Norris Posted February 14, 2015 Share Posted February 14, 2015 [quote name='Bloodaxe' timestamp='1423936646' post='2690617'] Yup - a Series 1. The thinking on the dating-by-serial sketch has changed in the last year or so... It used to be that first digit = year, but it's got a bit more complicated as it looks like they changed the system in 1980. The new interpretation runs like this: Pre 1980 — MM-Y-NNN, where MM is the month (05 = May, 11 = Nov etc.), Y = Year (either 7, 8 or 9) and NNN = the production number for that month (not necessarily restricted to SBs) 1980 7 beyond — Y-MM-NNN(N), where it goes Year/Month/Prod. This should apply to Clarky's. At some point the production number went from 3 to 4 digits. [/quote] Thanks for the info. I've not seen it for some time but I'm pretty sure mine is pre-80 but with a 00 serial number. I should get it back soon Quote Link to comment Share on other sites More sharing options...
garyod7 Posted February 14, 2015 Share Posted February 14, 2015 Hi clarky - pretty sure it was mr who sold you it... The original was the one given as a spare to preserve it, installed the replacement one rather than play the original into the ground! Didn't sound much different which was great, if anything a bit clearer! Quote Link to comment Share on other sites More sharing options...
Bloodaxe Posted February 14, 2015 Share Posted February 14, 2015 (edited) Carl's got back to me & confirmed that the green one is one of his as seen on Ebay. The 'V1.3' doesn't apply to the circuit, but indicates PCB layout revisions. P. Edited February 14, 2015 by Bloodaxe Quote Link to comment Share on other sites More sharing options...
Prostheta Posted February 14, 2015 Share Posted February 14, 2015 Thanks Pete. I'll try and chime in with a few comments to clear up some misunderstandings about both the BB ("black box") and the SB-1000 tomorrow. Quote Link to comment Share on other sites More sharing options...
Prostheta Posted February 15, 2015 Share Posted February 15, 2015 Hi again - I'll do my best to work through this page's posts and clarify what I am able to. As we've established with Clarky72, his bass is a 1984 second-generation SB-1000 whose pre-amp has been replaced with the ones I manufacture. The smaller more compact box is the replacement pre-amp whilst the larger flanged box with the double-sided tape attached is actually the original. "Norris' pre-amp runs one battery flatter than the other" This might be in part due to the LED circuit loading one half of the supply and not the other; sitting over one 9v supply and not the full 18v potential. The LED circuit is a simple blinker which only operates when there is battery power. There is no battery monitoring going on, except for "I'm monitoring your batteries by slowly killing one of them faster than the other". Component aging makes the caps on that (of itself weird) circuit become leaky and pushing spikes onto the supply rails which the BB can't discard as noise. A lot of people rip that LED out because of that. I don't blame them. I'd rather use up the fourth pole of the 3/4PDT to make an active/passive indicator using one high value resistor, a low-current LED and running it over the full 18v. That's just me though. "Thin farty noises" Those are guitarists and totally not the fault of your bass, Norris. The photo of the spare pre-amp is one of the second generation of BB pre-amps. In essence they are identical to the originals except that they include reverse polarity protection diodes. Whilst this isn't the most common mode of failure in BBs (that would be the trashy 70s Tantalums) they do protect the pre-amp from accidental reversal when fitting new batteries. Whilst you have a jack in the socket. In the real world, who does that? The socket is on the face of the bass which would be face down whilst operating within the ratnesting of cables going on in the SB-1000. Simple best practice, but perhaps not so from a manufacturing perspective. Nice weird you have going on there, Aria. "Unused pins" The first generation of SB-1000s ("batwings") were fitted with an MB-I pickup which had different internal wiring to the subsequent MB-1E. The MB-I could be coil split and (if I recall this correctly) the shielding wire was connected to the end of one of the coils? I haven't looked at this pickup configuration issue for a long time so feel free to fill me out on where I might be forgetting things here. The shielding of the pickup is still connected to ground in both circuits, albeit not through the connection in the pre-amp in some circuits is all. Feel free to do a continuity test between pin 8 and the shield braid of the pickup. ;-) It makes more sense to earth the shield closer to where that cable is anchored (the switch) rather