DAC directly connected to Speakers - Set-Up Advice Please

[JFraser]

Hi all,

 

Here's my current set-up:

 

Arcam rPac (rPAC - USB DACs - Arcam), which is connected to my PC.

 

Pair of KRK VXT6 (VXT6 Studio Monitors Speaker KRK SYSTEMS)

 

I'm looking for the easiest way to connect the speakers directly to my DAC. As you will see, the only connection output from the rPac is standard RCA. The speakers are active, so there is obivously no need for an amplifier here.

 

My other thing I'm not sure about is how I am going to be able to control the volume. The KRKs have small volume knobs but they're are on the back of the units and not really meant to be changed as these are studio monitors. Would the built-in volume controller on my media player and/or windows volume slider be good enough?

 

The only solution I can think of currently is simply to connect the them by [RCA to XLR] OR [RCA to 1/4inch jack] cables.

 

Many thanks in advance for your suggestions,

Jack

[Audio_ELF]

Your best bet is to connect the DAC direct via RCA to TRS (1/4" jack). Turn both media player and Windows to max; and turn the speaker level right down. Play some music and then adjust the level on the speakers up till it gets to a comfortable maximum.

 

Now everyday use the volume on your media player to control the level.

[JFraser]

Thanks for your response, Audio_ELF. Any recommendations on a decent RCA to TRS cable? Considering it'll be carrying an analogue signal, I assume the quality of the cable does matter somewhat? Also, the TRS input on the speaker is balanced, so does this mean I need to get a balanced cable or can I get unbalanced?

[mayhem13]

Canare cable has always proven itself for me both at home and professionally. Plenty of web dealers build to order short lengths. Also on Ebay.

 

I prefer RCA to XLR myself instead of TRS.......no spring connection to wear out.

 

TCElectronic also makes an analog desktop volume controller already fitted with XLR on both ends.....all you'd need is XLR/RCA converters.

[Audio_ELF]

To add to Mayhems comment... You can also get both XLR and TRS to phono adaptors so if you have some cables which are RCA to RCA this is a good way to go.

 

Eloise

[DigiPete]

TCElectronic also makes an analog desktop volume controller already fitted with XLR on both ends.....all you'd need is XLR/RCA converters.

 

I thought of the TC Electronic Level Pilot as well.

Great professional quality at no price at all!

Vintage King charges USD 89,-

[speavler]

emotiva just came out with a nifty passive volume control.

[mayhem13]

emotiva just came out with a nifty passive volume control.

 

Nice find!.....with unbalance both ends......and affordable!

[JFraser]

That looks perfect for my needs but I live in the UK and they only ship domestically in USA

How frustrating!

 

Another quick question; my active speakers only have balanced inputs (XLR & TRS) so does it matter that I'll be connecting an unbalanced (RCA) connection out of the DAC to them?

 

Overall what do you guys think is the best way to go? RCA to TRS cables, RCA to XLR cables, or RCA to either XLR or TRS adapter and then standard XLR or TRS cables from the adapter to my speakers?

[mayhem13]

My opinion is to skip the TRS wherever possible......XLR and RCA offer more contact surface area.

[pooger]

That looks perfect for my needs but I live in the UK and they only ship domestically in USA

How frustrating!

 

Another quick question; my active speakers only have balanced inputs (XLR & TRS) so does it matter that I'll be connecting an unbalanced (RCA) connection out of the DAC to them?

 

Overall what do you guys think is the best way to go? RCA to TRS cables, RCA to XLR cables, or RCA to either XLR or TRS adapter and then standard XLR or TRS cables from the adapter to my speakers?

 

As Mayhem said, TRS is not as solid a connection, so you'd be better off with XLR termination at the speaker end. The KRKs will work fine with an unbalanced source; my son's college set up is exactly that. He's using an extra set of mike cables I had with an adapter at the DAC end. If you get custom cables, even better would be skipping the adapter and using properly terminated ends. The KRKs are high enough resolution so that not having the extra adapter in line might be audible. (Once they were fully broken in, I've been very impressed with them.)

[JFraser]

Thanks for the reply, pooger. I've gone with these in the end, http://www.amazon.co.uk/Adam-Hall-Male-Audio-Cable/dp/B004BR2VIC/ref=sr_1_1?ie=UTF8&qid=1396469816&sr=8-1&keywords=rca+to+xlr, they are yet to arrive so haven't tested them. I hope using the volume control on my media player won't become annoying.

[dc2bluelight]

Ah, the miracles of confused priorities. TRS is "bad" (huh?), custom cables highly recommended, the KRKs have, apparently, such incredible resolution they can reveal an extra adapter in the circuit, but.... then use the media player volume control...which is about 100X more destructive than any of the above. Perhaps an email to Emotiva to work out international shipping (or ask someone on the forum to do it for you) then get pretty much any RCA/RCA and RCA/TS cables to lash it all together, and you'd have a real winner.

 

By the way, in 50 years in audio I can count TRS failures on one hand...about the same as XLR failures, excluding the routine cleaning that every connector eventually needs.

[One and a half]

To the OP, what's the cable length from the KRK to the rDac?

[One and a half]

As Mayhem said, TRS is not as solid a connection, so you'd be better off with XLR termination at the speaker end.

 

Also to Mayhem. I don't know what kind of 1/4in TRS connectors you use, to substantiate this statement. I find the TRS to be very dependable.

 

The XLR is a good connector, but the KRK is a 1/4in TRS connection only, how is this to work, oh another adapter?

[Audio_ELF]

The XLR is a good connector, but the KRK is a 1/4in TRS connection only, how is this to work, oh another adapter?

Don't the KRK have a Neutrix combined XLR/TRS connector.

