Bass Guitar and Amp

A couple of recent projects - a bass guitar conversion and another Ruby amp.

1. Bass

Above is the finished bass - it started out as a Fernandes Pie-Zo (called a Nomad Bass outside Japan, I believe).

Usually looks like the above - this was not the one I messed about with! The one I got was trashed - it came from a junk shop. There was a piezo pickup in the bridge with a built in amp and speaker. On my junk acquisition, these were sort of working but very temperamental and, when they did work, I couldn't get along with the sound.  I decided to rip it all out and install a magnetic pickup. I used an old Schaller humbucker. (I hope to use the piezo for something else if it does work OK). The neck was also a bit off but luckily it could be adjusted. The new bridge also allows the action to be set - the old one was fixed.

Filling the body.

Respray, red oak veneer and lacquered.

New bridge.

Done.

2. Amp.

This one turned out pretty decent sounding when hooked up to an old Hi-Fi speaker. Even with the gain cranked up it remains fairly clean and this particular speaker/cab gives a warm tone, so it became my bass amp.

Build your own amp, check out the Ruby page here: http://www.runoffgroove.com/ruby.html

Guess I should post some audio & video

Rotary Speaker - update

Some update on the rotary speaker project.

I finished the enclosure and decided it needed covering.

Blue vinyl table cloth.

Control panel - photoshop, printed on paper and laquered onto box.

I need to clean up the front a little. I have a temporary plastic grill in there until some wire mesh comes my way.

It's looking a bit 'Toys 'R' Us'.

I need to wire a socket for the power supply. The pot on the back sort of fine tunes the speed. One control would be better, but until I can build a proper speed control, this allows slower speeds. I did build a very simple PWM circuit but the motor actually makes too much noise as it pulses on and off. so either I need a more sophisticated circuit, or an enclosure to silence the motor? Anyway, at this stage it works as required, so aside from a few cosmetic jobs, it's more or less finished.

Audio/video to follow

rotary speaker

Been working on a rotary speaker project.

I spent a while experimenting with drive bands and pulleys before settling on a coffee cone/dripper attached directly to the shaft of an old motor from a tape deck.

A paper cone sticks out the side of the coffee dripper

A sawn-off funnel over the speaker channels sound into the coffee cone spinning above.

Using an old Fostex speaker.

I'm now thinking about how to finish the enclosure and mount the controls. I have a PC fan controller to adjust speed but it only has an affect from 12V down to about 6V - it needs to go down to about 3V for slow rotation. I might build a PWM circuit to control the motor.

Here's a video test drive:

My Junk Guitar - bake 1 - paint job

Been lacquering and waiting for it to cure.

In the end I went with a chocolate brown and sealed the gold flakes with clear overcoat.

not a great shot - i hoped the flash would make the gold sparkle more.

I gave the pick up shell, volume knob, bridge screws and tuners an ivory coat - the pure white was too harsh. The ply body has been bound with a few layers of wood banding tape and sealed with more clear lacquer.

first assemble

Though part of me thinks the natural wood had its charms, I'm quite pleased with the results - just the right amount of cheese. I'm happy how the logo turned out - bent from wire and sealed into lacquer.

The name is "Daizo". The "zo" coming from Z0-3 - the source of the neck, and the "dai" meaning big. However combined this way, they sound like "Daiso" which happens to be the name of a very well known 100yen store (dollar/under a pound store). A fiiting tribute to the 'build it cheap'.

The volume knob came from a tube of toothpaste. It has a nice 'tri-star' thing in the center.

Finally, here's a shot of the horrors lurking beneath the facade. I still need to make a cover to go over the electronics.

I've discovered the lacquer could have done with more curing as it's rippled in a couple of places under pressure from attaching things. I'll likely take it apart and touch it up.

Hopefully I can post some sound or video files shortly.

Junk guitar - bridge and pickup

A few small jobs done.

Reinforced the tail-piece with an aluminium blank. this should make it more rigid and prevent any give under string tension:

much better now !

I also routed out the hole and cavity for the pickup. Not the most precise cut - I hoped to get the edge much flusher with just a hair's width of space between the pickup cover and the body. Unfortunately the rounded corners came out a little wider. Still, maybe when I lacquer it, the space will be filled slightly?

You can just see the wider margin at the corners from this angle:

The grain looks nice from here!

I also cut and filed a new saddle. I used aluminium, but maybe I'll try some steel or brass later on and see if there is any discernable difference to the sound.

