Tom Wolverton wrote:Len, I just finished building a Mojotone Princeton Reverb kit. It turned out nice. But I upgraded a few parts and did some mods (per rob robinette). I put a 12†speaker in it. It makes a nice low volume steel amp.
Note: don’t trust Mojotone schematics and layouts completely. There are a few typos. Also, I recommend a good soldering iron and a good multimeter. Mike S recommended a Fluke 117 and I’m glad I got one. Very easy to check cap values.
Also note, you won’t save a lot of money building it yourself, but the education is very valuable.
I built the Mojotone Princeton Reverb too - great kit! I added grid stoppers, a mid control (mounted on the back in the ground switch hole), and 3-way NFB control (mounted in the 2nd speaker jack) so it also can do a great breakup tone that's more tweed than blackface. I stayed with a 10", but went with a Celestion Gold.
Re the schematics and layout, my recollection is that the layout was fine but the schematic is the same as the original which includes the unnecessary and potentially dangerous ground switch with 'death cap' (they were on the wiring diagram, but not connected to anything). I strongly recommend no one build it stock, and instead research how to properly wire this portion of the circuit.
After careful consideration, I am going to put this project on the back burner for a while. I recently put a new LED pilot light in Mesa Boogie Simul Class and it took me 2-1/2 hours. Had to remove the chassis and solder in the wire leads. Boy, changing a bulb in a Fender pilot light is a no brainer. Made me think about approaching the amp kit anytime soon.
Basically, I see maybe four levels of kits:
1. Mojotone--probably the best components, but the highest price.
2. Hoffman--can pick & choose your own parts; probably can save money compared to Mojo for like performance, but you have to have a bit more knowledge.
3. Weber--definitely the best bang for the buck, but sometimes use some really cheesy Chinee parts, so you have to be careful.
4. Totally from scratch, sourcing your own parts and schematics. Best left to experienced builders.
I've only added the George Le May customization to my NV 400. But I've designed and built many rather complex digital and analog devices including one with an old microprocessor and a guitar-to-digital-synth unit.
Am presently prototyping a radical tube amp departure that I think will kind of revolutionize electric guitar sounds. It will probably be too gainy in general for PSG, but we will see...
Designing and building a good amplifier power supply is a bit of a tricky business that requires trial and error it seems.
In the 70's I built a stereo Heathkit receiver and one of their guitar amps. Several years ago, I decided to build my own amp. I got several of the London power books by Kevin O'Connor and designed a 20 watt amp. I ended up building it a couple of times before I was satisfied. I also built speaker enclosures using designs by Kevin O'Connor. The down side was that these things were over-engineered and weighed a ton each. These have never left my house and currently reside in basement storage. From my perspective, the new solid state amps with lightweight speakers are where it's at. If you want to build an amp for the fun of it, go ahead. Any more, I just want to play music.
Karlis Abolins wrote:The down side was that these things were over-engineered and weighed a ton each. These have never left my house and currently reside in basement storage.
Karlis
Yes, that's an important consideration. If my new design works out and goes commercial I plan to offer 3 variations: a 10W dual class A single ended 6V6 variant in a tiny lightweight box that can alternately power a much bigger cabinet, i.e. a studio or small venue oriented box; a stage variant with 50W and one 12" speaker; a stadium variant with 100W that has a combination of 6L6 and EL34 output tubes with probably a separate combination 12" plus 15" speaker cabinet.
It really depends on your level of experience with soldering. I started building guitar pedals many years ago and recently completed a tube spring reverb unit. The biggest difference is the spring reverb was point to point wired which required more attention to detail and planning than just popping components in a PCB. Aa long as you take your time and follow all the instructions it shouldn't be too hard. My biggest advice is to have the proper tools. Get a decent soldering iron, they usually run about a $100 and some small soldering tools for bending component leads and such.
Rejoice in the Lord, O ye righteous; praise is meet for the upright. Give praise to the Lord with the harp, chant unto Him with the ten-stringed psaltery. Sing unto Him a new song, chant well unto Him with jubilation. For the word of the Lord is true, and all His works are in faithfulness. The Lord loveth mercy and judgement; the earth is full of the mercy of the Lord.
- Psalm 33:1-5
John Larson wrote:Get a decent soldering iron, they usually run about a $100 and some small soldering tools for bending component leads and such.
Also a parts holding fixture with at least 2 clamps that can be oriented to different angles and distances apart will really reduce the potential frustration of holding different parts together while you apply solder to them.
I built an Allen Accomplice from a kit several years back. David Allen's instructions are excellent, and he is available for tech support if needed. It certainly helps to have some technical and assembly experience. It's a great guitar amp with 6V6s, based on a Deluxe Reverb. It can be swapped out and re-biased for 6L6s and is then a killer pedal steel amp.
Steven Paris wrote:
4. Totally from scratch, sourcing your own parts and schematics. Best left to experienced builders.
I did that one! My first amp was my Showman I built, and my second was a Vibroverb, I had almost no electronic background, except YouTube and messing around with electronics, these were done last year when I was 16. Hand picked transformers/components.
'66 Sho~Bud Fingertip, Sho~Bud amps, Fenders, old cars and Tinkerin with steels!