[JFraser]

Don't the KRK have a Neutrix combined XLR/TRS connector.

 

Yes they do.

[JFraser]

Ah, the miracles of confused priorities. TRS is "bad" (huh?), custom cables highly recommended, the KRKs have, apparently, such incredible resolution they can reveal an extra adapter in the circuit, but.... then use the media player volume control...which is about 100X more destructive than any of the above. Perhaps an email to Emotiva to work out international shipping (or ask someone on the forum to do it for you) then get pretty much any RCA/RCA and RCA/TS cables to lash it all together, and you'd have a real winner.

 

By the way, in 50 years in audio I can count TRS failures on one hand...about the same as XLR failures, excluding the routine cleaning that every connector eventually needs.

 

Very interesting, thanks for your input. What is the problem with the volume slider in the media player? Does that mean that even set at maximum it's having an effect on the quality? The only concern I have about the Emotiva Control Freak and the TC Electronic Level Pilot, is that the cabling is such that you need to buy more adapters and cables because the way they have wired it on the speaker connection side, it does not leave room to set the speakers far enough apart otherwise. This seems a bit silly and I don't want to have endless run of cabling and adapters. See this review to see what I'm talking about:

[JFraser]

To the OP, what's the cable length from the KRK to the rDac?

 

All depends on what solution I go for, but they're both going to be sitting on my desk

[dc2bluelight]

Very interesting, thanks for your input. What is the problem with the volume slider in the media player? Does that mean that even set at maximum it's having an effect on the quality? The only concern I have about the Emotiva Control Freak and the TC Electronic Level Pilot, is that the cabling is such that you need to buy more adapters and cables because the way they have wired it on the speaker connection side, it does not leave room to set the speakers far enough apart otherwise. This seems a bit silly and I don't want to have endless run of cabling and adapters. See this review to see what I'm talking about:

 

It has to do with the method used to adjust volume. A volume control in a media player or computer does this by applying a mathematical operation to the digital data. Hopefully, it up-samples the data first to 32 bit float, but who knows? In any case, that operation changes the actual digital signal so that it's no longer bit-perfect. It has to, by definition of "digital level change". The operation adds distortion, changes the dynamic range (moves the signal closer to the noise floor) etc. For example, worst case, assuming no up-sampling, lowering the volume of a 44/16 file 12dB changes your 16 bit data to 14 bit data. Since average audio levels are already not using all 16 bits all of the time, probably more like 14 or less, you'll actually be at more like 12 bits, post volume control. -12dB is a more or less typical "normal" control setting, permitting a bit of turning up louder, and a lot of turning down. Things aren't as bad if the system up-samples to a higher bit-depth first and then sends that adjusted data to the DAC, but it probably doesn't.

 

The Emotiva or TC Level Pilot is just a set of passive, variable resistors...potentiometers, which are wired to create a variable voltage divider. A voltage divider adds no distortion or noise. In fact, all it does is alter the output voltage. That's it. In fact, you have two of them already in the circuit: the level controls on each speaker. You'll be balancing those against the action of whatever controls the volume from your listening position, regardless if digital or passive analog.

 

The changes a digital control makes are real, measurable, and necessarily so. So ask yourself, would I like to change just volume, or would I rather change every single byte of audio data?

 

As to cable length, yes, long cables can hit your extreme top end. They do this by adding capacitance, forming a simple RC low-pass filter. However, the filter cutoff frequency is determined by the series resistance and impedance of the driving circuit, and the load impedance of the receiving circuit. In this case, I'd guess you'll be around 5K considering both, and considering an average volume control position. Considering an average cable capacitance of 20pf per foot, if you had 50 feet of cable, the -3dB point would be at just under 32KHz. With 44/16 audio, there's no audio there, it's all gone by 22KHz, so no impact. But, of course, you won't be using 50' of wire, right? So, no impact.

 

As to the audibility of connectors and adapters, people may disagree, but it's a total myth. Nobody can really hear them, they just think they can, right up until they are about to stop being connectors. A really bad connector may become a diode as it's failing, injecting tons of distortion. It'll be obvious, and horrible, and you'll go find the problem and fix it immediately. Otherwise, they'll be completely harmless. I know I'm in an audiophile forum, and somebody's going to argue this. But it's not just opinion at work, it's science too.

[DigiPete]

As to the audibility of connectors and adapters, people may disagree, but it's a total myth.

Nobody can really hear them, they just think they can, right up until they are about to stop being connectors.

A really bad connector may become a diode as it's failing, injecting tons of distortion.

It'll be obvious, and horrible, and you'll go find the problem and fix it immediately.

Otherwise, they'll be completely harmless.

I know I'm in an audiophile forum, and somebody's going to argue this.

But it's not just opinion at work, it's science too.

 

 

He said Jehova.

He said Jehova.

He said Jehova.

[dc2bluelight]

He said Jehova.

Surreal.

[mayhem13]

Also to Mayhem. I don't know what kind of 1/4in TRS connectors you use, to substantiate this statement. I find the TRS to be very dependable.

 

The XLR is a good connector, but the KRK is a 1/4in TRS connection only, how is this to work, oh another adapter?

 

Used them consitently from nearly every brand for over 40 yrs. Every insertion wears the tip spring. Locking XLR is a far superior connection.

 

Wasnt looking at this from an SQ standpoint but a reliability position. Sorry if that wasnt clear.

[mayhem13]

He said Jehova.

He said Jehova.

He said Jehova.

 

How bout hanging Scanspeak instead for selling out to the Chinese?

[DigiPete]

How bout hanging Scanspeak instead for selling out to the Chinese?

 

 

How about hanging Naim for waisting audiophile money sponsoring Bentley GT3 racing?