Addicted to music Posted January 6, 2018 Share Posted January 6, 2018 10 minutes ago, andyr said: Not quite sure what you're inferring there, al ... are you saying your amps already have DC blockers built in? The power traffos in all my amps don't buzz either - and they are all plugged straight into the wall ... and they don't have a DC-blocking mechanism built in. All I can surmise from this is that: they are good quality power transformers - Aus-made ... no Jaycar/Chinese sh*t here! I'm possibly lucky enough not to have DC on my mains. Andy Many moons ago when Jaycar opened the store in Abekett St Melb they were supplying ILP toroidals up to 500W 55-0-55V. Link to comment Share on other sites More sharing options...
JSmith Posted January 6, 2018 Share Posted January 6, 2018 33 minutes ago, Addicted to music said: toroidal to buzz This is the key here and often why power conditioners/regen's that use large toroid's will buzz if DC offset is present. OP really needs to diagnose what device is causing the offset rather than trying to block it, as is likely a local cause. As you say, anything that uses a SMPS (which use half wave bridge rectifiers) can be a suspect. Switching off each circuit breaker one at a time while the amp is on can help. If it's due to normal operation of a device, then move to use a DC blocker that has a common mode filter. An Aussie version of this would be nice; http://www.bluecircle.com/page152a.html JSmith 1 Link to comment Share on other sites More sharing options...
andyr Posted January 6, 2018 Share Posted January 6, 2018 (edited) 9 hours ago, JSmith said: This is the key here and often why power conditioners/regen's that use large toroid's will buzz if DC offset is present. OP really needs to diagnose what device is causing the offset rather than trying to block it, as is likely a local cause. As you say, anything that uses a SMPS (which use half wave bridge rectifiers) can be a suspect. Switching off each circuit breaker one at a time while the amp is on can help. If it's due to normal operation of a device, then move to use a DC blocker that has a common mode filter. An Aussie version of this would be nice; http://www.bluecircle.com/page152a.html JSmith DTV hadn't joined SNA when an extensive thread on DC Blockers was started by Tam Nguyen - so you perhaps are unaware of this thread, JS. The circuit which has been used by a number of people on SNA is from Rod Elliott (upgraded in my case!) - here: http://sound.whsites.net/articles/xfmr-dc.htm Andy Edited January 6, 2018 by andyr 1 Link to comment Share on other sites More sharing options...
F18 Posted January 7, 2018 Share Posted January 7, 2018 (edited) Also forgetting another simple fact that another factor for buzzing transformers is simply loose lamination between each of the winding overlapping each other, especially true when the metal pieces that up the core for EI type transformers, a steady buzzing can be heard from vibration of broken adhesion of the lamination/utherane/varnish. Loose lamination can disturb the transformers magnetic field and design, adding impedence making the transformer working harder until it eventually burns out. Cheers, Edited January 7, 2018 by F18 Link to comment Share on other sites More sharing options...
andyr Posted January 7, 2018 Share Posted January 7, 2018 2 hours ago, F18 said: Also forgetting another simple fact that another factor for buzzing transformers is simply loose lamination between each of the winding overlapping each other, especially true when the metal pieces that up the core for EI type transformers, a steady buzzing can be heard from vibration of broken adhesion of the lamination/utherane/varnish. Loose lamination can disturb the transformers magnetic field and design, adding impedence making the transformer working harder until it eventually burns out. Cheers, That would seem to be the case with TWW's Parasound amp - it's mechanical buzzing ... not caused by DC on the mains. I've just got back from visiting his place. I took over one of my DCbloks ... and, inserting it between the amp and the wall ... there was no change to the buzzing. So, as the Parasound is a great-sounding amp, Louis is going to investigate what's involved in replacing its toroid. Andy Link to comment Share on other sites More sharing options...
F18 Posted January 7, 2018 Share Posted January 7, 2018 13 minutes ago, andyr said: That would seem to be the case with TWW's Parasound amp - it's mechanical buzzing ... not caused by DC on the mains. I've just got back from visiting his place. I took over one of my DCbloks ... and, inserting it between the amp and the wall ... there was no change to the buzzing. So, as the Parasound is a great-sounding amp, Louis is going to investigate what's involved in replacing its toroid. Andy That's a shame and seemed like the case based off his initial posts. If cost is a huge factor, the transformer can be impregnated with a mixed varnish epoxy resin (thin enough) so it can bond between the internal windings, but I suspect it will be too much of a hassle and may bring in other issues if not done correctly. Much more easier with with EI, double C or R core type's but toroidial's a bit more challenging. Cheers, Link to comment Share on other sites More sharing options...
Gremrock Posted April 14, 2018 Share Posted April 14, 2018 On 6 January 2018 at 7:38 PM, al said: i have solar and so do some of my neighbours and no issue maybe its not inexpensive my solar does cost more than one of my amps ! More than the cheap one maybe Link to comment Share on other sites More sharing options...
LogicprObe Posted April 14, 2018 Share Posted April 14, 2018 Maybe the mounting bracket is loose? Link to comment Share on other sites More sharing options...
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