Custom Semi Acoustic Modifications

[W1_Pro]

[quote name='Andyjr1515' timestamp='1468957376' post='3094709']
A pal of mine often says he likes watching the stuff I do (including playing) because I'm always on the very edge of disaster...
[/quote]

In the immortal words of David St Hubbins; 'such a fine line, between stupid and ([i]Nigel steps in[/i])....clever'. ...

[paul h]

The trapeze looks awesome. Great thread

[Andyjr1515]

[quote name='W1_Pro' timestamp='1469108102' post='3095823']
In the immortal words of David St Hubbins; 'such a fine line, between stupid and ([i]Nigel steps in[/i])....clever'. ...
[/quote]

[Andyjr1515]

OK, we have a playing and intonated bass







I will keep a weather eye out for another stop tail with slightly wider string spacing. On a bass it is less critical but I'd like the string runs between the bridge and the tail block to be a little straighter if possible.

Functionally, however, it plays fine, holds tune, intonates spot on and sounds pretty great even with the present electrics set up - and even through my 6-string electric practice amp!

On the strap it is definitely long scale, but I have no problem at all playing it at the lower frets or upper frets and I do not have a long reach.

So we now have a stable, playable and good looking bass.

Now for stage two - hole in the back and a fancy EQ! ...and MAYBE a tidy up of that horrible neck ivoroid cover strip if I can do that without b*******g it up!

It's going well. I'm pleased with this one so far

[W1_Pro]

That is amazing.
The tailpiece looks like it's always been there.
Just out of curiosity Andy, hows the action?

[Andyjr1515]

[quote name='W1_Pro' timestamp='1469118333' post='3095943']
That is amazing.
The tailpiece looks like it's always been there.
Just out of curiosity Andy, hows the action?
[/quote]
I've just got it set roughly at the moment at my usual starting point of 2.4mm on G and 2.7mm on E at the 17th fret. At that height no buzz. The trussrod is very responsive, by the way, allowing very accurate relief setting.

I'll do a proper check of the fret levels, etc, when the major surgery is complete.

[W1_Pro]

[Norris]

The bridge and tailpiece look spot on! Matching gold knobs required...

[Andyjr1515]

[quote name='Norris' timestamp='1469129009' post='3096041']
The bridge and tailpiece look spot on! Matching gold knobs required...
[/quote]
Thanks, Norris

In the interests of managing expectations, the SD EQ comes with black knobs which we will probably stick with

[Andyjr1515]

WARNING - Turn away if this offends your sensibilities! I'm going to cut an access hatch in the back of a carved semi-acoustic.

There's a second real warning, actually. The trouble with forums is that sometimes the 'old hands' come across to beginners as "this is what you should do and this how you should do it". [u]Most of the stuff I do is very much, "Blimey...don't do it the way I do it! Find someone who knows what they're doing!"[/u]

Below I will be showing how I cut a hatch in the back of a carved or curved hollow guitar. This is generally [u]not[/u] recommended and is highly risky to the bass's health if you have never done it before and don't apply strict checks and precautions.

Stuart may well be experimenting in the future with different pickups, etc, and so would find it very helpful to have an access hatch. As described earlier, I've done this on a curved back semi before, using the piece that has been cut out as the hatch so the profile and colour completely match - much nicer than a flat bit of plastic! :



Below is how I tackled the same with Stuart's precious custom (gulp)

First is cutting a paper template and making sure it - and the retaining strips I will be adding to the sides of the hole - don't show through the f hole:





I'm going to use a Dremel with a 1.5mm router bit in the Dremel router base. TBH, this is the ONLY thing I've ever used this base for (I normally use the excellent precision router base supplied by Stewmac and others), simply because it has provision for a template guide-ring:


You can also see, above, the 10mm guide ring offset for the MDF template I have measured around the paper

Template cut out and sanded smooth, stuck in position with heavy duty 2 sided tape and also clamped - trust me, you REALLY don't want this to move!!! Also I find it important, with the bit fully retracted, to carefully take the base around the template and workout how I am going to be able to hold it, where the base needs pressure to ensure it is consistently against the template side and fully vertical. I am going to be doing multiple passes of this - it has to be following EXACTLY the same path every time otherwise the resulting gap between the hatch and the body will - at best - be uneven and greater than 1.5mm :


And then with the bit only slightly proud, the first pass:


Scary the once, but I've got to do this another ten times in exactly the same way!

Eventually, I have first breakthrough:


At this point I reduce the increments of depth - I want a sliver to be holding the hatch so it doesn't drop in, catching the bit spinning at 20000rpm! Because ideally I want to razor-saw the last bridge:



Done....big PHEW!!!

Edited July 22, 2016 by Andyjr1515

[W1_Pro]

That is mental. Well done Andy. Fantastic work.

[scojack]

Scary Stuff m8! Nice job though:)
Wonder how he got those pots in there first time round?
Ian

[paulnb57]

Awesome skillage Andy……..

