So using a BNC-to-RCA adapter is a bad idea?

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Or is it OK?

I'm using a old Rega Planet as a transport with a Scott Nixon DacKit.

Currently, my SN DacKit has an RCA digital input, but I'm thinking of changing it to a true 75ohm BNC.

Since the Rega's digital out is RCA and I only have BNC-BNC cables, I'd have to use an BNC-to-RCA adapter.

Is this a really bad idea, or will it sound OK? I read a post in another forum that suggested this adapter may affect the sound in an undesirable way, but it wasn't proven one way or another.

Any ideas? I know that Ack D'ack offers their current cable as BNC-BNC with an BNC-to-RCA adapter if you need to go from one to the other.

Ack D'ack seems to build a good DAC, so maybe they are right and this scheme is OK? What do you think?

Thanks,
KT
 
I have changed all my Drive & DAC connections to 75 ohm BNC and I do believe it made a positive diference.
For a week or 2 I used Apogee Wyde Eye Digital cable terminated with RCA and plugged in via adaptors. I preferred this cable to my BNC'ed Monster.... I then terminated the Apogee with BNC plugs and thus got rid of the adaptors and noticed a further improvement...

My suggestion would be to eiter also change the Rega output to a BNC or if you do not wish to mess with it, make a cable with RCA one end and BNC on the other.

I would say BNC is better then RCA but RCA will outperform BNC-RCA conversions with adaptors.
 
I suspect KT is reluctant to modify a commercial product for whatever reason. I myself only mess with older long out of waranty stuff or stuff that is so tweaky (like the nixon dac) that it does not matter. The Nixon dac uses a std electronic box so modding it neatly is easy. The rega case would be a little harder to modify neatly... More stuff that could go wrong too as I am sure more experienced "stripping" of the unit is required if the hole in the case needs to be drilled bigger. Almost a certain thing with any panel mount socket vs the pcb mount type it probably has now....
 
Jack............

I have spent way too much time the last 15 years or so to get people way from RCAs to BNCs. That was hard enough..............now you want me to tell them about microwave connectors?

If it was a 50 ohm world, we could get them to use APC-7.........or APC3.5. Right?

Jocko
 
In my wayward youth I used type-N connectors -- I only operated on the 1296 MHz band once -- with a mil-surplus transceiver --

at the NY Home Theatre show, one thing which impressed me was that a manufacturer used SMA's inside an amplifier -- get this, the front panel used a high end RCA jack but the connection to the PC Board was an SMA connector -- the inside wiring looked like my HP 3586C measurement receiver.
 
KT said:
Currently, my SN DacKit has an RCA digital input, but I'm thinking of changing it to a true 75ohm BNC.

Since the Rega's digital out is RCA and I only have BNC-BNC cables, I'd have to use an BNC-to-RCA adapter.

Is this a really bad idea, or will it sound OK? I read a post in another forum that suggested this adapter may affect the sound in an undesirable way, but it wasn't proven one way or another.

Any ideas? I know that Ack D'ack offers their current cable as BNC-BNC with an BNC-to-RCA adapter if you need to go from one to the other.

Ack D'ack seems to build a good DAC, so maybe they are right and this scheme is OK? What do you think?

Thanks,
KT

I used a BNC/RCA adaptor and it clearly added a slight edginess or grittiness to the sound. I only use BNC now because they're 75 ohms, which avoids digital signal reflections and consequent jitter caused by RCA's with the wrong impedance.

Replacing an RCA connector with a BNC is about as simple as it gets. I suggest you modify the Rega. Even if you intend to sell it at some point, the new owner would benefit.
 
Re: Re: Why not use RCA on both ends?

Elso Kwak said:
Hi,
You want me to explain how a transmission line works? No you won't. Is Jocko writing in Texan dialect?
:clown:
I know how transmission lines work. It's half of what I do for a living.

But my System Two has a BNC output, and every once in a while I have to test a piece of equipment with an RCA input. Dismantling the piece of equipment, replacing the RCA with a BNC, performing the tests, then putting the RCA back in... well, that'll be a hard one to explain to the pointy hair types. :)

And hey, it's a BNC female -> RCA male adapter. They're less evil than the other gender. :devily:
 
For those who do not want to modify, a cable with BNC one end and RCA on the other will still offer the best performance, way beyond the best adaptor.... A piece of Belden 1695A with one BNC and one RCA will not cost much more then the adaptor.. I keep one in the wire box for testing/playing with non BNC gear....

My gear as said before is all BNC... Good BNC's are also cheaper then most good RCA's....
 
Re: Re: Re: Re: Why not use RCA on both ends?

jackinnj said:
When I looked at the NextGen connector, i saw what would appear to be a "radiator", not a transmission line !

I'm doing basic functional testing, not attempting to make musicians leap out of soundstages and dropkick listeners. If the SPDIF signal makes it into the box without any huge reflections on the cable that confuse the clock recovery circuit, then everything's OK.

And I suspect that the BNC->RCA connection might actually have a better impedance than the XLR jack next to it...
 
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