than making a separate run to pin 8. A star ground near to the switch is good practice if you're making up an SB-1000 loom from scratch. "11-pin BBs" Don't exist. I would like to be proven wrong because I love anomalies and picking them apart. This diagram was a PITA for me at one point. So I changed it to reflect reality instead. It might be that a limited run of 11-pin BBs were fitted to two-pickup instruments like the SB-R150 (I still want to capture one of those in the wild for "permanent examination") however I am sure that the pickups would be switched rather than individually sent through the pre-amp. Then again, Aria were certainly weird and fundamentally Japanese. "Enjoy The Gig With.... diagram" That is the first generation SB-1000 which was active only. [quote]“Everything should be made as simple as possible, ... I think nature teaches us that, and we learn it time and again in work and in life. - Albert Einstein[/quote] "Bizarre dual-gang pots" Yes, they are bizarre. Nobody makes them and for good reason. Nobody uses them. The reasoning for these in the second and subsequent generation SB-1000s is that you have two completely separate circuits living in there. On one hand you have what is more or less a first-generation SB-1000 circuit (active) whilst the second gang is passive. The output impedance of an active circuit can be far lower than a passive circuit, so the values of each gang reflect that. The active gang uses pot tracks in the order of 20-25k and uses a tone cap reflecting that difference in the LPF RC tone control. A lower impedance allows for less treble loss over cable runs from cable capacitance, no pickup loading and all that other good active stuff we love. The passive circuit on the other hand is your vanilla circuit. "RI BB circuit" I spit on this for a number of reasons. For one, it adds more complexity to the circuit which is does not need or benefit from. The SIL across the left is a Mitsubishi alarm control chip which serves as a battery blinker (ask me why mixing digital and analogue circuits onto one boards is bad practice), however my real issue is with the addition of transistors to the mix. The circuit does not need them. Also....tiny cheap carbon composition resistors? One would like to think that some effort were being made to kill all noise wherever it might appear....metal film resistors are not expensive, and given Aria's slack decision making in banging extraneous components in there anyway they could at least go that extra mile. The jury is out on whether the RI is any different to the original circuit, or is it? I have nothing to weigh in here other than the proliferation of what I see on the boards. "Mad Inventions" The work on that site is 100% correct as per the first generation BB. At risk of sounding like I am "pushing my product", I do question the component choice for the same reasons as the previous comments. Go big on everything; durable Nichicon caps, better ICs and socket and low-noise metal film resistors. In this case, "vintage-correct" is probably not for the best :-) "first/second generation BB compatibility" 100%. The only difference internally is the addition of reverse-polarity diodes. I've oven-baked, taken a hammer to and marmalised five different v1/v2 BBs and haven't seen any real oddities. Some questionable soldering and acid flux being left in situ (a minor failure possibility) but nothing that would make any of them incompatible. "BB circuit trace" (Pete) Yep, that's the plain old v1 circuit. The soldering is better on that one than the ones I've demolished. No cold joints or solder blobs to be seen! "v1,3" I only marked up the PCBs to differentiate between what was in stock. I upgraded components in addition to the PCB on this one. These were still single-sided boards whereas the newer ones (v1,4) are double-sided. Minor component placement changes also. This only removes the jumper link really, but does allow me to run a wide ground plane across the top of the board to capture any stray signals. In testing I couldn't find any difference between these revisions other than some minor satisfaction for my obsessive attention to detail. In other news, I am finishing up a custom bass build I started last summer. Work has caught up with me on my degree so everything has been crawling along at a pace I am not entirely happy with. The bass itself is a 5-string version of a '51 P-Bass which I have decided to equip with a single pickup and a hybrid Noisekiller circuit. Active only, with a volume and a varitone. I'll report in with more at some point! I really should get that pickguard cut.... [attachment=183943:10649078_10152850705510676_7367130201754990187_o.jpg] Quote Link to comment Share on other sites More sharing options...
