photos of the delta1

delta1

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Re: photos of the delta1

Postby amb » February 25th, 2011, 8:43 pm

Proof that digital "crap" is effectively isolated from the analog rails by having separate PSUs. :)
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Re: photos of the delta1

Postby DorkVader » February 25th, 2011, 10:06 pm

L-W, do you plan to do the 100 MHz "hack" someday?

Also, I origionally thought that it would'nt help much to have two seperate PSU's but now I'm staring to ting it may actually be an excellent idea.
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Re: photos of the delta1

Postby linux-works » February 25th, 2011, 10:12 pm

I have the files for the hack but just have not needed to do it yet. I will, though ;)

the a10 backplane forces you to install an s25 for digital and allocates a huge spot for the standard s22 board. my s22 went into 'zero tracking zero' mode, and so while it tracked just fine, it wasn't giving me anything to listen to ;) the s22 was swapped out and a make-shift dual 317/337 style setup was put in its place, using the same exact pinout. when the s22 comes back from extended vacation, it will have its reserved spot warm and waiting for it ;)
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Re: photos of the delta1

Postby linux-works » February 25th, 2011, 10:19 pm

DorkVader wrote:
Also, I origionally thought that it would'nt help much to have two seperate PSU's but now I'm staring to ting it may actually be an excellent idea.


remember that this is during a volume knob twist or IR remote up/down request. for a short time, there is relay 'run-up' and then once they are all in place, the chatter stops. there is physical chatter from the relays and its actually variable since sometimes the difference from 'there' to 'here' is only a few bits change. but if the jump requires a binary rollover (1000 to 0111, say) then a bunch of relays have to change state and there's just no getting around that.

I'm trying a 'make before break' method where you click down all the 1's (more precisely, the 0-to-1 transitions) in one pass; then you click down all the 0's in a separate pass. each relay is an attenuator stage that either 'does its thing' (adds the proper atten value) or its in bypass mode, not doing a thing to the signal level. and so if you attack the 1 bits, which cause the volume to go down, then you make a 2nd pass and flip 'up' the things that need to be 0's, you have gone down in volume and then adjusted from there, hopefully not causing too much of a click. I'm trying this out to see if it gets a better 'sound' as you run up and down the vol range. and also watching what its doing to the PSU lines.

of course, no matter what algorithm is used during vol-change, once the value is set it stays there and no noise happens and the power can even be removed from the controller and the relays hold their last-set state. you pay a little bit in complexity at the 'change' state so that you don't have to pay it during the 'hold' state.
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