BSAKing Posted November 25, 2008 Share Posted November 25, 2008 I am using it on some epiphone guitars just so we stay within acceptable posting limits. lol I just picked this thing up on Fleabay to play with (non-working). I have it going now, but it distorts with it hardly turned on. If I turn the pots down on the guitar, then it is not bad, but still distorts at nowhere near full volume. I swapped speakers just to check, and same thing. It is a 7-100 model. Anyone have one? I was just wondering if this is normal on these things. If it is normal - fine, if not I have no problem tearing it apart and re-engineeering the amp in this thing so it works better. I found schematics on the web and it looks pretty straightforward to troubleshoot I guess. Was just wondering. I have all sorts of amps, big and small, but nothing battery powered so wanted this for a lark. It sorta looks cool too. lol.:D/ Link to comment Share on other sites More sharing options...
tulsaslim Posted November 25, 2008 Share Posted November 25, 2008 It is normal for those things. I had one years ago and regret buying it. I've always been surprised that they still sell them considering the wide array of 'portable' amps that don't distort even at the lowest volume. Link to comment Share on other sites More sharing options...
BSAKing Posted November 25, 2008 Author Share Posted November 25, 2008 Did a quick check on the thing and the DC biasing on the transistors in the thing seems ok, so from a DC perspective it is ok. While I was in there I beefed up the supply rail iwth a 4700 Mfd instead of the 1000 they had in and also the 100 mf on the front end drive with a 320Mf. Of course all it did was clean up the bit of hum the thing had as I had expected. What I will have to get around to doing is drop a scope on the thing. I suspect the front end transistor has waay too much gain so that even at low volume levels it is distorted. You can compensate a bit with the input volume but as soon as you increase the signal, well it will start to clip again. So it just needs probably the front drive transistor gain reduced. One day when I get around to that I'll report back if anyone's interested. I think it should actually do a decent job once t hat is done. I notice they have a preamp out on the thing so obviously they designed it to be fed into a larger amp, but you get that overdrive aspect with thius thing. If I wanted that I'd use my tube screamer and my blackface 66 Super reverb. Just depends on the target audience. I just wanted a clean sounding small amp for trundlling about with. Sort of a neat little amp though. Link to comment Share on other sites More sharing options...
charlie brown Posted November 25, 2008 Share Posted November 25, 2008 Well, years ago, they were marketed to be a portable "Blues Amp," that sounded like a Tweed Fender, that was pushed to maximum...but at lower practice volumes. Then, they came out with more powerful versions, that a lot of folks used as a "head" to push a 4x12 cabinet, or preamped into a cleaner main amp, for that overdrive at more acceptable volumes. They (to me) were a bit TOO overdriven, to be of any real value, to what I wanted. So, I never really got past the "curiosity" stage of trying them out, in a store. It would be interesting, since you have one already, to see what you can do with it, to make it more "usable," in a wider variety of situations/tones. CB Link to comment Share on other sites More sharing options...
The_Buffalo Posted November 25, 2008 Share Posted November 25, 2008 Their ads claim they can be used to amplify any electric instrument (guitar, keys, etc.) so I ran an electric bass through it (at low volume, like they suggest) and thought I'd blown the speaker. I think they're supposed to sound like that - you can even buy Pignose pedals to give you "that legendary Pignose sound" through any amp. Link to comment Share on other sites More sharing options...
lpdeluxe Posted November 25, 2008 Share Posted November 25, 2008 I once owned the original Pignose, and now have a G40V (the one that supposedly drives a 4 x 12) and I have to say, they kill for harmonica. The G40V has a few mods (start by delivering the standard speaker to the local landfill) and sounds pretty good with an electric guitar, but blow some harp through it and it sings. Mods: replaced the speaker with an Eminence Ragin' Cajun 10"; replaced the power tubes with Sovteks; replaced the middle tone stack tube with a 12AU7; added a Weber Beam Blocker. It honks. Link to comment Share on other sites More sharing options...
charlie brown Posted November 25, 2008 Share Posted November 25, 2008 Their ads claim they can be used to amplify any electric instrument (guitar' date=' keys, etc.) so I ran an electric bass through it (at low volume, like they suggest) and thought I'd blown the speaker. I think they're supposed to sound like that - you can even buy Pignose pedals to give you "that legendary Pignose sound" through any amp.[/quote'] Have any of you tried those "Pignose" pedals? That makes more sense, to me...if you want that sort of tone, but want good cleans, too. And, lpdeluxe...I can see how a "blues harp" would sound great, through on of those... Interesting! CB Link to comment Share on other sites More sharing options...
Thermionik Posted November 25, 2008 Share Posted November 25, 2008 . . Sounds like every little PigNose I ever played through..... Hey - BSAKing - I was an A65 man for many years, used it for despatch riding and all sorts. Hot oil, mmmmm. Link to comment Share on other sites More sharing options...
BSAKing Posted November 25, 2008 Author Share Posted November 25, 2008 Yep - Lots more information around on tube amps for sure. There bout 7 zillion of them for the lowly Epi Valve Junior alone. This thing has 2 stages each with a transistor (s9014) and 2 drivers (TIP 41C in mine) coupled by a coupling transformer to the input stages. A new speaker will improve the tone if you can find one to fit, but the basic amp has to be reworked a bit. I could replace the transistor with a lower gain one I guess - that's the equivalent of shoving a 12AU7 in place of a 12AX7 in a tube amp. Or - just change the bias circuit a bit which is what I'll probably just do when I get to validate with a scope that the issue is the input stage gain as I suspect. It obviously is designed to overdrive like mad. I'd prefer something a lot more controlled in nature - like the Valve Jr. I have. That is a fun little thing. I run it thru my Fender BAssman bottom. So that's probably what I will end up doing with this thing. All I want is a small, portable, reasonably clean sounding amp for carting around. This thing has the small and portable part. lol. I found web schematics for older versions. This is fundamentally an updated version of that with silicon instead of germanium driving it. Ever notice how many 'get to it' projects there are!? lol. (And they mostly seem to be self inflicted....) PS. For $20 how could I ever resist yet another project??? Link to comment Share on other sites More sharing options...
lpdeluxe Posted November 25, 2008 Share Posted November 25, 2008 And' date=' lpdeluxe...I can see how a "blues harp" would sound great, through on of those... Interesting! CB[/quote'] Reason # 429 why I am a musician: I spent this month learning the harmonica score to the musical Big River (music & lyrics by Roger Miller). I wanted to use the Pig but in the event had to go through the house PA. Everything you don't like about the Pignose as a guitar amp makes it excellent for harp: it honks, it distorts, it sputters and damn does it wail with a Green Bullet plugged in! We performed 5 consecutive nights in performance and I am now the local notorious harp player.... Link to comment Share on other sites More sharing options...
charlie brown Posted November 25, 2008 Share Posted November 25, 2008 Reason # 429 why I am a musician: I spent this month learning the harmonica score to the musical Big River (music & lyrics by Roger Miller). I wanted to use the Pig but in the event had to go through the house PA. Everything you don't like about the Pignose as a guitar amp makes it excellent for harp: it honks' date=' it distorts, it sputters and damn does it wail with a Green Bullet plugged in! We performed 5 consecutive nights in performance and I am now the local notorious harp player....[/quote'] LOL...I was just going to ask you what mic you used...but, you beat me to it. Cool! CB Link to comment Share on other sites More sharing options...
lpdeluxe Posted November 25, 2008 Share Posted November 25, 2008 LOL...I was just going to ask you what mic you used...but' date=' you beat me to it. Cool! CB[/quote'] Here's a pic: Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.