Prostheta

Are you going 9v or 18v?

It looks like the black triangle is shorthand for a connection to the fifth point along the connector, at least in the diagram. There are 9+2 wires in total on both the PCB and the diagram, so the virtual earth 0v created by tying the two batteries together looks like it should be going to the black wire, or the sixth location across. Do not tie the virtual earth 0v to ground! This is part of how this differential preamp works....it might still function (I've not thought about this enough yet) however it loses some of the functionality in how it rejects noise. All the ground connections go to the pots, yes, so how you illustrated it in red is spot on. If you get hum that goes away when you touch the hardware, add a ground wire to the bridge. Just keep that 0v isolated from the grounding, since they're not the same thing.

I know right? I feel so weird in that I enjoy the process of design/development/problem-solving more than the end result. I just need to locate some good quality axial capacitors for the rotary tone filter in the right range. It works with that in isolation, and boy does "work" feel like an understatement.

Just finishing up the electronics and rear control plates (hence the peeking blue tape). Nobody gets to mention the wonky 7th fret under threat of floating home, kid. Plays really nicely, the active electronics make the fundamental very detailed rather than flabby. Currently figuring out whether I want to have a single switch for the varitone in/out or an additional one for series/parallel, coil cut, etc. This is a lot of bass.

That's a logical extension. I like the puzzle aspect of putting together a clearer picture on the why and wherefores of all sorts of things. For my own part, I enjoy reading into how modern instruments were made, and a little of the pressures and solutions behind those reasons. Detective work such as this helps stave off that "aging mind blindness" that we all seem to get from time to time. A hollow behind a fingerboard isn't something that I've seen in modern instruments so far, which leads me to think that in the absence of a practical reasoning then it could well be blind copying. I'd say that established practice is equal parts superstition/tradition and reasoned design....if instruments were made by master-apprentice or families of makers, aspects could easily be handed down without questioning the basis behind this or that. Of itself, that's a fascinating thing to see when laid out. Feasibly - having idly thought about this - it could be weight reduction or even to introduce stability. Disruption of growth rings in a workpiece reduces warping from moisture/dryness. Removing material from the top of the instrument makes it less ungainly, but not massively so. We may never know unless those hypotheses are tested.

Hmm. What purpose did that serve, or what design pressure caused that to be introduced? It doesn't seem immediately obvious as to why.

Fantastic! Thank you very much. This will be an excellent read on so many levels. It's interesting how the soundboards in recovered examples all used Oak and Maple; both hardwoods. My first instinct would be for those to be softwoods like Kuusi/Spruce. I presume that these would be more likely to dissolve in time if they were used, skewing the apparent representation of their use? I might be tempted to make one at some point in my life, in spite of me knowing that I have a vast capacity for ideas that I can't practically pursue

That's pretty much what I thought, if you could put what I do into words as "thinking" Is there much discussion on the evolution of the instrument family? I presume these things were very widespread at some point with variations popping up here and there rather than a linear line of changes. I suppose that you could easily fill a whole book full of prehistoric instrument development given that music is a universal factor wherever you find humans.

Giving everything a custom touch specifically for the project makes a huge difference.

Very interesting background information. I just remembered Maria Franz played an instrument from this same family on a track with Christopher Juul. Two members of Heilung, a "living history" musical performance group. Same, or similar? I would imagine that the cost of instrument maker's copies being expensive due to the speciality rather than complexity. As a fellow Yorkshireman, I share that same instinctual sentiment.

