Aristillus

Mains DC. Can it really be stopped?

Recommended Posts

Most of these mains transformer noise problems are caused by transformer makers running their products too near the flux density limit for cost reasons. So its easy for any dc component or overvoltage to cause saturation.  Some makers like Canterbury Windings use oversize cores ie a 500VA one on a 300VA transformer but they cost. This is not the same as just using a bigger transformer. Sorry that doesnt help much but at least its an explanation . Sometimes a step down autotransformer can help.

Share this post


Link to post
Share on other sites
8 hours ago, Nopiano said:

Steve, I don’t know what your budget is for remedying this, but I’m sure you know that Russ Andrews (amongst others) offers a trial period on their mains products.  They have a vast range, and offer advice over the phone. I’m thinking you could do worse than trying an item or two in your system to see what effect they have. 

https://www.russandrews.com/power/

I appreciate that some folk have strong feelings on these devices, but I’d definitely be tempted if faced with your issues.  I hope you find something that works for you.

Bit too pricey for me. Thanks though

Share this post


Link to post
Share on other sites

I use a power regenerator and  a conditioner. But that is only because they take up less room. If I had my way...and if my mains box powering my room was outside the  house. I would have added a  constant voltage transformer (CVT)  of my required capacity ( it hums in use so can't be in the music room ) and then would add a isolation transformer of the same capacity, and feed that power to the music room. This will give a steady voltage pure from emi, rf or DC :). And probably the best power possible. I have a friend who designs very high end , expensive and precise medical diagnostic equipment. And he vouches that if space is not a consideration nothing beats this combo. And if one is not running power hungry equipment like power amps, then the CVT can be replaced with a servo stabilizer. Which is slower to react and rectify power fluctuations ( the good ones correct at 25v per sec ). Where as a CVT will constantly output the require voltage continuously irrespective of input voltage fluctuations. But the negative as I already mentioned is the hum from its magnetic cores :D. Now add something like a isotek evo3 3 Polaris at the end of chain , so that emi and rf picked up by the power wiring is filtered here . One gets very very pure power, without sacrificing any dynamics.  Just my 2 cents... :)

Edited by newlash09
  • Like 1

Share this post


Link to post
Share on other sites

If you feel confident enough to try, you could measure your mains voltage and see what sort of level it is. If it's on the high side, it could be the transformer reacting to this. You can buy a cheap multi meter for less than £15.

Sent from my K3 using Tapatalk

Share this post


Link to post
Share on other sites
On 15/09/2019 at 17:47, Aristillus said:

Living as i do in a village not too far away from a steelworks and my house fed by overhead mains cables is it really possoble to prevent my power amps buzzing like a pylon? I have tried a DC blocker on my Pre-amp power supply to reasonable effect though i have been advised against using one with my power amps. Or would it be better just to buy an amp the simply isn't as suseptable to DC?

I live in an old cottage and despite having it completely rewired, I have had problems with DC offset on the mains for many years..

Don't know why, but British amps with Toroidal transformers seem to be a particular problem - both Rega and Creek amps have buzzed away happily. My last amp was a Creek Evolution 100A which has a large toroid in a slimline case. The result was transformer buzz that I could clearly hear when you got closer than 1m - my listening seat is close to my equipment rack. Totally silent when I took it back to my local hi fi shop, which was quite annoying. So here is a list of the things I have tried:

Separate mains spur with dedicated consumer unit for my hi fi - didn't work

DC blocker off ebay - looked well constructed, but didn't really do anything

Isol -8 Powerline axis - looked the business and nicely made, but no joy.

I was in Audio Emotion's demo room one day (I live in Scotland), and saw a Power Inspired mains regenerator sitting on the floor. I asked the price just out of curiosity and couldn't believe it when told it was £500. They gave me a loan - success! The transformer buzz was reduced by about 80% on the Creek amp and eliminated completely from psu for my Michell Gyrodec. The biggest surprise was the the effect on sound quality with noise floor reduced, bass having more impact, greater separation of instruments. The changes were not subtle, but clearly audible. I bought one immediately and consider it one of the best upgrades I have made to my system. I recently traded it in for the most recent model(AG1500S), which is more compact and has multiple output IEC sockets. It has twin cooling fans, but they are virtually inaudible from about 1m, where I sit. The price has gone up a little to £550, but I still consider this to be excellent value.

It is not as sophisticated as something from PS Audio, but then their cheapest unit is over £2000!

  • Like 1

Share this post


Link to post
Share on other sites
Super Wammer

I have posted as well on the other thread where you mentioned your experiences but I just wonder if you actually had DC offset?

I had main trannies buzzing and thought it might be DC offset and it just turned out to be simple high voltage which was of course sorted by a voltage controlled regenerator set to 230v (but it introduced other issues with the sound quality but that is a different story).

Share this post


Link to post
Share on other sites
Moderator
5 minutes ago, Fourlegs said:

I have posted as well on the other thread where you mentioned your experiences but I just wonder if you actually had DC offset?

I had main trannies buzzing and thought it might be DC offset and it just turned out to be simple high voltage which was of course sorted by a voltage controlled regenerator set to 230v (but it introduced other issues with the sound quality but that is a different story).

I agree with the doubt.

Basically, even the cheapest DC blocker blocks DC. It requires minimal components to achieve, and though it won't (can't) make the slightest difference to the quality of sound reproduction, it will kill stone dead any transformer stauration and buzz due to DC offset.

  • Upvote 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.