Salas hotrodded blue DCB1 build

I have moved my power amps so they are close to the speakers, i prefer this layout and it allows for very short speaker cables.

I borrowed a set of 5 metre interconnects to connect my DCB1 to the power amps. It seems to work ok but i'll need to make a set for myself.

I've been using Van Damme shotgun twin interconnect cable for some years now and plan to buy some more to make a 5m set. Has anyone else tried interconnects this long and did it cause any issues? i dont see any problems doing this, it's one of the main reasons for using a buffer in the first place is it not.

This is the cable i intend using - http://www.van-damme.com/_pdf/28%20UP-LCOFC%20Hi-Fi%20Interconnect%20&%20speaker%20series.pdf
 
RCA input sockets connect directly to the pot - the picture DrDyna posted above shows the wires at the pot for one channel, duplicate this for the other.

The wires labeled output in that picture connect directly to the input tabs/pins on the DCB1 board.

You should have the following signal path. Input RCA's - Pot - DCB1 in - DCB1 out - Output RCA's

The output tabs/pins on the board connect directly to your output RCA sockets.

Twist the wires to help reject interferance.
This is the short, concise, to the point response I have been seeking for nearly two weeks! Thanks so much.
 
I have moved my power amps so they are close to the speakers, i prefer this layout and it allows for very short speaker cables.

I borrowed a set of 5 metre interconnects to connect my DCB1 to the power amps. It seems to work ok but i'll need to make a set for myself.

I've been using Van Damme shotgun twin interconnect cable for some years now and plan to buy some more to make a 5m set. Has anyone else tried interconnects this long and did it cause any issues? i dont see any problems doing this, it's one of the main reasons for using a buffer in the first place is it not.

This is the cable i intend using - http://www.van-damme.com/_pdf/28%20UP-LCOFC%20Hi-Fi%20Interconnect%20&%20speaker%20series.pdf

Not that long, but my speakers are active so I have shielded ìnterconnects`from my DCB1 to the speakers. In my case about 3m per side though. No problems. My cables are nothing fancy, I think they are branded "Acoustic Research", store-bought, sold as "composite video cable".
 
All this twisting of cables to reduce interference is great, but isn't it predicated on the notion that equal and opposite currents flow in each conductor? Hence Andrew's use of the "flow and return" terminology.

Now in the DCB1 we have a common ground, uhh... "return" connector shared by the two channels. So let's assume for a moment that the connected source also has a common "ground" which puts the "shields" of the RCA connectors at the same potential. Now let's assume there is a signal being sent to just one channel, say the Right. So presumably the signal "flows" down the center conductor of one cable, and into the DCB1, and a correspond "return" current must flow down the shield (or second conductor of a twisted pair). But how does that return current know which path to take? BOTH shields (or "return" conductors, if you will) are physically connected to the same point on the circuit board, so from that connection the current sees two paths back to the "ground" of the sending equipment. Why would it take only the path that corresponds to the Right channel? Why wouldn't some of the current flow in the shield of the left channel cable? (Again, assuming both shields end up at the same place in the other equipment). So now we have a signal "flow" just on the right channel cable, but the "return" passing through the shields of both cables. Where is our equal-and-opposite current? What happens to the interference rejection?
 
I have moved my power amps so they are close to the speakers, i prefer this layout and it allows for very short speaker cables.

I borrowed a set of 5 metre interconnects to connect my DCB1 to the power amps. It seems to work ok but i'll need to make a set for myself.

I've been using Van Damme shotgun twin interconnect cable for some years now and plan to buy some more to make a 5m set. Has anyone else tried interconnects this long and did it cause any issues? i dont see any problems doing this, it's one of the main reasons for using a buffer in the first place is it not.

This is the cable i intend using - http://www.van-damme.com/_pdf/28%20UP-LCOFC%20Hi-Fi%20Interconnect%20&%20speaker%20series.pdf


I think better get this one for longer runs : Van Damme Silver Series Session Grade Instrument Cable Low Cap 55 by The Metre | eBay if you want something from van-damme.

I found that I always preferred lower capacitance for longer interconnects.

I use LC-1 blue jeans cable and I like very much, for my 6 meters interconnects.
 
I have moved my power amps so they are close to the speakers, i prefer this layout and it allows for very short speaker cables.

I borrowed a set of 5 metre interconnects to connect my DCB1 to the power amps. It seems to work ok but i'll need to make a set for myself.

