loweringthetone Posted July 24, 2014 Share Posted July 24, 2014 Apologies for cross posting from the amps section. I've tried three of these combos from new and they all have the same problem - with my older passive basses (75 Precision and 73 Ric) I get an earthing type buzz. The buzzing stops when I touch a machine head or the control panel of the amp ( I presume because I provide an alternative earth - somebody help me out here) and it seems to be related to how well the instrument is screened ( I wrapped the offending bass in aluminium foil and it reduced the noise) With more modern basses ( Ibanez SR800, Lakland 4401) the combo works great, and it's as silent as a mouse. This PJB combo runs on 20v DC, and the 'switching adaptor' transformer block supplied doesnt have an earth connection to a UK 3 pin mains plug. Dont know if this is the issue. Pity as otherwise its a crackin little combo, light as a feather, nice tone and with a more vintage sound than other PJB stuff I've tried. I'd love to use it with my older basses, but short of filling every cavity with copper tape, Im not sure how to do this. Can anyone recommend a solution ? COlin Quote Link to comment Share on other sites More sharing options...
loweringthetone Posted July 27, 2014 Author Share Posted July 27, 2014 No suggestions so far . Ill write to PJB and Synergy (UK distributors) , and hopefully post up a reply here for future purchasers. Quote Link to comment Share on other sites More sharing options...
loweringthetone Posted July 29, 2014 Author Share Posted July 29, 2014 (edited) Wow. Synergy distribution were really quick - they got back to me within 2 hours. Here's what they what they had to say : [size=3][color=#000000][font=Helvetica] We can help you. These older basses do not have the screening that modern instruments have and a buzz can occur. Your observation about the 20v DC connector is very perceptive, and there are two ways to over come the buzz.[/font][/color] [color=#000000][font=Helvetica]1, You could put a lead into the line out and plug into any device (mixer power amp etc), and as long as these are earthed the buzz should disappear .[/font][/color] [color=#000000][font=Helvetica]2. We have an earthed PSU on the way for such instances. Its a lot bigger and more expensive than the one supplied (It will cost £25) They should arrive in August[/font][/color] [color=#000000][font=Helvetica]Considering these guys are simply the distributors, and not PJB themselves, I was extremely impressed with their response time. I emailed them at 8pm and they emailed me back at 10pm ! [/font][/color][/size] Ive never had a 2 hour response from any music company, especially at night ! The present PSU (power supply unit) they supply is very light, I guess in keeping with the amps extreme portability. However, if the new PSU provides the solution, I will be one happy bunny, as this little combo will be a crackin amp to take down the pub, for the acoustic sessions I play in. Ill try and remember to post any future experiences Edited August 5, 2014 by loweringthetone Quote Link to comment Share on other sites More sharing options...
HowieBass Posted July 29, 2014 Share Posted July 29, 2014 Interesting, so they're saying that the induced noise picked up from your bass has no ground connection through the amp. Have you tried doing what they say and if so did it work? Quote Link to comment Share on other sites More sharing options...
loweringthetone Posted July 31, 2014 Author Share Posted July 31, 2014 (edited) [quote name='HowieBass' timestamp='1406667644' post='2513633'] Interesting, so they're saying that the induced noise picked up from your bass has no ground connection through the amp. Have you tried doing what they say and if so did it work? [/quote] Yes it did. I plugged the line out, into the input of another amp, and the buzz went almost completely. Edited July 31, 2014 by loweringthetone Quote Link to comment Share on other sites More sharing options...
loweringthetone Posted August 2, 2014 Author Share Posted August 2, 2014 Just found I can run the combo off my old laptop charger rated at 19v 3.42A and there is no noise ! The laptop transformer block has a three pin input so I guess its earthed. I had to first check the polarity of the power input plug (centre of plug is positive) to make sure I didnt reverse the power to the amp. I dont know if 19V is OK., so I'll email Synergy and ask. However, it's been on for 30 min now, no overheating, and its not gone bang...... Quote Link to comment Share on other sites More sharing options...
HowieBass Posted August 2, 2014 Share Posted August 2, 2014 You should be ok I think, if the voltage is pretty much matched you just need to make sure the mains adapter can supply enough current; it will never supply more than the combo needs so as long as the unit needs less than 3.42 amps you're not in danger of frying the adapter. Quote Link to comment Share on other sites More sharing options...
loweringthetone Posted August 5, 2014 Author Share Posted August 5, 2014 (edited) You're right. Their supplied (unearthed) adapter is 20v at 2.75A, whilst mine is a good quality laptop charger (earthed) which is rated at 19v 3.42A , so it should have plenty of juice, and it also has the right polarity. Once again Synergy were very helpful. They suggested that given the slightly lower voltage, I check for transients at full volume, and loss of power. I tried this and there was no obvious distortion, or loss of power with my adaptor, just a very satisfying quietness to the combo..... So this seems to be a good solution for me, and with the earthed adaptor, I can use my old and poorly screened basses with this excellent little combo. Synergy say they will be bringing out their own earthed adaptor very soon. Edited August 5, 2014 by loweringthetone Quote Link to comment Share on other sites More sharing options...
Mr Bassman Posted August 5, 2014 Share Posted August 5, 2014 I had the same advice from Alan Greensall at Synergy. He's a very nice helpful chap indeed. I found a suitable mains lead with a brass earth pin at the plug end, connected a length of thin cable to the earth pin and attached the other end at the combo under one of the pre amp screws. Works a treat. However this combo has to go back to the retailer because the mute switch crackles. Quote Link to comment Share on other sites More sharing options...
Wonky2 Posted September 11, 2014 Share Posted September 11, 2014 Read about the suggestion of a lead plugged into a line out and then the other end tucked in your sock ! Guess it would illuminate any noise whilst recording ???? Temporary solution i guess? Quote Link to comment Share on other sites More sharing options...
bumnote Posted September 12, 2014 Share Posted September 12, 2014 Synergie have great customer service as have Phil Jones if you email them direct. Quote Link to comment Share on other sites More sharing options...
Bo0tsy Posted November 18, 2014 Share Posted November 18, 2014 (edited) Sorry for re-opening an old thread. I had the exact same problem with my Phil Jones Bass Double Four, the existing Edifier switching adapter was inadequate. I've been dealing with Alan at Synergie, they now have new PJB branded earthed adapters in stock (model no. ADT-60200), they're larger than the old Edifier adapters, and hallelujah, my passive bass is now nice and silent through the amp, envelope filters seem less peaky or distorted too. Very pleased. Alan very helpful, (you'll also need a standard three pin kettle type power lead). Synergie sell them to the public for £25 delivered. Edited November 18, 2014 by Bo0tsy Quote Link to comment Share on other sites More sharing options...
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