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The Lavry DA11: For your ears only - Page 5

post #61 of 191
Thread Starter 
Quote:
Originally Posted by USAudio View Post
Here: Lavry Engineering
I see in the features list of the DA11 it lists "High power discrete headphone output".
Can someone more technically minded than myself explain exactly what that means?

By "discrete" I assume that means it's a discrete audio circuit and not an IC?
By "High power" I guess that means it will easily drive headphones from anywhere between say, 30 and 700 Ohms?
Ideally, the waveform is the same for all analog audio loads (destination device). The waveform “tracks” the air motion (the sound). While the ear response to air motion. The air “moves” with the music, the motion changes over time. The electronics itself utilizes electric signals such as voltage variations over time (moving electrons, not air molecules).

But keeping the wave shape identical is where the similarity may end. One can “keep the wave shape” and do so at different voltage levels, current levels and power levels.

Devices that need to regenerate sound (convert electrical signals to air motion) require more power then devices that simply receive and process audio. Passive speakers are real power hungry devices. Headphones are second in line. The input ports of power amp, mixers, AD’s, EQ, reverb and similar gear do not require much power.

The impedance range of headphones is very wide, but all have much lower impedance then a line level and pro gear device, thus they calls for more current drive then an ordinary OP amp can supply. They also typically operate at lower voltages then most other audio devices.

A typical OPamp device is a higher voltage and lower current device, thus not suitable for headphones. There are “specialty” semiconductor devices that can drive lower voltage and higher current, but I did not find one that is good enough, so I made my own from discrete parts.

For low power applications, there is nothing inherently wrong with OP amp, and there is nothing fundamentally advantageous about discrete. The difference is mostly about packaging. But when making higher power circuits, semiconductor solution cause very high temperatures (a lot of localized heat), and discrete circuits spread the heat over many devices. Spreading heat over larger area and many devices lowers the temperature very significantly. High temperature is not a good thing for best performance and for reliability.

But the main reason I made my own circuit is the headphone itself:
Most audio loads are resistive. When a driver is “looking at” a load that behaves like a simple resistor (or nearly so), the wave shape of the voltage and the wave shape of the current are nearly identical for any audio signal.

But headphones (and passive speaker) are anything but a resistive load. That makes the designer’s life much more complicated. The relationship between the voltage wave shape and the current wave shape is complex. The load (headphone) is not resistive, it complex, it “varies with the music”. The driver circuit must be able to supply the required voltage wave shape while accommodating some other current waveform. That poses additional requirements not normally encountered in transmission of analog audio signals.

I wish I could find a “good enough ready made device”. Instead I ended up with some 2-3 dozen parts. It sure takes some doing to drive a truck, as if it were a race car, but it was real fun circuit to design.

Regards
Dan Lavry
post #62 of 191

HD650's

Quote:
Originally Posted by Dan Lavry View Post
... The impedance range of headphones is very wide, but all have much lower impedance then a line level and pro gear device, thus they calls for more current drive then an ordinary OP amp can supply. They also typically operate at lower voltages then most other audio devices. ...
Thanks Dan, I very much appreciate your informative answers. Often it's over my head but I always learn something.

So it sounds like the DA11's headphone amplifier should have no problem driving my Sennheiser HD650's at 300Ohms to pretty much any volume level?
post #63 of 191
Thread Starter 
The DA11 manual (page 14) tells you details about the headphone level at various volume settings:

Volume=56 ---> headphone level=18dBu
Volume=55 ---> headphone level=17dBu
Volume=55 ---> headphone level=16dBu
.
.
Volume=50 ---> headphone level=12dBu
.
.
Volume=46 ---> headphone level=8dBu
.
.
Volume=56 ---> headphone level=18dBu
.
.
Volume=01 ---> headphone level=-37dBu
Volume=00 ---> headphone level=OFF

18dBu is the maximum level, enough to make your head "ring". The voltage equivalent is 6.14V, which is 17.36V peak to peak. I do not recommend listening to HD650 at 56 setting (My own personal headphone is HD650)

The point is that DA11 can supply the current, even for very low impedance loads.

There is also a built in output protection circuitry, to protect the DA11 circuitry from breakdown in case of accidental shorting of the output. Such feature is very desirable, and not uncommon, but some headphone amps have the protection cut in too early, which may distorts the peaks (the DA11 will not do that).

So 300Ohms impedance is very fine. Even 60 Ohms is fine.

Regards
Dan Lavry
post #64 of 191
Thanks again Dan.
post #65 of 191

Jude?

You've had the DA11 for sometime now Jude, any other feedback to give us?
post #66 of 191
I would also like to hear Jude's further thoughts on the DA11. Any conclusions? Comparisons?
post #67 of 191
Quote:
Originally Posted by USAudio View Post
You've had the DA11 for sometime now Jude, any other feedback to give us?
Quote:
Originally Posted by Jeremy View Post
I would also like to hear Jude's further thoughts on the DA11. Any conclusions? Comparisons?
USAudio, I'm sorry I missed your post until now.

To both of you: Yes, I'll be posting a review of the Lavry DA11; but first I'll be posting about it as a part of the HD800 rig I brought with me to Can Jam 2009 that wowed everyone who heard it (the Lavry DA11 was the source). That rig piece should be in part two or three of my Can Jam 2009 impressions/journal (I posted part one last night).

The DA11 is an awesome DAC, though--that much I'll say here.

