nacder said:
Correct on both counts.
JT2 stock output impedance is 750R, and the input impedance ranges from around 2.4k to 10K depending on volume setting, yes this is a very easy load for the IVY.
JT2 boards are done, but we are in the midst of reordering AC1 and the relay driver PCBs. These should come at the same time as the volumite.
In our testing we found a couple things that needed to be fixed, as well as a couple new features we wanted to add, on the AC1 and the Driver PCBs. Thats why there has been a delay getting those out.
It will probably be a few weeks until the new boards are here, and then I will need to write some firmware. The simple firmware will not take me long at all. More complex stuff will be a few later.
Cheers!
Russ
Russ White said:
Russ,
Thanks for the prompt reply.
To drive some power amplifiers with lower input impedance (e.g. 5Kohm) directly, the 750R output impedance is a bit on the high side. Do I need to add a buffer after JT2 or can JT2 be configured with a lower output impedance? If a buffer is required, any good module will you recommend?
Cheers
Nacder
Good inputs...
If you have not seen it already:
http://www.diyaudio.com/forums/showthread.php?postid=1617282#post1617282
Something for Russ to do on next Buffalo v2...?
Cheers,
Tom
If you have not seen it already:
http://www.diyaudio.com/forums/showthread.php?postid=1617282#post1617282
Something for Russ to do on next Buffalo v2...?
Cheers,
Tom
Re: Good inputs...
Hello Tom,
I have actually heard WMS' opinions already (long ago he suggested some of his design ideas to me) and lets just say his experiences regarding sonics not the same as those of others in regard to the Buffalo DAC with the IVY. His opinion is his, and I am interested to read it, but you cannot read too much into it, especially since he seems to be working on a design of his own. his design criteria and mine are not exactly the same nor are our experiences.
I applaud his adventurous sense of tweaking and "can do" attitude, but I designed my DAC with very careful adherence to guidelines set forth by the chip designer himself. I have a running dialog with Dustin who is very gracious to help, and I feel very comfortable with my design choices. And as many can attest, I think Buffalo turned out just splendid. I need much more solid evidence than a subjective testimony from an individual tweaker to start making radical changes to a proven and measured design.
That said, I am working on a something even a bit more refined than the current buffalo, and I would say with even better and less noisy power supplies and regulation than what WMS has proposed all the while without doing anything that does not make any sense to me or that would compromise performance further down the signal chain. Will it be a night and day difference? No.
You see, while I respect the design goals of WMS and I truly hope he loves his DAC and had fun building it. I just can't see using a non-linear output stage with 1% THD such as the particular transformer output stage he proposes...(I know some transformers are much better) he lost me completely when he went down that path, especially suggesting that people should not bother with using the DAC in current output mode. My experience is quite the opposite.
Suffice it to say he and I simply have different design goals and criteria. You will have a hard time convincing me that the distortion of the output stage will not trump the selection of a digital power supply. Also, the voltage reference (LPF on the DVCC 3.3V reference) I use on the buffalo has much lower noise than people might suspect. It is much better than good. Could it be better? Yes, it can, but how much impact would it have on the practicality of design and the performance? Any gain will not be realized if your output stage cannot resolve it.
Speaking of output stages, having tried and tested (as well as designed) quite a few of them I can say without any doubt it is the biggest single factor effecting the performance of the DAC. I know others will agree, and I also know many will have different tastes than I do in this regard. That is why I purposely designed my DAC to be flexible in this regard.
Wow, I have gone on and on a bit, but all this is to say that there is a lot I have learned by being first to market and having so much 'nuts and bolts' experience with the ES9008 chip. While many folks have been postulating, suggesting, or tweaking, (none of these are bad things) I have been designing, testing, listening, measuring, and actually producing a real measured and successful DAC.
Thanks to everyone who has given me valuable advice and insight. I do spend way too much time on this stuff, just ask my wife.
Cheers!
Russ
TBM said:If you have not seen it already:
http://www.diyaudio.com/forums/showthread.php?postid=1617282#post1617282
Something for Russ to do on next Buffalo v2...?
Cheers,
Tom
Hello Tom,
I have actually heard WMS' opinions already (long ago he suggested some of his design ideas to me) and lets just say his experiences regarding sonics not the same as those of others in regard to the Buffalo DAC with the IVY. His opinion is his, and I am interested to read it, but you cannot read too much into it, especially since he seems to be working on a design of his own. his design criteria and mine are not exactly the same nor are our experiences.
I applaud his adventurous sense of tweaking and "can do" attitude, but I designed my DAC with very careful adherence to guidelines set forth by the chip designer himself. I have a running dialog with Dustin who is very gracious to help, and I feel very comfortable with my design choices. And as many can attest, I think Buffalo turned out just splendid. I need much more solid evidence than a subjective testimony from an individual tweaker to start making radical changes to a proven and measured design.
That said, I am working on a something even a bit more refined than the current buffalo, and I would say with even better and less noisy power supplies and regulation than what WMS has proposed all the while without doing anything that does not make any sense to me or that would compromise performance further down the signal chain. Will it be a night and day difference? No.
