Audiolab has got a new product (a Direct Current Blocker): https://www.audiolab.co.uk/dc-block-6/
What about the credibility of this product?
What about the credibility of this product?
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RFI / EMI filter
- Thread starter Vhond
- Start date
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- current filtering emi rfi
DonR
Major Contributor
DC block can be useful if you have DC present on your power line which can lead to transformer hum. RFI filtering is rarely helpful as most power supplies can filter out the majority of RF noise. Their marketing is full of half-truths which would immediately discount the product for me.
- Thread Starter
- #5
Any difference with https://www.audiosciencereview.com/...view-power-conditioner-surge-protector.25443/ ?
In fact this Audiolab thing is also a power conditioner??
In fact this Audiolab thing is also a power conditioner??
DonR
Major Contributor
The Audiolabs device appears to be a purely passive device (with monitoring) so it is not a true power conditioner. It won't raise sagging voltages for instance. Unless you have truly horrendous power, which is highly unlikely, these things are generally ineffective. Here is a technical explanation of DC-blockers if want the deep dive. They are really trivial in practice.
pseudoid
Master Contributor
I smell something foul but I don't know the source!
The main one is the Magnetostriction effect
The second one is age related (and/or loosely wound windings) causing hum/vibrations to get louder.
IMO: Both are caused by an oscillating signal (alternating current) not DC.
... and I always had thought the hum has just a few causes (actually real ones can be counted on just 2 fingers) :
The main one is the Magnetostriction effect
The second one is age related (and/or loosely wound windings) causing hum/vibrations to get louder.
IMO: Both are caused by an oscillating signal (alternating current) not DC.
DonR
Major Contributor
Can't magnetostriction cause hum though through the deformation of the core? ... or maybe I am thinking of something else?
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pseudoid
Master Contributor
I thought that is what I said....
This is an issue for toroidals from about 500 VA up in particular. Their primary resistance is so low that it doesn't take much DC offset to push them appreciably closer to saturation. DC can be caused e.g. by things with half-wave rectification... if you have a hairdryer with two steps of heat that is a potential candidate. Somee occurrences have been thought to be related to nearby industrial areas.
Spontaneous transformer buzz can also occur with smaller toroids though. I think one of my K+H O110s may have a loose winding, as it will occasionally start to buzz and abruptly stop again. I have yet to find what it's linked to... doesn't seem to be my fridge in any case, and I don't think it's the elevator either.
Considering that the DC Block 6 is very fancy with 6 outlets (apparently individually fused) and an OLED voltmeter display in a HiFi component-looking box, the price of 349,95 £ actually seems somewhat reasonable by the standards of overpriced accessories. I still can't imagine their BOM cost is an awful lot more than 25% of that, but profit and dealer margins and stuff. The core components of any such apparatus are two big electrolytics and a fat bridge rectifier, and I'd guess the single most expensive part will be the case.
Spontaneous transformer buzz can also occur with smaller toroids though. I think one of my K+H O110s may have a loose winding, as it will occasionally start to buzz and abruptly stop again. I have yet to find what it's linked to... doesn't seem to be my fridge in any case, and I don't think it's the elevator either.
Considering that the DC Block 6 is very fancy with 6 outlets (apparently individually fused) and an OLED voltmeter display in a HiFi component-looking box, the price of 349,95 £ actually seems somewhat reasonable by the standards of overpriced accessories. I still can't imagine their BOM cost is an awful lot more than 25% of that, but profit and dealer margins and stuff. The core components of any such apparatus are two big electrolytics and a fat bridge rectifier, and I'd guess the single most expensive part will be the case.
Suffolkhifinut
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If DC is present in the mains supply to a transformer winding, it will have an effect on the incremental permeability of the iron circuit In effect acting as a current limiting device in the transformer.
pseudoid
Master Contributor
Hey @AnalogSteph, are you talking about a "buzz" that is conducted and you can hear thru the speakers, or the hum ("buzz"?) of a xfmr?
Per chance, does that hum "occasionality" related to the temperature of the K+H 0110s windings?
Is your karma operating anywhere near the powerline frequency (or its harmonics)??? May be it is your proximity that is causing the problem...
The mechanical kind. At least I'm pretty sure it is, going by the results of sticking my ear to various spots on the speaker's walls while the issue was occurring.
I don't think so, at least they are rarely stressed very much and stay at a pretty constant temperature once warmed up. The buzz also comes and goes abruptly.
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