Spider27 Posted November 7, 2020 Share Posted November 7, 2020 Item: DC Blocker Price Range: Cheap and cheerful Item Condition: Used Extra Info: I read many positive and not so great feedback on DC blockers. Some say that it helps reducing hum when the toroidal transformer is larger than 500VA and the other say that it did not do much on their system and in fact it does degrade the sound quality. I guess that it depends on the person's system.. Just want to test the theory if it really helps so no need fancy uber quality DC blocker. Any cheap DC blocker that functions would be fine. Colour or cosmetic condition is not important. If it is not pretty, i will put it behind the rack so it becomes invisible. If you have spare one that no longer needed, please shoot me a PM. Thank you.. Link to comment Share on other sites More sharing options...
mbz Posted November 7, 2020 Share Posted November 7, 2020 I understand that you just want to test a theory and don't mind blowing a few hundred dollars on the exercise, but at least you would have learnt something. However keep in mind that a DC blocker is for blocking DC voltage on the mains supply. This Vdc, if sufficiently large will cause the transformer to hum/buzz. If you don't have any transformer buzz in your gear then a DC blocker is probably a waste of money, but then again I recap vintage gear in the hope(?) that they sound better afterwards, not to mention peace of mind. Post your findings... 2 Link to comment Share on other sites More sharing options...
Volunteer sir sanders zingmore Posted November 7, 2020 Volunteer Share Posted November 7, 2020 I have one you can borrow if you just want to test if it works. 2 2 Link to comment Share on other sites More sharing options...
Spider27 Posted November 7, 2020 Author Share Posted November 7, 2020 19 minutes ago, mbz said: I understand that you just want to test a theory and don't mind blowing a few hundred dollars on the exercise, but at least you would have learnt something. However keep in mind that a DC blocker is for blocking DC voltage on the mains supply. This Vdc, if sufficiently large will cause the transformer to hum/buzz. If you don't have any transformer buzz in your gear then a DC blocker is probably a waste of money, but then again I recap vintage gear in the hope(?) that they sound better afterwards, not to mention peace of mind. Post your findings... Thank you for info. I will keep that in mind. I found that my power amp that has 2 x 300VA toroidal transformers low tone hum. Once music plays, cannot hear it but when I get close to it, I can hear the hum which is a bit annoying hence looking for possible solution. I will definitely share my findings. Link to comment Share on other sites More sharing options...
kffern Posted November 7, 2020 Share Posted November 7, 2020 I have the same problem with a 2x300va transformer ESP P110 amp. The transformers are old Aussie made eith a diyaudio softstart. If it is DC on the AC the noise should vary through the day as mine seem to do. I am waiting on a board by Peranders on diyaudio. Mine is worse in the evenings. Have you looked at rubber mounting? https://www.diyaudio.com/forums/group-buys/317094-buy-dct03-dc-trap-filter-toroidal-transformers-26.html Regards Kffern 1 Link to comment Share on other sites More sharing options...
Spider27 Posted November 7, 2020 Author Share Posted November 7, 2020 (edited) 49 minutes ago, kffern said: I have the same problem with a 2x300va transformer ESP P110 amp. The transformers are old Aussie made eith a diyaudio softstart. If it is DC on the AC the noise should vary through the day as mine seem to do. I am waiting on a board by Peranders on diyaudio. Mine is worse in the evenings. Have you looked at rubber mounting? https://www.diyaudio.com/forums/group-buys/317094-buy-dct03-dc-trap-filter-toroidal-transformers-26.html Regards Kffern Good point. I have not thought about checking where the toroidal transformers made and found that it looks like JayCar used to sell this exact transformers. https://www.jaycar.com.au/18v-0-18v-300va-toroidal-transformer/p/MT2132 No offence to JayCar since I use them often but it might be low quality after all. Rubber mount under the transformer are good If DC blocker does not reduce toroidal hum then next option would be replacing both toroidal transformers to better quality one. Edited November 7, 2020 by Spider27 Link to comment Share on other sites More sharing options...
Spider27 Posted November 22, 2020 Author Share Posted November 22, 2020 With big thanks to @lumholtzii who generously lended me his DC blocker. I tried it with my system and toroidal hum did not go away. It made little bit of difference and sounds a bit softer with the blocker. I believe that hum has not caused by DC but toroidal transformer itself. 1 Link to comment Share on other sites More sharing options...
mbz Posted November 23, 2020 Share Posted November 23, 2020 Maybe transformer is vibrating (slightly) against the chassis. Check mounting bolt is secure. Ther normally have a rubber washer/insert that should take care of vibrations. Jaycar does not fill me with confidence, will try and track down the specs... 1 Link to comment Share on other sites More sharing options...
mbz Posted November 23, 2020 Share Posted November 23, 2020 On 08/11/2020 at 10:27 AM, Spider27 said: Rubber mount under the transformer are good ignore above suggestion. No meanigful specs on jcar, their web page is mind numbing. Link to comment Share on other sites More sharing options...
Spider27 Posted November 25, 2020 Author Share Posted November 25, 2020 On 23/11/2020 at 6:32 PM, mbz said: Maybe transformer is vibrating (slightly) against the chassis. Check mounting bolt is secure. Ther normally have a rubber washer/insert that should take care of vibrations. Jaycar does not fill me with confidence, will try and track down the specs... Hi Mike. I think that I found the issue. I was tightening the torroidal transformers too tight which too tightly pressed against the chassis and stray magnet field makes it vibrate. I loose the bolt a bit and it is now much less noticeable. I might try sound deadening rubber material underneath to see if it further helps. Thank you for your suggestion... 2 Link to comment Share on other sites More sharing options...
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