The Lavry DA11: For your ears only

[USAudio]

Originally Posted by revenge

Also, from a consumer point of view (as I understand DA-11 is consumer orientated), I have to confess I am a bit dissapointed by your decision to keep the XLR as the only line-out option. The Neutrik adaptors (which I already have) are a nice addition to the standard package but they also add a certain length on the rear of the unit (the Neutrik adapter plus the phono plug plus the cable end) not to mention that, no matter how good, they still degrade the sound.

FYI - For a very reasonable price, Blue Jeans Cables will build you an XLR to RCA interconnect cable. I have one and it works great with no discernible sound degradation: Blue Jeans Cable UK -- Broadcast-Quality Cables at Reasonable Prices

[revenge]

Yes, that is true and thank you for the link (BTW, I didn't know it, I will have a look at their cables) but that's not the point. The custom cable offer is unfortunately limited and you have to pay extra. What if you have already some high-end reference phono cables that you would like to use but you can only do it via the Neutrik adaptors?!
Wouldn't have been so much easier to have some gold plated decent RCA line-outs instead?
The way I see things: both DACs could be sold in parallel, one addressed to the professional user, the other for the consumer market. XLR with a minimalistic interface and no bling-blings on one side, RCA, remote, crossfeed and a user friendly controller on the other. I doubt the studio engineer would ever use a remote or the crossfeed facility while there is just a minority of home users with balanced setups.
Again, this is not a criticism, it's just an opinion, my suggestion as a long time user.

[USAudio]

Originally Posted by revenge

... And the reason is not the USB out, the crossfeed or the infrared remote sensor that all come with the new DA-11 (and which are of no importance to me as I am not using the computer as a source or the headphones too much) but the SQ itself. So the big question for me is: is the DA-11 better sounding than the original version? Is it an improved version or just the same DAC in shiny, new clothes?

FYI -

From the original post in this thread:

Originally Posted by Dan Lavry

After attending your convention in San Jose a couple of years ago, I came home and decided to do a product that will optimize the experience of listening though headphones. Thus DA11 was born!

From this thread: Lavry Engineering • View topic - DA-11 Chipset

Originally Posted by Dan Lavry

I do not like to talk about the "insides of my products" on a forum. A product should be evaluated based on how it performs (sound and specs), the features, relaibility, cost, tech support...

But I can say that much: the DA11 uses the same DA "chip set" as the DA10.

From this thread: Lavry Engineering • View topic - DA11 ?

Originally Posted by Dan Lavry

The conversion is somewhat better then DA10 unit, I tightened up a few things.

HTH

[revenge]

Would you honestly expect Mr Lavry to tell you both DAC share the same sound or that his latest creation is worse sounding than DA10? I wouldn't. After all he has to sell them. So what I would really like to see is a review from an independent someone who has both DACs and can compare them side by side.
Also, as far as the headphones are concerned, even with the new crossfeed, I still doubt DA11 can compete with well known dedicated headphone amplifiers in the price range. My DA10 is well beyond average as a headphone amplifier and yet Prehead, Raptor or Headroom are significantly better. So I'm sure even if I buy the new DA11 I will still use my dedicated headphone amplifiers (and in order to do that, I will need phono out). Ergo I would like to see how well DA11 performs against, for instance, Symphony, Mr Meier's latest creation, or Headroom Desktop.

[USAudio]

Hi revenge,
I've been trying to help you out but am not having much success because it seems like you have a moving question target. Your first post addresses Mr Lavry directly:

Originally Posted by revenge

Dear Mr Lavry
First of all let me tell you it's a great honour to address you. ... So the big question for me is: is the DA-11 better sounding than the original version? Is
it an improved version or just the same DAC in shiny, new clothes?

But he hasn't responded so I've posted quotes I've read from Mr Lavry himself to try and help you out.
Now you're telling me those weren't useful as you then don't expect Mr Lavry to give you an honest answer even if he did answer?

Originally Posted by revenge

Would you honestly expect Mr Lavry to tell you both DAC share the same sound or that his latest creation is worse sounding than DA10? I wouldn't. After all he has to sell them. So what I would really like to see is a review from an independent someone who has both DACs and can compare them side by side.

I've done my best, I sincerely wish you good luck in finding your answer but sound quality is a relatively subjective thing and I suspect that only YOU can truly answer your question. Good luck!

[revenge]

I know those answers. If you do a Google search, you will find the exact same answers, word by word, in at least five different forums. But thanks for the links and your time anyway.
The problem when you design and produce a DAC as good as DA10 is that you leave little place for improvement (in the price range) and little desire to upgrade it (again, in the same price range). That's why I'm asking so many questions. Because I am a bit confused at the moment and most official declarations aren't very helpful. But then again you are right about the second part. Only I can decide if the DA11 is better and if it's a worthy upgrade for me. Probably not. An improved usability would have been a strong argument. Unfortunately I am not interested in any of the interface improvements of the DA11 or the USB input or the crossfeed or the remote. And as far as the SQ is concerned, according to the official statements ("the same chipset", "somehow better", as in marginally better) it is unlikely that DA11 is a significant step forward in SQ compared to my DA10. So unless the buyers or Mr. Lavry tell me something I don't know, I will probably keep the old toy.
Cheers

[shamu144]

I am about to pull the triger for the DA11...

