ChavSpaniel Posted October 19, 2021 Share Posted October 19, 2021 Aria pro ii BB noise killer circuit. Apologies for bringing a guitar into a bass forum. I have acquired an 1979 Aria Pro ii nk-700 which has the same noise killer circuit as in the later SB-1000 bass guitar. When the volume is very low it sounds awesome and full. But anything above 1 (on a scale of 1-10) becomes almost white noise. I have replaced the batteries in the circuit. The pickups are not the original power plus, but a PJ Marx in the bridge and some kind of super distortion in the neck. Probably changed some time in the early 80s. Weirdly they are both reading about 18 ohms when I measure them which doesn’t seem right. (They are crazy hot 80s pickups, but not that hot). Although the pickups have been replaced, it doesn’t look, to my casual eye, as if anyone has messed around with the rest of the circuitry. There is a black box in the middle of it all and I read on an old thread on this forum that this component can die, leading to this white noise and needs to replaced. I also read that there was a gentleman who made replacement black boxes and sold them on ebay, but the link had expired. Any help on this would be much appreciated. It is an amazing old guitar. many thanks, Ian Quote Link to comment Share on other sites More sharing options...
Bass Culture Posted October 19, 2021 Share Posted October 19, 2021 @ChavSpanial - the person you're looking for is our very own Prostheta. He made the repro BB noisekiller for my recent Zoot ZB-1000 bass - a fantastic sounding bass. Here's a link to a current auction on ebay: https://www.ebay.co.uk/itm/264696877010?hash=item3da129cfd2:g:CBIAAOxyBXNSU-Jh I'm sure you'll be able to contact him through Basschat too if you want to ask him any questions etc. 2 Quote Link to comment Share on other sites More sharing options...
ChavSpaniel Posted October 19, 2021 Author Share Posted October 19, 2021 Fantastic. Thanks for the quick reply. I have sent Prostheta a message via ebay. 1 Quote Link to comment Share on other sites More sharing options...
Prostheta Posted October 22, 2021 Share Posted October 22, 2021 Morning all, and thanks Mike. A new batch will be fabbed within about a month or so. Sourcing has been a mild nightmare due to the usual political and viral suspects, so I've decided to invest a bit more heavily and do a "doomsday prepper" level of stocking up. Congratulations on the NK-900! You don't see that many kicking around, and especially not ones needing the preamp! I think it's likely that a lot of owners with faults simply gutted them to passive, same as a lots of SB-1000 owners/acquirers. In principle the circuits are almost identical with the difference being the varitone values. It might be worth documenting those for future reference since APII never let their production schematic out from what I know. The replacement pickups work fine in this type of circuit, as will any pickup really. I've built both guitars and basses around the BB preamp and they're inky-quiet, even my custom single-coil 5-string '51 P-bass. Do you want me to keep you updated here? I'm leaning away from eBay right now, since I'm forced to use tracked mail (expensive) and their fees are astronomical amongst many other things. I'd rather try to keep costs lower instead of having to pass them onto customers, which is far more critical given the increase in well, everything these days. 1 Quote Link to comment Share on other sites More sharing options...
ChavSpaniel Posted October 23, 2021 Author Share Posted October 23, 2021 Thanks Prostheta. Updates on here would be perfectly fine. I’ll check back here periodically. Quote Link to comment Share on other sites More sharing options...
Prostheta Posted November 14, 2021 Share Posted November 14, 2021 Apologies for not picking up your post! For some reason I don't get notifications from BC. I'll be finishing up the next batch of preamps Tue-Wed this week. Quote Link to comment Share on other sites More sharing options...
ChavSpaniel Posted November 17, 2021 Author Share Posted November 17, 2021 What’s the best way to acquire one, still ebay? Quote Link to comment Share on other sites More sharing options...
Geek99 Posted November 17, 2021 Share Posted November 17, 2021 Does that kill noise on all guitars ? Just wondering …. 😉 Quote Link to comment Share on other sites More sharing options...
Prostheta Posted November 17, 2021 Share Posted November 17, 2021 (edited) It's best PMing me as I can do a way better price than I have to do on eBay. Their fees and requirement for fully tracked shipping ends up costing clients more than they should have to spend. That and eBay seem to be leaving sellers out in the cold more and more these days, or sellers having to turn the screws on buyers to turn a penny. Neither are cool in my book. Kill noise on all guitars or just kill guitars? 😉 Well, yes and no. The preamps work by floating the pickups around a virtual earth with a +9v/-9v supply rail, pretty much like a DI box, but in this case an active DI box I guess. The varitone filter is an active part of that circuit. The impedance is silly-low, so when combined with lower value pots (10k-25k) you get a robust signal that doesn't get rolled off by cable capacitance and all those negatives. Noise still occurs on some level, but only the stuff that you can't get rid of in any instance. Things like Floyd Roses or Telecasters. Those are pretty tenacious and require a 10kV active circuit to the noggin to remove. I just fabbed the new batch today and am taking a break in testing before encapsulating them. The messy bit. Get 'em whilst they're a few degrees above room temp! Edited November 18, 2021 by Prostheta 1 Quote Link to comment Share on other sites More sharing options...
