Fran,woodturner-fran said:Sorry Russ/Brian,
didn't mean to cause a derailment
and its probably not worth starting another thread on this.....
Fran
It's no problem at all. It's just there are any number possible PS approaches. Not that they are better or worse its just not the topic of the thread.
You should take heart that I am not sitting on my duff, even on vacation!
Buffalo is not meant to be anything more than it is. A practical affordable implementation. It actually turned out (in terms of listening) and measured (technically) far better than I ever hoped.
More is coming from us, much much more.
I would spill the beans, but I have an NDA. It will rock. Leave it at that.
But it will likely not be as open as Buffalo, and not as inexpensive either.
Cheers!
Russ
I'm hearing ya...
Its just that my recent experience is that farting about with different PS approaches does make a difference..... hence my off-the-cuff post (hard not to be enthuisiastic about it). Maybe I should start another thread about PS choices... although a lot of that is kinda covered over in pinkfishmedia. Also I suppose when fellas start getting their new buffaloes there will be a another rush of activity in all this area.
Looking forward to your new developments. FWIW, a friend currently has my buffalo which is TP supplies through teddyregs into the dac/IVY and he raves about it. He is not a DIYer and really only is interested in how it sounds - an impartial opinion. He talks about how placement is really good and how when you crank the volume the soundstage increases but the singer/guitar/whatever stays the same. That and a general feeling of sounding "right". I thought I'd add some fo his comments becuase usually you don't get many non-diyer reviews/comments here. He has put his money where his mouth is and I'm building one for him.
That and a shigaclone together make a pretty affordable hi-end experience that would take a long string of figures to beat.
end of OT stuff....
Fran
Its just that my recent experience is that farting about with different PS approaches does make a difference..... hence my off-the-cuff post (hard not to be enthuisiastic about it). Maybe I should start another thread about PS choices... although a lot of that is kinda covered over in pinkfishmedia. Also I suppose when fellas start getting their new buffaloes there will be a another rush of activity in all this area.
Looking forward to your new developments. FWIW, a friend currently has my buffalo which is TP supplies through teddyregs into the dac/IVY and he raves about it. He is not a DIYer and really only is interested in how it sounds - an impartial opinion. He talks about how placement is really good and how when you crank the volume the soundstage increases but the singer/guitar/whatever stays the same. That and a general feeling of sounding "right". I thought I'd add some fo his comments becuase usually you don't get many non-diyer reviews/comments here. He has put his money where his mouth is and I'm building one for him.
That and a shigaclone together make a pretty affordable hi-end experience that would take a long string of figures to beat.
end of OT stuff....
Fran
Hello everybody,
I purchased my Buffalo, some months ago, think its 2nd version.
I made some changes and i just want report my goals.
First, added a super jung regulator in serie of LCBPS, that feeds the DAC with exactly 6,25V.
Second, tryed some changes in the IVY, like gain and using the "new" schematic, bypassing resistor and adding a cap, i used a styroflex 4,7nF.
Well, in the first mod, i won a great soundstage, more aerial, a better clipping of the instruments more 3D. In the second mod, i won more detail, more natural sound, but a little harsh, with a lot of sibilance.
Now, i changed some caps in the buffalo DAC, changing the C1, C2, C3 and C5 to a 47uF, the C1 and C5 with standard aluminium cap, and the C2 and C3 with sanyo oscon cap, and the sound is amazing, no more harsh, no more sibilance, got a upper soundstage.
I'm just reporting my goals, any comments or doubts, are wellcome.
And Thanks for this great project, this definitively is the the best DAC i heard till now.
Let me try explain why i tryed to change the caps, well, reading about the super regs, they dont like a large capacitive loads, and i'm using a AD826, yes wrote it correctly, i built a dual super reg using a dual op amp.
Cya
I purchased my Buffalo, some months ago, think its 2nd version.
I made some changes and i just want report my goals.
First, added a super jung regulator in serie of LCBPS, that feeds the DAC with exactly 6,25V.
Second, tryed some changes in the IVY, like gain and using the "new" schematic, bypassing resistor and adding a cap, i used a styroflex 4,7nF.
Well, in the first mod, i won a great soundstage, more aerial, a better clipping of the instruments more 3D. In the second mod, i won more detail, more natural sound, but a little harsh, with a lot of sibilance.
