Using the built-in D/A converter on the K+H 300D?

[Lunatique]

It occured to me that I could maybe use the D/A converter in my K+H 300D's instead of using the likely inferior one in my Line 6 Toneport UX2 audio interface. Any K+H owners using the built-in D/A converter? How does it compare to the average audio interface D/A converter? Also, I assume all I need to do is to connect the SPDIF out of my audio interface straight into the 300D's and that's it?

[audiomichael]

I believe they only take AES-EBU in, no SPDIF.

But if you were to just connect directly, then you'd have to software control your volume, which is dangerous. If there's a computer crash or something resets you'll be sending audio full blast through the monitors with potential to blow drivers, or your ears.

[Lunatique]

I think it takes a BNC cable, and I can then use a BNC to RCA adapter. But the question then is, there's one BNC connection to each monitor, but there's only one SPDIF output on the audio interface. How the hell do I get the SPDIF out to BOTH monitors? (Sorry, never did this kind of thing before--dealing with digital connectors. I've always just used analog.) Maybe use a RCA splitter adapter to split the SPDIF out, then have two BNC to RCA adapters connected to each of the BNC cable to each of the monitors?

I see your point about the lack of volume control. I guess that's why K+H also sell that $3,000 digital controller unit (Pro C 28). I guess it's a good thing that the 300D's have clip protection--if shit goes wrong, just plug your ears, walk over to the back of the monitors, and turn them off. Of course not nearly as fast as reach out and turning down a volume knob though.

I did some research and it appears the 300D's use Delta Sigma D/A chips--I guess that puts them in the same league as standalone DAC units like the Lavry DA10 and Benchmark DA1?

[MJ Heck]

Hi Rob,

I am currently waiting on a pair of 110D's and had the sam questions prior to purchase.
My current conversion is from an Ensemble, so my questions to Ryan at Vintage King
were framed with that as a comparision point, but I thought his answer may be of use to you:

"The converts in them are quite good and I find them more transparent than Apogee
Rosetta 800 or DA-16X by quite a bit, which is important in a monitoring D/A. I would say
that if you’re currently using Apogee’s as your reference then they won’t let you down."


Also, in regards to conenctivity, the manual indicates the need for a couple of T connectors
and a terminator to use the SPDIF capability - here again is Ryan's response for more detail:

"You will need (2) BNC T-Connectors and (1) BNC 75 Ohm terminator"


I hope this helps a little -

Matt

[Lunatique]

Thanks for that! Very helpful.

So what are you going to do for volume control? You're not going to just use software volume control I assume?

I just dug out the manual and it actually confused me than helped me. According to what Ryan said, I'd need two BNC T-connectors (75 ohm), but in the manual there are also configurations for only one T-connector.

I'm guessing the best configuration is:

-Audio interface's SPDIF out, with RCA to BNC adapter connected to a 75 ohm BNC cable.
-That BNC cable is connected to a BNC T-connector. One side connects to one monitor, the other side connects to the second BNC cable.
-The second BNC cable connects to a second T-connector, with one side connecting to the second monitor, and the other side connecting to a BNC terminator.

Does that sound about right?

[Lunatique]

I just thought of something else. In the manual, it says you can't use both digital and analog inputs at the same time, but I'm guessing that means you can have both analog and digital cables connected at the same time, and you can switch between the two by setting that switch in the back? I think I want to connect both so that for very critical listening, I'm using the 300D's D/A converter, and in normal situations, I'm using its analog input.

[Marineville]

I've not used the digital ins on my 0300Ds yet. Is there really that much difference?

[Lunatique]

Originally Posted by Marineville

I've not used the digital ins on my 0300Ds yet. Is there really that much difference?

Well, I guess if your current default D/A Converter isn't a premium one, then using the ones in the 300D's will probably be a significant improvement. That's my main reason for wanting to try it.

[lazzaro]

Originally Posted by Lunatique

Well, I guess if your current default D/A Converter isn't a premium one, then using the ones in the 300D's will probably be a significant improvement. That's my main reason for wanting to try it.

Maybe you can find one of these in the used market:

Roland M1000

[Lunatique]

I wish I could find that Roland unit somewhere. I looked around and it's a pretty obscure product even when it was in production and being sold.

I talked to someone at K+H and he confirmed that using two T-connectors and one terminator is the way to do it, but unless I find a way to control the digital output volume with a physical knob, I'm stuck with software control only. He suggested maybe replacing the Toneport with another audio interface that can control the digital output volume with a knob. Anyone can suggest an audio unit like that?

[MJ Heck]

Hey Rob,

Sorry - I just had a chance to find this thread again.

As for the SPDIF config, is your manual the same as the info available on-line at the K&H site?
They had a couple of illustrations that helped me understand where the two T connectors fit into the equation.

I'm not really sure what I am going to do for volume control yet, as I won't have the K&H's in my
possession for a couple of weeks. I assumed the Maestro software that I use for the Ensemble would
be sufficient as it is so integrated with the Mac OS - I'll have to put it through the paces when
the monitors arrive.

Likewise, not sure about the either/or connectivity question -
one of my goals in getting the D's was to be able to use the two additional analog outputs for I/O routing when mixing.

Sounds like I'm going to be asking you some questions in a couple of weeks .

MJH

[lordmiguel]

Originally Posted by Lunatique

Anyone can suggest an audio unit like that?

some higher end 2 channel DA's like the lavry da10 has a digital analog volume control - but i know of no one who has a digital control to control aes or spdif gain. guessing it could be tough to find one in the audio market because there are not many digital monitors out there, if k+h doesn't know......

