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View Full Version : Wanted: cheap DC blocker


montesquieu
13-01-2018, 11:54
Anyone got a cheap DC blocker going spare they can part with - or even lend me as I'm really just wanting to check something out.

Just looked online and the only commercially available one seems to be a piss-taking £250.
AD Audio
13-01-2018, 11:58
Anyone got a cheap DC blocker going spare they can part with - or even lend me as I'm really just wanting to check something out.

Just looked online and the only commercially available one seems to be a piss-taking £250.Hi, I make them to order if you are interested. I'd have price one up for you but the last one I did was around £50 for one to add to an amplifier as a module, a bit more if you want it in an independent case.
David

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Bigman80
13-01-2018, 12:59
Anyone got a cheap DC blocker going spare they can part with - or even lend me as I'm really just wanting to check something out.

Just looked online and the only commercially available one seems to be a piss-taking £250.https://www.atlhifi.com/shop/fully-assembled-devices/dc-blocker-trap-filter-assembled-in-case/

I have two. Very good unit.

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killie99
13-01-2018, 13:29
you could build one, very easy.....

http://theartofsound.net/forum/showthread.php?52821-Sjostrom-DC-Blocker
montesquieu
13-01-2018, 19:22
you could build one, very easy.....

http://theartofsound.net/forum/showthread.php?52821-Sjostrom-DC-Blocker

You maybe could, where I could or not is another matter. :)
alphaGT
13-01-2018, 20:25
Ok, I’m confused? (It’s not that unusual), but why would you want a DC blocker? And where does it go in the signal chain? The ones in that URL look like they go in front of the power plug? And if you’ve got DC between the amp and speakers then you may have a major problem with the amp? Thanks for any help understanding this

Russell
montesquieu
13-01-2018, 20:38
Er, it's a mains issue. Plenty of info why needed in the links above or here (http://sound.whsites.net/articles/xfmr-dc.htm)
walpurgis
13-01-2018, 21:03
Ahem. :)

http://i68.tinypic.com/2natzsi.jpg

Sjostrom finished board. Not built into case yet, waiting for taller stand-offs, as I want to run the cable under the board.
Bigman80
13-01-2018, 21:13
Ahem. :)

http://i68.tinypic.com/2natzsi.jpg

Sjostrom finished board. Not built into case yet, waiting for taller stand-offs, as I want to run the cable under the board.Nice work Geoff. The ATL ones are good too.

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walpurgis
13-01-2018, 21:16
Nice work Geoff. The ATL ones are good too

Not my work Oliver. I bought a completed board, as it's not that much dearer than a self assembly item.

Whole thing will stand me in a little over fifty quid. Ther Sjostrom board is very nice quality.
Bigman80
13-01-2018, 21:17
Not my work Oliver. I bought a completed board, as it's not that much dearer than a self assembly item.

Whole thing will stand me in a little over fifty quid. Ther Sjostrom board is very nice quality.That's a great price! Mine was a bit more than that.

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lordmortlock
13-01-2018, 22:35
A question on this whilst it’s on topic chaps. I’m playing with a new power amp that apparently passes dc through to the pre. Interested to know if it’s causihg some noise, so was looking at dc blocking rca devices to put between pre and power. Are they any good? Or is the sense more that you’re better blocking the dc at source ie the mains ?
lilolee
13-01-2018, 22:44
A question on this whilst it’s on topic chaps. I’m playing with a new power amp that apparently passes dc through to the pre. Interested to know if it’s causihg some noise, so was looking at dc blocking rca devices to put between pre and power. Are they any good? Or is the sense more that you’re better blocking the dc at source ie the mains ?

These DC Blockers are for the mains, not for low level signals. Jake, do you mean the pre is direct coupled? if so then any dc would be amplified by the power amp and eventually fry your tweeters if your are lucky of both units if not. I'm never trust direct coupled unless via a transformer, so have always had a decoupling cap in there somewhere prior to the power amp
lordmortlock
13-01-2018, 23:07
Ah ok, thanks Lee, that’s helpful. The comment re the power amp suggested avoiding pres that could pass dc on, so I guess they meant direct coupled units.

The pre is an eastern electric minimax pre or a nelson pass b1 buffer clone. I’ll read up on these, try to understand what the designs do.
alphaGT
14-01-2018, 01:25
Er, it's a mains issue. Plenty of info why needed in the links above or here (http://sound.whsites.net/articles/xfmr-dc.htm)

Thank you sir, I have been schooled!


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lilolee
14-01-2018, 10:10
Jack, just to clarify, if your power amp has a cap blocking DC you would be ok. I see you have a 300b amp so I know that they have coupling caps between the 6sn7 and 300b so no worries, even with a direct coupled pre.
dennis
15-01-2018, 16:53
I am using two ATL units: https://www.atlhifi.com/shop/fully-assembled-devices/dc-blocker-trap-filter-assembled-in-case/
Excellent VFM and fast delivery

They work very well with my V20 and WA22
5acan
16-01-2018, 06:59
Hi Tom,
This one works great as well:
http://www.lcaudio.com/index.php?page=316
jda99
20-01-2018, 10:24
Thanks for this thread, the result of which was that I bought the ATL unit which arrived yesterday.
Would have done it years ago if only I had known - background silence - bliss.

JDA99