Jakester Posted October 25, 2016 Share Posted October 25, 2016 (edited) I recently had a Glockenklang 2-band pre-amp installed in my Warwick Streamer STD bass. The after the first time I used it, went back to it and the battery was flat. "Silly me," I thought, "I've left the lead plugged in". Replaced the battery, but it did it again. "I'm such an idiot," I thought, "I've left it plugged in again." Replaced the battery, and this time double-checked every time to make sure that the lead was not plugged in. Unfortunately I still have a flat battery Took it back to the shop that fitted the pre-amp for me - we both assumed the tech had just soldered to the wrong tag making the circuit permanently energised, but upon inspection that turns out not to be the case. It appears the pre-amp is drawing power irrespective of whether or not a lead is plugged in. It has an 'active/passive' switch which is a push/pull on the blend knob - unfortunately passive is pulled out, so when it goes in a case the knob is pushed back in. It's not clear whether this switches the circuit off or just bypasses it in any event. For the time being I have simply disconnected the battery but it's not ideal. All the controls work and the bass sounds fine, which suggests there isn't a short somewhere. The tech is stumped. Does anyone have any ideas? I will contact Glockenklang directly but as it was bought second-hand I'm not hoping for much. Edited October 25, 2016 by Jakester Quote Link to comment Share on other sites More sharing options...
BigRedX Posted October 25, 2016 Share Posted October 25, 2016 (edited) I'd check continuity through the screening in the control cavity and see if something there is keeping the pre-amp permanently switched on. A quick way to check would be to take the pre-amp out of the bass and see if it runs down the batteries like that. Edited October 25, 2016 by BigRedX Quote Link to comment Share on other sites More sharing options...
Dood Posted October 25, 2016 Share Posted October 25, 2016 If the jack IS wired correctly, then if there isn't anything connected to it, the circuit is not complete and a break in the power path will mean that the device shouldn't be able to draw any power. Yes, I would check as BRX says that there aren't any opportunities for wire to touch each other and that would include making sure there isn't a problem with the battery clip. I have, just once, seen an open type which had a hair thin wire strand sticking out touching the opposite terminal. The likelihood of that is slim, but worth checking. You say the 'tech is stumped'. The installer is actually a tech? Or just a bloke at a shop who knows how to use a soldering iron? Continuity testing, even basic use of a 'multimeter' should be able to track down how this type of preamplifier is remaining powered up. Quote Link to comment Share on other sites More sharing options...
ikay Posted October 25, 2016 Share Posted October 25, 2016 Use a multimeter to measure the voltage across the two points marked by the white arrows in the attached pic. If it's all wired correctly, then with the jack unplugged there should be no reading (ie. open circuit). With the jack plugged in it should read +9v (or thereabouts). If you're getting a reading with the jack unplugged then the earth wire is the culprit so try and trace it back to find the fault. [attachment=230775:Glock wiring.jpg] Quote Link to comment Share on other sites More sharing options...
MoonBassAlpha Posted October 25, 2016 Share Posted October 25, 2016 Excellent post^ Quote Link to comment Share on other sites More sharing options...
Jakester Posted October 25, 2016 Author Share Posted October 25, 2016 Great, thanks everyone. Quote Link to comment Share on other sites More sharing options...
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