Prostheta

If it was, I would recommend him highly since he would maintain the site with an active hand rather than simply maintaining it. Whilst I don't think he has a high degree of coding experience (that I am aware of anyway) he knows the ground, and will take it forward.

Would that be Jason by any chance?

Yep, that's me alright! If nobody else rises to the task, fantastic. Otherwise, I'll do what I can to maintain and develop it. Thing is, I tend to be a bit of a "new broom" and I think whatever is done should be representative of the labour you've put in Graeme.

That would be me. I spoke with Graeme briefly a few weeks back as I was genuinely surprised that we hadn't already crossed paths. For anybody who doesn't know me, I run ProjectGuitar.com and have been making bonkers-quality preamps for SB-1000s for a number of years now. I'd like to see somebody take the site on and keep her running in some form as it helped me a lot way back when also. I don't think I should throw my hat in the ring since I have a conflict of sorts, what with selling preamps and flirting with non-Japanese basses quite regularly.

I think you can shellac brass....

Keep me in the loop on this one Norris if you need help, or PM me on ProjectGuitar.com

You can always ask Veijo. I'm really not sure. Just tell him you're a friend of Carl in Pori.

What you'll have done is to set up a voltage divider. The input stages of each half of the differential preamp have 470k pull-down resistors. Refer to this: http://www.calculatoredge.com/electronics/voltage%20divide.htm It's not that straightforward, since the pickup itself has a DCR of about 11,8kOhms. Still, you can see the concept. Rb is the pull-down resistor, you have simply added Ra.

I take the phrasing of my previous message back; I understand in theory, however the input stage of the differential preamp has more or less a 14-18v peak to peak range before you start banging the rails. I doubt that any passive pickup is that hot by a long margin....even a hot dual ceramic bucker like an MB-I/1E! Regardless....it's good real-world information to take on. I'll pick this up with Veijo sometime soon.

Interesting. Curious as to why that would work....

I just realised....that suggestion didn't help....oops!

Very odd. This is where an oscilloscope would be handy.

You might want to see how it sounds after jacking up the bridge saddles to test what distance does before surgery. Pete is probably the best person for this one, however I suspect that there was little to no play in pickup height.

That of itself is an interesting observation. Does the pickup rout have the press-fit threaded inserts for the pickup or does it use simple wood screws? Worst comes to the worst, ask Andy to rout the cavity a few mm deeper to allow a bit more room for adjustment. I mean, it looks like it's sitting comfortably at a good height but a problem is a problem.

Firstly, congratulations! That is a restoration and a half. Given the initial condition, one would find it difficult to believe that was the same instrument. Seriously, top job. I'm not surprised that the pickup distorts the front end of your mixer. What came off the original pickups was hot to say the least, and I am sure that those and repros will clang against the rails quite happily on transients. I bet that had the BB circuit originally been designed to run off a single 9v supply it would have had....problems! That mid-range burp is perfect. Just perfect. Anyway. Can you find out how much shipping would be to Finland then? Ta.

It's difficult to figure out the source of that bit of noise without "opening up the patient". Graphite paint shielding is easy for the factory but not always effective. Unsure as to why though. It could be something as simple as a misplaced ground or a cold solder joint somewhere. Copper foil is probably a bit of a chore in the SB-1000 given the sheer amount of real estate in the cavities and the fact that the base is recessed around the pot locations, etc. I do stained glass work as an aside, so cutting copper circles for the recesses and laying strips around the perimeter would be no big deal. We have 1/4" foil kicking around all over the place, which is great for laying tracks under pickguards, etc. Just be mindful of shorts. That and mid-length pants too.

Sounds like the shielding could be improved, or a slight earthing fault exists. Don't trust graphite paint! Copper shielding throughout. Having to do this aro und the 5-string 51 P bass I'm fitting with a modified SB-1000 circuit. Hoping it silences even single coils!

PHOTOS!!!

Wow! That's quite an achievement. Also it seems, is the fact we've converted Norris' thread into an all-round SB-1000 maintenance love club.

[quote name='AntLockyer' timestamp='1431625932' post='2773402'] 1990 to 1994 second series SB1000s were 2 pick up. Allegedly [/quote] If they were, they were SB-1000s in name only. A new model number would have been more honourable.

