[Martyn]

Here are a couple of pictures of my just-completed project that combines a DC blocker with a pair of Felix AC filters:

http://www.audiocircle.com/index.php?action=gallery;area=browse;album=1389

This was inspired by Gary's "Felix meets the Squeezebox" thread (http://www.audiocircle.com/index.php?topic=50284.0) which I've supplemented with the earlier "Felix project" http://www.audiocircle.com/index.php?topic=25757.0 and the DC Blocker from "Buzzing Toroids (take two)" http://www.audiocircle.com/index.php?topic=50908.0. Thus the project provides a filtered 3 amp outlet to supply a Squeezebox or piece of source equipment and a filtered 10 amp outlet to supply an amplifier in a single case.

I intended to fit the components on a 100 mm by 160 mm prototyping board in a Hammond 1455T2201 case. Unfortunately one of the coils turned out to be too tall for the case, thus I had to improvise the mounting of two smaller boards on edge. I also got the orientation of the larger coil wrong and had to reposition it on its board, hence the space between it and the small capacitors either side. I discovered this when I powered up for the first time and promptly blew the 10 amp fuse (which I was uncharacteristically cautious enough to fit). Both hot lines are fused at their respective levels.

I decided to build two identical units - one for my Squeezebox/AKSA rig and one for my Denon/Arcam set-up - thus I suppose this was really a double Double Felix project, but I think this is complicated enough already. I've only tested for basic operation so far; I haven't done any listening tests.

My thanks to Occam, Gary, Gordy, and Josh without whose help I'd never have done this.

Martyn

[tanchiro58]

Here are a couple of pictures of my just-completed project that combines a DC blocker with a pair of Felix AC filters:

http://www.audiocircle.com/index.php?action=gallery;area=browse;album=1389

This was inspired by Gary's "Felix meets the Squeezebox" thread (http://www.audiocircle.com/index.php?topic=50284.0) which I've supplemented with the earlier "Felix project" http://www.audiocircle.com/index.php?topic=25757.0 and the DC Blocker from "Buzzing Toroids (take two)" http://www.audiocircle.com/index.php?topic=50908.0. Thus the project provides a filtered 3 amp outlet to supply a Squeezebox or piece of source equipment and a filtered 10 amp outlet to supply an amplifier in a single case.

I intended to fit the components on a 100 mm by 160 mm prototyping board in a Hammond 1455T2201 case. Unfortunately one of the coils turned out to be too tall for the case, thus I had to improvise the mounting of two smaller boards on edge. I also got the orientation of the larger coil wrong and had to reposition it on its board, hence the space between it and the small capacitors either side. I discovered this when I powered up for the first time and promptly blew the 10 amp fuse (which I was uncharacteristically cautious enough to fit). Both hot lines are fused at their respective levels.

I decided to build two identical units - one for my Squeezebox/AKSA rig and one for my Denon/Arcam set-up - thus I suppose this was really a double Double Felix project, but I think this is complicated enough already. I've only tested for basic operation so far; I haven't done any listening tests.

My thanks to Occam, Gary, Gordy, and Josh without whose help I'd never have done this.

Martyn

Martyn,

Very nice work.

I have question about DC blocker. I know that DC blocker using in this circuit to trap the buzzing DC (correct me if I am wrong!) and wonder did you connect them before or after the Felix and it does not seem to have switching PS in your project pictures. In this case how could you use with your SB? Reason for asking is because I plan to build double Felix + high quality switching PS for my Altmann Attraction DAC and BYOB amp to compare with battery PS. Thanks.

Regards,
Tan

[Occam]

Martyn - Very, very nice! I'm pleased to see I'm not the only person working with both CMCs who confused the wiring. I like to thinik of it as full blown destructive testing.

How did you cut the square holes for the outlets? Is that a grommet that you used to secure the cord, or an actual strain relief? If so, which strain relief?

I'm looking forward to you evaluation of whatever benefits your Felix provides in your system.


Tan - I believe a DC blocker should go before the Felix. Substantial DC offset on a CMC is likely to cause the CMC itself to buzz.

Regards,
Paul

[JoshK]

Martyn - Very, very nice! I'm pleased to see I'm not the only person working with both CMCs who confused the wiring. I like to thinik of it as full blown destructive testing.

I did that once.  But I put in a breaker before the filter so it just tripped the breaker.  Then I realized I had wire it wrong.     Live and learn, just hope you live to learn. 

[BradJudy]

Nice.  Laying them on their side is a nice solution to the tall CMCs.  How are they held in place?

[Martyn]

Thanks for your positive comments.

