Electric Kool-Aid Amp Test: Day 164

The amp is done.

finito1 finito2 finito3

Today I screwed the 12-inch speaker onto the cabinet’s baffle (minor hassle) and bolted the amp chassis onto one of the two back panels of the cabinet (major pain in the heinie). Both jobs required a little bit of shoehorning, but finding the right place to drill holes in that gorgeous stained cherry took hours. At least I knew that I didn’t know what I was doing, so I quadruple-checked all my measurements before I put drill to wood. It ended up going in fine. Check out the photo of the back of the amp—those four bolt heads in the middle of the upper panel are what’s attaching the chassis (the electronics part of the amp) to the cabinet.

Even though I think I did a good job, the whole thing rattles when I set it down. I figure I’ll probably disassemble it soon and try to put some kind of buffer in all the joints that can’t be glued. I’ve heard that an amp needs to be super-tight so that the only things rattling while you’re playing loud are the audience’s teeth.

It’s Sunday evening and most of my neighbors are probably home, so I don’t want to make too much noise, but I did briefly crank the amp up to 10 and play some rock riffs on my Les Paul. What a roar! This thing is a fire-breathing monster.

Of course, now I’m looking forward to my next project. Maybe a 50’s era Fender Deluxe….

Comments 12

  1. Looks great!

    How much did the speaker cost you?

    You’ve got me all excited and while I can’t afford to build an amp right now, I’m instead trying to make me some effect pedals, fuzz face here I come!

  2. The speaker is an 8-ohm Celestion G12M Heritage, which the guys at http://www.18watt.com said would be close to what was in the original 18-watts. It cost $200.

    I’m also thinking an effects pedal might be a good project if I want to keep costs down. Let me know how yours goes! Where are you looking to get designs?

  3. Thanx for the info.

    I only really started searching around last few days (was just thinking about the idea before that). The net seems great so far for designs and general information, these are the most useful sites I have come across:


    Also listed in order that I’m planning on trying.

  4. Search for the holy grail! As a fellow guitar and gear junkie (30 years of too many guitars and amps – some of which I wish I still had). Yes I have the tone bug. Finally found the grail of guitars (yes I think I have played enough) and now search for the right recording and practice amp. If only digital modelers really could satisfy! (Maybe with higher res signal processsing some day they will.) My 18 watt is still too loud for anything but gigs and honestly can’t get clean (making it a one trick classic rock pony). I can only handle so many hours of ear ringing (too many years of abuse).

    Trying to decide what to build (maybe a small tweed of some kind).

    Cool amp project here that I might do:


    Not sure if I can get over the sparkle cabinet – must be a UK vibe – but I like the idea of tube swapping and I really enjoyed this guy’s book.

    Also these kits look really good:


    Not to change the subject, but this guy makes amazing tone monster guitars, better than you might ever suspect until you play them:


  5. Hey Rob,

    It looks fantastic. Congratulations on your patience and perseverence.

    I can’t wait to hear it.

    For your poster Frank, my friend Ken built the two-stroke amp you’re looking at. He has a very detailed blog about it and could tell you about his impressions. Ken said it was a good amp but not constructed exactly as described in the book. I’ve suggested he post the link to that site here. Ken also just built the AX84 firefly, which is a half-watt amp. All the distortion without all the decibels. And I’ve built the AX84 High-Octane – an 8-watt amp with two AX7s and an EL84. That gets a very nice crunchy sound, and cleans up very well. http://www.ax84.com

    My amps are at http://www.flickr.com/photos/45127912@N00/

    Al in Seattle

  6. Great blog & nice looking amp!

    Gerald Weber of Kendrick Amps http://www.kendrick-amplifiers.com/

    is a great resource for classic tube amp tips. Ck out the site. He has a pretty substantial tube book. You can also call down there (Austin,TX) and the guy will talk to you– really laid back.

    Also, in Seattle, there’s Andy Marshall founder of THD.

    Both guys are super tube amp gurus. Gerald in TX is probably easier to hook up with. He’ll talk about fishin’ too.


  7. Thanks JP! I’d never been to the Kendrick site—that’s really cool. I did talk to Andy Marshall when I was first thinking about building an amp, and he discouraged me from using every beginner’s amp-building book out there, referring me instead to a 1000-page electrical engineering textbook. Yikes! I hear he makes great amps, though…

  8. Hi,

    Where can I get the schematic diagram of the Two-Stroke?
    I’ve got the book, but whould like to see the schematics first before ordering the kit.
    (hard to visualize from just the component layout in the book)


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