Transformer Hum

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Lurcher300b
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Re: Transformer Hum

Unread post by Lurcher300b » Mon Jun 11, 2018 8:11 pm

Dr Bunsen Honeydew wrote:
Mon Jun 11, 2018 7:11 pm
Nick I sold you something last summer that I thought might make be great improvement, but it was too big and heavy for me and I had no room for it. It seems it is still at MCRU. That would be worth experimenting with.
Yep, like you space is at a premium here ATM.

Geoff.R.G
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Re: Transformer Hum

Unread post by Geoff.R.G » Tue Jun 12, 2018 8:27 am

Having noted the enthusiasm for the Tesla Power Wall I did some research into high power conversion systems, basically inverters. The research paper I skimmed covered an AC-DC-AC Variable Speed Constant Frequency generator rated between 40KVA and 250KVA. What I noticed fairly quickly was the amount of filtering applied to the output to get a sine wave. The paper also showed plots of the output with noise prior to filtering which was quite significant. Given that the paper was dated 2017 it is reasonable to assume that the principles are current.

I accept that we won't be concerned with the generation of the original AC waveform and that any rectification in a domestic environment will be single phase with a final single phase output. The point being that the inverter isn't the only factor affecting source impedance, the filters would appear to have some effect too. Source impedance wasn't immediately noticeable as a consideration in the paper.

You can find it here: VSCF proposal

BilliumB
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Re: Transformer Hum

Unread post by BilliumB » Thu Jun 14, 2018 8:13 pm

Dr Bunsen Honeydew wrote:
Mon Jun 11, 2018 7:11 pm
Nick I sold you something last summer that I thought might make be great improvement, but it was too big and heavy for me and I had no room for it. It seems it is still at MCRU. That would be worth experimenting with.
Hello Doc

Was that the large isolation transformer that you posted about some time ago? I was hoping to hear how you got on with that.

Cheers. Bill

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Dr Bunsen Honeydew
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Re: Transformer Hum

Unread post by Dr Bunsen Honeydew » Thu Jun 14, 2018 9:46 pm

Yes I sold to Nick (lurcher) as I couldn't even get it in the house.
Image

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CN211276
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Re: Transformer Hum

Unread post by CN211276 » Fri Jun 29, 2018 7:56 am

Dr Bunsen Honeydew wrote:
Sat May 26, 2018 7:59 pm
You have lots of big transformers and noisy mains. There is one more thing you can add to try and drop it more - a DC blocker - this one seems the best value.

https://www.atlhifi.com/shop/fully-asse ... d-in-case/

The last thing in the line of things before the system should be the BMU then you know you are balanced..
I have bad mains so bought one of these on the Doc's advice to plug the BMU into. It has been in place over a week and the BMU has been completely silent. Prior to this it sometimes made a noise and could get quite loud first thing in the morning for some reason. A slight hum (not through the speakers) still comes from the A80s, but seems less than before. Sound quality has not changed. A bargain when you consider what MCRU is charging for them. :)
I set a course just east of Lyra
And northwest of Pegasus
Flew into the light of Deneb
Sailed across the Milky Way

NVA BMU, Sonore microRendu/McRU PS, AQ J-bug, Wirewold Ultraviolet, Chord Qutest, NVA P50SA, NVA A80sMk2, NVA Cube 3s, NVA LS6, NVA TIS mk2. Rega Planar 3, Denon DL-110, NVA Phono 1, NVA SSP Mk2, Grado SR 325e, headphones, Chord Mojo.

Second system
Arcam Miniblink Bluetooth DAC, Marantz pm 5004, Wharfdale Diamond 121, NVA LS2.

Out and about
Oppo PM3, Audioquest Dragonfly Red.

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BrandonMarlow
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Re: Transformer Hum

Unread post by BrandonMarlow » Sat Jun 30, 2018 2:14 pm

CN211276 wrote:
Fri Jun 29, 2018 7:56 am
Dr Bunsen Honeydew wrote:
Sat May 26, 2018 7:59 pm
You have lots of big transformers and noisy mains. There is one more thing you can add to try and drop it more - a DC blocker - this one seems the best value.

https://www.atlhifi.com/shop/fully-asse ... d-in-case/

The last thing in the line of things before the system should be the BMU then you know you are balanced..
I have bad mains so bought one of these on the Doc's advice to plug the BMU into. It has been in place over a week and the BMU has been completely silent. Prior to this it sometimes made a noise and could get quite loud first thing in the morning for some reason. A slight hum (not through the speakers) still comes from the A80s, but seems less than before. Sound quality has not changed. A bargain when you consider what MCRU is charging for them. :)
Did you buy it from that site? If it was OK for you I'll buy one too - the signing certificate on that site looks a bit iffy.

How long did it take to arrive?

Thanks in advance

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zebbo
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Re: Transformer Hum

Unread post by zebbo » Sat Jun 30, 2018 2:35 pm

Brandon, I bought one too but it made no difference in my set up, good or bad. Certainly couldn't hear any negative effect on the music. I bought the version with cable glands so I could try it in different locations which needed different terminations.
With post it is €90 but you could have it for £55 delivered. It is currently set up with UK 13A plug in and IEC out but you can change that to whatever you want.
Audio Grail "Sable" Garrard 401 with constrained layer plinth / SME V / Benz Micro Gullwing SLR, Phono 3 + 2X BBPSU - MEGA!, NVA P90sa, NVA Cubix-Pro, (top & mid sections). (Oh and a Pioneer BDP LX70A when I just want some background music!)

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kellerist
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Re: Transformer Hum

Unread post by kellerist » Sat Jun 30, 2018 3:56 pm

I bought it from that site too. Flawless.

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CN211276
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Re: Transformer Hum

Unread post by CN211276 » Sat Jun 30, 2018 4:02 pm

I bought it from the site. Came from Bulgaria and took around a week to arrive. Had to buy a kettle lead to connect it, not from MCRU. :) A few quid on eBay.
I set a course just east of Lyra
And northwest of Pegasus
Flew into the light of Deneb
Sailed across the Milky Way

NVA BMU, Sonore microRendu/McRU PS, AQ J-bug, Wirewold Ultraviolet, Chord Qutest, NVA P50SA, NVA A80sMk2, NVA Cube 3s, NVA LS6, NVA TIS mk2. Rega Planar 3, Denon DL-110, NVA Phono 1, NVA SSP Mk2, Grado SR 325e, headphones, Chord Mojo.

Second system
Arcam Miniblink Bluetooth DAC, Marantz pm 5004, Wharfdale Diamond 121, NVA LS2.

Out and about
Oppo PM3, Audioquest Dragonfly Red.

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zebbo
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Location: As close to France as you can get.
Great Britain

Re: Transformer Hum

Unread post by zebbo » Sat Jun 30, 2018 4:08 pm

zebbo wrote:
Sat Jun 30, 2018 2:35 pm
Brandon, I bought one too but it made no difference in my set up, good or bad. Certainly couldn't hear any negative effect on the music. I bought the version with cable glands so I could try it in different locations which needed different terminations.
With post it is €90 but you could have it for £55 delivered. It is currently set up with UK 13A plug in and IEC out but you can change that to whatever you want.
That offer applies for anyone else here also if he doesn't want to take advantage. :grin:
Audio Grail "Sable" Garrard 401 with constrained layer plinth / SME V / Benz Micro Gullwing SLR, Phono 3 + 2X BBPSU - MEGA!, NVA P90sa, NVA Cubix-Pro, (top & mid sections). (Oh and a Pioneer BDP LX70A when I just want some background music!)

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