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Old 3rd April 2008, 09:44 PM   #1421
Russ White is offline Russ White  United States
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Quote:
Originally posted by _atari_
Hi,

I am one (little step) further in planning for my DAC (OPUS, Metrnome, USB, prob. SPDIF).
Now I am thinking about the power supply:
Is 2*9v for the DAC sufficient? And how should it be spend?
9v for Controller, SPDIF and DAC, 9v for DAC analogue & metronome or
9v for Controller, SPDIF, DAC Metronome and 9v for DAC analogue?

The 9v will of course be regulated to something like 8v/5v respectively (The OPUS, Metronome and SPDIF have regulators for smaller voltage on board?!)
It will work great!

They have 3.3V regulators. 5V input is fine. A little more gets a bit better regulation.

I would use one supply for everything but the DAC, and one supply for the DAC.

This is the way I have been running the DAC in my office.

Cheers!
Russ
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Old 4th April 2008, 06:11 AM   #1422
ssmith is offline ssmith  Kenya
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Quote:
Originally posted by Russ White

2) Those transformers should be just fine.

Cheers!
Russ
Hi Russ,
On the verge of making an order -- but wondering if the PSUs for the opus and the balsie be run off a single transformer of sufficient capacity -- just by branching the secondaries, one to the LCDPS and one to the LCBPS?
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Old 4th April 2008, 04:59 PM   #1423
kevinkr is offline kevinkr  United States
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Mr White's "Opus", designing a simple balanced DAC
Quote:
Originally posted by ssmith


Hi Russ,
On the verge of making an order -- but wondering if the PSUs for the opus and the balsie be run off a single transformer of sufficient capacity -- just by branching the secondaries, one to the LCDPS and one to the LCBPS?
No, You need separate secondaries for each, in this case 4 would be required. The LCDPS needs approximately 9V/1A x 2 and LCBPS needs approximately 18 - 20V/0.5A x 2. They must be totally separate windings. Overall rating should be in the vicinity of 50VA based on TPA recommendations.
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Old 4th April 2008, 05:09 PM   #1424
BrianDonegan is offline BrianDonegan  United States
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Mr White's "Opus", designing a simple balanced DAC
Quote:
No, You need separate secondaries for each, in this case 4 would be required. The LCDPS needs approximately 9V/1A x 2 and LCBPS needs approximately 18 - 20V/0.5A x 2. They must be totally separate windings. Overall rating should be in the vicinity of 50VA based on TPA recommendations.
Actually, LCBPS can use 12-18V secondaries. We have switched back to 15VA trafos, which we had originally. Last order, Avel was out of stock of the 15VAs, so we got 25VAs.
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Old 4th April 2008, 05:15 PM   #1425
kevinkr is offline kevinkr  United States
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Quote:
Originally posted by BrianDonegan


Actually, LCBPS can use 12-18V secondaries. We have switched back to 15VA trafos, which we had originally. Last order, Avel was out of stock of the 15VAs, so we got 25VAs.



The 15VA should be much more compact. I used a competing company's 20VA/25VA transformer and they take up more space in my dac than I originally anticipated.
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Old 4th April 2008, 11:07 PM   #1426
culture is offline culture  Netherlands
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Hi All

Finally finished my opus dac today, nice project but i have to confess i expected a bit more of a difference compared to the internal dac of my harman kardon hd720 cd player. I'm using it in combination with my pass p1.7/f4 and rega r5 speakers. Both rca from the cd player and xlr from the dac are connected next to each other so i can switch instantly from one source to the other but to be honest... i couldn't tell the difference

makes me wonder, am i worthy this dac....

ok, this is only my first impression, i'm just listening to this dac for an hour now and maybe i should give it some time to burn in or what ever and do a bit more serous listening session at a later time..

cheers,

c.

ps, doesn't make me less happy with the dac, only makes me appreciate my old harman kardon cd player a bit more
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Old 6th April 2008, 09:16 AM   #1427
OneyedK is offline OneyedK  Belgium
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Quote:
Originally posted by culture
pass p1.7/f4
That's the part I suspect most in the chain you described.
Maybe you should try (borrow) another amp and redo the comparison...
Unless you are 100% sure that the Pass is perfect (measurements???).
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Old 6th April 2008, 05:32 PM   #1428
123chris is offline 123chris  Netherlands
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Quote:


makes me wonder, am i worthy this dac....

No sorry, you are not. So send me your DAC.
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Old 6th April 2008, 07:56 PM   #1429
orthoefer is offline orthoefer  United States
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Default Re: USB jack take 2.2

Quote:
Originally posted by orthoefer
Ok. Let's try the USB jack again.

Here is what I have this time: Datasheet

Click the image to open in full size.
Click the image to open in full size.
I posted a description of the above USB jack days (months?) ago and am finally getting around to using it. Let me say, I don't like this jack at all. There are two major problems with it. First, the manufacturer put the text on the jack upside down. USB convention calls for the jack to be mounted in a certain orientation, yet the name and descriptor on this jack are printed opposite--no big deal. It just shows that their "designers" are not paying attention to the standard. Second, the power leads on this jack are comprised of 20 ga wire whereas the data lines are 24 ga. The 24 ga is fine and can be easily soldered into Twisted Pear's USB board. However the 20 ga wires are too big to fit through the PCB holes. The solder pads on the USB input module are very small, so drilling them out is not an option. The only option is to shear off some of the strands so that the wire can fit through the hole. This is a little messy and does not give a clean result. So there you have it. This jack stinks. I don't like the bulkhead connectors that require another USB cable either--too many connections. I'll be on the lookout for a better solution. For now, I will use what I have even though I don't like it.

I think I should have used this instead. It has only 24 ga wires.
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Old 6th April 2008, 08:25 PM   #1430
.: ZMN :. is offline .: ZMN :.  Europe
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Thanks for the warning. Have you seen the Neutrik NAUSB-B (Mouser) chassis part? I have used it with a short USB (Mouser) cable and found it is easy to work with. Required a round hole and a connecting USB cable inside the chassis (A-B type can be reverted if you wish). Only thing is, it is a bit expensive.
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