Duet Mods

[Zaragon]

The word on the street is removing it adds detail and space to the music, although it adds a "wrapped-in-gauze" effect to frequencies between 3000 and 3700Hz.

Actually I'd say it lowers the noise floor ......... by about 3mm

Sorry couldn't resist. No comment on mods.

[pelliott123]

My SBR is stock and interested in modding but only if it makes since. I recently completed a Buffalo DAC build from Twisted Pear Audio and the improvements over my old DAC was dramatic. Attached is a scope pic that with probe attached at the SPDIF input of the DAC driven by the SBR. No music playing just setting at idle. The wave is much better looking than my other source but curious what this actually represents

[Phil Leigh]

My SBR is stock and interested in modding but only if it makes since. I recently completed a Buffalo DAC build from Twisted Pear Audio and the improvements over my old DAC was dramatic. Attached is a scope pic that with probe attached at the SPDIF input of the DAC driven by the SBR. No music playing just setting at idle. The wave is much better looking than my other source but curious what this actually represents

It represents the fact that you need a scope with a higher bandwidth! :-)

[pelliott123]

This scope has a 20mhz bandwidth what would be approriate?
thanks in advance

[Phil Leigh]

This scope has a 20mhz bandwidth what would be approriate?
thanks in advance

I've got a 60MHz scope and that can't do it either!
I think from memory a 200Mhz scope is required, but I'm not exactly sure...

[pelliott123]

I was noodling around the WEB and discovered:

http://www.lampizator.eu/LAMPIZATOR/...queezebox.html

Some interesting stuff, just curious of other opinions

[ar-t]

This scope has a 20mhz bandwidth what would be approriate?

20 MHz is much too low. I use 100 MHz, usually sufficient. Also have a 200 MHz one, so I can safely say that 100 MHz is probably good enough. (I also have a button on both that reduces BW to 20 MHz, so yes, I do know what it looks like.)

Pat

[ar-t]

This stuff cracks me up, modding a digital output.

Stuff like this, from guys who have not tried it, but also lack knowledge of RF, cracks me up.

No, actually, it irritates the hell out of me.

Pat

[seanadams]

I was noodling around the WEB and discovered:

http://www.lampizator.eu/LAMPIZATOR/...queezebox.html

Some interesting stuff, just curious of other opinions

I really liked this "cargo cult" analogy: http://forums.slimdevices.com/showpo...5&postcount=14

The resistor that he removed is what sets the output voltage and impedance of the s/pdif output. He made the signal "look right" to him while nothing was attached to the connector, then proclaimed that everything would be perfect once the capacitance (?) of the cable was accounted for. He's lucky to get any signal at all

[ar-t]

What an idiot. Why am I not surprised that his knowledge is worse than his soldering "skills". I use the term "skills" rather loosely.

I hope that everyone who tries to measure the SPDIF output realises that it must use a 75 ohm cable, with a 75 ohm termination at the 'scope. Anything else is a useless method. About as good as removing the resistor that sets the level and impedance.

I won't mention names, but a very famous amp designer cranked out a CD transport using the same bone-headed approach. And several who either did not terminate the input of the DAC box, or used the wrong impedance. Ignorance is not limited to laymen.

Pat