goonieman Posted August 9, 2015 Share Posted August 9, 2015 Hi All, I can't quite figure out this jack for an active preamp. http://www.axetec.co.uk/axetec_media/sckt07_connections_550b_2.gif Jack tip (Signal +ve) is hot, right? [white?] Jack centre (signal +ve) - battery ground? Jack barrel and case: link the grounds? thanks Quote Link to comment Share on other sites More sharing options...
SubsonicSimpleton Posted August 9, 2015 Share Posted August 9, 2015 Usually the tip carries the signal, and the battery(-ve) and preamp(0v) are connected to the ring and sleeve so the preamp only powers up when a mono jack plug is inserted in the plug, shorting the ring and sleeve together. It is usually fairly obvious when you look at the wiring in the cavity, but it would probably be a good idea to post full details of the bass/preamp and a pic of the cavity if you want help wiring it. Quote Link to comment Share on other sites More sharing options...
goonieman Posted August 10, 2015 Author Share Posted August 10, 2015 Thanks for this. MY problem is with the terminology in the diagram more than anything. For instance, what is the difference between 'centre' and 'barrel' in the diagram? ...and when you say "[color=#282828][font=helvetica, arial, sans-serif]battery(-ve) and preamp(0v) are connected to the ring and sleeve " , do you mean "respectively" - or that they are wired together?[/font][/color] [color=#282828][font=helvetica, arial, sans-serif]thanks again[/font][/color] Quote Link to comment Share on other sites More sharing options...
SubsonicSimpleton Posted August 10, 2015 Share Posted August 10, 2015 Standard terminology for stereo 1/4 jacks is TRS(tip, ring, sleeve), I would guess that on the diagram tip=tip, center=ring, barrel=sleeve, but if there is any doubt, then I would verify the connections on the component with a multimeter/continuity tester and a patch cable before getting started. In order for the jack to perform switching for the preamp power, then the connections have to be made "respectively" in order for the circuit to be broken when the jack plug is removed from the socket, if you wired them together, the preamp circuit would remain on continuously until the battery was drained. Quote Link to comment Share on other sites More sharing options...
goonieman Posted August 10, 2015 Author Share Posted August 10, 2015 Excellent - thanks a lot. That makes sense and should be easy now! Quote Link to comment Share on other sites More sharing options...
goonieman Posted August 12, 2015 Author Share Posted August 12, 2015 Actually - not attempted this yet (still waiting on the preamp) but it still does not make sense according to this wiring diagram... Any suggestions? Tip - hot (easy) and Battery to earth (barrel or case? are they the same thing?) That leaves 'jack centre' (ring) totally untouched? Surely not Quote Link to comment Share on other sites More sharing options...
goonieman Posted August 13, 2015 Author Share Posted August 13, 2015 Anyone? Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted August 13, 2015 Share Posted August 13, 2015 (edited) [quote name='goonieman' timestamp='1439398173' post='2842490']...does not make sense according to this wiring diagram... [/quote] The wiring diagram is wrong (or rather, incomplete...). The battery negative never gets to the pre-amp, only to the (grounded..?) bridge. There should be a black wire from the missing 'ring' TRS socket connection to the black wire on the pre-amp, such that insertion of a mono jack into the socket makes the connection, thus switching on the power. Without that 'ring' connection, the pre-amp never receives battery power. I'd be wary of following that wiring 'as is', anyway. Any conductive shielding around will make a connection between the bridge and the pots, and thus turn on the power and waste the battery. The bridge should be grounded to the pots, not to the battery terminal. The battery negative would be better connecting to the 'ring' of the TRS' socket, not the base (or 'sleeve', to use the conventional term...). The missing black wire to the pre-amp should then be connected to the sleeve connection on the socket. The mono jack turns it all on, but current is cut when the jack is removed, something like this... I'd recommend checking the source of the diagram to be sure. Hope this helps. Edited August 13, 2015 by Dad3353 Quote Link to comment Share on other sites More sharing options...
goonieman Posted August 13, 2015 Author Share Posted August 13, 2015 That is REALLY helpful - especially i'm a 'paint by numbers' guy! Just to be sure: the only thing you're saying is wrong with your version of the diagram is that the bridge should be connected to the pots, not the sleeve? cheers again Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted August 13, 2015 Share Posted August 13, 2015 [quote name='goonieman' timestamp='1439467169' post='2843063'] That is REALLY helpful - especially i'm a 'paint by numbers' guy! Just to be sure: the only thing you're saying is wrong with your version of the diagram is that the bridge should be connected to the pots, not the sleeve? cheers again [/quote] Not exactly 'wrong', just more convenient to connect to the pots, where soldering is easier and spacious, rather than on the jack socket, where there's not much room. One connection is fine, but several can be tricky for the 'less-than-dexterous' among us. It was too much of a faff to 'correct' the diagram, so I left it. Electrically, there's no difference at all, it's simply the practicality which changes. Good luck with the project; have fun... Quote Link to comment Share on other sites More sharing options...
