Build a K-MOD102 Guitar Amp Kit

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I recently had the good fortune to become the proud owner of a MODKits DIY K-MOD102 guitar amp kit. I’ve been wanting a tube amp for a while and this little five watt tube amp seemed like a great place to start.

This amp is very simple and very basic and a joy to build. There is nothing not to like about the MOD102. If this amp is any indication, their MOD101 amp has got to be a winner.

I am totally pleased with the results of this build. Let’s see how it went.

The kit arrived on my doorstep at about 6:30 on a Friday evening in a 12 X 10 X 8.5 inch box that weighted about 5 lbs. I opened it and found figure 1. This time I remembered to shoot pics as I went so I waited until Saturday morning to unpack the box.

I was impressed with the thoroughness of the packing. There just isn’t much chance of damage under normal handling. I was lucky as my box had escaped the standard packaging test by the guys in the brown truck.

All the fragile stuff is safely packed inside the chassis.

All the components, both electronic and mechanical, are packaged in numbered bags. Resistors in one bag, capacitors in another, terminal strips in a third. The coolest thing was the wire. It looks exactly like the old vintage, cloth wrapped wire from the ’60s, except the insulation is modern and molded onto the wire. When you get done, it looks like NOS wiring!

The power transformer is a Hammond, made in Canada. (That was a surprise.) The little output transformer was very thoroughly wrapped up in newsprint paper.

The printed, self-stick labels were a little worn looking, like some of the ink had worn off or there hadn’t been enough applied. This was my only real complaint with the kit.

The directions are pretty specific on cutting them out and I did that as I wanted to shoot some sealer over them after application. I did that first and went on while the chassis was drying.

Figure 7 shows the labels are a little “faded” looking. Actually, they look a little better in person than the picture shows.

The inventory sheet lists every part, right down to the chassis. The parts are grouped together but there are no bag numbers to help you find the mechanical parts, which are sometimes in bags where they don’t seem to fit (like the fuse holder in one bag and the fuse in with the caps). I suppose there is a method in the madness (breakage prevention?) but I was a little mystified at times. I had no trouble finding everything, though, and it was all there, down to the last lock washer.

Let me take a minute to talk about the chassis. In a word, heavy. Thoroughly painted with thick, industrial paint, just like the Tremolo kit box. Keep buying these, MODKits. These are very nice.

Figure 9 shows my grinding of the paint for ground connection. The reason I do this is 1) good grounds. The amp will be useless without good grounds as they complete many of the circuits. 2) Noise. The amp will be noisy if the grounds aren’t good.

The amp is built around terminal strips as figure 10 shows. Everything is wired between, and supported by, the strips. When you get done with this kit, you have a hand wired amp. How much do you pay for that on the open market? Lot’s!

Break time! The first part is complete. Now we start hanging components. I worked up to here on Saturday afternoon. Unwrapping, pictures, labels, clear coat and inventory took me about 2 hours and I quit for the day. Sunday morning, I started in again on the wiring.

I just knew that all was well. That should’ve been my first clue that I screwed up! I’ll show you my simple mistake later.

Figure 13 shows the next stage of wiring. It gets to looking pretty complicated but it actually isn’t as you work along.

You have to love this strain relief. Nope, not kidding. That is right in the instructions.

The wiring is done. It’s about 11 am, Sunday morning. Now I start the double check routine, where you go around and compare everything you see in the chassis to the drawings, and check all your solder joints. Here is the spot I should have seen my small mistake but… I didn’t.

Figure 15 shows the second attempt. The first time, there was no sound at all. At least there was no smoke!

Whoever did these instruction sheets did a fabulous job. They are clear, simple, easy to follow and totally complete. There are soldering tips, wiring tips, hardware tips… these could pass for a “MOD102 Amp for Dummies” book.

As promised, figure 17 shows my simple mistake. I just swung it the wrong way when I put it in. In perusing the circuit, the 12AX7 had no plate voltage either. Both tubes just sat there looking smug but were doing absolutely nothing. I spent 10 minutes finding and swapping it over and the amp worked just fine. All told, it took me about 5 hours, start to successful test.

You guys that want to invest in a small practice or recording amp and want the tube sound have your answer in the MODKitsDIY MOD102 amp. This little thing is just perfect for that. Into the right speakers, this amp is a powerhouse. You can’t believe how much 5 watts can hurt your ears!

The circuit is a mixture of Fender preamp and Vox back end. It has a true mixture of the Fender “Ring” and Vox “Chime”, rolled into one. It stays crystal clear up to about 4.5 on the volume pot, then the dirt starts to roll in. I tested it with my Strat, my dual humbucker Ibanez and my Takamine w/the K&K Sound system. The amp reacted differently with all three guitars, but it seemed to really be right for single coils.

The Strat had the widest range of sounds available, from hurt your ears treble to blow the speaker bass. It is set up to play through the 10″ speaker in my little Peavey at the moment and has much more power than you can use in a small room. I am really stoked with this little amp. I intend to build a case for it and a matching speaker cabinet with a pair of 10’s or 12’s. I think I’ll make the whole thing match my pedal board, so my “studio” has nice “furniture” for recording.

Visit or for more info on all their stuff. Click the “home” button and check out all the other stuff they have. Not quite a one-stop-shop, but pretty close if you’re into tube amps.

Check out the sound:
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More of Doug’s DIY articles:

Installing a Sound System in an Acoustic Guitar
Build Your Own Guitar Pedalboard
Building the Mod Kits DIY Trill Tremolo Guitar Pedal

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Doug Knight

Our “Man on the Street” reporter, with his “What’s New in Music Stores?” series, resides in Coos Bay, OR. You can find him on Friday nights at The Small Events Center at OrCoast Music in Coos Bay.

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9 years ago

Well, Nachob… I’m not sure I got all that but the amp is 5 watts and is complete with everything you need to build it for, I believe, $215.00 ( plus shipping) at You’ll need an 8 ohm speaker cab. All the specifications are available on the website. Good people to work with. I love my amp. Simple and easy to build, but you need good soldering skills which they teach you in the instructions. I can highly recommend this project to anyone.

9 years ago

i feel faboulous!! how much amp?¿ watss!!?¡ and money?¿ LOVELLY TO BEGAN TO KNOW MORE, THAN BENDING CIRCUIT THAT IS WHAT I’M SO DOING

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