neepheid Posted August 9 Share Posted August 9 I need a bit of hive mind on this headscratcher. My Epi Jack Casady is havnig weird problems. It works fine played normally, but as soon as I engage my overdrive, it feeds back like a mofo. Normally, one needs to be pretty close to the amp to induce feedback and it's a slow build. This is happening when I'm nowhere near my amp. I was doing some checking tonight and I found that the transformer/coil was not securely fastened to the body inside the bass. I tightened up the screw so it's all solid again but that wasn't it. But during further testing, I was finding that with the volume on the bass turned all the way down, there was nothing coming out of the amp if no effects engaged. But when I turned on my OD, I got output through the amp! Also my harmoniser pedal was able to find a faint something to work with when engaged even when the volume is turned all the way down. It's also noisy, and the compressor makes the background hiss worse. I'm not having any issues with any of my other basses so I'm disinclined to blame anything on my pedalboard. Ground appears to be connected because touching the bridge or the position indicators on the pots lessens the background noise. I'm stumped - WTF is going on? Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 10 Author Share Posted August 10 Does anyone in Aberdeen city or shire have a Jack Casady and if so, would they be willing to help me out with an A/B test? Can pay in tea and biscuits! Quote Link to comment Share on other sites More sharing options...
tauzero Posted August 10 Share Posted August 10 Has this suddenly come about, or might it always have been happening and you've just not used the OD with it? Any environmental changes? Are you using it in a different room? Is the OD a true bypass and before any other effects? Just a thought, if it's true bypass and very high input impedance, it might be picking up a very small signal because the volume control isn't an on-off switch. Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 10 Author Share Posted August 10 38 minutes ago, tauzero said: Has this suddenly come about, or might it always have been happening and you've just not used the OD with it? Any environmental changes? Are you using it in a different room? Is the OD a true bypass and before any other effects? Just a thought, if it's true bypass and very high input impedance, it might be picking up a very small signal because the volume control isn't an on-off switch. It's been annoying me for a while, I first noticed it with my old OD pedal (TC Electronic Mojomojo) where it had two levels of OD and the JC would get angry with the higher level of OD. These days I use a Joyo Monomyth and I think the JC hates this one more. I suspect I'm going to have to gut the JC and check all the wiring. Life is pain. Quote Link to comment Share on other sites More sharing options...
tauzero Posted August 10 Share Posted August 10 Whereabout is the transformer? Just wondering if there could be some signal induction from the pickup to the transformer. Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 10 Author Share Posted August 10 3 hours ago, tauzero said: Whereabout is the transformer? Just wondering if there could be some signal induction from the pickup to the transformer. Here it is - lives right next to it Quote Link to comment Share on other sites More sharing options...
tauzero Posted August 11 Share Posted August 11 I'm going to stick with inductive coupling as the answer then. ICBW of course. Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 11 Author Share Posted August 11 5 minutes ago, tauzero said: I'm going to stick with inductive coupling as the answer then. ICBW of course. Well, it's not supposed to happen, I can't imagine they put my coil in a special place versus all the other Jack Casady basses out there so perhaps my coil has gone bad in some nebulous way. I wonder if some sort of shielding between the pickup and the coil might mollify it (although I'm pretty sure that's what the metal case that the coil is placed inside and potted/epoxied into place is for). The other test would be to move the pickup out of the way (but still near a string) and then plug it in. I'll be back... Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 11 Author Share Posted August 11 Well, that was a lot of pricking about to achieve not much. I tried removing the pickup, stringing it back up and then holding the pickup above the strings. No feedback. I tried putting a rudimentary copper shield between the coil and the pickup (more like a curtain really) but that did naff all - put it all back together again and back to feeding back with OD engaged. It only happens when the amp gets involved - it doesn't happen through headphones straight out of the Monomyth. I don't know what that means. I think my next test would be to jump the pickup out of the circuit and wire it directly to a jack socket, see if that makes a difference. Or am I barking up the wrong tree? Quote Link to comment Share on other sites More sharing options...
Hellzero Posted August 11 Share Posted August 11 To me it looks like the pedal is the culprit, not the bass, as you seem to generate a feedback loop with your amp. You can try to remove the grounding in your pedal. Did you try another overdrive, except the TC Electronic, of course? Quote Link to comment Share on other sites More sharing options...
Hellzero Posted August 11 Share Posted August 11 And are you going straight to the amp or using the effects loop with your pedal? Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 11 Author Share Posted August 11 1 minute ago, Hellzero said: To me it looks like the pedal is the culprit, not the bass, as you seem to generate a feedback loop with your amp. You can try to remove the grounding in your pedal. Did you try another overdrive, except the TC Electronic, of course? There's the OD section of the Behringer BDI21 I guess I could test with. What puzzles me is that this is only affecting the Jack Casady. Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 11 Author Share Posted August 11 (edited) 1 minute ago, Hellzero said: And are you going straight to the amp or using the effects loop with your pedal? Bass > Pedalboard > amp input Try the pedalboard in the effects loop instead, for a test? Edited August 11 by neepheid Quote Link to comment Share on other sites More sharing options...