Norris Posted February 15, 2015 Share Posted February 15, 2015 Thanks for a great informative post. However my mk 1 doesn't have an LED. I ended up putting a small piece of gaffer tape on the battery lead of the one that flattened quickest so I knew which one to change Quote Link to comment Share on other sites More sharing options...
Prostheta Posted February 15, 2015 Share Posted February 15, 2015 (edited) No problem! Happy to share. I should have put two and two together and realised that yours is a first gen SB-1000. I'll have a look over the circuit again and figure out why it's lopsided on the supply end of things. That's quite weird. Short of a component age issue in the BB itself, nothing springs to mind in the design at the moment. I guess you could measure the current consumption of each side of the supply. Another possibility is one pole of the DPDT switch in your jack socket might be seized closed, causing the battery to permanently be in circuit? Edited February 15, 2015 by Prostheta Quote Link to comment Share on other sites More sharing options...
Norris Posted February 15, 2015 Share Posted February 15, 2015 (edited) Like you said, it's active only. The switch alters the tone but it doesn't make any sound without batteries in it. It put me off active basses - every bass I've bought since has been passive. It's always drained batteries quickly. I bought it second hand in around '86 Edit: I'll check the jack socket power switch when I get it back. Although there's only one if I recall, which disconnects both batteries Edited February 15, 2015 by Norris Quote Link to comment Share on other sites More sharing options...
Prostheta Posted February 15, 2015 Share Posted February 15, 2015 I'm not sure of the battery life of the original 4558s, but it doesn't look fantastic on paper. They're early 70s design and the supposed mojo about them in overdrive pedals is just a myth. It wouldn't surprise me if the Tantalum supply smoothing caps in the BB were just leaking current. 4558s are a minor step up from the legendary u741 in terms of junk mass tech. Cheap is the word. Quote Link to comment Share on other sites More sharing options...
Clarky72 Posted February 15, 2015 Author Share Posted February 15, 2015 Thanks for all the info Carl, and thanks Pete too! Yes Gary, I think it was you I bought the bass from! I get a huge variation in tone when I flick the switch, it brings the bass to life. I'll double check the impact at full left on the varitone tomorrow evening for dead sure, I usually run with one of the middle settings, 3 or 4. I'll get some more pics with the loom out of the way tomorrow too! Quote Link to comment Share on other sites More sharing options...
AntLockyer Posted February 16, 2015 Share Posted February 16, 2015 Now I'm really confused. I've got a series 1 and always assumed it was passive with the switch on the rearward most position. What is being switched in and out if not the pre amp? Quote Link to comment Share on other sites More sharing options...
Norris Posted February 16, 2015 Share Posted February 16, 2015 [quote name='AntLockyer' timestamp='1424078105' post='2692161'] Now I'm really confused. I've got a series 1 and always assumed it was passive with the switch on the rearward most position. What is being switched in and out if not the pre amp? [/quote] I must admit it's always confused me too Quote Link to comment Share on other sites More sharing options...
Prostheta Posted February 16, 2015 Share Posted February 16, 2015 The first generation SB-1000 was active only. No passive option at all. The switch brought the varitone in or out of circuit. Have a look at the circuit diagram posted previously if that makes sense. Quote Link to comment Share on other sites More sharing options...
Clarky72 Posted February 17, 2015 Author Share Posted February 17, 2015 Here's the best I can get of the pots. Quote Link to comment Share on other sites More sharing options...
Clarky72 Posted February 17, 2015 Author Share Posted February 17, 2015 So they are stacked pots. Quote Link to comment Share on other sites More sharing options...
Prostheta Posted February 18, 2015 Share Posted February 18, 2015 Yep. It states both values on the upper (lower?) casing; 20k and 500k. Quote Link to comment Share on other sites More sharing options...
