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Twisted Pear Buffalo Sabre DAC - Page 5

post #61 of 1283
4/27/08 at 8:17am
Quote:
Originally Posted by MrMajestic2 View Post
Dang, I missed the Buffalo. I fell asleep while waiting for the release 10PM EST is 4AM here.
Well, hopefully we never have to do something like this again. If I do, I will pick a better time. My wife is out of town this weekend so there was no time to do anything during the day. I had to wait for the kids to go to bed (8pm) and time to make a web page for it.

Should only be a few weeks until we have more though.
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post #62 of 1283
4/27/08 at 9:59am
ah blimey, missed out due to time difference here too =(
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post #63 of 1283
4/27/08 at 2:55pm
Quote:
Originally Posted by BrianDonegan View Post
Well, hopefully we never have to do something like this again. If I do, I will pick a better time. My wife is out of town this weekend so there was no time to do anything during the day. I had to wait for the kids to go to bed (8pm) and time to make a web page for it.

Should only be a few weeks until we have more though.
No worries, my wallet thanks you
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post #64 of 1283
4/27/08 at 7:40pm
Thread Starter 
I am definately in on one too! I have been waiting for the WM8741 Opus to come out and then this! It's meant to be, it will be! Brian, I would like DAC and power supply kit and maybe the IVY. The problem I have with the IVY is that I seem to be allergic to opamps. Can you put my mind at ease that the opamp is a good idea? I want an I/V that will not leave me wanting. Regardless of what is next, this will be my last rig for 10 years or so. No more upgradeitis!

I would like to continue sourcing parts for my Box'O'Goodies project which is for me the end all and be all project. I am waiting for the Buffalo and the Aikido boards to come in and these will be the hub. Rig will include, HTPC with I2S out to DAC, modded SACD player to output DSD to DAC, Buffalo, Aikido and HD650. What I would like to know is what I ill need from TP and others to get what i would like. SE output is what I would like as I have deemed balanced throughout the rig would cost too much and can always be added later.

I would like the Buffalo to accept DSD from the modded spinner, I2S from the HTPC, and an extra S/PDIF coax input would be great. What will I need for this?

I would like to use the on board volume contol if it works with DSD without conversion as some chips do and must sound great too. How does it work and sound?

The idea of a seperate I/V stage appeals to me and my belief that sometimes you need to go old school and have larger and more powerful output stages since this is where most manufacturers skimp! The problem I have Russ and Brian is that I applaud the IVY idea of an active I/V stage instead of just a passive resistor one. But if I was to be going all out, would I want a discrete(no opamp) tube or FET I/V converter, or the IVY? Size is not an issue and cost is not(within reason). If anyone has any great ideas for great I/V converters please chime in.

I am very very excited! I have been without my cans for almost a year!
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post #65 of 1283
4/27/08 at 8:01pm
Hi Rodentmacbeastie,

I'll offer my thoughts, in addition to Russ/Brian's if that's OK. The Sabre DAC can work in voltage or current mode. In voltage mode, distortion is a little worse, but still excellent at -107db. That's still better then either the WM8740/41. I'm not sure getting even better distortion figures will help the sound, but I'm open minded.

The point of going the I/V route is to get the absolute best distortion figures possible - up to -117dB. But most I/V stages based on discrete transistor or valves won't get near that, so are really not worth worrying about with this DAC, IMO.

I use a transformer with my eval Sabre DAC, and it sounds excellent, so that's an option too if you want something a little different.

So, you have a number of options, and the only way to know which is best is ultimately to experiment - and that of course is made easier by the modular nature of Twisted Pairs approach. A final note - I wouldn't pre-judge the IVY just because if uses monolythic devices. The OPA1632 is superb and uses the super-symetrical technology developed by Nelson Pass. I find it hard to believe you would be disappointed if you were to go this way.
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post #66 of 1283
4/27/08 at 8:15pm
sleepy_dan, are you saying the IVY uses the OPA1632? I thought it uses the THS4031?

Can you expand on the xformer for I/V? I've seen it somewhere before, but I haven't paid much attention to it.
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post #67 of 1283
4/27/08 at 8:28pm
The IVY uses the THS4131 which is virtually the same as the OPA1632. The THS4031, which some people also like to use for I/V , is a conventional opamp.

I'm using the transformer as a voltage device. They don't give state of the art THD figures, but can sound very good none the less.
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post #68 of 1283
4/27/08 at 9:11pm
Thansk, I misread their webpage. THS4131 it definitely is. I thought it was just another opamp I/V at first glance. I'm glad I'm wrong.