Now, i changed some caps in the buffalo DAC, changing the C1, C2, C3 and C5 to a 47uF, the C1 and C5 with standard aluminium cap, and the C2 and C3 with sanyo oscon cap, and the sound is amazing, no more harsh, no more sibilance, got a upper soundstage.
I'm just reporting my goals, any comments or doubts, are wellcome.
And Thanks for this great project, this definitively is the the best DAC i heard till now.
Let me try explain why i tryed to change the caps, well, reading about the super regs, they dont like a large capacitive loads, and i'm using a AD826, yes wrote it correctly, i built a dual super reg using a dual op amp.
Cya
Forgot to mention my set.
SB3 with modded digital output.
True balanced amplifier 50Wrms Class A.
Speakers Thor, with some mods, using two mids from my country Akron KB6, and Hiquphon OW1, with series xover using solen litz and Obbligato caps.
More info.
Akron KB6
and a friend's homepage with a pict of my box.
Thor by Eddie
merry xmas
cya
SB3 with modded digital output.
True balanced amplifier 50Wrms Class A.
Speakers Thor, with some mods, using two mids from my country Akron KB6, and Hiquphon OW1, with series xover using solen litz and Obbligato caps.
More info.
Akron KB6
and a friend's homepage with a pict of my box.
Thor by Eddie
merry xmas
cya
Wima 10nF Caps for IVY
A few notes on recent changes to the IVY kits...
First, I have changed the IVY for Buffalo kit from what appears in the manual. The new config adds 10nF MKP caps for C13-C16, and replaces the 22R resistors for R17-R20 with o-ohm jumpers.
Also, I recently switched the 10nF IVY filter caps from Panasonic MKP to Wima MKP (FKP2 actually), as the Panasonics are being End Of Lifed. Please note that because these caps are wider, for C1-C4 they should be mounted under the board. C1 and C4 are a tight fit, but you can make it work.
A few notes on recent changes to the IVY kits...
First, I have changed the IVY for Buffalo kit from what appears in the manual. The new config adds 10nF MKP caps for C13-C16, and replaces the 22R resistors for R17-R20 with o-ohm jumpers.
Also, I recently switched the 10nF IVY filter caps from Panasonic MKP to Wima MKP (FKP2 actually), as the Panasonics are being End Of Lifed. Please note that because these caps are wider, for C1-C4 they should be mounted under the board. C1 and C4 are a tight fit, but you can make it work.
Dear Santa
Dear Santa,
We've all been very good kids this year! We all know that your
precious assistants always try their best to give us our unique
toys. We all indeed enjoying our Buffalos and listen to endless
christmas songs.
But something is missing to make our DACs perfect...
So here is our wish list - the perfect companion to Buffalo is a
board with a controller and I/O to support:
1. Display (VFD/LCD) showing info: kHz/bits, lock, mute, volume, input
2. Input selection SPDIF, I2S, DSD with buttons and/or rotary encoder
3. Mute button
4. Internal/external clock button
5. Volume control buttons and/or rotary encoder
6. On/Off button
Yours,
DIYers
PS The cookies are on the workbench by the oscilloscope...
Best wishes to all Buffalo addicts out there!
Dear Santa,
We've all been very good kids this year! We all know that your
precious assistants always try their best to give us our unique
toys. We all indeed enjoying our Buffalos and listen to endless
christmas songs.
But something is missing to make our DACs perfect...
So here is our wish list - the perfect companion to Buffalo is a
board with a controller and I/O to support:
1. Display (VFD/LCD) showing info: kHz/bits, lock, mute, volume, input
2. Input selection SPDIF, I2S, DSD with buttons and/or rotary encoder
3. Mute button
4. Internal/external clock button
5. Volume control buttons and/or rotary encoder
6. On/Off button
Yours,
DIYers
PS The cookies are on the workbench by the oscilloscope...
Best wishes to all Buffalo addicts out there!
Noise in regulators
I would like to understand the science behind why an improved regulator to the Buffalo such as Teddyreg would improve the sound of the DAC.
