010 I did the mod on my Pathfinder. Sounds great. I can put the gain knob above 12 (3 is a good spot) and get some very usable sounds. With my '69 Thinline, its a nice, barely broken-up, very Voxy tone. With my Squier Tele Custom II, I get a more aggressive, but more natural than before, fuzzy grind. Adding my RAT with low-gain on top yields a very nice tone with both guitars. It really serves its purpose of being my mini Ac15 now. Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted October 5, 2010 Author Members Share Posted October 5, 2010 SnorkelMonkey, would there be any drawbacks when adding a DPDT switch You might find that you'll leave the LED/Diodes out of the circuit 99% of the time because of the volume drop with them in. So the only drawback I could see is the purchase of a switch that's never used and having drilled a hole for it? Also you only need a SPST switch as they are both tied to the signal buss at the same point and then to ground. Off would just lift them from ground. Link to comment Share on other sites More sharing options...
Members wanderoo222 Posted October 5, 2010 Members Share Posted October 5, 2010 Thanks, I'll leave the switch out. You've been very helpful. Link to comment Share on other sites More sharing options...
Members juri Posted October 5, 2010 Members Share Posted October 5, 2010 Does anyone know anything about the Vox Cambridge 15 there's on on our local craigslist for $85... http://www.voxshowroom.com/korean/amp/nu_cambridge_15.html Link to comment Share on other sites More sharing options...
Members walrus1 Posted October 6, 2010 Members Share Posted October 6, 2010 After a few more days, I can say this mod definitely ruined the character of the amp for me. It's more generic and lifeless now, and doesn't have that cool, lo-fi indie kind of grind it had before. Other people notice, too. I used to get comments on the sound all the time, now it's just kind of like "meh," sounds bland. Like someone said, YMMV, but if you *like* the way the amp sounds stock, I would think twice before messing with it. Sometimes the best mod is just to change your head. Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted October 6, 2010 Author Members Share Posted October 6, 2010 After a few more days, I can say this mod definitely ruined the character of the amp for me. Sorry to hear that. You are the first in about 20 or so that have reported back to say anything to that effect. But it's all subjective, everyone has their own taste in tone. In the posts that you deleted you stated that you liked the stock gain distortion a lot. Many don't like it at all and find the boost useless. This mod makes the amp more usable for them, and provides more output volume. YMMV Link to comment Share on other sites More sharing options...
Members walrus1 Posted October 6, 2010 Members Share Posted October 6, 2010 Sorry to hear that. You are the first in about 20 or so that have reported back to say anything to that effect. But it's all subjective, everyone has their own taste in tone. In the posts that you deleted you stated that you liked the stock gain distortion a lot. Many don't like it at all and find the boost useless. This mod makes the amp more usable for them, and provides more output volume. YMMV Actually I didn't really like the stock gain above a certain point, I always used pedals for gain, and I never used the boost function. I set the amp to the edge of breakup, gain at about 10-12o'clock max (definitely never above 12) and then just kicked on some OD. Gave a nice crunch. With the mod, I have to set the gain way higher to even get to that pre-breakup point, and then kicking on the OD doesn't seem to give it the same character. I can see how it might be better if you wanted a louder amp for live use, but the increase in headroom didn't necessarily equate to an increase in tone, in my own test, at least. Like I said, it seems more generic, and I liked that lo-fi sound. If I wanted more volume live, I'd probably just get a second pathfinder and run them in stereo, or use a different amp entirely. YMMV! Link to comment Share on other sites More sharing options...
Members IamBurnout Posted October 6, 2010 Members Share Posted October 6, 2010 The diodes should be bleeding some treble to ground as well as clipping the signal. By installing sockets, more options are easily available (be aware of forward voltage and how it may effect volume). Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted October 6, 2010 Author Members Share Posted October 6, 2010 it seems more generic, and I liked that lo-fi sound. See there you go, it's all subjective. I found that it was the opposite for me. The gain control distortion sounded IMO like some sort of 80's hair metal/prog metal, very plastic and un-lively, processed and like you said generic. For me removing the LEDs made the amp more responsive and lively, improving the distortion with the added bonus of increasing the output volume quite a bit. What's great? Like in your case if you find out you don't like the amp with the LEDs removed you can very easily solder them back in minutes and have your old amp back. Link to comment Share on other sites More sharing options...
Members walrus1 Posted October 6, 2010 Members Share Posted October 6, 2010 See there you go, it's all subjective. I found that it was the opposite for me. The gain control distortion sounded IMO like some sort of 80's hair metal/prog metal, very plastic and un-lively, processed and like you said generic. For me removing the LEDs made the amp more responsive and lively, improving the distortion with the added bonus of increasing the output volume quite a bit. What's great? Like in your case if you find out you don't like the amp with the LEDs removed you can very easily solder them back in minutes and have your old amp back. I can't, because one broke. Plus I don't really know how to solder. I think you also said something about the polarity of the LEDs, but I don't know how the other one goes anyway. Both sides look the same to me. So I might just have to sell it at a loss and get a new one. Link to comment Share on other sites More sharing options...
Members SnorkelMonkey Posted October 6, 2010 Author Members Share Posted October 6, 2010 I can't, because one broke. Plus I don't really know how to solder. I think you also said something about the polarity of the LEDs, but I don't know how the other one goes anyway. So I might just have to sell it and get a new one. Sorry to hear that. I understand the situation now. You could send it to me and I could solder a set in for you free if you would like? Link to comment Share on other sites More sharing options...
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