Agreed on pretty much everything there, but especially on the whole "vintage correct" thing. That said (the contrarian that I am) the term isn't as clear as it should be. On one hand it pays respect to the weight of experience and knowledge gained through the evolution of the craft, whilst on the other it implies a backwards-looking insistence on maintaining old methods for the sake of it. In that respect, learning about "vintage correct" methods with the right eyes allows you to divine the whys on the choices behind methods, perhaps a degree of the constraining forces but generally a better grasp of how much you can take from old ideas to form your ongoing personal scheme of things. Yes, definitely. Changing a wood's colour radically through dye/stain kills chatoyance and makes it look like a veneer. The exact reason that dyes accentuate the figure is that it is harder to remove from end grain of rising/falling fibre ends than it is from the side of fibres. The more work you need to put into a sandback because of heavy accent colours, the less natural it looks. It's far better to do multiple light sessions of highlighting with say, tobacco and amber in various mixtures than it is to use coarse heavy pigments like blacks. To really pop the figure, shellac makes Maple pretty killer but there's a lot of consideration on the exact ordering of what quickly becomes a very complicated schedule. I've never been a fan of tobacco bursts either. My personal favourite "look" is the slightly sick looking honey-green of a faded burst. It's right in the same field as the wood underneath, so it has a wonderful warm organic glow and texture. One of those things that I'll spend another ten-twenty years hunting down just to get right for that-one. Which is weird.

It looks a lot better in motion than in the still. Is that the case? I'm certain that I recommended 8Bomb Custom's videos on YouTube, however if I didn't then I would be at fault for not mentioning. His work is deeply trad-repro sort of stuff, but his approach shows that level of subtlety and detail which take things so many levels up. I'm sure you'll take a lot from it. Everything that he does seems to be toner rather than stain/dye. I've always wanted to try my hand and extend my skills out to there, but it's so much time and investment that I keep remembering how many hours there are in a day. And that I need to sleep during some of them. ....plus he uses aniline specifically because it fades, and he UV bombs it in pt. 4

Oh sure, plenty of people have used Lignum Vitae. Moreso years ago when supply was better and the whole "exotics" thing was less fraught with conscience-destroying....well, you know what I mean. I look at it pretty much the same way, that its specific properties are suiting the end use. For a fingerboard, hmm, difficult to say. I'd want to hint at fretless bass here, however oiliness is not the key but durability. Saddles and nuts would be perfect, and I believe that Carl Thompson has used LV in wooden saddles in a fully-wooden whale-tail bridge before. I don't fully imagine that the oiliness offers all that much to an instrument beyond what "traditional" choices do, which is already very little. I fully support experimentation of course, but I'll add a bit of experience of super-oily woods to this to help form a better methodology. Stripping surface oils with a solvent only goes so far. The remaining oils/extractives in the piece will migrate across that gradient in no time, causing any delay in glueing to reduce success or encouraging failure over the longer term with "less suitable for purpose" glue types. Woods such as Cocobolo are about as oily as you can go before special measures are required, and even then it can be dicey with some pieces, however PVAc can still glue Cocobolo well if everything is done correctly. I'd recommend physical keying of the surface (80 grit sort of idea) and consider using a mechanical adhesive such as epoxy or urea formaldehyde. PVAc and other water-based glues have an extremely difficult time forming a strong wetted film between the mating substrates. With super oily woods (Teak being one I have used the most), wiping with acetone and using a resorcinol-formaldehyde glue has always been most successful, the end use being marine. An initial adhesion might not be indicative of long-term service.

B3 is very standard. I've most commonly seen it in drums at my workplaces. For everything but parts under tension (see creeping issue) it's a solid choice. The only thing I don't like about it is the cosmetic glueline, but that's easily sorted with tight joinery work and correct clamping pressure.

Well, that brought it back home. A little clear changes a lot.

Lignum Vitae isn't much use on a guitar really. It is however, excellent as the sole of a plane or water bearings. My last teacher turned one for a water mill in Noormarkku, and said that it was throwing water all the while. It seems too far a throw from typical woods to be useful.

It might creep under tension or other load, for example a scarf joint or neck joint. It's an issue.

