Build #3 DHB-4 fretless

[Simon Barden]

That 2nd wiring diagram will work, but there are points to note.

The ‘stereo jack’ refers to the barrel-type jack supplied with the Ibanez-style kit the diagram was drawn for. Whilst you can get mono (TS) barrel jacks from Switchcraft, the Chinese kits have standardised on using a ‘stereo’ (TRS) style barrel jack. The term ‘stereo’ is misleading, as they are rarely used for stereo outputs on guitars and basses, but the third terminal is more often used to switch battery power on active circuits (most common on basses). So despite being a TRS jack socket, only the T and S contacts are used, so just wire it up to a standard output jack as normal.

The 2nd wiring diagram has the volume pots wired up differently to the 1st. The pickup signal now goes to the central wiper connection, with the output from the end tab on the pot (reversed from diagram 1). This is to prevent the output from one pickup being grounded when the other one is set to 0 i.e. the same as selecting a single pickup on the switched version. But this means that both pots are always connected to the pickups, halving the resistance the pickups see to ground.

In the switched version, when selecting just the neck or bridge pickup, they’d gave 500k resistance to ground at full volume, but with the 2nd arrangement, having one pickup on 10 and the other on 0, the pickup on 10 would see a 250k resistance to ground across the volume pots. This will knock off some of the treble and move the pickup’s resonant peak frequency down a bit. So the single pickup sound of arrangement 2 will sound a bit duller compared to arrangement 1.

It’s a bass, so this may not be a problem for you, especially if the pickups are quite bright sounding to start with. The both pickups on situation will sound just the same though.

But if you like to have a bright sound available (its easy to loose treble but harder to add it) then you can always use 1Meg volume pots instead, which will give the original 500k resistance to ground through the pots. This will mean that the ‘both pickups on 10’ sound will be slightly brighter than before. Keep the tone pots at 500k.

Swapping the volume pots is something you can do at any time, so you can see how it goes with the original values and see what you think.

If you want brighter sounds, you can always fit some mini toggle switches so you can have the pickups in series, parallel and split modes. If you don’t want two mini-toggles you can have a common tone control and fit a single 3-position rotary switch for common pickup mode selection, which still gives lots of sound variations.

[FaustoB]

Thank Trevor and Simon! very helpful!

Commenting on Simon's points

That 2nd wiring diagram will work, but there are points to note.

....

with the 2nd arrangement, having one pickup on 10 and the other on 0, the pickup on 10 would see a 250k resistance to ground across the volume pots. This will knock off some of the treble and move the pickup’s resonant peak frequency down a bit. So the single pickup sound of arrangement 2 will sound a bit duller compared to arrangement 1.

It’s a bass, so this may not be a problem for you, especially if the pickups are quite bright sounding to start with. The both pickups on situation will sound just the same though.

This worries me a little bit! I agree it's a bass but would love to keep the max tonal range.
I'm installing round wounds to begin with (generally speaking rounds are nice and bright) , but likely to swap to half round or tape wound in the future (which are darker sounding strings, with different tension and feel)

But if you like to have a bright sound available (its easy to loose treble but harder to add it) then you can always use 1Meg volume pots instead, which will give the original 500k resistance to ground through the pots. This will mean that the ‘both pickups on 10’ sound will be slightly brighter than before. Keep the tone pots at 500k.

I like this option! thank you so much. I'm slowly slowly getting my head around electronics but my knowledge is way more limited than this!

Swapping the volume pots is something you can do at any time, so you can see how it goes with the original values and see what you think.

If you want brighter sounds, you can always fit some mini toggle switches so you can have the pickups in series, parallel and split modes. If you don’t want two mini-toggles you can have a common tone control and fit a single 3-position rotary switch for common pickup mode selection, which still gives lots of sound variations.

I like also this option with common tone control with a single 3-position rotary switch for common pickup mode selection!
Losing one tone knob means that I could put the switch right there in the electronics cavity, instead of placing it far away in that pre drilled hole on the opposite side on the body. a long way away and probably a nightmare to fit the switch via the f-hole in the body...

[FaustoB]

ok then, some progress in the last couple of days.. or better three steps forward and two steps back.. but still technically moving forward it is....

I have decided that the finish has to go. I am just no happy with what I am getting. Will sand it back and will try a different technique.

Before re-sanding it, I've decided to assemble most of the bass to see what else to expect.

Lined up and drilled the neck, placed the floating bridge, and put the strings in.

The issues that stood out were:
#1 the action is crazy high!! almost 8mm at the 12th fret
#2 the neck pick up is way to high, although at its lowest position (screwed all the way down)

I have taken everything apart and got to work.