[Andyjr1515]

[quote name='scojack' timestamp='1469189899' post='3096458']
Scary Stuff m8! Nice job though:)
Wonder how he got those pots in there first time round?
Ian
[/quote]

It's normal semi-acoustic stuff to be honest - basically through the f-hole, pulled through either with string or surgical tube. If you were doing a one-off, it's very fiddly but do-able (I've changed all the electrics on my 335 clone in the past) - but it's a right PITA if you want to experiment a bit and chop and change!

[roman_sub]

Were you a surgeon in the past? Nice clean cut, Andy....

[W1_Pro]

One thing that has occurred to me Andy, should there be some shielding in there somewhere?
I just wonder that if it's absent, which it seems to be, could that have been the cause of my original buzz issues?

[Andyjr1515]

[quote name='W1_Pro' timestamp='1469252522' post='3096933']
One thing that has occurred to me Andy, should there be some shielding in there somewhere?
I just wonder that if it's absent, which it seems to be, could that have been the cause of my original buzz issues?
[/quote]
I'm not quite sure why, other than the difficulty of doing it, but as far as I know, semi acoustics generally aren't shielded. Anyone got a view?

When I tried it out I didn't get excessive buzz at all, but I would have thought the single coil in the neck would have been the main culprit rather than any of the wiring runs and other extraneous stuff...

I suggest we see how the present arrangement fares with the EQ. Because we now have a hatch, any subsequent changes if necessary become much more straightforward

[Andyjr1515]

I've glued the rebate strips for the cover this morning:


I think it's probably too heavy a cover to be able to attach with magnets but I'll have an experiment.

The other thing I've had a look at is the humbucker.

W1_Pro would like to add a split coil option to the humbucker. Assuming that we will initially try the present pickups, at the moment the humbucker is wired as 2 conductor only. However, this is what it looked like at the back:



Six solder tabs plus an earth tab (there's a bit of shielding, Stuart!).

The red is the hot so pretty sure the middle two bridged ones are earth and the two coils are joined by the black wire with a coil tap provision leading off the 1st coil 'out' (5th tab from the left). The tap wasn't connected and there was something a bit odd about the tone pot connections (neither tone worked when I tried it out on the initial stringing trial) so I've gone back to a basic approach of four wires plus earth:



Red is hot, purple the finish of coil 1, joins to B&W of coil 2 ending in white, the coil 2 ground. The multimeter seems to tally so I think that's right

[Andyjr1515]

...and here's the hatch, with the rebate stained dark brown:



I've had a look and I think it will need to be screwed in place. Having said that, it is a thick piece of wood so I will be able to drill a countersink and bring the screwheads down below the surface of the cover.


That's the next job and, while I'm waiting for the EQ to arrive, I'm going to have a good look at that rather bodgy neck joint ivoroid strip:






It will need a strip of some sort, but...well, let's see...

[Chris Sharman]

There are no other words for it but that is a beautiful looking bass.

Andy, your work never ceases to amaze me.

It is also a great example of the phrase "the gap between genius and madness is measured only by success"

[Andyjr1515]

After scoring all the way round to minimise wood or varnish chipping, I heated the ivoroid with a soldering tip set on cool at around 200c and then eased the soft plastic away from the backing wood with a fine chisel:





Eventually, the whole piece came away. Starting to look better already!

[Andyjr1515]

[quote name='Chris Sharman' timestamp='1469275854' post='3097114'] There are no other words for it but that is a beautiful looking bass. Andy, your work never ceases to amaze me. It is also a great example of the phrase "the gap between genius and madness is measured only by success" [/quote]

Well, you're probably right about the madness bit....

[W1_Pro]

Looking great Andy.
I have to admire your thoroughness, attention to detail and craftsmanship.
I take my hat off to you, I really do.
What do you reckon should go on there in place of the binding then?

[W1_Pro]

I'm not quite sure why, other than the difficulty of doing it, but as far as I know, semi acoustics generally aren't shielded. Anyone got a view?

I only asked, as I have a vague memory of a guitarist mate of mine having an Ibanez semi from the eighties, I have an even vaguer memory of that having a sort of tinfoil bath around the controls (on the inside of course).
Having said that, I fully accept that I'm not as young as I was, and memory can be a finicky mistress.
In short, I might be talking total sh*t.....

Edited July 23, 2016 by W1_Pro

[Andyjr1515]

[quote name='W1_Pro' timestamp='1469279010' post='3097146']
Looking great Andy.
I have to admire your thoroughness, attention to detail and craftsmanship.
I take my hat off to you, I really do.
What do you reckon should go on there in place of the binding then?
[/quote]

It's a very nice bass and worth the effort

I have some maple veneer that I am going to try. It will always look like an infill but, if I can continue the heel black line too, hopefully it will look more like it's supposed to be there...