In the review, I discuss PIC more specifically, as I find it a very important feature. Here's a tip for anyone with a DA11 for now: If your'e using headphones, there's virtually no circumstance I can think of to set PIC in the "+" settings range--that should only be used for loudspeakers, in my opinion. PIC should only be used with headphones at "0" (bypassed), or in the "-" (narrowing) settings.
post #68 of 191
dan
I was looking around for the dimensions and weight of the DA11 and i couldn't find them in reading the pdf or your website. could you tell me what they are? also someone asked earlier about whether the unit comes with feet or not and i didn't see an answer if it does or not.
thanks
joe
post #69 of 191
Quote:
Originally Posted by jallis View Post
dan
I was looking around for the dimensions and weight of the DA11 and i couldn't find them in reading the pdf or your website. could you tell me what they are? also someone asked earlier about whether the unit comes with feet or not and i didn't see an answer if it does or not.
thanks
joe
Hi Joe,
Not sure about the weight but I just measured mine and it's approx. 10"D x 8"W x 1.75"H.
I posted the question about the feet and it does come with feet, they're pretty short but are adequate. You could easily replace them.
Great sounding unit.
post #70 of 191
usaudio
thanks for the reply on the feet and dimensions. i was hoping to see that indepth review by jude on the da11. have you enjoyed the da11 enough to make it your one and only headphone dac? i personally don't mind the volume toggle switch.
joe
post #71 of 191
Quote:
Originally Posted by jallis View Post
usaudio
thanks for the reply on the feet and dimensions. i was hoping to see that indepth review by jude on the da11. have you enjoyed the da11 enough to make it your one and only headphone dac? i personally don't mind the volume toggle switch.
joe
Hi Joe,
I read in another post somewhere here on head-fi that Jude's review has been delayed by an illness in the family.

Yep, it's my one and only headphone DAC and amplifier. I personally don't want any coloration in my headphone amp (or DAC for that matter) and find the one in the DA11, to my ears, to be neutral with plenty of power and detail. IMHO, you hear what's on the recording with the DA11, good or bad.

One of the primary reasons I even considered the DA11 is it's remote control support. I frequently adjust the volume while listening with the remote so I rarely even interact with the toggle switch.
post #72 of 191
usaudio
your enthusiam for the da11 and my continued conversation with todd over at ttvj convinced me to pull the trigger and buy one. i should see mine next wednesday, as it will be coming straight from dan and his wonderful wife. btw, i spoke with dan's wife yesterday about the da11 and she told me that she plays the harp which i thought to myself, "now thats a cool instrument!". when i was a kid back in the early sixties, my parents bestowed upon me, an accordion(go figure) and for a few years it was cool. then along came the beatles and that all changed. i went from playing to listening to music.
oops, i am rambling a bit here.
anyways, thanks so much for your input on the da11. do you listen to lossless from your pc or apple? or do you do wav or aiff? i am presently using wma lossless on my win 7 machine, but i have considered getting a mac mini and doing aiff. i am just dreading adding yet another system to the mix.

jude
sorry to hear about the illness and i hope you and or your family has a speedy recovery.
joe
post #73 of 191
Quote:
Originally Posted by jallis View Post
usaudio
your enthusiam for the da11 and my continued conversation with todd over at ttvj convinced me to pull the trigger and buy one.
...
anyways, thanks so much for your input on the da11. do you listen to lossless from your pc or apple? or do you do wav or aiff? i am presently using wma lossless on my win 7 machine, but i have considered getting a mac mini and doing aiff. i am just dreading adding yet another system to the mix.
Hi Joe,
I hope I didn't oversell it, I try not to do that just because I own one but I've been very happy with my DA11. Afterall we put our good money down! Now I'm looking forward to my HD800's to roll in next week.

I have a Mac Mini whose sole purpose in life is to rip CDs to Apple Lossless using iTunes and to run SlimDevice's SqueezeCenter for my SqueezeBox3. I then feed my DA11 from the SB3 and use a universal remote to control both the SB3 and DA11.
post #74 of 191
usaudio
you didn't oversell the da11 at all. i think you added your humble opinion to the mix and that was important to me.
speaking of the hd800. i have had mine since shortly before canjam thanks to todd at ttvj and i can say that i think you will be extremely happy with them. i found them to be a huge step up over my hd600. i found the clarity of sound to be so much more expressive in hd800. now bear in mind that i am very new at expressing my feelings about sounds involving headphones, headphone amps, and music from computers.
before buying the da11 i owned the grace design m902 and although it is a very well made headpone amp, i found the soundstage to be very bright and somewhat harsh to my ears. presently i am listening to a luxman p200 on loan from todd. unfortunately it is being fed right out of the analog speaker out of my motherboard. i have also tried connecting my 3gs iphone's 1/8 jack out to the p200 and i found it to be fair.
i know the big test will be the da11 and i am very confident that it will be a winner for me. like you i really want to have an all in one dac+headphone amp solution that will last me for many years to come.
i'll give the mac mini/mac book pro some more consideration as well.
joe
post #75 of 191
Quote:
Originally Posted by jallis View Post
...
speaking of the hd800. i have had mine since shortly before canjam thanks to todd at ttvj and i can say that i think you will be extremely happy with them. i found them to be a huge step up over my hd600. i found the clarity of sound to be so much more expressive in hd800.
...
i'll give the mac mini/mac book pro some more consideration as well.
I am REALLY looking forward to hearing the HD800s with some recordings I'm very familiar with. Should be fun.

My Mac Mini is an older PowerPC-based version that I bought years ago for my wife, but she didn't like it so it is serving admirably as my music server. I'll bet you could get an older Mac Mini very cheap these days! Just not sure how much longer Apple will be sending me updates for the PowerPC version of OS X...
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