Geek99 Posted November 17, 2021 Share Posted November 17, 2021 Just Killing all guitar noise is fine by me - they don’t need to die as without a guitard they make no weedy sounds Quote Link to comment Share on other sites More sharing options...
Prostheta Posted November 19, 2021 Share Posted November 19, 2021 (edited) On 19/10/2021 at 19:04, ChavSpaniel said: The pickups are not the original power plus, but a PJ Marx in the bridge and some kind of super distortion in the neck. Probably changed some time in the early 80s. Weirdly they are both reading about 18 ohms when I measure them which doesn’t seem right. (They are crazy hot 80s pickups, but not that hot). Although the pickups have been replaced, it doesn’t look, to my casual eye, as if anyone has messed around with the rest of the circuitry. There is a black box in the middle of it all and I read on an old thread on this forum that this component can die, leading to this white noise and needs to replaced. I forgot to pick up (no joke intended) on this part of your opening post Ian. The high DCR doesn't tell us much without knowing the wire AWG or number of turns in the coils. They do seem a bit hot, however given that the 80s were when experimentation and crazyness went full-on in the new aftermarket world, it's difficult to say. I've seen all sorts of weird values for coils that are intended for active circuits from ridiculously-low ('86 Aria Pro II Integra and SB-Int, only a few k and super hifi) to rare fault conditions in pickups with DCRs in the regions of MOhms that are still able to drive the ultra-high impedance (TOhms) of a preamp without issue. Coincidentally, the pickups in SB-1000s and others that use the MB style have a tendency to fail by going high resistance. Normally pickups drop in DCR through corrosion shorting or just go dead. These pickups were wound for passive end use, so that doesn't add anything useful to the mystery....especially when they are both reading oddly-high DCRs. Perhaps the explanation is that the previous owner who modded it was under the impression that high DCR means more tone? Edited November 19, 2021 by Prostheta Quote Link to comment Share on other sites More sharing options...
ChavSpaniel Posted November 25, 2021 Author Share Posted November 25, 2021 Installed the new preamp this morning. Instant fix. The guitar sounds amazing. The cleans are lovely and full, but it gets to breakup very quickly. Probably a combination a Marshall DSL 20 head and the 10 inch speakers from a mini stack and the very hot pick ups. Full gain causes the speakers to collapse. Will try a cleaner amp with more head room this evening. Will also look for some original power plus pickups online. Many thanks to Prostheta! 1 Quote Link to comment Share on other sites More sharing options...
Prostheta Posted November 26, 2021 Share Posted November 26, 2021 Congrats on NGD! Great to help keep these vintage birds flying. Quote Link to comment Share on other sites More sharing options...
tatxin32 Posted June 14 Share Posted June 14 Hello, I think the same thing happened to me on an Aria Pro II SB 1000 bass, the noise eliminator circuit is broken. We have tried to subtract it with the schemes we have seen out there, and make a new black box, but nothing remains the same. could you help me ? Quote Link to comment Share on other sites More sharing options...
tatxin32 Posted June 14 Share Posted June 14 this is the current state of the bass Quote Link to comment Share on other sites More sharing options...
Norris Posted June 16 Share Posted June 16 I don't know if @Prostheta still comes on here, but he's your guy If/when he makes any black boxes he sells them via eBay Quote Link to comment Share on other sites More sharing options...
Hellzero Posted June 16 Share Posted June 16 Here it is: https://www.ebay.com/itm/265814794036 1 Quote Link to comment Share on other sites More sharing options...
Norris Posted June 20 Share Posted June 20 On 16/06/2024 at 10:22, Hellzero said: Here it is: https://www.ebay.com/itm/265814794036 That's it. The postage is a bit high because he's based in Norway. You won't get a more accurate reproduction of Aria's original circuit anywhere else though Quote Link to comment Share on other sites More sharing options...
tatxin32 Posted June 23 Share Posted June 23 ok, thank you very much, I will try to mount it on my aria pro II and then I will comment, thank you very much again 1 Quote Link to comment Share on other sites More sharing options...
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