[aln]

I would be interested to.  Not worried about saving a few bucks when I'm using the blocker on a Van Alstine amplifier. 

[cheap-Jack]

Hi.

As all competent DC blockers have, there is a full wave rectifier on both the positive and neutral feeds.  Regards, and open to suggestions.

Frank Van Alstine

Sorry, I don't know why there is any need of a "full wave rectifier" on BOTH live & neutral feeds?? We need DC blocker, not any rectifier to allow DC to go thru!!!!

As I already pointed out there is not a must for any audio components using power transformers of standard EI cores with air gaps. DC blockers are a MUST for toroidal power irons to prevent powerlines
DC offsets from saturating toroidals with iron cores of zip air gaps.

Why should there be a "full wave rectifier instead of 2 sand diodes head-on series connection? Any DC + or - can NOT go thru such 2-diode head-on series design. This is the designated function of a DC blocker, correct??

Also why there should be any "full wave rectifier" on the neutral line which gets no connection to the power iron?????

c-J

[avahifi]

I think maybe that if you had two diodes in series, either back to back or front to front you would not only block DC, but also block the AC at the same time.  This might do a good job of keeping DC out of your power transformer, but it would keep AC out of it too, not quite as useful.

Why full wave rectifiers on both hot and neutral? Because that by far works best.

The connections to the full wave rectifiers are as follows.  The AC in is connected to one of the AC lugs on the bridge, the + and - outputs of the block are connected to each other. The AC output is connected to the other AC lug on the bridge.  Then two diodes conduct on the positive swing of the AC power line, and the other two diodes conduct on the negative swing.  This allows full AC through the bridge with only a slight loss of two diode drops. The neutral is connected the same way to the other diode bridge.

Then various blocker designs use a multitude of capacitors across the AC line in a variety of connections, some of which we don't really have a good reason for.  Our blocker tests best with only a single 0.47uF 630V cap across the line after the two bridges.  You will have to ask the PS Audio designers why their arrangement is so much more complex. The Emotiva unit also has a RFI filter and a little diode display to tell you if your wall AC power plugs are wired the right way.

The single most important factor in the cost of make a unit is the cost to tool and product a decent metal chassis for it.  This is more than you would think in small production lots.

Regards,

Frank Van Alstine

[cheap-Jack]

Hi.

I think maybe that if you had two diodes in series, either back to back or front to front you would not only block DC, but also block the AC at the same time.  This might do a good job of keeping DC out of your power transformer, but it would keep AC out of it too, not quite as useful.

No, I think you did not read properly my relevant posts earlier.

I stated very clearly many such simple DC blockers using 2-sand-diode-head-on design on live line ALL get a large 'lytic capacitor bypassing each of the diodes in series. So the AC loading currents will go via the bypass 'lytic caps to the components downstream without any obstruction.

I want to do it better by using AC rated oil caps instead of DC rated 'lytic caps.

c-J

[Mountain-ear]

Frank -

If the enclosure is the limiting factor, could you build the HumDingers in a project box or some other standard enclosure at a lower scale just to get a few into the field?  Mark them as prototypes since they wouldn't have your normal chassis quality.  I'm more interested in the guts than the appearance, and I like the idea of buying American as often as I can.

Steve

[2gumby2]

Frank -

If the enclosure is the limiting factor, could you build the HumDingers in a project box or some other standard enclosure at a lower scale just to get a few into the field?  Mark them as prototypes since they wouldn't have your normal chassis quality.  I'm more interested in the guts than the appearance, and I like the idea of buying American as often as I can.

Steve

Agree with Steve. I care about how it works, not so much what it looks like.

[underdawg]

I would be interested in a inexpensive prototype also.

[avahifi]

Even to do the DC blocker in a stock chassis box, we still would need to have a metal shop do the metal work for the IEC input and line fuse, the AC output hardware, and add all the necessary mounting holes for the other stuff.  By the time we pay to have all that done, they might as well just do the entire enclosure and the cost of the raw metal is not all that significant, its the tooling, setup, and handling time that is expensive.

If we were pretty sure of 10 orders, we could do them at $125 each.

Regards,

Frank Van Alstine

[Devil Doc]

I'm in. I'll phone in my order as soon as you give the OK.
Doc

[martyo]

Frank, I'd be interested in one too.

[Big Red Machine]

Even to do the DC blocker in a stock chassis box, we still would need to have a metal shop do the metal work for the IEC input and line fuse, the AC output hardware, and add all the necessary mounting holes for the other stuff.  By the time we pay to have all that done, they might as well just do the entire enclosure and the cost of the raw metal is not all that significant, its the tooling, setup, and handling time that is expensive.

If we were pretty sure of 10 orders, we could do them at $125 each.

Regards,

Frank Van Alstine

For $125, put me down for one.

[rollo]

  How about a hardwired AC cord ? An IEC for may be overkill. I'm a PC fan but not i this case. A simple plastic or wood enclosure would do fine. It doesn't have to be purdy most will be hidden from view anyway.
   I'll take one as well. A very good idea.



charles

[rlee8394]

Looks like either one of these would work, depending on what you stuff it with.

http://www.homedepot.com/h_d1/N-5yc1v/R-100404038/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=junction+box&storeId=10051#specifications

http://www.homedepot.com/h_d1/N-25ecodZ5yc1v/R-100404096/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=junction+box&storeId=10051#.UQGDDCqOutM

Ron

[underdawg]

ill take one for 125.00

[rollo]

Looks like either one of these would work, depending on what you stuff it with.

http://www.homedepot.com/h_d1/N-5yc1v/R-100404038/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=junction+box&storeId=10051#specifications

http://www.homedepot.com/h_d1/N-25ecodZ5yc1v/R-100404096/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=junction+box&storeId=10051#.UQGDDCqOutM

Ron

   Good find Ron. Like Mick Jagger used to say " paint it black you devil "



charles

[avahifi]

Unfortunately, I don't think a plastic box would be very good at heat sinking the diode bridges.

My engineer is running heat and stress tests on the blocker circuits right now.  More info soon.

Frank

[JerryM]

It's ironic (to me) that Frank is being told to forgo an IEC. 

At $125.00, chalk me up for one also.  No IEC 'required'.

Have fun,

Jerry

[rlee8394]

Ok, how about these:

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=202188662&R=202188662#specifications

http://www.lowes.com/pd_74222-53911-521511234EW_0__?productId=3747123&Ntt=junction+box&pl=1&currentURL=%3FNtt%3Djunction%2Bbox&facetInfo=

http://www.lowes.com/pd_19850-53911-72171+1/2+3/4+E_0__?productId=3744301&Ntt=junction+box

There are plenty of steel junction boxes available, duplex, quad, etc. that would probably work.

Ron

[resonance]

I'd definitely take one, maybe even two since I have a stack of amps on each side of the TV next to each of the L/R front speakers. 

David

[jackman]

I'll take one!  It would be great if it had at least ousts for four plugs.