Kev Posted January 20, 2013 Share Posted January 20, 2013 Recently acquired an Old Warwick with EMG pickups, one J and one P type. Whilst i am having no issues with the J, the P pickup is producing some distortion. If i have the pickup at a normal proximity away from the strings, EQ on the bass flat, when initially attacking any note on the bottom two string (E and A) hard, there is a distortion, less than half a second or so but very much there. Looking online, this is typical of the preamp in the bass being overloaded, or the battery being low. Given the EQ is flat i cannot see how it can be the former, and i have tried numerous fresh batteries with the same results. Also tried with two different sets of strings and ruled out my Amp being overloaded. Screwing the pickup right down almost as far as it will go removes the distortion, but obviously a lower output comes with it which i don't really want. All original electronics as installed in 1988 so should all be compatible with one another so i doubt pot values are a problem. Anyone any thoughts? I vaguely remember having a similar problem with an EMG P type pickup in a bass i owned many years ago, and not sure the problem ever really resolved itself. Quote Link to comment Share on other sites More sharing options...
Kev Posted January 20, 2013 Author Share Posted January 20, 2013 Il just add that it does only distort if i really dig in hard; my normal playing will not trigger it. Its more common when using a pick hard too. Quote Link to comment Share on other sites More sharing options...
Dood Posted January 20, 2013 Share Posted January 20, 2013 Is it an EMG preamp? Quote Link to comment Share on other sites More sharing options...
Kev Posted January 20, 2013 Author Share Posted January 20, 2013 It will be an MEC preamp. Quote Link to comment Share on other sites More sharing options...
Kev Posted January 20, 2013 Author Share Posted January 20, 2013 As far as pickup height goes, the following picture is how i have it set now and at this height there is almost no distortion unless i dig in really hard. Raising the pickup reduces the heaviness of attack needed to trigger distortion. I shouldn't have to have the pickup this low, should i?? [IMG]http://i75.photobucket.com/albums/i287/KevMan69/Snapbucket/6A80C7D5.jpg[/IMG] Quote Link to comment Share on other sites More sharing options...
Dood Posted January 20, 2013 Share Posted January 20, 2013 Ok, I think the EMG pickup's output is too hot for the preamp. I've heard of this happening before. Indeed, my EMGs on my bass can easily overdrive some pedals, so I have to be careful. The design of EMG pickups is actually that they shouldn't be that far away from the strings anyway. They use weaker magnets to cut down on 'string pull' problems and 'wolfing' in guitar pickups then use a high spec internal preamp to boost the output back up. The instruction I believe do actually say to raise the pickups close to the strings. So, in short - no, the pickup shouldn't be that low. - It's time to grab a different preamp me thinks! Quote Link to comment Share on other sites More sharing options...
Kev Posted January 20, 2013 Author Share Posted January 20, 2013 Thanks for your help, but the majority of old Pre 1990 warwick basses have the EMG pickup MEC preamp combination and iv not seen many complaints so surely the preamp should work fine with it?? Quote Link to comment Share on other sites More sharing options...
Dood Posted January 21, 2013 Share Posted January 21, 2013 I wasn't aware of that, so no, i'd assume it'd be ok. A possible fault then? Have you inspected the electronics to make sure they're untouched? Next up will be bypassing the pre to see if its a problem with the active pickup or the preamp. Quote Link to comment Share on other sites More sharing options...
Dood Posted January 21, 2013 Share Posted January 21, 2013 The pickups *are* active types, right? Quote Link to comment Share on other sites More sharing options...
Kev Posted January 21, 2013 Author Share Posted January 21, 2013 Sadly I'm fairly amateur when it comes to this kind of stuff, fairly sure the EMG's are active. Certainly is a MEC preamp in there and all visible connections seem secure, pots are quiet and the bridge pickup works fine and is quite close to the strings. My first thought was to check if the MEC has a internal gain trimpot, but cannot see that it does... Quote Link to comment Share on other sites More sharing options...
Dood Posted January 21, 2013 Share Posted January 21, 2013 Hmmmm, its gonna be hard to make a call now that everything else has been exhausted. Certainly if you have ruled out amp, cab, battery and cables, then there's only a few bits left. I cant see the jack socket being to blame so will point my suspecting finger at the preamp. Quote Link to comment Share on other sites More sharing options...
charic Posted January 21, 2013 Share Posted January 21, 2013 Are you sure the p pickup hasnt been upgraded to a newer one with a hotter output? Quote Link to comment Share on other sites More sharing options...
Kev Posted January 21, 2013 Author Share Posted January 21, 2013 No there is no sign it has, the output doesn't sound particularly hot either. Quote Link to comment Share on other sites More sharing options...
Kev Posted January 21, 2013 Author Share Posted January 21, 2013 Messed around this evening and turned the bass n mids down on the amp and cranked to try and enhance the distortion, turns out it actually happens with both pickups, just less so with the j, and even with the p pup all the way down as in the pic it still distorts when attacked hard or using a plectrum. Preamp or some sort of wiring issue? Doesn't sound like a quick fix anyway, unless anyone else has any experience driven ideas?? Quote Link to comment Share on other sites More sharing options...