Tan, I nearly included a linear power supply for the SB in the design, but Gary had commented that the standard switching supply sounded just fine, plus I didn't want to fall into my usual trap of being too ambitious. Here's the general layout: the fuses are in the hot input line; the DC blocker is in the neutral input line; there is no power supply built in - the standard SB wall-wart plugs into the 3 amp outlet. I still have to get around to labelling the fuses and outlets. I tried instant lettering but couldn't get it to adhere - I'll probably adjust my standards and use a marker pen instead!

Paul, the holes for the outlets (Digikey 486-1082-ND) are actually an asymmetrical cruciform shape. I marked them out in pencil, then used a step-drill in a drill press to cut away the bulk of the material, and then filed the remainder. It was not too painful, although achieving a precise shape takes some care. I wasn't as careful as I might have been, but the outlets have quite good mounting clips. I would have taken more care had I been doing just one outlet, but I had four to do and am not very patient. The strain relief bush is a Heyco part. The part number from my local supplier is SR7W2, although I don't know whether this is Heyco's part number or not. I started with a smaller bush (SR6P4), but this was too small for my power cord (Digikey Q112-ND) which is a 14 AWG 3 conductor cord. I chose this because both my amps use 14 AWG cords; a Felix for just an SB could obviously use a smaller cord and bush. The bush needs an elongated hole and thus requires a few minutes of fiddly filing. I would have been less inclined to use these components if the enclosure's end plate had been steel!

Brad, I cut a pair of strips of 1/4" MDF that fit along each side of the enclosure. Each strip has two saw kerfs in it to locate the circuit boards. The circuit boards hold the MDF strips against the sides of the enclosure and the end covers hold them longitudinally. It was the simplest fail-safe arrangement I could come up with.

Maybe I'll take some better photographs...

[kyrill]

Thanks for your positive comments.

Tan, I nearly included a linear power supply for the SB in the design, but Gary had commented that the standard switching supply sounded just fine, plus I didn't want to fall into my usual trap of being too ambitious. Here's the general layout: the fuses are in the hot input line; the DC blocker is in the neutral input line; there is no power supply built in - the standard SB wall-wart plugs into the 3 amp outlet. I still have to get around to labelling the fuses and outlets. I tried instant lettering but couldn't get it to adhere - I'll probably adjust my standards and use a marker pen instead!

Paul, the holes for the outlets (Digikey 486-1082-ND) are actually an asymmetrical cruciform shape. I marked them out in pencil, then used a step-drill in a drill press to cut away the bulk of the material, and then filed the remainder. It was not too painful, although achieving a precise shape takes some care. I wasn't as careful as I might have been, but the outlets have quite good mounting clips. I would have taken more care had I been doing just one outlet, but I had four to do and am not very patient. The strain relief bush is a Heyco part. The part number from my local supplier is SR7W2, although I don't know whether this is Heyco's part number or not. I started with a smaller bush (SR6P4), but this was too small for my power cord (Digikey Q112-ND) which is a 14 AWG 3 conductor cord. I chose this because both my amps use 14 AWG cords; a Felix for just an SB could obviously use a smaller cord and bush. The bush needs an elongated hole and thus requires a few minutes of fiddly filing. I would have been less inclined to use these components if the enclosure's end plate had been steel!

Brad, I cut a pair of strips of 1/4" MDF that fit along each side of the enclosure. Each strip has two saw kerfs in it to locate the circuit boards. The circuit boards hold the MDF strips against the sides of the enclosure and the end covers hold them longitudinally. It was the simplest fail-safe arrangement I could come up with.

Maybe I'll take some better photographs...

very clever very handy thx

[tanchiro58]

Tan, I nearly included a linear power supply for the SB in the design, but Gary had commented that the standard switching supply sounded just fine, plus I didn't want to fall into my usual trap of being too ambitious. Here's the general layout: the fuses are in the hot input line; the DC blocker is in the neutral input line; there is no power supply built in - the standard SB wall-wart plugs into the 3 amp outlet. I still have to get around to labelling the fuses and outlets. I tried instant lettering but couldn't get it to adhere - I'll probably adjust my standards and use a marker pen instead!

Martyn,

Felix with linear PS do not sound good (constricted to me). But Felix with high quality switching PS sound excellently.



Tan

[alana106]

 

Felix with linear PS do not sound good (constricted to me). But Felix with high quality switching PS sound excellently.
Tan

Tan,

   Where did you find a your switching PS.  I'd like to pick one up. I tried the felix with the stock SB3 switcher PS, and seemed to find my linear sounding better.

Thanks,
Alan

[tanchiro58]

 

Felix with linear PS do not sound good (constricted to me). But Felix with high quality switching PS sound excellently.
Tan

Tan,

   Where did you find a your switching PS.  I'd like to pick one up. I tried the felix with the stock SB3 switcher PS, and seemed to find my linear sounding better.

