DC filter
For a good while now a lot of my kit has had large transformers.
All, except the TOCA SECA have intermitently hummed when plugged directly into the mains.
An AG1500 sorted the hum, and had many positive effects on the sound of the system, but seemed to compress the bass somewhat when used with the TOCA.
Hence my move to Sovereign's MTBPS balanced power supply. This sounds great, and keeps the transformers upstream quiet.
One slight problem is that the MTBPS itself has the largest power supply of all (3KVA with a 5KVA core). Most of the time (98%) it is utterly silent. But, occasionally, especially in the day it can rev up a bit. Usually just for a few moments then dies away. It is inaudible if I'm listening to music at anything but the quietest levels.
I decided to look into a cheap way of addressing this. It seemed like "DC on the mains" may be the problem. Some commercially available products are out there...
This one: "The Excelsior DC Blocker" costs £595.
I didn't want to spend that much.
On my second sweep I came across this from LC Audio Technology:
About £35 including delivery from Denmark. Clicky. A nice man called Anders was very helpful.
It arrived today.
So I connected it up to a bog standard IEC lead...
Encased it inside a temporary insulation box...
And plugged it in...
Now, the first thing I always look for whenever I do any electronic engineering is no deaths. So far, this has been achieved.
Secondly I hope that no kit will explode. Again, so far so good...(Please note the lights are on on the TFS and the TOCA!
>- )
If things work as hoped then that is a bonus. So far, the LC Audio Technology DC filter is doing exactly what it claimed it would do. There has been not a hum nor a buzz nor a rev from the MTBPS. =D>
Finally, it is possible that the bass coming out of the system is a just a tiny bit more...scary? Possibly more impactful and deep? I was expecting the DC filter to effect only the occasional humming of the MTBPS. I don't really understand how it could change the system sound beyond it... So I may be imagining it. :-? It certainly hasn't effected the sound adversely. I was a little nervous that this might happen as the rating of the DC filter is at the limit of what the TOCA and TFS are drawing, and obviously well below the MTBPS. I don't know how important these things are with passive components. Maybe it either works or it blows up. (So far no smoke.)
In any event, I'm delighted with it. I love making stuff when no-one gets injured.
Next step is to buy a more secure and nice looking box to encase the thing in.
All, except the TOCA SECA have intermitently hummed when plugged directly into the mains.
An AG1500 sorted the hum, and had many positive effects on the sound of the system, but seemed to compress the bass somewhat when used with the TOCA.
Hence my move to Sovereign's MTBPS balanced power supply. This sounds great, and keeps the transformers upstream quiet.
One slight problem is that the MTBPS itself has the largest power supply of all (3KVA with a 5KVA core). Most of the time (98%) it is utterly silent. But, occasionally, especially in the day it can rev up a bit. Usually just for a few moments then dies away. It is inaudible if I'm listening to music at anything but the quietest levels.
I decided to look into a cheap way of addressing this. It seemed like "DC on the mains" may be the problem. Some commercially available products are out there...
This one: "The Excelsior DC Blocker" costs £595.
I didn't want to spend that much.
On my second sweep I came across this from LC Audio Technology:
About £35 including delivery from Denmark. Clicky. A nice man called Anders was very helpful.
It arrived today.
So I connected it up to a bog standard IEC lead...
Encased it inside a temporary insulation box...
And plugged it in...
Now, the first thing I always look for whenever I do any electronic engineering is no deaths. So far, this has been achieved.
Secondly I hope that no kit will explode. Again, so far so good...(Please note the lights are on on the TFS and the TOCA!
>- )If things work as hoped then that is a bonus. So far, the LC Audio Technology DC filter is doing exactly what it claimed it would do. There has been not a hum nor a buzz nor a rev from the MTBPS. =D>
Finally, it is possible that the bass coming out of the system is a just a tiny bit more...scary? Possibly more impactful and deep? I was expecting the DC filter to effect only the occasional humming of the MTBPS. I don't really understand how it could change the system sound beyond it... So I may be imagining it. :-? It certainly hasn't effected the sound adversely. I was a little nervous that this might happen as the rating of the DC filter is at the limit of what the TOCA and TFS are drawing, and obviously well below the MTBPS. I don't know how important these things are with passive components. Maybe it either works or it blows up. (So far no smoke.)
In any event, I'm delighted with it. I love making stuff when no-one gets injured.
Next step is to buy a more secure and nice looking box to encase the thing in.
Comments
The DC blocker I've got is rated up to 1200VA. So your 13A has a lot more capacity...
You did offer the DC blocker at the time. We (I) decided against it. Just one of my many poor judgements... :-B
Things have gone a bit weird over here.
I've been listening for 3 hours solid now at higher volumes. And I am feeling a bit frightened.
Parts of my brain that expect obviously realistic sounds to have visible sources are unnerved: The soundstage and overall resolution of sounds appears to have further crystalised.
Bass seems to have found another octave, so the parts of my brain that are alert to the fact that distinct low noises might signal large objects crashing towards me or large monsters coming to kill me, are firing off big time.
