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Buffalo II

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Russ White

Russ White

Member
Joined 2005
twistedpearaudio.com
steve jones said:
Was wondering how warm/hot the Sabre chip runs on the Buffalo II PCB?

Was intending to mount it bottom side flush (with reliefs cut for misc capacitors and inductors) on a piece of spruce like my Attraction DAC.

Russ, any opinion if this would overheat the chip or not?
Click to expand...

It runs very cool.

On the Buf32S it ran pretty warm because of the hot opamps adjacent to it.
 
F

fierce_freak

Member
Joined 2007
lightmedark.com
steve jones said:
I've got a custom 48% nickel core pair ordered from Bud Purvine at Onetics. The primary will simply be connected between + and - outputs (for each DAC channel) and primary's center tap left floating.

1:1 ratio for a single ended output voltage of around 3.03V peak to peak dependant upon AVCC voltage. Or ground the secondary's center tap for a balanced output.

Simple. Hopefully not too much so.
Click to expand...

Thanks for your info. Is that 3.03V balanced out?

I've read that it's best to use the sabre chip as voltage out when pairing with transformers. What kind of specs would this require for the transformer? Higher DCR of the windings or a resistor strapped across the primaries?
 
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flocchini

Member
Joined 2004
Returned home to find the BII

Just returned home to find my BII. Thanks


My goal is too build the PS this weekend if I get my taxes done and first
I will try the Lundahl LL1674 amorphous core transformers.

I also have Welborne's Cato unit available set up for differential output using load resistors for passive conversion.

From the Lampizator's article

"Then after consulting Mr. Russ I tried loading the output by resistor 39 Ohms to pull the output to current mode.
This time again - no caps. I marginally prefer the latter solution.
Your mileage may vary.
In all these experiments I used SRPP config driven by only one leg of the balanced output of ESS"

He also has another circuit (this time balanced) using a 6SN7

Time to experiment !!!!
 
steve jones

steve jones

Member
Joined 2002
fierce_freak said:
Thanks for your info. Is that 3.03V balanced out??
Click to expand...

Half the single ended value for balanced output voltage.

fierce_freak said:
I've read that it's best to use the sabre chip as voltage out when pairing with transformers. What kind of specs would this require for the transformer? Higher DCR of the windings or a resistor strapped across the primaries?
Click to expand...

Beats me. The intricate inner workings of transformers at this level confuses the hell out of me. That's why I'm leaving the hard design engineering to Bud. :)
But in anycase I won't be paralleling a resistor across the primaries.
 
Russ White

Russ White

Member
Joined 2005
twistedpearaudio.com
sureshm said:
Brian, as the first round of Buffalo IIs seemed to be shipped out, could you please please verify and release the new Sympatico? I have been dying to build one of these :)

Appreciate your efforts!

PS any reason why everything is set to 'out of stock' on the website?
Click to expand...

Thank you.

It is a lot of effort ,and Brian along with his extremely understanding wife and family deserve a bit of a break.

Brian is taking a bit of well deserved time off from TPA. That's why things are marked out of stock.

Sympatico PCBs were redesigned, and because of an error had to be made twice. :) They are set to be prototyped soon after Brian gets back.

We will also have another run of Buffalo II made soon.

We are only two guys doing this the best we can with our spare time. We really appreciate our fellow DIYers and your understanding that things don't happen as fast as they might if we were doing this full time.

Your feedback and support are precious to us.

And, importantly I must add, we love to see the creative work you guys do with the modules we produce.

Cheers!
Russ
 
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H

harruharru

Member
Joined 2005
IVY-III: Please help me understand 2vrms and 4vrms

Hi,

I am reading the manual for the IVY-III. In this manual the default configuration is 2VRMS and the manual states that this is "industry standard consumer level".

I thought −10 dBV which is standard consumer level was about 0.316VRMS.
Pro level is +4 dBu which is about 1.228VRMS.

I am goind to connect the IVY-III directly to a professional power amplifier so i believe I will have to change the resistors R13-16 to 356Ohm. But this will according to the manual give me 4VRMS.

Please help me understand this.
 
Russ White

Russ White

Member
Joined 2005
twistedpearaudio.com
Hi harruharru.

What output level is it you want to achieve?

Also if you read around you will find that 2VRMs works out to -10dBu with +15db headroom. This a concession to the way CDs were created from analog recordings and has basically been this way since the earliest Phillips CD players.

Anyway you can easily get any reasonable output level you like. :)

Cheers!
Russ
 
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Duffy Moon

Duffy Moon

Member
Joined 2008
Magsy said:
Mine arrive today, thanks, looks excellent and packaging is good! :D

Bloody OPA1632 appears to be in short demand and my already delayed back order by RS is nowing showing late July for delivery! Hah, serves me right.
Click to expand...

Lucky! Still no whiff of it here:mad:

Did you get stuck with a huge tax/duty bill? What's the OPA1632 for?

merlin el mago said:
@Russ

Do you mind project a Firewire input module for the BII? or if you don't, you know other manufacturer that do it?
Click to expand...

I think there are several Firewire-SPDIF converters already available (Fireface?). TP have no plans to make one AFAIK. They intend to produce a new USB input module though, which I'm looking forward to. Firewire is dead, long live USB!
 
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