Looking at the datasheet for LDO regulators, I find that the inherent noise of these devices is in the order or 30 uV. The LCDPS with LM317/337 has a noise figure of .003%, so for a 10V output, we are talking 300uV (Probably in the order of 30uV with the adjust resistor bypassed, which is optional in the specsheet). The onboard LDOs have pretty good PSRR (in the order of 60 db) so the pre-regulator noise is filtered and the dominant noise figure is the noise figure of the last regulator before the DAC electronics.
Now a Teddyreg noise figure is in in the single digit uV, but the noise of the local regulator remains at 30 uV.
So my question is, how would this result in cleaner power after the local regulator?
The other parameters are load regulation and line regulation. Load regulation is again determined by the last regulator. With double regulation, line regulation is already very good.
Now, I think the HF opamp filter/buffer for the analog side could also benefit the digital side as the clock and sample rate conversion are in the MHz range, so lowering the noise at those levels will be of benefit.
Any technical/engineering insights appreciated, and Merry Christmas
I would like to understand the science behind why an improved regulator to the Buffalo such as Teddyreg would improve the sound of the DAC.
Looking at the datasheet for LDO regulators, I find that the inherent noise of these devices is in the order or 30 uV. The LCDPS with LM317/337 has a noise figure of .003%, so for a 10V output, we are talking 300uV (Probably in the order of 30uV with the adjust resistor bypassed, which is optional in the specsheet). The onboard LDOs have pretty good PSRR (in the order of 60 db) so the pre-regulator noise is filtered and the dominant noise figure is the noise figure of the last regulator before the DAC electronics.
Now a Teddyreg noise figure is in in the single digit uV, but the noise of the local regulator remains at 30 uV.
So my question is, how would this result in cleaner power after the local regulator?
The other parameters are load regulation and line regulation. Load regulation is again determined by the last regulator. With double regulation, line regulation is already very good.
Now, I think the HF opamp filter/buffer for the analog side could also benefit the digital side as the clock and sample rate conversion are in the MHz range, so lowering the noise at those levels will be of benefit.
Any technical/engineering insights appreciated, and Merry Christmas
Re: Noise in regulators
Any preregulation will be beneficial as far as it goes.
But you are correct to say that the final noise/regulation performance will be dictated by the local voltage regulators.
Now keep this in mind. The single most critical regulation is at AVCC. If you measure the noise there you find its not bad at all. And load regulation is very very good. Output impedance is nice and low. The guys at ESS new what they were doing when they suggested the opamp supply. You can clearly see it in their paper about performance. They tried many strategies and many opamps.
The digital regulators on the Buffalo are more than adequate for the task.
Cheers!
Russ
glt said:
Any preregulation will be beneficial as far as it goes.
But you are correct to say that the final noise/regulation performance will be dictated by the local voltage regulators.
Now keep this in mind. The single most critical regulation is at AVCC. If you measure the noise there you find its not bad at all.
And load regulation is very very good. Output impedance is nice and low. The guys at ESS new what they were doing when they suggested the opamp supply. You can clearly see it in their paper about performance. They tried many strategies and many opamps.The digital regulators on the Buffalo are more than adequate for the task.
Cheers!
Russ
Merry Christmas to you too glt.
The noise figure quoted for these regs is the noise actually generated by the reg itself rather than a measure of it's ability to reject noise. If you look at a graph for a typical monolythic reg, you'll see it's performance is say 60- 80db up to a few hundred Hertz. After that they deteriorate very quickly. A high quality reg such as those you mentioned will not only generate less noise themselves, they will also be much more effective at high frequencies.
I was surprised at how much the Buffalo benefits from a good PSU. My finding was that one high quality PSU was much better than two LM317 based regs - one each for digital and analog. I'm thinking that the PSRR of the SABRE is pretty modest.
Dan
The noise figure quoted for these regs is the noise actually generated by the reg itself rather than a measure of it's ability to reject noise. If you look at a graph for a typical monolythic reg, you'll see it's performance is say 60- 80db up to a few hundred Hertz. After that they deteriorate very quickly. A high quality reg such as those you mentioned will not only generate less noise themselves, they will also be much more effective at high frequencies.
I was surprised at how much the Buffalo benefits from a good PSU. My finding was that one high quality PSU was much better than two LM317 based regs - one each for digital and analog. I'm thinking that the PSRR of the SABRE is pretty modest.
