tag:blogger.com,1999:blog-4452757648026922149.post876331710522228404..comments2023-10-06T08:16:43.035-04:00Comments on Wombat Amplification: Raffle Amp Main BoardWombat Amplificationhttp://www.blogger.com/profile/01158985830246321559noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-4452757648026922149.post-86758135320767346442012-05-28T23:18:29.741-04:002012-05-28T23:18:29.741-04:00Hmm ... Aikido.... Well, I use an Aikido line stag...Hmm ... Aikido.... Well, I use an Aikido line stage day in day out, 6SN7's in it. That one has been built and left alone a LOOOONG time now! My most recent project, almost finished (yeah, right) has been uber-fun: my first guitar amp in a long, long time.<br /><br />As always, there's a story:<br /><br />I was reading the DIY Stompbox forum a bit recently and a circuit caught my eye: it is a FET-based distortion pedal called Supreaux Deux, based on a little guitar amp, a Supro 16T. The pedal was developed on the basis of scaling down the tube voltages for FETs but keeping the original amp's circuit otherwise, and also scaling some of the filter-type components to go with the different input and output impedances of each stage. Kind of fascinating, but all it got ME interested in was in building a Supro-like little guitar amp with tubes. It's a basic little screamer, similar to a Champ in terms of simplicity but a very different circuit overall. <br /><br />So then I started looking at this schematic here:<br /><br />http://www.valcopages.com/Schematics/gretsch6151.pdf<br /><br />This amp is similar to the Supro 16T (and supposedly identical to a 1616T) except it has a tremolo circuit, and I had been wanting to try my hand at a tremolo too.<br /><br />So I was pricing out all the various components, and meanwhile I got a call from a friend: "Somebody left a tube AM/FM radio in the trash - do you want it?" Initially I was kind of lukewarm - I don't really have any idea what to do with an All American Five, line-powered heater-string radio, which is what usually seems to turn up, but I asked what tubes it had. "5Y3, 6V6 ..." he started and of course I jumped right on it - I didn't really even have to rewire parts of the power supply, it was such a perfect starter chassis for the Supro/Gretsch circuit. A nice GE 5Y3 and a few other decent tubes in it.<br /><br />So that's coming along nicely - I've built it PRETTY MUCH as you see it in the schematic, the only differences are some adjusted values in the tremolo circuit to slow it down, get wider speed control, and also to add a trem intensity adjustment. And I added a switchable .33 cathode bypass to the V1B section to try and get more raunch/overdrive out of it. I tried the amp with a Strat and it didn't get nasty at all - with my P-90/humbucker/fat flatwound-equipped guitar I get a lot more signal driving the amp to begin with, but the Strat wasn't pushing it much.<br /><br />The trem sounds wonderful, really great. The overdrive option isn't quite right - I may try a pentode input stage, I think I got some 6AU6's out of it when I stripped it.<br /><br />So that's the latest!<br /><br />I don't really need to win the raffle, I just wanted to chip in at least a little to be supportive - I'm kind of broke these days, which is one reason trashpicking parts is so attractive! Good luck on your run!<br /><br />Best,<br /><br />-jJer.Epshttps://www.blogger.com/profile/03505967128773009552noreply@blogger.comtag:blogger.com,1999:blog-4452757648026922149.post-32210602409866199462012-05-15T12:33:22.074-04:002012-05-15T12:33:22.074-04:00Jer, Thanks very much for your generous donation! ...Jer, Thanks very much for your generous donation! I'll run as fast as I can! If you want in on the amp raffle though, you'll need to kick in another $15 per the post above - each ticket requires a $25 donation. Are you working on anything lately? How did the Aikido inspired unit turn out? Cheers, PaulWombat Amplificationhttps://www.blogger.com/profile/01158985830246321559noreply@blogger.comtag:blogger.com,1999:blog-4452757648026922149.post-84380188584446707522012-05-14T20:54:21.461-04:002012-05-14T20:54:21.461-04:00I went for $10 - run really fast, OK!I went for $10 - run really fast, OK!Jer.Epshttps://www.blogger.com/profile/03505967128773009552noreply@blogger.comtag:blogger.com,1999:blog-4452757648026922149.post-335739652063013872012-05-14T09:00:49.903-04:002012-05-14T09:00:49.903-04:00Hi Jer.
Thanks for the comments! I think the h...Hi Jer. <br /><br />Thanks for the comments! I think the hybrid approach will work well for this amp.. I've hand made a few PCB boards for a few pedals, so this should be no different with the exception of mounting it on a turret board instead of in a pedal enclosure. <br /><br />The raffle isn't a for-profit thing, so you can't exactly "buy" a ticket... Instead, every $25 donated on my Leukemia and Lymphoma Society fundraiser page counts as one ticket. Donate more, get more chances, it's as easy as that. The link is here: http://pages.teamintraining.org/va/rnr12/pfawcetnbgWombat Amplificationhttps://www.blogger.com/profile/01158985830246321559noreply@blogger.comtag:blogger.com,1999:blog-4452757648026922149.post-81245344673215760472012-05-13T21:40:13.792-04:002012-05-13T21:40:13.792-04:00This is a very unusual approach to things, with th...This is a very unusual approach to things, with the PCB/turret hybrid. I look forward to following the progress.<br /><br />Can I buy a ticket?<br /><br />-j (tubegeek)Jer.Epshttps://www.blogger.com/profile/03505967128773009552noreply@blogger.com