I've been using Van Damme shotgun twin interconnect cable for some years now and plan to buy some more to make a 5m set. Has anyone else tried interconnects this long and did it cause any issues? i dont see any problems doing this, it's one of the main reasons for using a buffer in the first place is it not.

This is the cable i intend using - http://www.van-damme.com/_pdf/28%20UP-LCOFC%20Hi-Fi%20Interconnect%20&%20speaker%20series.pdf
I used 3m star quad as outputs from my mezmerise.
These are quite high capacitance interconnects.
 
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Now in the DCB1 we have a common ground, uhh... "return" connector shared by the two channels. So let's assume for a moment that the connected source also has a common "ground" which puts the "shields" of the RCA connectors at the same potential. Now let's assume there is a signal being sent to just one channel, say the Right. So presumably the signal "flows" down the center conductor of one cable, and into the DCB1, and a correspond "return" current must flow down the shield (or second conductor of a twisted pair). But how does that return current know which path to take? BOTH shields (or "return" conductors, if you will) are physically connected to the same point on the circuit board, so from that connection the current sees two paths back to the "ground" of the sending equipment. Why would it take only the path that corresponds to the Right channel? Why wouldn't some of the current flow in the shield of the left channel cable? (Again, assuming both shields end up at the same place in the other equipment). So now we have a signal "flow" just on the right channel cable, but the "return" passing through the shields of both cables. Where is our equal-and-opposite current? What happens to the interference rejection?
This is a problem in most 2channel audio equipment.

I have been "banging on" about it for years.
A commoned Return creates a loop in the two returns, if an when they get "commoned" again.
That extra loop picks up interference.

Keep this extra loop area as small as possible (that means the 2 channels must be very close together) and introduce a interference current reducing element.

Unfortunately the DCB1 has "extra" loops on it's input side and on it's output side, (because the Designer adopted commoned returns!).
The effects of the output side loop can be alleviated by following D.Joffe's added resistor. But the effects of the input side loop seem not to be solvable by his method.
 
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What happens to the interference rejection?

This is what happens with Mezmerize i.e. the most complex one regarding inputs number with common returns (including a stereo pot).
 

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This appears to ignore the interference picked up by the TWO looped Returns feeding one stereo input to the Mez.
What if there are 6 stereo inputs, using 12 returns?
And these are Looped at their remote ends?

Virtually all stereo audio Source equipment uses a commoned Return.
That becomes a LOOP when connected to a DCB1.
 
No.
The screen of the coax is the return of that one channel.
The screen of the other coax is the return of the other channel.

If the two screens are commoned at the source equipment and the two screens are commoned at the receiver equipment then the two screens form a LOOP.
That loop will have interference impinging on it.
The two halves of that screen LOOP will have interference voltages on them. The Receiver will read these interference voltages as a signal on each channel.

It is the common at source and at receiver that creates the LOOP.


Coax is just as good/bad as twisted pair at picking up interference in the Return halves that form the LOOP.
Coax is NOT a solution.
Breaking the screen RETURN at one end does not offer a solution, that just introduces a bigger LOOP into the channel that has it's screen connection broken.
 
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diyAudio Chief Moderator
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Can use double core and return the shield to one end only if there is some measurable interference problem in a system. I haven't seen hum region or other interference spikes rising above -118dB in conventionally wired DCB1 with coax when looped through a 24 bit audio card.
 

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I think better get this one for longer runs : Van Damme Silver Series Session Grade Instrument Cable Low Cap 55 by The Metre | eBay if you want something from van-damme.

I found that I always preferred lower capacitance for longer interconnects.

I use LC-1 blue jeans cable and I like very much, for my 6 meters interconnects.


Thanks for the link, I will need to check out a few options. I like the twin shotgun stuff, it is very flexible and affordable. I would need 10m of the other stuff for both channels which is starting to get expensive.
 
A groundlifted dual mono on the recieving end would not create a loop though. Given separate PSUs in dual mono and no common ground connection between signal and chassieground on that side.
The standard D.Joffe explained solution works for Loops created between the Source (DCB1) and the two channel Power Amplifier.

But that solution does not apply to a Loop created before the DCB1.
The effects of the output side loop can be alleviated by following D.Joffe's added resistor. But the effects of the input side loop seem not to be solvable by his method.