I'm always circumspect about any product bought from a hardware store, since the expectations of performance at "consumer grade" are always less precise and generally lower than "professional", simply because they don't need to be and it's cheaper to produce a vaguely glue-like product than an engineered consistent one (I exaggerate). D3 as a term is only an indication of suitability in a non-dry environment, and I think Titebond Original/I might even just be a D1 or D2 adhesive. Once manufacturers start publishing technical specifications for an adhesive of course, you're instantly working with a product that is engineered to a working standard as opposed to "good enough to go on the shelf". Gorilla Glue or any of these other "brand" names are meaningless, and I would rather pay more for a product that I know will work as specified, not "as implied". So yes, exactly. Titebond isn't better by any specific means, but it's consistent and known to work. That's worth the ticket for entry right there. I don't subscribe to the whole "transfer vibrations" thing when it comes to glues. An ideal glue film is so thin that it's negligible by comparison to plain old good woodworking. Too many good conversations have gone to ass by ending up as a deleterious navel gaze. In some cases a circle gaze! hahaha Bottom line with Titebond. Don't buy Titebond II or Titebond III as they're intended to have a degree of plasticity to the adhesive to retain joint strength whilst the wood flexes with moisture intake/loss. This is nothing that a guitar needs to consider. Titebond Original all the way. As a point of interest, I heard talk that Gibson used urea formaldehyde glue (fenoli liima) for bonding the Maple caps onto the Mahogany backs of Les Pauls back in the 50s. Whether this is true, partially true or completely false I did a test and found that it produces a superb bond with a very glassy thin film. If this were practical for enthusiast use, I would advocate its use more. It's dodgy stuff in that the jury is out on whether it will kill you or not. Likely, the jury is out getting fresh air from the stink of the glues in the evidence bins! Piltti jars are great for all sorts of parts as well, but not so good for shellac storage as the top gets glued shut....

No wedge needed. It would be superfluous to requirements. I did a hunt in my photo archive and couldn't find a good example, never mind how I learnt about this. I'd like to say that I picked it up from Chris Verhoeven and/or David Myka. I might be wrong, however I am pretty certain.

I break mine out into empty bottles of Turun Sinappia! The gallon jug isn't exactly a precision instrument

When building a neck joint using a tapered tenon, the mortise in the body is extended backwards to say, the back end of the neck pickup rout. Because of the taper, it's wider so the neck tenon can be inserted vertically without mechanically scraping adhesive from the sidewalls. A clamp reversed into a spreader pushes the neck forward into the narrower portion of the taper which provides a tighter fit without need of easing. Obviously this is nothing to do with the hairline space, but it made me think of this technique. For heelless neck joints, it's a neat trick.

Funny, reading back on these old conversations. Plektra Trading are ridiculously expensive, still. I bought a gallon of Titebond from Axminster in the UK before that dumb Brexit thing they did. FWIW, a lot of standard D3 glues like Kiilto's basic adhesives are just as strong. Metal pickup rings might be just as good as covers.

I'm surprised that you managed to close up the gap that way, and I don't know whether it'll be permanently closed or is sat waiting to open itself up when you turn your back. Neck joints can be a bit weird. Since you use fulĺ-width tenons (at least here, anyway) have you considered extending the mortise a little further back, allowing the neck to be fitted at the looser end, then pushed into place with a spreader? That is by far the strongest layup, however the remaining gap behind the mortise seems to send some builders into crazy lunatic fits of disgust and paranoia!

That sounds like good news. I presume that you've worked African Blackwood before? It smells amazing but likes to kill tooling and burn up a treat. It is amazing stuff though, and a good choice.

It's difficult for me to comment on the neck block repair without physically inspecting it, however I feel somewhat doubtful that anything more than a cosmetic repair can be achieved from the outside. The dovetail or tenon inside the body is where the real repair may lie. If you're able to manipulate the neck enough to get glue to work around the crack, it should be apparent whether the joint itself is good or not. That said, steaming off the entire neck when the problem might simply be cosmetic is a mammoth task just to flick a stray hair out of your vision! After a little reflection (and Internet searching) I found this to illustrate the point better: https://www.tdpri.com/threads/full-crack-in-neck-heel-of-acoustic-bass-how-to-fix.847809/ If that crack extends through the dovetail (likely) then any issue is likely going to be hidden and/or delayed from reappearing. The tooled-up repair would be to remove the fret directly over the neck join, razor the lacquer around the seams, drill out a hole through the fret slot and force steam (Espresso makers are a popular choice, oddly) into the joint to remove the neck. To recover a Brazilian Rosewood instrument, this isn't entirely unreasonable. The bad news here is that PVAc glues are terrible to remove when doing repairs, as they don't clean up or work well with finishes/stains. If the instrument plays, then put it into service. If it proves to be unstable or unplayable, then consider the hard route....possibly professionally if the right tools are not to hand.