Dan
Spartacus said:
The PSRR at AVCC of the Sabre is actually next to nothing. Ok its pretty much exactly nothing. The output is centered at 1/2 AVCC all the time. So if AVCC moves, well so does the output.
But thats not the whole story.
Basically PSRR will be dictated by the AVCC supply. So if you use a good voltage regulator there with excellent PSRR (say a really nice opamp like the one we use). You get great PSRR.
This is also why a super low output impedance is critcal. Even half an ohm there would cause the output to modulate with the signal. Yuck. That would add a lot of even order distortion.
Cheers!
Russ
Re: Dear Santa
I would like to add one more item to your list, remote control for at least the volume.
Anyway, the items on your list would truly turn the Buffalo into the perfect DAC.
I believe TP have already thought of most of this and are working on the the AC1 to address some of these issues.
sp502 said:
Dear Santa,
We've all been very good kids this year! We all know that your
precious assistants always try their best to give us our unique
toys. We all indeed enjoying our Buffalos and listen to endless
christmas songs.
But something is missing to make our DACs perfect...
So here is our wish list - the perfect companion to Buffalo is a
board with a controller and I/O to support:
1. Display (VFD/LCD) showing info: kHz/bits, lock, mute, volume, input
2. Input selection SPDIF, I2S, DSD with buttons and/or rotary encoder
3. Mute button
4. Internal/external clock button
5. Volume control buttons and/or rotary encoder
6. On/Off button
Yours,
DIYers
PS The cookies are on the workbench by the oscilloscope...
Best wishes to all Buffalo addicts out there!
I would like to add one more item to your list, remote control for at least the volume.
Anyway, the items on your list would truly turn the Buffalo into the perfect DAC.
I believe TP have already thought of most of this and are working on the the AC1 to address some of these issues.
Some VREF fun...
Ok for you die hard tweakers out there. I will throw you a bone.
Here is one mod which I know will pay dividends.
It requires you cut a trace, so do not do it unless you are quite confident you can pull it off.
Near R4 on the bottom of the board there is a via, and a trace that runs to DVCC(3.3V). You have to cut that trace right near the via.
Then make yourself a little cct that looks like the attached picture.
The two LEDs are two standard green types.
The cap should be low ESR.
I solder the cap to the opamp side of C6 and the GND side of C13, but there are many ways to do it.
Ok then you simply run the ref to opamp side of C6.
Now you have a sub 100nv (I will have to measure it later but I know its quite low) noise voltage reference that is not connected to the digital supply in any way.
You still have the excellent PSRR of the LM4562 and milliohm output impedance.
Now see guys, I have fun modding too.
The next version of Buffalo will have something quite similar to this.
Cheers!
Russ
Ok for you die hard tweakers out there. I will throw you a bone.
Here is one mod which I know will pay dividends.
It requires you cut a trace, so do not do it unless you are quite confident you can pull it off.
Near R4 on the bottom of the board there is a via, and a trace that runs to DVCC(3.3V). You have to cut that trace right near the via.
Then make yourself a little cct that looks like the attached picture.
The two LEDs are two standard green types.
The cap should be low ESR.
I solder the cap to the opamp side of C6 and the GND side of C13, but there are many ways to do it.
Ok then you simply run the ref to opamp side of C6.
Now you have a sub 100nv (I will have to measure it later but I know its quite low) noise voltage reference that is not connected to the digital supply in any way.
You still have the excellent PSRR of the LM4562 and milliohm output impedance.
Now see guys, I have fun modding too.
The next version of Buffalo will have something quite similar to this.
Cheers!
Russ
Attachments
One more note, you are shooting for slightly more than 3.3V.
I got 3.4V which is just fine.
Adjust R3 to get it dialed in. Do this prior to actually connecting it to the DAC.
My experience is that the DAC sounds better when AVCC is a bit greater than DVCC. I have no idea why. But I have tried it both lower and higher and find it sounds better to me higher.
Cheers!
Russ
I got 3.4V which is just fine.
Adjust R3 to get it dialed in. Do this prior to actually connecting it to the DAC.
My experience is that the DAC sounds better when AVCC is a bit greater than DVCC. I have no idea why. But I have tried it both lower and higher and find it sounds better to me higher.
Cheers!
Russ
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