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Heads up - more Buffalo sighted!

Hi PD.

The reason the IVY was unstable when I first tried the caps at input was because I simply had a bad opamp. Probably because I had killed it prior to test the cap mods. :) That made me think it was the cct that was off, when in fact I simply had a flawed test.

That said, the resistors at the filter caps should be removed/jumped as they cease to beneficial and actually have a lot of drawbacks.

We now ship the IVY for buffalo with jumpers for those Rs and the caps from the inputs to GND.

Some of you folks hot for killer regulation at the AVCC pins will be very very pleased with what is coming next.

It won't be as simple and cheap as the current Buffalo, but it should be a step forward. :)

The prototype counterpoint had some issues, but they are worked out now, it should be ready soon too. Thanks to a few folks who help me test it out.

I am also working on a new and improved IVY thanks to some time I got to spend in the physics lab at UT. The prototype of the new version is measuring (with the Buffalo) about 6db better DNR and better than -117db THD+N (this is about as good as the DAC itself can do). On its own its doing about -122db THD+N.

The level of trimming required to reach those levels is simply not possible going discrete. But I will be testing counterpoint just for kicks.

So I am pretty pleased with progress right now.

Cheers!
Russ
 
Russ,

My Buffallo Ivy and PSU's arrived in the UK today making my Christmas a nice one..... Many thanks

Graham
 
Must try that new mod on the CCS (bottom page 42 of the DIYaudio thread). Looks fairly simple, although I need to pull out my boards and see exactly where Russ is talking about.

Anyone else interested in it?


Fran
 
I'd try it but I'm currently using Paul Hynes regs feeding the AVCC.

Russ's mod is easy to try and worth a shot, the supply to the AVCC has quite an influence on the Sabres performance
 
So, Russ has very kindly loaded up some PDF files which allows you to etch a little board to do this. So I hope to do one in the next few days and report back.

Fran
 
This seems to be a very worthwhile mod. Its simple enough to do too, especially if you make some PCBs using the info Russ has posted. One word though on the LEDs. When I first made mine, I used some red LEDs I had - I couldn't get the output voltage high enough. I had to change the LEDs and also run a little more current through them to get the output voltage high enough.

So sonically this is definitely an improvement, just brings a bit more to the party. Its now 01.20 and I had intended being in bed at 11.30 so that tells its own tale.

Well worth doing fellas.

Fran
 
James - any standard brightness LED, red, amber or green will work but you might need to adjust R4 or R3 to get the right output. I used some bog standard cheap red LEDs from ebay, but needed to reduce R4 to 147R and used R3 at 10k. That gave me 3.45V unloaded and in use its 3.34V.

Fran
 
Installed + and - ALWSR's between the LCBPS and the Ivy. Been listening for a couple of days now and can't hear any difference. If there is one it's very small. There might be some improvement in stereo separation and even that might be my imagination. Oh well, you win some and lose some I guess. It's all about experimentation.

Colin
 
colscot said:
Installed + and - ALWSR's between the LCBPS and the Ivy. Been listening for a couple of days now and can't hear any difference. If there is one it's very small. There might be some improvement in stereo separation and even that might be my imagination. Oh well, you win some and lose some I guess. It's all about experimentation.

Colin
Click to expand...

The PSRR of the IVY is exceptional. So I am not really very surprised. :)

The new Counterpoint also has the same PSRR attributes and a very nearly constant current draw no matter the signal. It is a very easy load for almost any PS. :)

Cheers!
Russ
 
ron said:
Anybody bag the new Buffalo32? http://www.twistedpearaudio.com/digital/buffalo.aspx
Click to expand...

I managed to bag one, I knew the overpriced but speedy Virgin broadband would come in handy one day!

I'm looking forward to receiving it, if it is only marginally better than the previous Buffalo it will be very good thing indeed. It may even be my final DAC...

I'll let you know when I have it up and running but delivery is some time off yet. I'm also looking forward to the AC1 controller stuff, which looks excellent.

p.s. Has anyone tried their new Sympatico Amps yet? Any comments?
 
sparts155: Do you really think there will be any gain in putting that chip on the old board? I thought part of the benefit of the new design was the fact that the ivy was all on the one board better layout etc etc.
 
fran said:
sparts155: Do you really think there will be any gain in putting that chip on the old board? I thought part of the benefit of the new design was the fact that the ivy was all on the one board better layout etc etc.
Click to expand...

The new chip is without doubt better, but how much audible difference it makes .... dunno. Having said that, Russ seems to think it's an improvement, as does some other guy who specialises in valve output stages ....

"The taste and feeling is same in both DACs. The older one is really great, but they do differ. The newer chip does everything that the old one does well, but a little bit better. There is more air, more light in the scene, it is less cold, less sterile, and more magical. I dont think that the owners of the old Buffalo should RUSH to upgrade but at the same time - I bet they will. Because audiophilia is such mental state of mind.
The difference is best compared to the same dac being connected by two digital cables - a normal coax and a great digital cable. So the sound seems the same, but better at the same time. If you ask me - I am staying with the new Sabre32. "

http://www.lampizator.eu/LAMPIZATOR/REFERENCES/Buffalo%20DAC/BuffaloDAC.html
 
Guys, some help would be appreciated. I finally got round to building a buffalo and Ivy I've had for a few months last w/end. A very nice sound and a lot better than the Beresford dac I've been using on my squeezebox. I built the Ivy with 10nf at C1-4 and jumpers at R17-20. But the latest manual shows all of those omitted so today I took 'em out. I've still got 10nf at C13-16. It doesn't sound as good. I've read all the threads here and on DIY Audio and I'm completely confused. Have I f***d up? And also, I'm not entirely sure I understand the "cap mod". Does that mean adding caps in parallel with existing ones at C13-16? I would appreciate some advice from someone who knows what they're doing, because I sure as hell don't!
 
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