The only thing I've added today is this DC blocker between the wall socket and the balanced mains transformer. I was not aware of having any expectation that it would do anything more than reduce the mechanical hum from the balanced transformer. Which it has done. Am I deluded or has filtering out DC had some unexpected effect?
@-)
More than adequate.
It's rated to 1Kg. Which, I believe is the best way of measuring electrical safety.
:-bd
My mind's gone fractal...
Coleslaw fractal...
My own MTBPS sits on the end of my dedicated radial straight from the house tails, bypassing the house all together, and it's dead quiet.
So the only way to answer your findings Ben is for me to get off my increasingly fat arse and instal a good quality DCblocker to my MTBPS. or have a clever bloke comment on this thread, although I wouldn't believe anyone unless they have direct experience and not just a brainbox hypothesising an answer.
I would invite the designer of the toroid we both have, but he is not the type of chap to post.
Give me a few days, maybe the end of the weekend and I'll see what I can do.
All thoughts appreciated. Especially by he in the know.
I may have time tomorrow to take out the DC blocker cable and put a normal one in to see if I'm not just imagining it.
But I'm enjoying things too much right now.
"Probably none!
caps are only 0.18R at 50hz and due to the semiconductors only one
conduct in each half period. Hence the series impedance should only be
in the 1/4R range.
fairly confident that your amplifier will not "sense" it in any way.
And since it's a class A (with constant power draw) it shouldn't even be
sensitive to mains impedance... ;-)
My only worry might be the lifespan of the caps with high current draw.
But they are rated at over 5.5A (>1200W at 230V) at full wave 50Hz -
so there should be no problems there either.
conservative - my thought was to allow for 110VAC use and the start-up
of large transformers without soft-start circuits. We probably should
elaborate (or even step up the spec) a bit eventually..."
As I say, Anders is a very nice man. Lovely customer service. =D>
(Hope you didn't find the cat under that backside of yours...)
Oh, and I'm not surprised that you're keeping your efforts under wraps given the slick pro job I did on mine...
Well bugger me, everything you said above Ben is absolutely true, The first thing I noticed was a deeper and punchier bass, secondly I noticed A significantly greater tonal accuracy and the music seemed to stand away from the speakers a bit more, so the advice you were given by the manufacturer of your DC blocker is wrong. Physics may say one thing but you can never question what you're hearing because your ears should always outweigh what someone else might say.
There is one negative in that even though the music is more punchy it seems to have slowed down slightly, I remember asking Nick Gorham who makes my DC blocker if having his DC blocker in position would increase impedance and he his response was always not to any significant extent, so maybe the perceived slowing down of music is not due to increased impedance but something else , I guess the DC blocker is a filter at the end of the day and filters always seem to sit on music somehow. However the increase in sound quality is so much so that it may outweigh the slight perceive slowing down of music. I'll spend some more tunes later on tonight and give you some more feedback.
I may give Nick Gordon a quick email to see if we can get his advice as he is a complete hi-fi nut and a complete physics nut at the same time, of course Colin Wonfer would also be very helpful, I'm sure because Colin is a mad scientist and somewhat of a genius he would easily have a way to block DC totally without affecting the sound quality.
I like feeling validated. And to feel confidence in my sanity.
I'd be fascinated to hear an explanation.
What effect the DC blocker without the MTBPS do you think? Might try that. I wonder if the DC blocker simply helps the MTBPS...?
What bit of Anders explanation are you taking issue with?
I'm wasted on you people!
Anders is the manufacturer to whom you refer.
:-B
How's the sound?
I'm left annoyed that the studio didn't use better / better positioned microphones.
What a boorish thing to write. X_X
Just listened to Harry Connick Junior - SHE if you haven't heard this album you must listen to it it's nothing like the Frank Sinatra rip-offs Harry Connick is famous for this is his own style and it's just incredible . Anyway this is one of my favourite albums and I know it probably better than any other album I have . The difference that this high-quality DC blocker has made is quite substantial. Bass is deeper and more tought, lovely tonal balance, everything seems to have a longer echo and Longer decay , far more detail and far more emotion in the music . I know we read these words in hi-fi speak many times before and we kind of switch off but these are genuine findings and I can't believe that such a small item on an already very good balance of power supply can make such a substantial difference . I only regret that I haven't installed this DC blocker before. I've only used it on poorer quality to toroidals that hummed like mad but as theMTBPS (mother trucker balanced power supply) is almost silent I never felt the need to install it im very glad I have now
I returned to the Chris Botti album I was listening to earlier on today where Sting performs one of his songs and there is still a slightly more plodding or pronounced speed to the bass but this may be greater accuracy as opposed to a slowing of the music. I'll have to give the DC blocker some more time and then take it out and let you know what my findings are but even if there is a slight trade off the benefits that I have found with it in place far out weigh anything that I may have lost . I emailed Nick Gordon who makes the DC blocker earlier on today which I will put it in the next post for fear of trying to cut and paste his email in this post and end up deleting the whole thing as I've done before
Quite a while ago I had a balanced toroidal designed and built for me, it's 3kVa with a 5kVa core. Works a dream, I always left your DC blocker off as the toroid is dead quiet, just put it in the toroid for fun and it has improved every aspect of the sound, quite amazing.