I wired the pickup to a lead and plugged it in. It works and sounds promising. I'm still wondering about electronics, but I think it's just going to be a single volume pot and no onboard tone control - that will keep the design simple and spare and save me from lapsing into buying any new parts. That would defeat the object since this project's about re-fried scrap all the way!

Here's a view of the whole thing as it stands. Hopefully the onlooker will note that the horn of the body echoes the shape of the headstock...

Starting to think about the finish. The grain on the front is quite pleasing. I think the patterns work well with the shape of the body. I could try staining it to bring that out more, but being ply, the edges will need some treatment.

On the other hand, I'd like to try some new lacquering techniques and this would make a good practice piece. Recently, in my rummaging, I came across some small sachets of gold flakes. This is real gold that, I kid you not, came free with beer. In less austere times, there was trend here in Japan to decorate food and drink with gold flakes. Perhaps it still goes on? Not being one for ostentation, I put them aside and forgot about them. They must have been sitting in the kitchen draw for over 10 years. I'm now thinking these could be employed for a sparkle effect over dark blue, brown or black.

Junk guitar - checking the bridge

I fitted the bridge earlier in the week and strung the guitar up. I thought I should leave it for a while to see how it behaves under tension. So far all is well on the wood front but I think some attention is needed for the tail-piece - a lot of re-tuning was needed at first and I suspect it wasn't just the new strings. I believe the tail-piece has too much give in it. After about three days it seemed to settle more, but I've decided to insert an extra piece of metal to provide more support.

before stringing. the ply facade sits over the bridge so it's slightly recessed.

strung. the black marker pen is just to see if anything drifted

so far, so good

While the guitar was settling under string tension, I began work on the pickup, or pickup housing to be precise. One thing that I will have to buy is wire for winding the pickup but so far I haven't found a ready supply. I will have to either order some on line or take a trip across town to Akihabara, and hope to find some in a shop there.

Anyway, I've begun construction on what will house the pickup and allow height adjustment. This is a actually half of a plastic pill box with a hole cut out. A sheet of aluminium mesh sits inside and acts as a cover. You can just fit a humbucker in there and I used an old one for guidance when making the housing. I expect to make a single coil for this guitar but it's good to know a humbucker will fit in there should the need arise. I should get some more photos of the construction, but here's one for now:

I think it looks like some bizarre cross between a transistor radio and an electric shaver circa 1963 - very Pifco!

(that's good)

Junk guitar - progress - adjustable bridge

I've been working on the bridge. I wanted something adjustable in order to set the action and intonation. As I don't have many tools for metal work (no milling machines here!) it has to be a wood job. Fortunately, I found an old box made from something that seems hard and tropical and decided to use that.

My initial idea was to construct something akin to the bridges found on archtops. After a rummage through my nuts and bolts I realised I didn't have anything that was really suitable, but it then dawned on me that I could use a couple of the saddles fom the ZO-3's original bridge. These are the regular sort with worm-screws for height adjustment that are found on strat-type bridges. There were six on the original bridge, one for each string, but three of them were so badly rusted up that their worm screw couldn't be removed. My idea however only requires two - one at either end of the bridge. I'm not sure if it really provides sufficient strength, but the bridges on a couple of my old Japanese twangers are similarly raised by just two, not so heavy-duty, bolts.

I found some bolts with grippable heads to replace the worm-screws.

Hopefully these photos show how it all works:

side view - the saddles from the original bridge are now upside-down

the wooden blank

as seen from below - two of the original saddles - one at each end

from the front

and from above - the plastic saddle is temporary and will probably be replaced with something like brass. there is still some shaping to do once I see how it works with the body

There was also a tail piece to make, plus a bracket for the scale length adjustment. For these I used some sheet steel from the casing of an old Technics hi-fi amp.

cutting and bending the tail piece

slots for strings

still needs a lot of polishing

testing the bridge

the bridge and tail piece are fitted to a block of cherry wood

there's about 3-4 mm of vertical play at the bridge which means I can get an acceptable action at the 12th fret - hope that's still the case when it's fully strung and up to tension!

checking the alignment down the neck

Next step is to glue the bridge block to the body block, I'll probably add some dowels for extra strength. After that, I'll be routing cavaties in the plywood facade to sit over the bridge. I'm thinking the electroncis will be entirely mounted into the facade - that way it can all be removed as one unit which may make maintenance easier.