[DSMrehearsal]

the focusrite saffire and saffire LE have a knob on the front to control the software output volume.

[Lunatique]

You know what guys? I just realized something.

Even if I am able to control the digital output volume level somehow, it is still prone to unresponsiveness as soon as there's a software/computer crash, and I'd still end up with a loud noise I'd need to kill fast (although I can use the analog volume attenuators on the back of the monitors to set an acceptable loudness level so they'd never actually damage anyone's hearing in that situation). Someone in another thread also suggested putting the power switch to the monitors somewhere within reach (maybe a power strip/extension cord).

Does the Focusrite Saffire and Saffire LE's volume controls on the box for the software volumes resist computer/software crash, or as soon as something goes wrong those controls become unresponsive?

[lordmiguel]

Originally Posted by DSMrehearsal

the focusrite saffire and saffire LE have a knob on the front to control the software output volume.

a digital spike through expensive monitors at full level is a feeling like someone rear ended you in your new mercedes. you should really think this through.

btw here is your focusrite answer:

"The stereo output sections are all identical except for the last one, 9/10, which is the SPDIF output and so contains no level control as the digital output level is fixed" (from the manual)

[Lunatique]

Originally Posted by lordmiguel

a digital spike through expensive monitors at full level is a feeling like someone rear ended you in your new mercedes. you should really think this through.

btw here is your focusrite answer:

"The stereo output sections are all identical except for the last one, 9/10, which is the SPDIF output and so contains no level control as the digital output level is fixed" (from the manual)

Thanks!

So I guess the safest way discussed thus far is to:

1) Set the volume attenuators on the back of the monitors to acceptable level, so even during a volume spike, it's still relatively safe. (The 300D's also have built-in clipping detector and a limiter for protection.)

3) Put the power switch within reach via a powerstrip/extension cord.

[squeegybug]

You can certainly just connect any cheap digital mixer and use its fader for output control. You do realize you will lose 1 bit for every -6 dB change in level? So you will be monitoring a variable word length as you raise or lower the digital volume. And that will not be dithered.

Maybe worth the tradeoff? But how do you even know how good/bad the K+H DA is, and whether it is worth all this trouble...

I'd be far more inclined to get a simple transformer volume control (TVC) and a good DA. Or just get something like the DA10.

this

I did some research and it appears the 300D's use Delta Sigma D/A chips--I guess that puts them in the same league as standalone DAC units like the Lavry DA10 and Benchmark DA1?

is not necessarily the case at all. Far more to it than just what chips are used, that is the easy part.

Steve

[Lunatique]

Yeah, I see your point. I've already ordered the necessary BNC connectors/cables, so I'll at least hook them up and see if the D/A converters in the 300D's are that much better than the one in the Toneport. If they are significantly better, it might be worth it. I'll maybe try the tactic of setting the digital out volume to as high as it should go, and then attenuate the volume level control on the 300D's (post conversion) to optimal listening level (the level which majority of my critical listening is done). That way, when I'm pulling the volume down via software, it's during times when the listening doesn't need to be critical anyway.

I really would rather not spend another $1,000 just for a D/A converter that may or may not be better than the ones in the 300D's. Considering the 300's (the analog only version of the 300D's) are cheaper by more than $1,000, it leads to my speculating that the D/A converters in the 300D's are probably near that price range if they were to be ripped out and sold by themselves.

[lordmiguel]

Originally Posted by Lunatique

1) Set the volume attenuators on the back of the monitors to acceptable level, so even during a volume spike, it's still relatively safe. (The 300D's also have built-in clipping detector and a limiter for protection.)

3) Put the power switch within reach via a powerstrip/extension cord.

1) hopefully the attenuators are more than just trims / small adj. and they can go down to critical listening levels.

1a) if the the clipping detector is like others, its the back bumper on your car...the gas tank might not blow up but you will still want to kill someone when getting hit...

3) hey where's 2? the power strip may probably be too little too late. not a bad idea anyway for a software lockup, but playing with fire and matches is usually dangerous anyways.

Originally Posted by squeegybug

You can certainly just connect any cheap digital mixer and use its fader for output control. You do realize you will lose 1 bit for every -6 dB change in level? So you will be monitoring a variable word length as you raise or lower the digital volume. And that will not be dithered.

what steve said - look into the digital mixer thing, which is not my strong point. did you do the calculation re how many bits you would be listening at proper monitoring levels?

i do think the c28 is primarily intended for digital operation. however, if you can feed the full wordlength and attenuate the speaker where you need it from the back you will be set.

[Lunatique]

C28 is too rich for my blood. My wallet is still weeping from the 300D's...

I have tested my critical listening level before and it's usually between 80db~90db.

The truth is, I'd be less upset about someone hitting my bumper than if I were to damage my 300D's! Hell, the 300D's are worth a lot more than my car! (I just checked last night--a 1991 Acura Legend is going for about $2,500~$3,500 these days.)

[chasman]

the value of your klein + hummel studio monitors far exceeds the value of your automobile................mister lunatique sir, my hat is off to you...........I do hereby find it good and appropriate to nominate you for GS of the Month and immediate and unqualified admittance to the GS Hall of Fame (should such a thing exist presently or in the future).......

Originally Posted by Lunatique

C28 is too rich for my blood. My wallet is still weeping from the 300D's...

I have tested my critical listening level before and it's usually between 80db~90db.

The truth is, I'd be less upset about someone hitting my bumper than if I were to damage my 300D's! Hell, the 300D's are worth a lot more than my car! (I just checked last night--a 1991 Acura Legend is going for about $2,500~$3,500 these days.)

[Tim Davis]

well.. I sold my car for 0300d's!