Hellzero Posted August 11 Share Posted August 11 So you have a pedalboard... How many pedals do you have on it and how are they wired? Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 11 Author Share Posted August 11 Just now, Hellzero said: So you have a pedalboard... How many pedals do you have on it and how are they wired? bass > Boss TU-2 > Hotone Harmony pitch shifter/harmonizer/detuner > Yamaha CO-10MII compressor > Joyo Monomyth > amp Powered by a T-Rex Fuel Tank Jr. Quote Link to comment Share on other sites More sharing options...
Hellzero Posted August 11 Share Posted August 11 Did you try a simple signal chain? Bass > OD > amp. Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 11 Author Share Posted August 11 2 minutes ago, Hellzero said: Did you try a simple signal chain? Bass > OD > amp. I'll put it on my list to try. Need to go some place I can be noisy - a terraced house is not the place to be making super obnoxious feedback noises at war (gig) volume... 1 Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 11 Author Share Posted August 11 One thing I would also really like is to A/B with another Jack Casady to see if the problem applies to all JCs or if it's just mine. Dunno if anyone local to me has one that they wouldn't mind me borrowing - for science! Quote Link to comment Share on other sites More sharing options...
Hellzero Posted August 11 Share Posted August 11 Ok, I think I understood your issue. How loud are you and in what room size are you in when you engage that overdrive with your Jack Casady bass? Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 11 Author Share Posted August 11 4 minutes ago, Hellzero said: Ok, I think I understood your issue. How loud are you and in what room size are you in when you engage that overdrive with your Jack Casady bass? Loud enough to be heard over a drummer and a guitarist - Mark bass Mini CMD 121P IV (250W, 1x12"), gain set so it's just tickling the clip light, master volume probably around half. Room is large-ish - I don't have measurements to hand but it's very roughly 1.5 of my house's living room. Quote Link to comment Share on other sites More sharing options...
Hellzero Posted August 11 Share Posted August 11 Ok. Any hollow body instrument will feed back at this really high volume. Try to start with the master at zero and go up until it starts feeding back, then you'll know you've reached the non return point. It reminds me of a friend having huge feedback issues with his guitar equipped with EMG's and after trying everything at my home and having no feedback at all I decided to go a step further. I came to his home when they were rehearsing and everything became crystal clear: less than one meter away from a full stack Mesa Boogie at stadium concert level in a 20 square meter room with a crazy drummer and a full stack SVT at delirious level too... 🫣😳🤦 No need to say that this friend and his drumming brother are now almost deaf as they continued to play at amazingly high level. The bassist stopped playing with them a few weeks later and can still hear normally today. Quote Link to comment Share on other sites More sharing options...
neepheid Posted August 11 Author Share Posted August 11 37 minutes ago, Hellzero said: Ok. Any hollow body instrument will feed back at this really high volume. Try to start with the master at zero and go up until it starts feeding back, then you'll know you've reached the non return point. It reminds me of a friend having huge feedback issues with his guitar equipped with EMG's and after trying everything at my home and having no feedback at all I decided to go a step further. I came to his home when they were rehearsing and everything became crystal clear: less than one meter away from a full stack Mesa Boogie at stadium concert level in a 20 square meter room with a crazy drummer and a full stack SVT at delirious level too... 🫣😳🤦 No need to say that this friend and his drumming brother are now almost deaf as they continued to play at amazingly high level. The bassist stopped playing with them a few weeks later and can still hear normally today. But it doesn't feed back at "war" volume when there's no OD... Quote Link to comment Share on other sites More sharing options...
Hellzero Posted August 11 Share Posted August 11 Which is almost normal, add distortion at this volume and it'll start feeding back which is also almost normal for a feedback machine aka a hollow body instrument. Try starting with the master volume at zero (and lower your gain a bit too as it will help containing the feedback) and go up until the non return point. Quote Link to comment Share on other sites More sharing options...
Hellzero Posted August 11 Share Posted August 11 You can also wax your pickup to minimise the feedback: remember what happened when holding it (with your fingers I guess) outside the bass body. Quote Link to comment Share on other sites More sharing options...
BigRedX Posted August 12 Share Posted August 12 IIRC the Jack Casady Bass doesn't have a central block in the body and pickup is attached to the free-floating top. Hollow-bodied basses are notoriously prone to feedback issues with high-gain signal paths. My Reverend Rumblefish would feedback like mad at when using anything more than the most subtle of drive settings, and I believe that @Bassassin had problems with the hollow aluminium body of his Tokai Talbo bass - I never used mine at anything above home practice volumes so never had a problem. My Warwick StarBass II was much better behaved but it had a solid wooden block extending all the way through the middle of body and the top was relatively thick and rigid compared with other hollow-bodied instruments I have owned. Quote Link to comment Share on other sites More sharing options...
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