Thanks,
Alan

Alan,

I see one on sale on ebay. Here is the link:

http://cgi.ebay.com/Shindegen-AC-DC-Power-Supply-5-VDC-5-Amps_W0QQitemZ160219161122QQihZ006QQcategoryZ58286QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Get this one and connect it after the Felix. I never like the sound of Felix+linear PS since I had tried several different linear PS. The stock switching PS sounds better with Felix at least in my system.

Tan

[Martyn]

Two more photographs added to my gallery: http://www.audiocircle.com/index.php?action=gallery;area=browse;album=1389. They are a little sharper than the previous ones.

The strain relief bushes are a pain (but not too serious). I suspect that the screw type that Gordy has might be easier.

Martyn

[alana106]

Thanks Tan.  I'll let you know if I win it.  There is no buy it now on the auction.

Tan,

   Where did you find a your switching PS.  I'd like to pick one up. I tried the felix with the stock SB3 switcher PS, and seemed to find my linear sounding better.

Thanks,
Alan

Alan,

I see one on sale on ebay. Here is the link:

 
[/quote]

[tanchiro58]

Martyn,

What is the value of the caps that you bypassed the DC blocker? Thanks.

Tan

[GBB]

Two more photographs added to my gallery.  They are a little sharper than the previous ones.

Martyn,
Your filter looks really nice - good job putting it together.
I took a look at your photographs and I do have one concern.  It looks as if you have shorted out the CMC chokes.  The wires should go from the input (or output) to one side of the CMC and then stop.  The CMC should provide the only connection from the input to the output.  But it appears from the photographs that the wire actually bypasses the choke.  Is this just an optical illusion? 
Thanks,
---Gary

[ecramer]

I think you may be right on that sure looks it 
 

Two more photographs added to my gallery.  They are a little sharper than the previous ones.

Martyn,
Your filter looks really nice - good job putting it together.
I took a look at your photographs and I do have one concern.  It looks as if you have shorted out the CMC chokes.  The wires should go from the input (or output) to one side of the CMC and then stop.  The CMC should provide the only connection from the input to the output.  But it appears from the photographs that the wire actually bypasses the choke.  Is this just an optical illusion? 
Thanks,
---Gary

[tanchiro58]

Two more photographs added to my gallery.  They are a little sharper than the previous ones.

Martyn,
Your filter looks really nice - good job putting it together.
I took a look at your photographs and I do have one concern.  It looks as if you have shorted out the CMC chokes.  The wires should go from the input (or output) to one side of the CMC and then stop.  The CMC should provide the only connection from the input to the output.  But it appears from the photographs that the wire actually bypasses the choke.  Is this just an optical illusion? 
Thanks,
---Gary

Martyn,

I noticed that too. The wires should not be there between the two posts of the coils of the hot and cold lines. Could you double check them?

Tan

[Martyn]

Thanks for pointing that out, Gary. I did wonder...

A little knowledge is a dangerous thing, but fortunately I haven't reached that level yet! I'll take care of it and up-date the photographs.

Tan, the caps are Digikey 493-1573-ND. The details are in the "Buzzing Toroids" reference. Cheers,

Martyn

[JoshK]

You just have to cut the copper between the ins and outs of the choke, so long as the choke is wired correctly.  I think it is but I can't really tell from the photo. 

[Martyn]

Done and new photographs posted.

[Martyn]

Did some listening over the weekend. The set-up was: double Felix with DC blocker, Squeezebox 3, AKSA 100N+ power amplifier (no preamp), patient wife. There's a photograph in my Felix gallery showing the arrangement (sans wife). There's a bit of a nest of wiring, but that's because the shelf is very narrow.

So far, I have only half a dozen CDs ripped to FLAC (I keep spending too much time building things), but they include a few of my favourite test tracks. We spent most of our time With Alison Krauss and "The Lucky One", trying the SB and AKSA with various combinations of power source. I think I could hear an improvement with either of them running from the Felix, but my wife did not hear a difference.

Since this was not a blind test, I would normally not take the findings too seriously, but I'm convinced that there really was a difference when we tried Mark Knopfler's "All That Matters" - his voice became more raspy and the guitar more precise. This might not be a very good choice of adjectives, but it seems to me that most improvements in the audio amount to improvements in the resolution of the sound, and this was the case here.

There was also a reduction in hum from my AKSA, especially the mild twang on power up. I should mention that the hum was minor anyway and audible only from less than a metre anyway; it is now lower still.

So that's it for a preliminary audition. I'm convinced that there is an audible improvement, although it's not earth-shaking. I would much prefer to do a blind test, but this will have to do for now. Cheers,

Martyn