Jude, if you have any additionnal comments to your first impressions, they would be most welcome

Thanks in advance,

[jude]

Originally Posted by shamu144

I am about to pull the triger for the DA11...

Jude, if you have any additionnal comments to your first impressions, they would be most welcome

Thanks in advance,

Pull it (the trigger). Great piece of gear, the DA11. Very nice headphone amp. Very nice PIC crossfeed (which does more than crossfeed, it does soundstage widening, which I can't imagine ever using with headphones, but could be handy with speakers--I'll play with that soon). For me, it's almost all about the awesome DAC, though. I see you have a balanced amp, and tapping the DA11's balanced outputs (versus single-ended via the included Neutrik adapters) helps wring the best from it. There's excellent synergy with the DA11 as a DAC feeding my Luxman P-1 headphone amp.

I'll say a lot more down the road. But, so far--especially as a DAC--I love the DA11.

(I know some of you want to know how it compares to the DA10, but I can't answer that for you, as I've not used one.)

[USAudio]

Originally Posted by jude

Pull it (the trigger). Great piece of gear, the DA11. Very nice headphone amp. ... There's excellent synergy with the DA11 as a DAC feeding my Luxman P-1 headphone amp.

Thanks Jude!
You've obviously heard a lot of different headphone amplifiers over the years ...
Speaking in terms of the DA11 headphone amp section only; in your view can you give some examples of other amps the DA11 headphone amp is in the same league as?
Thanks!

[shamu144]

Originally Posted by jude

Pull it (the trigger). Great piece of gear, the DA11. Very nice headphone amp. Very nice PIC crossfeed (which does more than crossfeed, it does soundstage widening, which I can't imagine ever using with headphones, but could be handy with speakers--I'll play with that soon). For me, it's almost all about the awesome DAC, though. I see you have a balanced amp, and tapping the DA11's balanced outputs (versus single-ended via the included Neutrik adapters) helps wring the best from it. There's excellent synergy with the DA11 as a DAC feeding my Luxman P-1 headphone amp.

Thank you Jude for your comments. I have actually pulled the trigger five minutes ago.
As you mentionned, I will use the Lavry's balanced outputs to feed my balanced amp. I also hope there will be great synergy between both.
Thanks.

[philodox]

Technical explanation aside, from a usability point of view I have to agree with Edwood on the switch. If you are using the DA10 or DA11 as a DAC only, then you are just setting the output level that your separate amplification will be then handling, so it is no issue... but if you are trying to market this as an all in one headphone listening device, that switch is going to get old real fast. Then again, I'm a stepped attenuator kind of guy, so take that with a grain of salt.

Either way, looks like a good update to the DA10. Nice work.

[Dan Lavry]

Originally Posted by philodox

Then again, I'm a stepped attenuator kind of guy, so take that with a grain of salt.

Either way, looks like a good update to the DA10. Nice work.

Hi philodox,

So let’s talk about step attenuators. The advantage is clear, you are using passive parts (resistors), and that enables one to set reasonably precise attenuation levels.

Initially it sounds very appealing because there is no active device in the circuit, but that is an illusion. Sooner or later, you will need to tap the signal with some active circuit, be it a headphone amplifier, an input to a power amp, some mixer or what not.

There are 2 problems with the passive attenuator:

The first one I already mentioned – the signal has to pass through mechanical contacts, thus wear and tear becomes an issue.

The second problem is bigger. The output resistance of a passive attenuator changes from position to position (attenuation setting). In fact in most positions the resistance is very high, it can be many KOhms. That is not a good thing. The output of the attenuator is “connected” to the next device by a cable, and a cable with high impedance at both ends is very susceptible to picking up electromagnetic noise (from ac line to radio station to an electric drill next door….). This is a fact of life, and that is one of the reasons that driving cables is best done with low impedance.

One can solve the issue by using a very short cable between the passive attenuator and the next device (which is typically at least a few KOhms). Alternatively, one can put an active circuit to “tap” the high impedance point and drive the cable via low impedance source resistance (impedance conversion). Typical impedance for driving a cable is less then 100 Ohms, not many KOhms. Of course putting an active circuit makes it into an active, not passive attenuator.

Many passive attenuators are over 10KHm to 20KOhms at the middle position. Again, you will end up needing to do such active impedance conversion anyway (the only question is where), and it is best to do it right next to the resistive attenuator tap.

In addition, having a high output resistance (passive attenuator) driving the destination device can really screw up the frequency response. Say you have an active driver with 10KOhms resistance, and a 10 foot cable with say 100pF per foot (pretty typical value). That will limit the bandwidth to around 15KHz! (3dB loss at 15KHz is terrible) In fact, you are already 1dB down at 8KHz!

