Finished! A Bridge Too Far?

[Andyjr1515]

Well, this looks almost artistic...

...which is probably more than the carve itself is




The carved chamber's essential kit:[list=1]
[*]Thickness gauge
[*]Chisel
[*]Deepest item you're going to need to fit under a flush cover
[/list]
I'm at another "Sit and THINK, Andyjr1515, before even touching anything that is going to remove wood".

It is a great temptation to get out the pullshave and start the back curved carve - but I mustn't...yet

Factors include:[list]
[*]I need to preserve the present flat surfaces until I'm sure all and any routing has been completed. It is extremely difficult to rout on a scooped surface - ask me how I know! The one thing that probably will be routed is the covered shallow chamber the pickup coils will sit under
[*]I probably should finish the reference point roundover along the back edge
[*]I need to add the two small sycamore fillets at either side of the tuner block support
[*]I need to work out just how much depth will be lost from the control chamber when I scoop - and where. Almost certainly I will need to go deeper (and therefore thinner) with the control chamber carve if I want to have a flush cover
[/list]
So I'm going to spend much of the day just sitting on my hands, looking at it

Edited May 19, 2017 by Andyjr1515

[Si600]

Why haven't you finished carving the front before starting the control cavity?

[samhay]

[quote name='Andyjr1515' timestamp='1495111495' post='3301356']
Oh...that's interesting, samhay.

How do you get the blend? I assumed you would blend between the piezo pre output and the mixer output. Is it just a single pot off the mixer output? The PDF on the web site isn't overly clear....
[/quote]

Indeed, the MPM01 'detailed' information sheet is pretty poor. I would expect input and output impedance and some suggested wiring schemes at a minimum. (John - if you are listening...).
Sound like you may have this covered now though.

The MPM01 page confirms that 'Outputs can be mixed with the addition of a simple single gang blend pot.'
I assume that both the mixer and piezo outputs are low-impedance. The pictures of the unit show an 8 pin IC, which I assume is a dual op-amp, which would almost certainly be configured this way.

I would try a small-ish value pot - maybe try 10k - wired with lug 1 to the mixer output, lug 3 to the piezo output (or vice versa) and lug 2 connect to lug 3 of the volume pot. I would then use a 100k pot for the volume. You could scale these values up, but the key is to keep the mix pot much smaller resistance that the volume pot.
The problem you will have is that the tone control won't work very well if wired as for a passive bass - i.e from lug 3 (or 2) of volume pot. However, if you don't have room for a tone control anyway, then that problem is solved.

Edited May 19, 2017 by samhay

[Andyjr1515]

[quote name='Si600' timestamp='1495183187' post='3301870']
Why haven't you finished carving the front before starting the control cavity?
[/quote]
It's a bit iterative.

It's only the lower bout that's critical but where I've got to so far on that is the minimum curve I would be happy with:


I then need to work out how deep my chamber can go without breaking through the top, and how deep it needs to go to accommodate the components, the cover and the scoop at the back. If it's generous, then I will go back to the top and increase the curve a tad. If it's tight, it will stay where it is.

Also, what I do with the rest of the top carve will depend on what I've done to the back carve. So the sequence will be:
[list]
[*]Sort the back carve
[*]Review the top carve of the lower bout
[*]Finish the top carve
[/list]

...if that make any sense whatsoever!

Once I have the final top curve sorted of this boutcurve

[Andyjr1515]

[quote name='samhay' timestamp='1495183857' post='3301884']
Indeed, the MPM01 'detailed' information sheet is pretty poor. I would expect input and output impedance and some suggested wiring schemes at a minimum. (John - if you are listening...).
Sound like you may have this covered now though.

The MPM01 page confirms that 'Outputs can be mixed with the addition of a simple single gang blend pot.'
I assume that both the mixer and piezo outputs are low-impedance. The pictures of the unit show an 8 pin IC, which I assume is a dual op-amp, which would almost certainly be configured this way.

I would try a small-ish value pot - maybe try 10k - wired with lug 1 to the mixer output, lug 3 to the piezo output (or vice versa) and lug 2 connect to lug 3 of the volume pot. I would then use a 100k pot for the volume. You could scale these values up, but the key is to keep the mix pot much smaller resistance that the volume pot.
The problem you will have is that the tone control won't work very well if wired as for a passive bass - i.e from lug 3 (or 2) of volume pot. However, if you don't have room for a tone control anyway, then that problem is solved.
[/quote]
That's great info, samhay.

I've just read Jez's mail which pretty much confirms what you say - I'll post the pics that John East did for Jez...and drop John a mail suggesting he just adds this to his website to replace the out of date one that's there at the moment!

Thanks
Andy

[Andyjr1515]

[quote name='Jabba_the_gut' timestamp='1495179414' post='3301823']
E-mailed you the drawings Andy. Cheers
[/quote]

Brilliant!

In addition to a couple of more technical drawings explaining the shunt options, this is the one that, for me, clarifies the basic wiring options and is pretty much what samhay says above:


Now I don't reckon many of us would have been able to work that out without the diagram!

Many thanks samhay and Jabba_the_gut

Andy

[samhay]

^That all makes sense. Why that's not on the website escapes me.
John's potentiometer suggestions of 5k blend, 25k volume seem quite sensible, so that's what I would use. You may find it easier to get hold of 4.7k and 22k pots. These will work fine too.