Norris Posted May 5, 2015 Share Posted May 5, 2015 If you don't mind me resurrecting this old thread (as it's relevant)... I have just got my SB-1000 mk1 back from a refinish but have a bit of an issue with the tone selector. The volume seems to drop a lot with each step away from 'bright'. Any idea why? The rest of the controls seem to work fine and I've had the worn out jack socket replaced. It's working lovely apart from the tone selector rotary switch Quote Link to comment Share on other sites More sharing options...
Norris Posted May 5, 2015 Share Posted May 5, 2015 Actually I just compared it to another (passive) bass and the volume is way down. Quote Link to comment Share on other sites More sharing options...
Bloodaxe Posted May 6, 2015 Share Posted May 6, 2015 How does it fare with the varitone switched out? Is it the original BB circuit or one of Prostheta's re-issues? Quote Link to comment Share on other sites More sharing options...
Prostheta Posted May 6, 2015 Share Posted May 6, 2015 The rotary is a hardcore LPF so some drop is to be expected, but a large drop in volume might be an issue. Possibly old components? The only way to know for sure is to AB it. I haven't gotten around to making replacement rotaries yet. Designing a PCB to make it simpler to choose values first... Quote Link to comment Share on other sites More sharing options...
Norris Posted May 6, 2015 Share Posted May 6, 2015 It's the original circuit, so is 35 years old. The bass spent a couple of years in storage in less than ideal conditions i.e. slightly damp - and hence why it's had a complete refinish. So there is a high probability the circuit has degraded. The rotary tone selector works to a certain extent but the output in all modes is way too low. Possibly an op-amp not working correctly? Quote Link to comment Share on other sites More sharing options...
Bloodaxe Posted May 6, 2015 Share Posted May 6, 2015 [quote name='Norris' timestamp='1430894382' post='2765564']It's the original circuit, so is 35 years old. The bass spent a couple of years in storage in less than ideal conditions i.e. slightly damp - and hence why it's had a complete refinish. So there is a high probability the circuit has degraded. The rotary tone selector works to a certain extent but the output in all modes is way too low. Possibly an op-amp not working correctly?[/quote] Could be the op-amp on the fritz, but the reference to "damp conditions" makes me think that the contacts in the varitone switch might have become oxidised. If possible, shoot some switch cleaner into it and give it a good going back & forth. Same goes for the toggle switch. P. Quote Link to comment Share on other sites More sharing options...
Norris Posted May 6, 2015 Share Posted May 6, 2015 [quote name='Bloodaxe' timestamp='1430895476' post='2765572'] Could be the op-amp on the fritz, but the reference to "damp conditions" makes me think that the contacts in the varitone switch might have become oxidised. If possible, shoot some switch cleaner into it and give it a good going back & forth. Same goes for the toggle switch. P. [/quote] Good call. I've just whipped the black box out of the bass and it looks in good condition. The potting compound is still shiny and looks well sealed. The volume is still well down though even with the rotary control switched out. Still going by the link to the chap that reverse engineered his mk1 circuit, there's not a lot in there. I might follow him and make a replacement. Time for a trip to Maplin I think. Btw to confirm, mine has the 10 pin connector Quote Link to comment Share on other sites More sharing options...
Bloodaxe Posted May 6, 2015 Share Posted May 6, 2015 [quote name='Norris' timestamp='1430897223' post='2765583']The volume is still well down though even with the rotary control switched out.[/quote] On the basis of that, there's a few things I'd be inclined to try before going down the BB re-creation route... 1: Measure the pickup's DC resistance just to see if it's on the low side - it **should** read 11-12kΩ. 2: Wire the pickup direct to the jack & compare volumes (i.e. bypass everything). 3: Wire the pickup direct to the V & T circuit & compare (bypass BB & Varitone). That should give an idea if the problem lies somewhere other than the BB. P. Quote Link to comment Share on other sites More sharing options...
Norris Posted May 6, 2015 Share Posted May 6, 2015 (edited) Thanks. I'll give that a go and let you know Edit: Just in case I need to find the Kent Armstrong page again for a replacement p/up ... http://www.armstrongpickups.co.uk/miscellaneous-pickups/ Edited May 6, 2015 by Norris Quote Link to comment Share on other sites More sharing options...
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