Dichloromethane is bad stuff, Pete. I used a hammer. Not sure about a casing. I can't see why not, however I suspect that like myself Veijo will get enclosures made in batches and pot up all the stock as far as you epoxy stretches. He might have spares if he underrun on epoxy or none if he ended up with a free black lump :-) @AntLockyer - yes, the tone still works in active but is somewhat redundant. It is feasible to re-purpose that gang off the tone pot for other nefarious uses like a semi-coil tap or anything that a 25k linear pot can pull off in that ratsnest.

All SB-1000s have been single pickup. The SB-R150 was a two-pickup version, and those are super rare. The 1979 catalogue shows that the RSB-900 was also the same circuit as the SB-1000, but that was single pickup also. Other than the SB-R150 I can't recall any Mat active bass models as being dual pickup (however their guitars are a different thing altogether). The difference between the MB-I and MB-1E is that the original's coils were all connected internally with only a two-conductor wire and a shield available. The MB-1E was all out in the open FWIW, so you could modify it for series/parallel or coil cut. Hell, since the varitone takes the place of the tone control in active mode for the 80s SB-1000s, a nice fun mod would be to dump in a huge cap onto the half of the tone control corresponding to the active section and use that to dial out one coil as a "semi coil tap". It's more useful on guitar I guess, though. For all intents and purposes, the MB-1E is factory configured as an MB-I in how it connects to the loom. The only difference is that the connections are made externally in the MB-1E rather than internally. That's the crack isn't it, Pete? @bartelby - the MB-II has a bit more of a P-bass character than the MB-I/1E, which is essentially a dual Jazz with ceramic mags. Immense output, but depends on which character you prefer. If you like warm, go MB-II. That's my preference, at it turns out.

[quote name='AntLockyer' timestamp='1431596562' post='2772888'] I'm not so sure. Mine was up for sale for 15 months with only silly offers made. [/quote] A bit like Greece then. <edit: or No.10>

Obviously I don't say ALL of that a lot, only the main points.

I know I say this a lot, but the choice of words with "modern" components skirts a bit of an infamous line with us musicians, especially those that value "vintage" for no real world reason. The existing stock of preamps uses Yageo resistors which will eventually be upgraded to Vishay Dale RN55Ds. I do this just to ensure quality out of the gate, plus longevity and stability over the long term. There are no (and should be no) alterations in the function or tone, otherwise it would not be a satisfactory appropriate reproduction item. That is why I think "vintage-correct function/modern component benefits" is better. Noise inherent in the 4558 is not too far removed from the old 741 which is no surprise given they share(d) a relatively similar input stage and production methods. Back in the 70s when the 4558 was produced for the original preamps, you didn't have expensive fabs with ULPA clean rooms so die quality was highly variable. Old chips could be crazy noisy and real carburettor-era stuff without any carburettor benefits; a 4558 sucks about the same amount of juice as a 741! We're talking a dreary 16MPG '70s slug rather than a modern unleaded performance machine with a tenth of the fuel consumption (and no smoke belching). New 4558s are far better in terms of manufacture, however producing a Ford Cortina in a modern factory still leaves you with a Ford Cortina. The modern APII BB preamp still uses crappy carbon comp resistors and other "Maplin-grade" components. Then again, they're not intentionally making them as a "lifetime bass" out of the gate. You can see where the accountants have had their say. I make preamps which are total overkill in too many ways (non-Eutectic solder, 2oz copper traces, flux clean, etc.) but hey, Aspergers. In my book, basses like the SB-1000 are the "new vintage" which can be seen with prices going sillier each year. Replacing the preamp should logically be done with one that matches where Matsumoku SB-1000s are going in the vintage market. I want these preamps to last [i]at least[/i] another thirty years! Hell, I'll be in my seventies by that point (and we still won't have flying cars) and my vanity would like to imagine playing SB-1000s changing hands for 5-6 figures (8 with inflation) in a state that is as close to "restorable original" as is humanly possible. Depending on how life pans out over the rest of the year (hopefully Putin doesn't try messing with us, etc.) I hope to make a solder-free drop-in replacement SB-1000 circuit, so the original looms can be pulled and stored in a ziplock with a dessicant for preservation. ProTip: Even if they are not working. Vintage collectors are weird. ProTip 2: Keep a box of silica gel sachets from shoes or whatever you find them in. They're great for drying out phones or use a sockful on the dash in winter to prevent your windscreen icing inside overnight.