[Andyjr1515]

[quote name='samhay' timestamp='1495185667' post='3301909']
^That all makes sense. Why that's not on the website escapes me.
John's potentiometer suggestions of 5k blend, 25k volume seem quite sensible, so that's what I would use. You may find it easier to get hold of 4.7k and 22k pots. These will work fine too.
[/quote]
Great - thanks

[TheGreek]

It's all Greek to me!!

[Andyjr1515]

[quote name='TheGreek' timestamp='1495191845' post='3301992']
It's all Greek to me!!
[/quote]

[Andyjr1515]

One of the jobs to be done while the back is still flat is the holes for the magnetic pickup coils:





The other is the rout to flush fit the hatch at the back that will cover those holes - which will be a longer version of this...

[Andyjr1515]

Final couple of jobs ready for starting the carve on the back over the weekend, MrsAndyjr1515 permitting.

I've glued a couple of sycamore fillets either side of the tuner block wedge and routed the back of the neck ready for the coils access cover:


The stripy cover will be flush with the stripy neck, and the body rebates will be carved down to the neck level as part of creating the concave curve at the back.

Edited May 19, 2017 by Andyjr1515

[Andyjr1515]

OK - couldn't wait until tomorrow

Back carve has started:

[Andyjr1515]

Softly, softly, catchee monkey,

[mcnach]

This whole thread is fascinating, wow

[Joebethell]

Stunning work. Liking the whole back carve and pickup area progress.

[Andyjr1515]

Thanks, folks. It means a great deal

[Andyjr1515]

The carve continues. I don't know if everyone else is the same but, after sorting a basic concept out and the absolute functional positions, I carve on the basis of removing what doesn't seem to belong and what creates the illusion I am attempting. It's a slow process and this is probably half way through time-wise... so another couple of days for the basic carve.

What I am trying to do is to create the illusion of the 'contact lens' without compromising the functional needs of the controls, neck and pickup provisions.

Here is is so far end on:


Mick doesn't want the edges to be sharp so the tip won't be much narrower than this, However, on the left hand side I will increase the under-scoop and bring the top radius just a touch closer to the fretboard.

The right hand side is scooped more once you get past the chamber, but I'm leaving the back flat until I've safely got all the electronics and cover confirmed to fit OK.

So there is a bit of artistic licence going on. Nevertheless, even though it will be even closer when finished, the radius does actually visually look compatible on the top:


... and it already is starting to look sleek and contact lensy:




Also, the neck carve will transform the look.

Maybe it's familiarity with the shape on my part and me now starting to see in wood what I've broadly had sitting in my head for the past few months - but don't you agree that there is an undeniable elegance creeping in here?

Edited May 21, 2017 by Andyjr1515

[JPJ]

I've got to admit that I didn't like the original concept. I'm a 'dyed in the wool' Fender shaped bass type of guy, who prefers big slabs of wood. But this is shaping up (no pun intended) to be something really special.

I love how the flame in the body wing wood has 'popped' as you've carved away the excess material, and the whole thing is a testament to your woodworking skills. One question though, how is the overall weight now you've done most of the wood removal and how is the balance?

[Andyjr1515]

[quote name='JPJ' timestamp='1495360004' post='3303173']
I've got to admit that I didn't like the original concept. I'm a 'dyed in the wool' Fender shaped bass type of guy, who prefers big slabs of wood. But this is shaping up (no pun intended) to be something really special.

I love how the flame in the body wing wood has 'popped' as you've carved away the excess material, and the whole thing is a testament to your woodworking skills. One question though, how is the overall weight now you've done most of the wood removal and how is the balance?
[/quote]
Thanks, JPJ

I must add the hardware so I've got for a better estimate, but at the moment it's sitting at around 5lb 4oz for all the wooden bits. That will reduce a tad with the carving of the neck then plus the tuner block and pickups, etc.

Balance wise, it's OK at the moment and the headstock equipment will be very light indeed so I suspect it will be fine. Difficult to know exactly where it will hang in terms of arm reach but, again, I have high hopes that it will be good

[Andyjr1515]

The basic body carve pretty much done - just need to check with Mick how rounded he wants the lower horn. Lots of sanding to do but here's how it's looking:







I talked about there being a drop-away after the 24th fret to at least provide a modicum of playing clearance from the bass's top. This is what I meant:


I've also deepened the control chamber and now know I can get a battery in and a cover on! So that and the pickup cover are shortly due on the list.

I can't carve the neck until the fretboard's on and I can't glue the fretboard on until I have the coils, that are being made at this very moment, so the covers are probably next on the 'to-do' list

Oh - and Mick and I are crystallising the design thoughts of the headstock...

Edited May 22, 2017 by Andyjr1515

[Owen]

You know, fancy dan wood tops are all well and good, but when you can follow the grain all the way round an instrument - that is where it is at!

[Andyjr1515]

[quote name='owen' timestamp='1495460356' post='3303882']
You know, fancy dan wood tops are all well and good, but when you can follow the grain all the way round an instrument - that is where it is at!
[/quote]

[Andyjr1515]

Mick and I are getting close to finalising the headstock shape and in the meantime I've been starting to round the edges:


Mick has asked that there are no flat surfaces anywhere so the headstock will also be radiused and rounded.

In the meantime I've just head that the custom pickup coils are ready

[TheGreek]

The beauty of the design is really starting to come through - look at how soft all the surfaces are beginning to look. I just hope that I don't get too precious about it and this doesn't become too beautiful to play.

Keep on doing what your doing, Andy..