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View Full Version : We're going to need a bigger...external PSU?



ezkcdude
2008-01-06, 08:18
So, the new headless receiver takes an 9V DC supply and has internal linear regulators (makes sense given the 6Vpp analog output + overhead needed for the regs). Does anyone here know what type of regulators are being used internally? I'm wondering if some preregulation is warranted. I never really bought into the need for an external PSU with the SB3 given the internal regs were switchers, but now...I've always wanted to build a Jung regulator, and this may just be the excuse I needed.

04dgmsilv
2008-01-06, 09:12
After reading the release I thought about this as well, I currently run a hidden away SB3 (i.e. display is useless to me here) to a NOSDAC in my family room setup. Seems like this little box could have some neat mod potential for us DAC users.

seanadams
2008-01-06, 10:12
Power supplies in the receiver are simpler because it does not have a display. The DAC is just powered by a linear reg from the input. Also the total power draw is down by a half of so.

ezkcdude
2008-01-06, 10:24
Power supplies in the receiver are simpler because it does not have a display. The DAC is just powered by a linear reg from the input. Also the total power draw is down by a half of so.

Thanks for the info.

opaqueice
2008-01-06, 10:26
Power supplies in the receiver are simpler because it does not have a display. The DAC is just powered by a linear reg from the input. Also the total power draw is down by a half of so.

Sean, since this is an audiophile forum I have to ask why the THD level is slightly (5.5dB) higher? Is that due to the Wolfson DAC? And how's the jitter?

Phil Leigh
2008-01-06, 10:47
Power supplies in the receiver are simpler because it does not have a display. The DAC is just powered by a linear reg from the input. Also the total power draw is down by a half of so.

aaaargh! - Sean you know that's just opened a can of PSU worms...now there is no switching reg to hide behind, all sorts of "super reg PSU's" upgrades will appear :o)

(Having just upgraded the PSU in my DAC to an Invisus super-reg I feel qualified to comment...)

seanadams
2008-01-06, 11:14
Sean, since this is an audiophile forum I have to ask why the THD level is slightly (5.5dB) higher? Is that due to the Wolfson DAC? And how's the jitter?

The entire digital section including s/pdif circuitry is identical to SB3, so if you want a high-end external DAC, go for it. Jitter is the same. Specs for the Receiver's DAC are good but not quite as good as SB3's. However, I think the numbers currently posted on the site are the worst-case bounds from the data sheet - we may revise them based on measurements of mass-production units, which are usually better. Of course a single THD figure is not that useful in characterizing total DAC performance. In all the listening tests we've been done it seems quite a good performer.

seanadams
2008-01-06, 11:16
aaaargh! - Sean you know that's just opened a can of PSU worms...now there is no switching reg to hide behind, all sorts of "super reg PSU's" upgrades will appear :o)

(Having just upgraded the PSU in my DAC to an Invisus super-reg I feel qualified to comment...)

I have not yet tried a super reg on it but it should be a good improvement. However, it would still need to be put on the DAC's power rail to be most effective.