Macca's System Blog

[Dr Bunsen Honeydew]

I am doing this for you as I want to prompt some thought. When a system gets to a good level of window cleanliness one of the over riding remaining problems with the view is mains related. If you are getting day by day variation or especially time of day variation then it is mains related not cable run in related.

[Macca]

Thanks. I was going to raise this with you but wanted more time first. I've had suspicions about my mains before so not ruling it out. It's the time thing that doesn't fit though. Almost all my listening is at the same times on the same days. But I hear you about cable burn in, I've never found it to be an obviously observable phenomonon if it exists at all.

[_D_S_J_R_]

I've stated this before, but when I lived in Luton in the 90's, the mains definitely varied from day to day, both for me with AVI and active ATC's (it was the latter that really suffered) and a pal at the other end of the estate with an all Linn system. One day every week, it was awful and I just didn't bother. Vauxhall were still very much in evidence back then, but I'd have thought they'd generate their own power, as the docks do here at t'other end of town.

Here, the systems both sound fine all day every day and it's my ears which dictate the sonics (I have an adult version of glue-ear I was told, as well as Tinnitus, the former of which comes and goes when it bloody well likes ) . It doesn't mean I can't hear differences, but bad TV sound and mumbled speaking is more difficult for me to decipher now.

Sorry, don't mean to thread crap. I'm sure the BMU makes a worthwhile difference to those that need it - the transformer's bloody big enough

[zebbo]

I recently sold my mains regenerator and am actively trying to buy it back!
With the BMU running everything the system sounds great and I thought I could put up with the mains induced hum/buzz so I sold the regenerator as I thought it was expensive overkill. I was wrong. my mains is madly variable. As I sit eating my breakfast every workday morning at 07:45 EVERYTHING, including the BMU starts buzzing/humming like mad and then settles after a few minutes. At all other times the BMU runs silently but the A80's vary from a mild hum to quite a loud buzz. I honestly don't listen often enough to make a valid comparison of sound quality at various times but I would bet it varies quite a bit.

[Dr Bunsen Honeydew]

You have got some factorie(s) near you powering up at 7.45am. I think you have every right to complain to your supplier as if they are injecting that much shit back into mains then they are behaving illegally, and it is the responsibility of your supplier to find out who is doing it.

It is not just hi-fi but everything with a motor like fridge or freezer will have its motor life cut.

[Dr Bunsen Honeydew]

Thanks. I was going to raise this with you but wanted more time first. I've had suspicions about my mains before so not ruling it out. It's the time thing that doesn't fit though. Almost all my listening is at the same times on the same days. But I hear you about cable burn in, I've never found it to be an obviously observable phenomonon if it exists at all.

Burn in is a silly expression, but I suppose we must have a name. Well what ever you call it it exists, but it doesn't come and go, that is my point. My point is *if* it is the case, and *I* think it is the case that the cable has cleaned the window a lot, then existing problems that weren't so apparent become more apparent, and the only thing that has a variable quality like you describe is the mains.

[BilliumB]

I recently picked up a second hand DC Blocker for just the £8 cost of postage, it's an old sjostrom audio board (see sjostromaudio.com DCT01) fitted in a plastic box with a couple of 13A sockets on the outside and a fairly thin captive lead feeding it from the mains. I simply connected it in the supply to my isolation transformer (an old Ben Duncan box that I also picked up second hand some months ago) - this in turn feeds my system (Squeezebox Touch, Jolida Dac, Conrad Johnson CA200 amp, Amphion Xenon II speakers).

Before fitting the DC Blocker, I got regular 'mechanical' buzzing from the amp (I assume from the 600va toroid), and to a lesser extent from the isolation transformer toroid (1000va); with the DC Blocker in the mains feed buzzing has been VASTLY reduced at all times and though the DC Blocker must be increasing the impedance of the supply somewhat, to my ears the sound quality/musicality of the system has improved considerably - 'cleaner windows'.

I wonder if transformer buzzing causes more system problems than just the noise of the buzzing itself.

Cheers. Bill

[Dr Bunsen Honeydew]

You throw out the baby with the bathwater. DC blockers really ferk up the music.

[BilliumB]

That's not what has happened in my experience - that's why I posted!

Cheers. Bill

[Dr Bunsen Honeydew]

It is good to get your opinion Bill, but general consensus is with me, but we are all individuals with individual needs from our systems. Myself personally I would prefer to live with a little hum than put up with the compression effects from a DC blocker.