But with an output resistance of 100 Ohms, the response of the same cable capaitance is flat to better then .001dB at 20KHz, and .02dB loss at 100KHz. In other words, low source resistance is very important to overcome capacitance. Again, short cable helps a passive attenuator. In fact putting that active stage right at the tap of the passive attenuator is ideal, because you eliminate the cable capacity loading effect.

To summarize, driving a cable with high source resistance with an active circuit at the end of a long cable is real bad practice, it makes for susceptibility to external noise, and it screws up the frequency response (loss of highs). The illusion of less active circuitry is just that, an illusion:

One stage of active circuit is very little in the context of the audio signal path (from recording to playback). The mic pre at the recording space, the analog mixer circuits, the AD analog circuits, the DA analog, the power amp or headphone amps and possibly more circuits amount to dozens or more of active circuits. Saving one stage while asking for the trouble I pointed out is not wise…

Well, my DA11 attenuator is in fact a precision resistive passive circuit, just the way you like it (I also like it), followed by internal impedance converter stage to overcome the issues I pointed out – minimize noise susceptibility and have a good and predictable cable independent and load independent flat frequency response…

And while at it, most passives are single ended (unbalanced outputs). My output stage offers both balanced and unbalanced low impedance output drive.

Regards
Dan Lavry

[Wodgy]

Dan, you seem to be missing the core of what people are saying to you. They're not saying to ditch your system, and they're not saying to add a stepped attenuator. They're suggesting you use a rotary encoder, a digital rotary encoder rather than an up/down toggle switch. That's all they're suggesting. A rotary encoder would be more usable.

[thomaspf]

Originally Posted by Dan Lavry

Here is the point:

Yes, a toggle switch, or a rotary, or a relay are still a mechanical switch.
But I am NOT passing the analog signal trough the mechanical contact.

I am using the switch to generate a control signal for setting the volume level. But the analog signal (music) does not pass through a mechanical switch contact; it passes trough solid and permanent soldered contacts.

Say you have a switch connected between 0V and 5V. You also have a detection circuit that tells you if the signal is over or under 2.5V. The output of such a circuit is the same if you feed it 5V or 3V (both are over 2.5V). You get the same result if you feed the circuit 0V or 2V (both cases are under 2.5V). So you can "live with" 2V error in the signal. That is OK, because your switched based digital control circuit is only being used to send a message to the analog circuit (made with soldered connections), and the digital message is to increase volume or to decrease volume.

The switch will have to deteriorate very badly to yield 2V error. I am exaggerating the error to make a point, to show that even 2V will not do you any harm.

Now try and put some .002V AC signal on mechanical contacts that carry the analog signal (music), and you have a badly broken unit.

So yes, a switch can wear out, and so can a rotary. But that is not the point. When you pass a signal trough a switch, a slight amount of wear can impact the result a lot. Such is the case with much of the gear out there, certainly with the rotary based resistive attenuators. My method lets me bypass the wear and tear issue completely. My switch can heave ridiculously high contact resistance, even 100 Ohms (that will not happen) without impacting the sound at all.

Regards
Dan Lavry

For any analog volume control with discrete resistors you need some form of signal switching to get to different resistors. The question becomes what is the most durable and lowest noise and distortion way to do this switching. Relais are pretty durable and can be very low noise.

Integrated switch solutions do not have mechanical parts but as far as I know have higher noise. I am not not inquiring about any circuit details here just repeating some findings from studying data sheet of available semiconductor switches.

Interesting trade-off.

Cheers

Thomas

[Dan Lavry]

Originally Posted by thomaspf

For any analog volume control with discrete resistors you need some form of signal switching to get to different resistors. The question becomes what is the most durable and lowest noise and distortion way to do this switching. Relais are pretty durable and can be very low noise.

Integrated switch solutions do not have mechanical parts but as far as I know have higher noise. I am not not inquiring about any circuit details here just repeating some findings from studying data sheet of available semiconductor switches.

Interesting trade-off.

Cheers

Thomas

Hello Thomas,

Yes, you are correct that getting away from switch mechanical contacts requires one to find alternate ways to switch, such as semiconductors, relays or what not. What counts is the result, and a good design will yield good results.

The high value resistors used in a typical stepped attenuator typically introduce more noise that a well selected and well utilized semiconductor switch.

A single 10KOhm resistor at room temperature measured over 20KHz bandwidth is about 1.8uV noise source. That alone is more noise then many OP amps circuits. For comparison, many semiconductor switches yield .15uV to .5uV.

I am talking about the noise of a device that is not connected, the random noise in the material. Of course one needs to use the devices well...

The typical noise of the DA11 is very low, typically -114dB unweighetd. I chose to specify it at -112dB typical and -110dB minimum, giving myself some margin. The DA11 is about 2-3dB better then DA10 (which is also very good DA).

Note: almost all the converter makers specified converter noise with "A weighted" curve which makes things look better by a few dB, but I prefer to specify with flat response 20-22KHz. I just do not like it when the same folks that sell you 96KHz (48KHz audio bandwidth) telling you that you need all that extra bandwidth, and at the same time they specify the noise floor with "A weighting" which virtually eliminate the noise measurement at frequencies over 10KHz. This is what I call "marketing"...

Regards
Dan Lavry