Dacs

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karatestu
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Re: Dacs

Unread post by karatestu » Fri Apr 13, 2018 5:04 pm

Lurcher300b wrote:
Fri Apr 13, 2018 4:54 pm
karatestu wrote:
Fri Apr 13, 2018 4:18 pm
I have been wondering how many voltage supply pins are on this dac chip. The TDA1305 in my Naim CD3.5 has 3. Naim gave each pin its own regulator but it was all on the main psu along with everything else. I gave each dac supply pin its own dedicated psu. It was a hell of an improvement from what i remember. With this Chinese dac using surface mount components it will probably be a bit harder to do or impossible. That's if there is more than one supply pin.

When i get it the first thing i will probably do is have a look inside :lol:
But conversly if you embrace surface mount there is a lot you can do. There are some very good regulators that are small enough so you can have one and a couple of caps next to every supply pin on your dac and supporting circuits. I found the LT1761 was good for example.
Embrace surface mount ? I have used resistors and caps in the past but they are the work of the devil and my Master will not allow it :lol:
CycleCoach wrote:
Fri Apr 13, 2018 4:58 pm
karatestu wrote:
Fri Apr 13, 2018 4:18 pm
When i get it the first thing i will probably do is have a look inside :lol:
Something I've been thinking about for a while now!
I liked the "cheapo" DAC powered by the USB-out on my laptop, but couldn't believe how much better it sounded with the power provided by the standalone supply. It really is something special.
I have been wondering if there is anything else that could be done to improve it even more - whether the amplification to bring the output up to line level could be done off the chip for instance (with another power supply?)
I'll be following this thread with interest.
Well you can watch me blow one up :epopc: At £3.76 i can just get another one. It depends how small everything is inside it - not sure my magnifying glass will be up to it. :grin:
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_D_S_J_R_
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Re: Dacs

Unread post by _D_S_J_R_ » Fri Apr 13, 2018 7:50 pm

I don't have a free image hosting account any more so can't post pics of the innards on mine. From memory, there's two multi-pin surface mount chips fighting for space with the TOSLINK input socket and really, there's no room to play unless you try with a needle soldering iron and a loupe ;) What's the point anyway? The standard article sounds pretty darned good even with a wall-wart supply. Going to a linear type I made derived from the Rock Grotto 12VAC thing I made years ago and fitted with a cheapo Chinese regulator circuit set to a smidge over 5V made enough of a difference in 'scale,' it's fitted and forgotten about. One thing perhaps is that the output is a touch lower than the conventional 2V, but it does mean the P50 is wound well round on some earlier mastered CD's done at too low a level.

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karatestu
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Re: Dacs

Unread post by karatestu » Sun Apr 15, 2018 2:35 pm

Thanks for your thoughts Dave. Always very much appreciated.

Does anyone know the current draw of this dac ?

If there are no specs i will have to put a 1R resistor in the supply line, measure voltage drop across it and work out the current using ohm's law.
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Dr Bunsen Honeydew
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Re: Dacs

Unread post by Dr Bunsen Honeydew » Sun Apr 15, 2018 3:34 pm

Stop being daft, it draws next to nothing, the one I use if I remember right is 15va or 30va, I forget, and there is a 80va on ebay I think, it really doesn't matter apart from the biggest transformer will make better music - put a 1000va 5v on it :mrgreen: :mrgreen: :mrgreen: :mrgreen: :mrgreen:

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karatestu
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Re: Dacs

Unread post by karatestu » Sun Apr 15, 2018 3:43 pm

I only wanted to know if a lm317 reg would cope with the current drawn. I take it the psu you use has a regulator or is it just transformer, rectifier and caps ?
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Dr Bunsen Honeydew
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Re: Dacs

Unread post by Dr Bunsen Honeydew » Sun Apr 15, 2018 3:55 pm

I imagine it would cope with about 10 of them, parallel them. ;) :whistle:

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karatestu
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Re: Dacs

Unread post by karatestu » Fri Apr 27, 2018 8:40 am

£3.76 Dac arrived the other day. It is tiny. Opened it up to look inside (pic later). They are very small smt components and a solder mask over the area where the power connector is soldered in which makes it hard to see where the power rail tracks run and if they split off.

Enclosure is steel so can get rid of that :grin: Power can be hardwired in if the power supply connector is removed. Need to try and trace the power rail track to see if it can be split and another psu added.
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Quarknosis
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Re: Dacs

Unread post by Quarknosis » Fri Apr 27, 2018 10:50 pm

I'm still waiting for mine to arrive, I think I ordered mine about a week after you did Stu

The 30VA PSU which I ordered about 10 days after the DAC has already arrived though :-?
NVA BMU - NVA Phono 1 - Systemdek IIX/Rega RB250/Denon DL160 & Philips CD 104 with NOS mod - TIS & SSP mkii - NVA AP70sa - Epos ES11.

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karatestu
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Re: Dacs

Unread post by karatestu » Sat Apr 28, 2018 7:00 am

Quarknosis wrote:
Fri Apr 27, 2018 10:50 pm
I'm still waiting for mine to arrive, I think I ordered mine about a week after you did Stu

The 30VA PSU which I ordered about 10 days after the DAC has already arrived though :-?
Oh jolly good. You will be amazed at how small the thing is. I decided to build my own psu(s) but then i always do things the hard way. :roll:
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Quarknosis
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Re: Dacs

Unread post by Quarknosis » Thu May 03, 2018 9:51 pm

Yes it's small Stu but it looks much better than I would expect for the price. Not that it's going to be on view of I can help it.

I've been listening to it for a few days now and I like what I hear. It has more detail than my modified vintage CD player which I expected but there's a lot more spatial information coming off CDs which I haven't experienced before with any player or DAC. It seemed to take a while to come on song when first switched on over the first few days but tonight it seemed to get there much quicker. At the moment I think the Philips player has a more natural sound with acoustic instruments, probably because it sounds very relaxed, but the DAC is really good with electronic music.

I've got to do something about that horrible blue led though :o
NVA BMU - NVA Phono 1 - Systemdek IIX/Rega RB250/Denon DL160 & Philips CD 104 with NOS mod - TIS & SSP mkii - NVA AP70sa - Epos ES11.

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