goonieman Posted August 13, 2015 Author Share Posted August 13, 2015 ok, as soon as the preamp arrives I will give it a whirl. Thanks so much again for your help and time on the diagram, Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted August 13, 2015 Share Posted August 13, 2015 [sharedmedia=core:attachments:167485] Quote Link to comment Share on other sites More sharing options...
goonieman Posted August 20, 2015 Author Share Posted August 20, 2015 Hi everyone - problems here... Wired it exactly as above - however, 1. I wired the green/white/ground to the back of the bass pot, not vol pot (tried it back on vol pot - no difference) 2. there is no ground from the preamp?! - so I wired an extra wire from the vol pot to the sleeve I've got no signal to the pup (tapping with scredriver gives nothing). When I touch vol pot, I get a noisy ground loop. I'm still not sure i've wired the jack correctly though: As per this: http://www.axetec.co.uk/axetec_media/sckt07_connections_550b_2.gif I have signal (white) to the 'tip' ; battery to 'jack centre' and bridge/vol pot ground to 'jack barrel/earth'... I've joined the case to the jack barrel (the outer two lugs) any thoughts? Quote Link to comment Share on other sites More sharing options...
goonieman Posted August 20, 2015 Author Share Posted August 20, 2015 (edited) I should add, i'm only getting a basty buzzing with vol on min. With vol up high, I touch the knob and no buzzing. No sound at all from the pickup... I get 1.31 K when I hold a multimeter across the black/red wires vs the green/white/plain wires (it's a seymour duncan SMB-4D). And I get 2.6K DC for each wire (the black and red separately) ([url="http://www.seymourduncan.com/comparetones"]http://www.seymourdu...om/comparetones[/url]). So at least I know the pup works. Edited August 20, 2015 by goonieman Quote Link to comment Share on other sites More sharing options...
goonieman Posted August 21, 2015 Author Share Posted August 21, 2015 (edited) Update: I wired the pickup ground to the back of the vol pot (instead of bass), and now at least I get a signal. It doesn't really seem to matter how I wire the battery negative and the grounds to the output jack, I still got a very basic signal that doesn't seem to be affected by the treble OR bass. The volume DOES go up and down though. I've noticed that I can remove the battery... and the signal remains. So the circuit is somehow acting in passive mode. The battery is working (9v) - but somehow the preamp is completing the signal, but not adding any EQ...?! Thoughts anyone?! Edited August 21, 2015 by goonieman Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted August 21, 2015 Share Posted August 21, 2015 [quote name='goonieman' timestamp='1440148733' post='2848603'] Update: I wired the pickup ground to the back of the vol pot (instead of bass), and now at least I get a signal. It doesn't really seem to matter how I wire the battery negative and the grounds to the output jack, I still got a very basic signal that doesn't seem to be affected by the treble OR bass. The volume DOES go up and down though. I've noticed that I can remove the battery... and the signal remains. So the circuit is somehow acting in passive mode. The battery is working (9v) - but somehow the preamp is completing the signal, but not adding any EQ...?! Thoughts anyone?! [/quote] Maybe it's time to get in contact with the BC expert in this domain, [url="http://basschat.co.uk/user/7835-kiogon/"]KiOgon[/url] ..? I can't see your location; he's on the South coast. Someone else needs to look at what you've got; the solution is probably very simple, but is just eluding your gaze. Hope this helps. Quote Link to comment Share on other sites More sharing options...
goonieman Posted August 21, 2015 Author Share Posted August 21, 2015 ok, as the famous irish saying goes...try, try, try again, then STOP: there's no point in making a fool out of yourself. I'm sending to the tech thanks for all your help anyways Quote Link to comment Share on other sites More sharing options...
goonieman Posted September 4, 2015 Author Share Posted September 4, 2015 Ok, just for the sake of closure - the preamp assumed a collective grounding plate attached to the cavity of the bass (like a real musicman has) Given the preamp was attached to unshielded wood, there were all sorts of grounding issues. Fixed! Thanks for all your help anyway. Quote Link to comment Share on other sites More sharing options...
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