You see, while I respect the design goals of WMS and I truly hope he loves his DAC and had fun building it. I just can't see using a non-linear output stage with 1% THD such as the particular transformer output stage he proposes...(I know some transformers are much better) he lost me completely when he went down that path, especially suggesting that people should not bother with using the DAC in current output mode. My experience is quite the opposite.
Suffice it to say he and I simply have different design goals and criteria. You will have a hard time convincing me that the distortion of the output stage will not trump the selection of a digital power supply. Also, the voltage reference (LPF on the DVCC 3.3V reference) I use on the buffalo has much lower noise than people might suspect. It is much better than good.
Could it be better? Yes, it can, but how much impact would it have on the practicality of design and the performance? Any gain will not be realized if your output stage cannot resolve it.Speaking of output stages, having tried and tested (as well as designed) quite a few of them I can say without any doubt it is the biggest single factor effecting the performance of the DAC. I know others will agree, and I also know many will have different tastes than I do in this regard. That is why I purposely designed my DAC to be flexible in this regard.
Wow, I have gone on and on a bit, but all this is to say that there is a lot I have learned by being first to market and having so much 'nuts and bolts' experience with the ES9008 chip.
While many folks have been postulating, suggesting, or tweaking, (none of these are bad things) I have been designing, testing, listening, measuring, and actually producing a real measured and successful DAC. Thanks to everyone who has given me valuable advice and insight. I do spend way too much time on this stuff, just ask my wife.
Cheers!
Russ
Buffalo performance comparison
I'm so happy to be one of the lucky-ones to purchase a Buffalo and IVY module at the last sale. I'm like a kid waiting for Christmas to arrive.
When I get my system built, my hope is to take it over to ESS HQ and compare it with their prototype system. I think this would be an interesting comparison. Not that I expect the Buffalo to compare badly, and I'd be the first to suspect my construction as the source of any problems. I'll bet the Buffalo sounds as open and effortless as the ESS prototype.
This won't happen for a few weeks or more. I'll report my results here.
Ross G.
I'm so happy to be one of the lucky-ones to purchase a Buffalo and IVY module at the last sale. I'm like a kid waiting for Christmas to arrive.
When I get my system built, my hope is to take it over to ESS HQ and compare it with their prototype system. I think this would be an interesting comparison. Not that I expect the Buffalo to compare badly, and I'd be the first to suspect my construction as the source of any problems. I'll bet the Buffalo sounds as open and effortless as the ESS prototype.
This won't happen for a few weeks or more. I'll report my results here.
Ross G.
Re: Verbage, and paraphrases
Alas, poor WMS, I did not know him at all...
Actually I am not sure who is protesting (must be you?), but I always find it entertaining to see someone paraphrase Shakespeare.
I have no beef with you or anything you have done, I just disagree with you on some principles. But very agreeably.
Cheers!
Russ
wildmonkeysects said:
Alas, poor WMS, I did not know him at all...
Actually I am not sure who is protesting (must be you?), but I always find it entertaining to see someone paraphrase Shakespeare.
I have no beef with you or anything you have done, I just disagree with you on some principles. But very agreeably.
Cheers!
Russ
Re: Re: Re: Good inputs...
Dustin was kind enough to measure a very early Buffalo/IVY example I sent him.
THD+N = 117dB
DNR = -122dB A-weighted.
This was with an early version of the IVY in which the filtering scheme was very much less than ideal.
We have made some changes which have actually improved things in the DNR measurement a bit since then, but I don't have adequate equipment to give you an accurate number yet. Soon.
Cheers!
Russ
okapi said:
Dustin was kind enough to measure a very early Buffalo/IVY example I sent him.
THD+N = 117dB
DNR = -122dB A-weighted.
This was with an early version of the IVY in which the filtering scheme was very much less than ideal.
We have made some changes which have actually improved things in the DNR measurement a bit since then, but I don't have adequate equipment to give you an accurate number yet. Soon.
Cheers!
Russ
Buffalo Stampede
My Buffalo, IVY, and power supply kits arrived today
Just wanted to compliment the Twisted Pear fellows on a superb job of organizing and packaging the modules. They are pros without a doubt, these are the best packaged kits I've ever seen.
Very well done!
Cancelling plans for the weekend to build and play
My Buffalo, IVY, and power supply kits arrived today
Just wanted to compliment the Twisted Pear fellows on a superb job of organizing and packaging the modules. They are pros without a doubt, these are the best packaged kits I've ever seen.
Very well done!
Cancelling plans for the weekend to build and play
I have a Denon DVD-2910. I see in the other thread that some
including Russ have modded their Denon players to run this
board in stereo. When the Buffalo becomes available again,
would I be able to use three Buffalo's and get full surround?
Would it be possibe to do for both SACD and DVD-A's?
If so, would anybody have some direction on doing that?
I'm also looking for SM/schematic for DVD-2910.
including Russ have modded their Denon players to run this
board in stereo. When the Buffalo becomes available again,
would I be able to use three Buffalo's and get full surround?
Would it be possibe to do for both SACD and DVD-A's?
If so, would anybody have some direction on doing that?
I'm also looking for SM/schematic for DVD-2910.
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