Norris Posted November 28, 2015 Author Share Posted November 28, 2015 Update: I've finally got around to slapping a pair of 10K resistors in line with the pickup wires and it seems to have cured the distortion. I'll take it along tonight and give it a blast during sound check Quote Link to comment Share on other sites More sharing options...
Prostheta Posted November 28, 2015 Share Posted November 28, 2015 Interesting. Curious as to why that would work.... Quote Link to comment Share on other sites More sharing options...
HowieBass Posted November 28, 2015 Share Posted November 28, 2015 [quote name='Prostheta' timestamp='1448731798' post='2917740'] Interesting. Curious as to why that would work.... [/quote] Are the resistors attenuating the signal level so it doesn't overload the pre-amp input stage? Quote Link to comment Share on other sites More sharing options...
Norris Posted November 28, 2015 Author Share Posted November 28, 2015 (edited) That was my theory - to attenuate the signal a bit. Fingers crossed it seems to have worked Edit: I'll check it for volume against my passive P tonight. I guessed at the resistor values, so may have overdone it. Sounded ok though my practice amp (old tatty powered monitor wedge) Edited November 28, 2015 by Norris Quote Link to comment Share on other sites More sharing options...
Prostheta Posted November 28, 2015 Share Posted November 28, 2015 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. Quote Link to comment Share on other sites More sharing options...
Prostheta Posted November 28, 2015 Share Posted November 28, 2015 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. Quote Link to comment Share on other sites More sharing options...
Norris Posted November 28, 2015 Author Share Posted November 28, 2015 It sounds a lot better although too quiet. I'll try some smaller ones Quote Link to comment Share on other sites More sharing options...
Norris Posted November 29, 2015 Author Share Posted November 29, 2015 I've been pondering this a little more. It's been a long time since I played with analogue electronics, but in a passive circuit the pickup induces the current. It can therefore be considered a kind of AC battery for the sake of the circuit. The resistors are acting as shunts. The fact that they are in an active circuit shouldn't change anything as the pickup is still providing the impetus. There again, I've had a couple of glasses of wine Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted November 29, 2015 Share Posted November 29, 2015 I'm not at all sure how I've missed this thread before, but that is a [i]stunning [/i]restoration. Top job. Pleased you did the update - not only that you've sorted the electrics but because I'd have missed this otherwise! Quote Link to comment Share on other sites More sharing options...
Norris Posted November 30, 2015 Author Share Posted November 30, 2015 I've not sorted the electrics yet - it's not gigable yet, but I think I'm on the right track. Glad you like the resto - it was done by one of the instructors at my Monday night guitar building club, who has been a mate of mine for years Quote Link to comment Share on other sites More sharing options...
Norris Posted April 2, 2016 Author Share Posted April 2, 2016 As a bit of a coda on this, the lacquer has cracked/crazed in a couple of places. Andy isn't happy with it so he wants it back to refinish again. He's a top bloke is Andy! Btw, whichever BCer has the Ibanez Musician with Andy at the moment - that's a gorgeous bass! I'm wondering what all the knobs do though Quote Link to comment Share on other sites More sharing options...
Prostheta Posted April 2, 2016 Share Posted April 2, 2016 You can always ask Veijo. I'm really not sure. Just tell him you're a friend of Carl in Pori. Quote Link to comment Share on other sites More sharing options...
Norris Posted May 9, 2016 Author Share Posted May 9, 2016 Now that I just plain weird. Hours before the Midlands Bass Bash, I was frantically swapping resistors around trying to get a reasonable sound out of it. Then I finally decided to get rid of the resistors completely again and find out just how bad the overloading was. As I un-soldered the resistors I accidentally over-stressed one of the cables and it broke. Having re-made the broken connection... no distortion. The only issue now is that my passive Squier is about twice as loud as the active Aria. There definitely seems to be something up with the wiring. I'll have to see about getting a new molex connector and re-making all of the connections. I'm not convinced that it is making a good connection with the terminals on the pre-amp Quote Link to comment Share on other sites More sharing options...
Prostheta Posted May 9, 2016 Share Posted May 9, 2016 Keep me in the loop on this one Norris if you need help, or PM me on ProjectGuitar.com Quote Link to comment Share on other sites More sharing options...
Mark Dixon Posted May 13, 2016 Share Posted May 13, 2016 (edited) [quote name='Norris' timestamp='1431370053' post='2770640'] [b]Where There's Muck There's Brass[/b] The hardware that came off the bass was pretty grimy. Andy took his dremmel to the brass bridge, nut and back covers. T [/quote] I bought a SB-1000 Mk I off a guy in Manchester about 4 years ago. This thread inspires me to restore it.. Mainly a refret, the body work is in pretty good nick, but the frets are badly worn. Did you lacquer the bridge or leave as polished brass? Thx Mark Edited May 13, 2016 by Mark Dixon Quote Link to comment Share on other sites More sharing options...
Mark Dixon Posted May 13, 2016 Share Posted May 13, 2016 [quote name='Norris' timestamp='1431201440' post='2768809'] [b]A Bass Barely Alive...[/b] (We can rebuild it!) OK, here are some 'before' shots. Remember - I did warn you! [/quote] Glad to see the case is in better condition than mine!! Quote Link to comment Share on other sites More sharing options...
Norris Posted May 13, 2016 Author Share Posted May 13, 2016 [quote name='Mark Dixon' timestamp='1463173689' post='3049357'] I bought a SB-1000 Mk I off a guy in Manchester about 4 years ago. This thread inspires me to restore it.. Mainly a refret, the body work is in pretty good nick, but the frets are badly worn. Did you lacquer the bridge or leave as polished brass? Thx Mark [/quote] The bridge was just polished up with a Dremel wire brush I think. It wasn't lacquered because it will always chip and then need stripping to clean up again Quote Link to comment Share on other sites More sharing options...
Norris Posted May 13, 2016 Author Share Posted May 13, 2016 [quote name='Mark Dixon' timestamp='1463173903' post='3049358'] Glad to see the case is in better condition than mine!! [/quote] It's not stable enough to carry the bass. I might try to fix it but some of the ply is pretty damaged and not easy to repair Quote Link to comment Share on other sites More sharing options...
Prostheta Posted May 14, 2016 Share Posted May 14, 2016 I think you can shellac brass.... Quote Link to comment Share on other sites More sharing options...
Mark Dixon Posted May 14, 2016 Share Posted May 14, 2016 [quote name='Prostheta' timestamp='1463200219' post='3049456'] I think you can shellac brass.... [/quote] I wonder what the factory used originally? Quote Link to comment Share on other sites More sharing options...
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