You may change your mind once you use the BUF03 instead of the 844's own buffer, even though it's good, the BUF03 is much more powerfull, sweeter, detailed and also has a richness to the sound without being syrupy.
Cheers George
is buf03 that much better than any other solution? i take the signal from tz pin to jlh buffer and it is still bettered by double stacked internal ad844 buffer in terms of dynamics, and i don't see much other benefit in going active i/v for two of my favorite chips (Tda1543/1387) other than the dynamics, so internal buffer it is for me 
oh, i took my dac to a hifi shop this weekend and the owner was floored. it easily beat a sonic frontier and wadia dac of several thousand bux. and then there was a korean dac with rather elegant discrete i/v> muse opamp lpf for cs4398 and then it was also beaten by my humble dac.
844 is something special, indeed.
oh, i took my dac to a hifi shop this weekend and the owner was floored. it easily beat a sonic frontier and wadia dac of several thousand bux. and then there was a korean dac with rather elegant discrete i/v> muse opamp lpf for cs4398 and then it was also beaten by my humble dac.
844 is something special, indeed.
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The BUF03 is a large step above the internal buffer, the subjective difference are in my last post.
Here is an adjective way of explaining it, to me is like the difference of a "good" 150w class A/B linear amp that's running just a couple of watts bias current, to the same amp with a far beefier power supply and 30 watts of class A bias.
Cheers George
Here is an adjective way of explaining it, to me is like the difference of a "good" 150w class A/B linear amp that's running just a couple of watts bias current, to the same amp with a far beefier power supply and 30 watts of class A bias.
Cheers George
Here's an experiment to try - slap a couple of hundred uF in 1206 ceramics between the 844's supply pins and listen again to the internal buffer.
I tried this one (attached), but the BUF03 was better. There are similar other buffers, but from what i saw they all have global feedback, I'm not sure if it is this lack of global feedback on the BUF03 that makes it sound so good to me.
Cheers George
Cheers George
Attachments
That's a pretty dumb buffer on a few levels.
You are much better off sticking with P & P solutions like BUF03 if you are
getting great results.
It does take a fairly deep understanding to optimize discrete circuits for a
given application and get the best outcome. If you are just P & P'ing
discrete circuits but don't know what too look for and tweak, you will waste
a lot of time trying to get there.
At some stage I'd like to do some measurements on BUF03. By all accounts
they will probably measure very well. Any chance you can send one down so
I can see how it measures? The base line on my test setup is round about
0.0005% or better.
cheers
Terry
T
I only got enough to do mods to two cdp's Terry, but ebay has got them. Don't forget get some good heavy duty TO-99 heatsinks for them, they run very high bias.
BUF03 | eBay
Cheers George
BUF03 | eBay
Cheers George
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Hi George,
Indeed the Buf03 is quite special as I recalled when I build
Aunt Corey's passive preamp for a friend years back but
I wonder how good it is compared to say the Cen -Zen stage.
In anycase it's always about matching your equipment. J-fets
in general do have great transparency but can be their down
fall if match to the wrong front end. Many thanks for sharing
your experience. Will build my Tda 1541 base on your IV circuit.
Cheers
Indeed the Buf03 is quite special as I recalled when I build
Aunt Corey's passive preamp for a friend years back but
I wonder how good it is compared to say the Cen -Zen stage.
In anycase it's always about matching your equipment. J-fets
in general do have great transparency but can be their down
fall if match to the wrong front end. Many thanks for sharing
your experience. Will build my Tda 1541 base on your IV circuit.
Cheers
Yeah X5R is fine. The reason I said a few hundred uF is they all lose appreciable capacitance when biassed up. Some of the larger values (I'd not go above 47uF myself) lose 90% or so at full rated voltage. I recommend TDK and Samsung as the brands giving the least drop-off with applied voltage.
The only thing that concerns me is fakes from China. But how do you fake
a BUF03 - it's a pretty specific device (not like an opamp).
I'll order one and see how it fares. I can think of quite a few uses for these,
it's a bummer they are so damn noisy, they could be used for low level stuff.
T
...based around the PCM1704 is the way forward. If I listen to the Delta Sigma dacs then switch to the R2R dac's I am always surprised how smooth the R2R sound. Once I do that I never switch back to DS. All that says is my ear likes R2R better.
The problem with d-s DACs is the post-DAC filter. Get that right and you get what you miss out with R2R ladder DACs. The problem is that the new filter is highly controversial and breaks the cardinal rule that the filtering should be OOB (out-of-band) which is another way of saying, the filter should be flat at 20KHz. That means at least 2nd order and well above 50KHz (say 80KHz) - they all do that and rarely listen what happens when you let the filter intrude @ 20KHz as that is a big no-no. In the future, commecial DACs should have switchable post-DAC filters on d-s based DACs. We are working on getting a commercial manufacturer of a USB DAC about this. No name yet.
The AD844 works very well with d-s DACs and new post-DAC filter.
Cheers, Joe
Joe,
As per usual Joe, you are getting a little bit excited about not much. There
is no real rule WRT OOB noise filtering on d-s DAC's. I don't see this "highly
controversial" issue that you keep pounding in to us.
Some people use a lot, some use a little. Some do use lower order and as a
consequence impact the audio band slightly, some use higher order and
don't. Just like you, many base their decisions purely on listening others base
their decisions on what is theoretically correct.
Why don't you just post a response plot from say Ltspice or filter free.
These will show straight away all the supposed compromises like response,
phase, group delay.
Then we could have at least some sort of intelligent discussion on the matter
WRT the various filters characteristics versus subjective outcome.
cheers
Terry
The evidence to the contrary is amassing. Inded there is something here to get excited about - it will just take time and patience. The number who has now heard what the filter does is getting near 50.
So what if I get whacked about saying it, all the more sweeter in the end.
Hope you are doing well.
Cheers, Joe
OK - so what is different about this filtering. That's what I have been trying
to get you to explain. I see a single order LPF.
Terry
Hi Terry
What's the difference? The filtering is not limited to above 20KHz, that's the difference - it breaks an unwritten OOB rule - and that it just cleans everything up, from bass up. It sounds more like a ladder DAC and that Michael Lenehan says they just don't like d-s DACs up there, they sound subtly thin and lack tonal authority. Pretty much what the NOS-DAC crowd says.
The only 'difference' that seems to make this a taboo subject is that it is not flat @ 20KHz. Nothing else.
Just hearing it and not trying it and then make a comment, that is all that is required.
I have totally blind tested people and they had no clue what I did and they told me that it was obvious and not even subtle. Simple as that.
As Val says, who cares how it measures, it is what it does.
I am not just going to go to sleep and ignore it as if nothing happened. No way. And the only criticism we are getting is from those who couldn't even be bothered to try it or listening to it.
When a house wife heard it when her husband turned on the music, only one change had been made and only he knew and yet did not know what it was, while she just happened to be in the room and had no intention to listen, then says "that's different, I can't put my finger on it, but I like it" and just floored here husband who rang me back excitedly to tell me what happened "I heard it all right, but when she heard it and said that within 60 seconds, that amazed me, I had to call you." Then he said to me "Joe, you are going to be very busy" and to which I replied "not just me, more should hear this".
Don't worry, there are now some serious people taking an interest, but I can't name names yet.
Cheers, Joe