Andy0217 Posted April 26, 2020 Share Posted April 26, 2020 Hi Folks I have a pair of these to power my Atmos Speakers, one is dead silent, and the other buzzes like crazy...this happens when they are powered on without any connections to either the speakers or SSP, , I dare say they are probably 10 years old now and I have had them both boxed for the last 5 years pending the completion of the HT build...yes I know it’s been a long friggin time Any suggestions...is this an easy fix? Assume it’s the transformer...maybe not seated or it it’s come loose...but to be honest I have NFI on these things, I have plenty of other Parasound gear and this is the only one that buzzes, Otherwise I will get onto NetworkAV for a local service rep here in Melbourne, or box it and send it up to them, Any help appreciated, Cheers, Link to comment Share on other sites More sharing options...
audiohippo Posted April 26, 2020 Share Posted April 26, 2020 Could be an incoming power issue, maybe try one of these: https://holtonprecisionaudio.com/collections/power-conditioners/products/holton-dc-blocker-one Link to comment Share on other sites More sharing options...
spottie Posted April 26, 2020 Share Posted April 26, 2020 If I were you, I would measure the frequency of the buzzing sound first before trying anything. If you do not have a pro meter, just find a spectrum analyzer app on the app store - my two cents. Link to comment Share on other sites More sharing options...
Addicted to music Posted April 26, 2020 Share Posted April 26, 2020 43 minutes ago, Andy0217 said: Hi Folks I have a pair of these to power my Atmos Speakers, one is dead silent, and the other buzzes like crazy...this happens when they are powered on without any connections to either the speakers or SSP, , I dare say they are probably 10 years old now and I have had them both boxed for the last 5 years pending the completion of the HT build...yes I know it’s been a long friggin time Any suggestions...is this an easy fix? Assume it’s the transformer...maybe not seated or it it’s come loose...but to be honest I have NFI on these things, I have plenty of other Parasound gear and this is the only one that buzzes, Otherwise I will get onto NetworkAV for a local service rep here in Melbourne, or box it and send it up to them, Any help appreciated, Cheers, If you have 2 identical units and when speakers are unplugged and the noise is coming from only one unit, then send that unit in for repairs... it could be a transformer or something drawing more current overloading the power supply causing it to buzz but without looking at it that’s just a wild guess. I doubt it’ll be incoming power as only one unit exhibit the fault..... Link to comment Share on other sites More sharing options...
Andy0217 Posted April 26, 2020 Author Share Posted April 26, 2020 Many thanks to you all....yes I agree I doubt it’s the power supply...both units are plugged into a PS10, and one goes off it’s head and the other doesn’t say boo... Yes I think it will have to go in for repair...will get it off this week as I am still a few months from completion so I would rather get it fixed now, NetworkAV have previously repaired my pre amp and their service was stellar, so will shoot off an email to them tomorrow, Cheers Link to comment Share on other sites More sharing options...
mattd2308 Posted April 26, 2020 Share Posted April 26, 2020 (edited) JLS Electronics in Doncaster is a certified Parasound repair agent. Had similar issues (hum from transformer, buzz through speakers-got a quote, was over 4 figures to repair, similar age) Ahh, no thanks. got rid of it. Edited April 26, 2020 by mattd2308 Link to comment Share on other sites More sharing options...
Addicted to music Posted April 26, 2020 Share Posted April 26, 2020 2 minutes ago, mattd2308 said: JLS Electronics in Doncaster is a certified Parasound repair agent. Had similar issues (hum from transformer, buzz through speakers-got a quote, was over 4 figures to repair, similar age) Ahh, no thanks. got rid of it. Looks like a common issue with this model Link to comment Share on other sites More sharing options...
Andy0217 Posted April 26, 2020 Author Share Posted April 26, 2020 Holy Crap Matt 4 figures to repair it... I haven't even got to the stage on wiring up speakers yet...I will give them a ring tomorrow and sound them out, Cheers Again Link to comment Share on other sites More sharing options...
mattd2308 Posted April 26, 2020 Share Posted April 26, 2020 1 hour ago, Andy0217 said: Holy Crap Matt 4 figures to repair it... I haven't even got to the stage on wiring up speakers yet...I will give them a ring tomorrow and sound them out, Cheers Again Amp was goodness knows how old,bought off ebay, from US. Took a punt as wanted to dip into pre/power pool. Only paid US$400 (approx. 650-700 aud at the time) had P3 preamp, was serviceable but developed above issues. Ended up getting Denon PMA2500. Far more vivid and beautiful sounding amp, more low level detail and bass. Checked JLS Electronics website, doesn't mention Parasound as being brand they are service agent, which is odd. National AV told me at the time they were. (18 months ago) Link to comment Share on other sites More sharing options...
