Tag: marshall

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Amps DIY

Mojotone British 45 Kit

I almost always play small combo amps of 20 watts or less. But I wanted something with a bit more clean headroom for a possible upcoming project — and to demo my stompboxes. I’ve always enjoyed playing JTM-45s when I’ve reviewed them for guitar mags, so I ordered Monotone’s British 45 kit.

I’d previously had a great experience building Mojotone’s Marshall 18 watt clone kit when I reviewed it for Premier Guitar a couple of years ago. It turned out great, and I use it regularly.

Mojotone provides high quality parts, nearly labelled and organized in plastic compartmented boxes. But beware: The company provides no build instructions — just a layout diagram and a schematic. You need amp building experience or help from an expert. Click play for a slideshow about he build:

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This is Mojotone's new offset head cabinet. (The amp chassis first in other Mojotone cabinets as well.)

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The two power tubes can be either EL-34s or KT-66s. (I chose the latter, just for a new experience.)

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The parts come neatly labeled and organized in plastic bins — a BIG help!

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Warning: the kit includes no build instructions — just this layout diagram and a schematic.

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I ALMOST managed to assemble it, but I needed a rescue at the end. (Thanks to Bruce Clement of BC Audio, a brilliant boutique builder here in San Francisco.)

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Mojotone supplies their own branded transformers (which sound fab).

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It's a turret board build. (The board and turrets are pre-made, as opposed to some kits, which require you to insert the turrets yourself.)

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This is probably not a good first build — maybe start with a nice little tweed Champ kit?

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The a plexi faceplate, which I left omitted. I also substituted my own knobs.

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I nearly made it through myself. (Translation: I soldered everything together and it didn’t work.) So I had to hire Bruce Clement of BC Audio here in San Francisco to rescue me. (Bonus: Bruce loaned me one of his JTX50 heads. Man, it’s one of the best-sounding Marshall derivatives I’ve ever heard. It’s among his Octal-Plex series amps, which use octal preamp tubes in Marshall-inspired designs.)

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Amps Uncategorized

The 18-Watt, Bletchley-Style

How come my DIY amps never look this pretty inside?
How come my DIY amps never look this pretty inside?

A couple of weeks ago I posted here about a Premier Guitar project in which I built two Marshall 18-watt clone kits. Meanwhile, the magazine received a review model of Marshall’s latest iteration of the 18-watt, a high-end, hand-wired version that sells for $2,700. My new review is online at PG, if you’re curious to hear a proper Marshall as well as the clones.

My take: It’s a beautifully built, hand-wired amp that sounds as least as good as either clone. Unlike the kits with their single 12″ speakers, the Marshall has a pair of 10s, which I think I prefer in this circuit. At $2,700, though, it’s pretty darn expensive, even for a beautiful, hand-made instrument. But I’ll be sad when I send the review model back to Bletchley.

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Amps

18 Wicked Watts

I had a blast building and testing two Marshall 18-watt kits for a Premier Guitar story — and I emerged with new respect for this cool 1965 design.

These mini-Marshalls were neglected in their day, but are now treasured. The oft-heard claim that they provide plexi tones at reasonable volumes is only partially true — these are open-backed combos powered by a Vox-like pair of EL-84s tubes. But while they have roughy the same horsepower as the era’s Fender Deluxe and Vox AC15, their tone is undeniably ’60s Marshall. In the studio, they sound far larger than their actual size. And out of the studio, they’re still pretty darn loud.

I've never seen three 18-watts in the same place before.
I’ve never seen three 18-watts in the same place before.

Even though the Mojotone and Tube Depot kits I built share the same schematic (and identical cabinets, both made by Mojotone), the build experiences and final results differed greatly.

And just when I thought I’d scaled the Everest of 18-watt ecstasy, I get a real Marshall 18-watt reissue for an upcoming Premier Guitar review. Stay tuned.

Are any of you guys 18-watt fans? Any observations to share?

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Amps

The Class A vs. Class A/B Slugfest!

Which kick more ass? Class A or Class AB?
Which kick more ass? Class A or Class AB?

The recent experience making a DIY Class A Champ  reignites for me the eternal debate between the merits of Class A and Class A/B amps. (I link once more to Dave Hunter’s excellent short article on the topic, since he explains the distinction so much better than I can.)

Like most American players of a certain age, I grew up without access to great Class A amps. (I’m going to take the lazy way out here, and lump Voxes and their kin into the Class A category, despite the distinctions that Dave H. explains so well.) My initial exposure to various ’90s Vox reissues and other “Voxoids” of the era was enough to spark my interest. (And is “spark” the perfect verb for great Class A amps, or what?) But it wasn’t till I encountered Matchless amps and real vintage Voxes that I totally got it.

But still, I go back and forth constantly. And whenever I switch between categories, I think, “Ah! There’s what I was missing,” though I tend not to miss it when I’m playing an amp of the opposite type. So at least I’m usually happy.

Overall I’ve probably favored Vox-type amps over Fender- and Marshall-flavored ones, though I’m the sort of player who’s rarely interested in macho rock and metal distortion. (If that weren’t so, I’d be an A/B purist!) But having said that, my fave amp these days is the decidedly A/B brownface Tremolux I use in the lion’s share of my videos. So put me down as perennially undecided.

How about you? Do you pledge your allegiance to the explosive harmonic energy of Class A or the focused impact of Class A/B? And has anyone explored switchable schemes, as found on some Mesas and modded Marshalls?