Can you tell I haven't been keeping up with the Twisted Pear development?
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post #69 of 1283
4/27/08 at 9:17pm
OK...so I'm in need of a DAC that takes USB, and outputs single-ended stereo.

So it looks like I will need the second larger bundle:

Buffalo DAC + IVY Active I/V Stage + Power Supplies Combination

..and also the USB input module. I can't tell, does this also need its own power supply?

And lastly, is it possible to use a single toroidal with all of this, or would I have to go multiple? I've only used wall warts with my diy projects thus far, and am pretty clueless when it comes to toroidals.
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post #70 of 1283
4/27/08 at 9:24pm
Quote:
Originally Posted by slowpogo View Post
OK...so I'm in need of a DAC that takes USB, and outputs single-ended stereo.

So it looks like I will need the second larger bundle:

Buffalo DAC + IVY Active I/V Stage + Power Supplies Combination

..and also the USB input module. I can't tell, does this also need its own power supply?

And lastly, is it possible to use a single toroidal with all of this, or would I have to go multiple? I've only used wall warts with my diy projects thus far, and am pretty clueless when it comes to toroidals.
the USB module is bus powered, so you don't need a power supply for it. This is fine since its only output will be SPIDF, or I2S. And yes, toroidal trafos work fine for this. In fact we stock very good ones at a reasonable price. You will want two. One for the DAC. and one for the IVY.
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post #71 of 1283
4/27/08 at 9:30pm
The THS4131 is as close to ideal as I have even found for differential IV.

Many people are scared off by the product info page which shows the THD at -80db. What they don't seem to understand is that this is at 1mhz!!! with no filter!! At 20khz is is well below -120db and at 1Khz the distortion floor is far below the noise floor for loads > 1K. And its stll awesome even into 90 ohms!!!

Super symmetry is a great solution for I/V. I have tried all sorts of schemes and have come up with two I like best.

The THS4131 (with is a bit better believe it or not than it OPA cousin) and a discrete version I have created which can deliver a bit more current.

I am a huge believer in balanced and fully symmetrical systems.

Cheers!
Russ
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post #72 of 1283
4/27/08 at 9:44pm
Hi Russ,

Will it be possible to buy the Buffalo DAC with the IVY output stage as a kit? This would be a good option for people who already have the Opus DAC, the Dual Power Supply and the bipolar Supply for the Balise (e.g. like me). I would be all over that.
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post #73 of 1283
4/27/08 at 10:57pm
Quote:
Originally Posted by Clutz View Post
Hi Russ,

Will it be possible to buy the Buffalo DAC with the IVY output stage as a kit? This would be a good option for people who already have the Opus DAC, the Dual Power Supply and the bipolar Supply for the Balise (e.g. like me). I would be all over that.
Hi,

I think all you would need in that case is a Buffalo module, and an IVY module. I will talk with Brian about it.

Cheers!
Riuss
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post #74 of 1283
4/27/08 at 11:22pm
Quote:
Originally Posted by Clutz View Post
Hi Russ,

Will it be possible to buy the Buffalo DAC with the IVY output stage as a kit? This would be a good option for people who already have the Opus DAC, the Dual Power Supply and the bipolar Supply for the Balise (e.g. like me). I would be all over that.
That's what I bought (for the same reasons)
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post #75 of 1283
4/27/08 at 11:57pm
Thread Starter 
[QUOTE=sleepy dan;4142671]Hi Rodentmacbeastie,

I'll offer my thoughts, in addition to Russ/Brian's if that's OK. The Sabre DAC can work in voltage or current mode. In voltage mode, distortion is a little worse, but still excellent at -107db. That's still better then either the WM8740/41. I'm not sure getting even better distortion figures will help the sound, but I'm open minded.

The point of going the I/V route is to get the absolute best distortion figures possible - up to -117dB. But most I/V stages based on discrete transistor or valves won't get near that, so are really not worth worrying about with this DAC, IMO.

I use a transformer with my eval Sabre DAC, and it sounds excellent, so that's an option too if you want something a little different.





Thanks,
I will give the IVY a try then. I just did not want as was said, "just another opamp I/V."

So Brian and Russ, you'll have to keep us updated as to stock because it looks like I am all go for a Buffalo, IVY, and ps from you guys. Do you have answers for my other two questions? How good is the onboard volume control compared to yours or a good stepped attenuator? And is there going to be a problem with DSD, I2S, and S/PDIF inputs and if not, how do i switch them?
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