Dood Posted January 21, 2013 Share Posted January 21, 2013 My only suggestion now is to have someone take a look at it for you if you're not favouring the soldering iron option. A component on the pre could have failed or failing - but it'd be hard to say what exactly. Quote Link to comment Share on other sites More sharing options...
3below Posted January 21, 2013 Share Posted January 21, 2013 (edited) At this point it is the options time: i) measure pickup(s) output with suitable voltmeter, ii) visual inspection, look for dull / cracked solder joints, resolder. iii) Beg/Borrow an oscilloscope and investigate the output from pickup(s), and at various stages in the circuit. Ideally with a signal generator. Might be a faulty op amp (unlikely) or dry solder joint, more likely. iv) pay someone to find same ££. v) replace pre-amp £££. vi) buy high output passive pickups, more ££ and possibly not to taste. With logic and a circuit diagram i) through iii) will solve most issues. Find someone (Physics / science teacher or Electronic Engineer) to borrow the kit. It is not hard. Warwick have diagrams available on net. Pm me if you need further advice. Edited January 21, 2013 by 3below Quote Link to comment Share on other sites More sharing options...
iiipopes Posted January 22, 2013 Share Posted January 22, 2013 Since the EMG has its own internal preamp, I'm thinking the EMGs are overpowering the MEC preamp. Quote Link to comment Share on other sites More sharing options...
Kev Posted January 22, 2013 Author Share Posted January 22, 2013 But there must be a problem then considering it is a stock setup? I think I will have it looked at by a professional, needs the neck looking at anyway. Quote Link to comment Share on other sites More sharing options...
Kev Posted February 10, 2013 Author Share Posted February 10, 2013 (edited) Bump Any further suggestions on this? I'm not getting any response out of local luthiers i am trying to contact... Sadly i don't have access to any of the equipment to test the preamp/pickups and not really willing to invest. Edited February 10, 2013 by Kev Quote Link to comment Share on other sites More sharing options...
MiltyG565 Posted February 11, 2013 Share Posted February 11, 2013 [quote name='Kev' timestamp='1360538118' post='1972134'] Bump Any further suggestions on this? I'm not getting any response out of local luthiers i am trying to contact... Sadly i don't have access to any of the equipment to test the preamp/pickups and not really willing to invest. [/quote] Isn't distortion kind of what EMG's are known for/supposed to do? If we think about where the P pickup is in relation to the J pickup, it's easy to say that the magnetic field will be disturbed more (creating a higher output) because the string will have more space to move at that point, than at the bridge. Maybe that's what's causing the slight distortion. It also probably wouldn't happen with passive pickups. Quote Link to comment Share on other sites More sharing options...
iiipopes Posted February 11, 2013 Share Posted February 11, 2013 [quote name='MiltyG565' timestamp='1360579016' post='1972466'] Isn't distortion kind of what EMG's are known for/supposed to do?[/quote] No. 1) EMG pickups are known for being so clean as to almost be sterile in tone. They get the distortion reputation from, among other models of their pickups, their 81 guitar pickup having a high output that easily overdrives amplifiers. 2) Because they use onboard preamps to set the output level of the pickups, the magnets they use are actually much "softer" in their magnetic pull than conventional Hi-Z pickups. Quote Link to comment Share on other sites More sharing options...
Kev Posted February 12, 2013 Author Share Posted February 12, 2013 This sound clip should show the distortion, first half of the clip with pickups where they should be, second with it screwed right into the body. http://soundcloud.com/thumbbassgk/streamer-neck-pup-alteration-2/s-KJ4ZJ?utm_source=soundcloud&utm_campaign=mshare&utm_medium=email&utm_content=http://soundcloud.com/thumbbassgk/streamer-neck-pup-alteration-2/s-KJ4ZJ Quote Link to comment Share on other sites More sharing options...
Kev Posted February 14, 2013 Author Share Posted February 14, 2013 Bump Quote Link to comment Share on other sites More sharing options...
MiltyG565 Posted February 15, 2013 Share Posted February 15, 2013 The first part of the clip- The distortion isn't that bad. If you aren't happy with it, you'll have to speak to an expert though. Quote Link to comment Share on other sites More sharing options...
Kev Posted February 17, 2013 Author Share Posted February 17, 2013 Perhaps my playing style in the clip is hiding it, trust me it isn't usable when the pickups are where they should be, and as already said EMG's if anything are [i]too [/i]clean as standard. Im trying to get an expert to look at it but the only one local enough to me who looks at electronics is bizarly ignoring my emails :S Quote Link to comment Share on other sites More sharing options...
_polarrS.thumb.jpg.0ad302df85c39f8a1bbc8e01834664d4.jpg)
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.