In order to lower the action i did some work on the bridge.
I placed some rough sanding paper on the body and sanded the bottom of the bridge over it. This is to maintain the correct curvature (which the kit bridge didn't have by the way).

here prepping for sanding and first shy attempt:


Sanding the bottom of the bridge over the body to maintain the curvature (thanks Tom for the tip!)


and here after I got the hang of it


a digital caliper came handy to keep one eye on how much I was taking off.

I also used a Dremel to take out the part of the bridge over the nuts.

this is the finished bridge: the orange lines on half of the bridge to illustrate the work done, and the arrows to show the string slots i prepared while working on the bridge, will finesse them at some point.


I quickly restrung the bass, didn't measure the string height but it was evident that it was waaay better. The current height is definitely manageable by placing a small shim under the neck.

[FaustoB]

the other job was to lower the neck pick up, which was a bit too high even at its lowest position.

To make the pick up slot deeper, I tried first with the Dremel and a routing bit... but it was messy.
Then moved to cisel and it was definitely the way to go.

Took out about 2-3mm.


Finished job, first time using a cisel ever (thanks Aldi)
I didn't need to touch the bridge pickup which seemed fine

[FaustoB]

Another job I did, was to fit the ferrules and run the ground wire.
This was fun.

I tried to solder the wire to the bottom of the ferrule, but it didn't work. The pressure of pushing the ferrule in the body was breaking the soldering.

Then I decided to twist the wire around the ferrule, and push it in

.


This almost worked, but it was too hard to push the ferrule down ground with the wire twisted like that around the ferrule.

What worked at the end, I forgot to take a photo but it's a solution similar to the one pictured above.
I made a sort of little spring with the exposed wire twisting it around with small pliers. Put the ground wire/spring in the slot, and pushed the ferrule in.
I measured with a multimeter and it was fine. I proceeded like that for all 4x ferrules, checking with a multimeter, it worked!

[Simon Barden]

Some nice work there.

With a bolt-on neck, as you've mentioned, a shim is the easiest way to adjust the neck angle, which can be very useful in achieving a good action height. A 1mm thick shim can normally make a 3-4mm difference in the string height over the end of the neck.

It's always good to have some upwards and downwards pickup height adjustment available. You'll want to try and balance the pickup outputs and tweaking the pickup height can also make small adjustments to the tone as well.

[FaustoB]

You know when you read on the forum that someone didn't like the finish they were getting and they re-sanded the entire body and neck?
Well... this is one of those posts!

here a couple of photos of the job almost done

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I am so happy I started over because I wasn't fully convinced of the colour and didn't like the finish at all.

I have decided to leave some spots of Black Japan here and there, for a sort of distressed feel, and stained using cedar stain (which is dark red..-ish)

I am using Tru Oil for the finish this time.
After 4 or 5 applications I have started applying the TO with fine sandpaper and I am liking the results so far. I am up to grit 1000.
To be precise, I apply with a cloth, then use fine sand paper, then use the same cloth to even it out. It's looking good!

[Rabbit]

I am so happy I started over because I wasn't fully convinced of the colour and didn't like the finish at all.

I know it can be hard sometimes to start over, but well worth it. The temptation is to go "bugger it, I just want it to end!", but it will bug you later on down the track.

[FaustoB]

Totally agree Rabbit!

While I am working through the final coats of Tru Oil, I have began working on the cover that I will use over the hole I drilled at the back of the body to install and access the switch.

As a test a few days ago I managed to feed a string from the f hole to the switch hole on the front of the body. It is possible to feed and secure the switch to the body that way, but I didn't like it. It's hard to access, it's hard to get there (the switch got stuck several times), it's not serviceable, I didn't like it.

So I drilled a 38mm hole at the back of the body, to make the switch installation and access easier, and today I fabricated a cover.

I looked up online and I could find pre-made plastic circles of pretty much any diameter, thickness and colour, but often come in sets of 10 (or 50, or 100..), and I had no idea what to do with the remaining 9 (plus shipping time, shipping costs, more plastic in the world and all that).

I decided to make my own plastic cover using part of the pick guard that I have cut out from my #2 build.

To add stability I screwed the plastic to a scrap piece of wood, used a 50mm drill bit as a template for my circle, and cut with a jigsaw following the line the best I could.


then I covered with masking tape the rough circle I cut, and glued it to the drill bit I used as template with two drops of superglue.


With an electrical sander I did a first pass of rough sanding, spinning around the drill bit gently.


and then with finer sand paper I sanded by hand for the final pass

.

[FaustoB]

here a photo of the circle almost fully sanded


a bit more sanding.
Here the finished plastic cover, home made to specs!


I've taken the plastic cover apart with a blade, it came off very easily


Now I've just spray painted it black a couple of coats and will seal it next time I'll work on this.

Would love to route a 50mm circle around the 38mm hole, as deep as the thickness of the cover I made, to make the cover sitting flash.
I don't have a router, only a Dremel, and I am too tired now to think how to do it!

Time to play some music.