Andy0217 Posted April 28, 2020 Author Share Posted April 28, 2020 Ok Folks, I spoke with NetworkAV to confirm and yes JLS Electronics here in Melbourne are their authorized service centre so I have logged an enquiry on their website, but haven’t heard from them yet, In the meantime I pulled the cover off and loosened the bolt from the underside of the amp holding transformer and lifted it off the chassis and bingo no buzz... The transformer casing doesn’t feel like it is vibrating, and is silent, but as soon as It goes back on the chassis it buzzes... Will see what JLS have to say, but if the fix is going to be over the top I will probably just live with it... Cheers Link to comment Share on other sites More sharing options...
betty boop Posted April 28, 2020 Share Posted April 28, 2020 40 minutes ago, Andy0217 said: Ok Folks, I spoke with NetworkAV to confirm and yes JLS Electronics here in Melbourne are their authorized service centre so I have logged an enquiry on their website, but haven’t heard from them yet, In the meantime I pulled the cover off and loosened the bolt from the underside of the amp holding transformer and lifted it off the chassis and bingo no buzz... The transformer casing doesn’t feel like it is vibrating, and is silent, but as soon as It goes back on the chassis it buzzes... Will see what JLS have to say, but if the fix is going to be over the top I will probably just live with it... Cheers website ? just give them a call. theyre just conventional repairer. pretty busy usually. doubt be able to tell you anything via email or phone, will want to you to lodge it so can have a look. probably then quote to resolve. usually a cost to look at it as most places have these days... sounds to me just kind of typical vibration can get from large torroid. not unusual. usually the fix is to tighten not loosen Link to comment Share on other sites More sharing options...
myhifiacct Posted April 28, 2020 Share Posted April 28, 2020 12 hours ago, Andy0217 said: In the meantime I pulled the cover off and loosened the bolt from the underside of the amp holding transformer and lifted it off the chassis and bingo no buzz... If you are getting buzzing from the transformer it is DC offset in the AC mains power. Large toroidal transformers are very sensitive to DC offset, resulting in core saturation and a mechanical hum. If the hum is lower at 3am on Sunday morning, due to less industry/people using power, then you have confirmed your source. 1 Link to comment Share on other sites More sharing options...
pwstereo Posted April 29, 2020 Share Posted April 29, 2020 1 hour ago, myhifiacct said: If you are getting buzzing from the transformer it is DC offset in the AC mains power. Two identical amplifiers, both connected to same mains power, one does the buzzing, the other doesn't. So this idea doesn't seem likely. OP has found lifting the transformer off the chassis in the buzzing unit stops the buzzing, it sounds like a mechanical vibration from the transformer is the cause. 1 Link to comment Share on other sites More sharing options...
myhifiacct Posted April 29, 2020 Share Posted April 29, 2020 47 minutes ago, pwstereo said: Two identical amplifiers, both connected to same mains power, one does the buzzing, the other doesn't. So this idea doesn't seem likely. I would normally agree except I've had this exact example in my home. Two amplifiers connected to the same mains supply except one sounded like a power substation and the other was virtually silent. My guess is slight differences in windings makes some toroids more audible than others. 1 Link to comment Share on other sites More sharing options...
pwstereo Posted April 29, 2020 Share Posted April 29, 2020 2 minutes ago, myhifiacct said: My guess is slight differences in windings makes some toroids more audible than others. Ah, I see, I thought you were saying that the DC offset made all transformers buzz. Link to comment Share on other sites More sharing options...
Andy0217 Posted April 29, 2020 Author Share Posted April 29, 2020 Thanks Folks It may be D.C. on the line...it was plugged into a GPO that no doubt shares all sorts of appliances in the house...you name we have it, all manner of crap... I am just waiting on the dedicated circuits into the HT to be wired in, once that is done, will give it another go and hopefully dedicated circuits will solve the issue...here’s hoping, so have decided to wait and see, Although with this Covid caper I no idea when I can get him over to complete the install, Cheers, Link to comment Share on other sites More sharing options...
audiohippo Posted May 10, 2020 Share Posted May 10, 2020 On 29/04/2020 at 10:45 AM, pwstereo said: Two identical amplifiers, both connected to same mains power, one does the buzzing, the other doesn't. So this idea doesn't seem likely. OP has found lifting the transformer off the chassis in the buzzing unit stops the buzzing, it sounds like a mechanical vibration from the transformer is the cause. It is likely and a DC blocker would fix it. Link to comment Share on other sites More sharing options...
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