However the sound does seem 'slower' is that because impedance has been raised? Is there anything I can do to the DC blocker to improve this?
Thanks again
Hi James
Yes, I am getting reports of the DC blocker doing very good things, seemingly to the level I don't fully understand why, I sold 12 to one chap, and he loves them. You must have bought five from me at least.
It will increase the mains impedance a fraction, but its possible (cant say without hearing) that the slowness is related to a reduction in over emphasis of edge. I certainly cant think of any specific change that would improve things.
--
Nick
The bass especially is a big leap in terms of depth and definition.
Like you, I simply can't my head around how something so cheap and tiny and upstream of the MTBPS is effecting things like this...
Can you write a bit more about "slowing". I want to better understand what you mean by this.
:-?
You have 5...?! :x
This mention of an insignificant increase in mains impedence... The Anders fellow who sold me mine suggested that Class A amps don't notice mains impedence...? So from both sources, can we discount this then...? (I am simply believing what I'm reading there obviously.)
What do you think is meant by "a reduction in over emphasis of edge"?
And, I still want to better understand what you mean by "slowness". You seem to have really noticed something there.
AFAIC the sound simply sounds "deep cleaned". Like one's teeth after a visit to the dentist. I can hear nothing but improvement. Tonally and spatially more natural. E.g. more perceivable variations in production equipment / styles on different albums. Simply bizarre.
I don't know how it will effect the sound of your system. And, I'd be fascinated to know. :-?
My only reason for inserting dc filter was to stop the occasional intermittent mechanical hum from the big toroid in my balanced power supply, which the DC filter has done 100%.
The additional effects on the sound coming out of the speakers was completely unanticipated.
So a dc filter or blocker should stop any mechanical hum in your integrated. As I say, I don't know what else it might do!
I'd be interested to see what SQ difference it did or didn't make for you Mark.
Sov wasn't getting any hum prior to the dc blockers and had still got a major improvement, and my intermittent hum prior to dc blocking didn't have any perceptible effect on sq, so it's not as simple as less loud mechanical hum = better sq.
The DC effect on sound quality and on mechanical hum appear not directly related (tho presumably they are indirectly related via the DC somehow... :-? )
Who knows...
You may want to do it with a short extension cable first. Just to check the effect before butchering your amp cable...?
And I'm glad you ask, as I'm wondering to what extent the DC blocker is "merely" further facilitating the MTBPS.
I must check this by bi-passing it!
The bass drum is immense on Modul 2. Deep, impactful, defined.
A really sparse, well miced, underproduced percussion piece.
Never heard my system this good before!
One overriding factor is the DC Blocker is staying, without question. I'm going to refrain from answering the various points raised above as my hifi sounds better than before I installed the DC blocker but I made some fundamental changes to the MTBPS this afternoon in its re build which I think may have apeffected the sound a little as a whole. I will try and improve on those tomorrow and report back again tomorrow night.
Yes it is a DIY product and not made in a factory. I have been messing around with balanced power for about nine years or so and the MTBPS is a culmination of that experience. A couple of years ago I set out to really research the topic, my main mission was to learn as much as I could and I was priviladged to find an expert in this field and who is a toroidal manufacturer. He told me the only way to make the ultimate balanced toroidal, but because I had been doing a lot of reading I had a million questions for him. He told me all these things wouldn't work, but he made different toroidals for me to try and none of them worked better than his design, after I felt like I was wasting his time I settled with what we gap have now.
This is not a product made to a price but rather a product made as best as it can regardless of price. Basically they are a 3kVa toroidal with a 5 kVa core, quite large and heavy mothers, hence the name. I have made 9 of these for others including Ben.
Always have been. Even more so now with the DC blocker just before it in the chain...
There are others around that have tried to make another balanced toroidal of this size, but it hasn't made the difference he was looking for and it hums so loud that he has had enough of it and is now selling it. However the MTBPS sits dead quiet, or in bens case almost. People need to understand that the hum or rattle that large toroids make makes its way onto the audio frequency and can be heard audibly. That why it was so important to get this design correct. I have had this design made in various sizes, 1, 2 and 3kVa, each step up has made a significant chance to the sound of the music. However if your balanced toroid rattles then the bigger it gets sometimes the worse the sound of the hifi.
James, what thoughts have you on the fact that your MTBPS didn't hum audibly before (with no DC blocking), but removing any DC has still improved the sound of your kit?
All I know is it sounds better, significantly better. I had a hunch it would as the difference on old Airlink toroids was brilliant, but I put that down to the fact that they stopped humming, but I always had a suspicion it was more than that, and I was right. I just wish I hadn't left it so long before I tried it. Well done Ben for inspiring me !