Help me decide which ebay dac please?

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Andrew
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#406

Post by Andrew »

Do you have the original circuit?

Andrew
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Max N
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#407

Post by Max N »

Andrew wrote:Do you have the original circuit?

Andrew
Here is a link to the AK4393 datasheet which shows on page 19 the recommended LPF
http://www.asahi-kasei.co.jp/akm/en/pro ... 3_f02e.pdf
I believe that the DAC kit implements this as shown

I have also attached a schematic for the DAC kit

Here is a link to the AK4396 datasheet which recommends a different LPF (p34)
http://www.asahi-kasei.co.jp/akm/en/pro ... 6_f00e.pdf
AFAIK the 4396 Ebay DAC kits come with the LPF from the 4393 datasheet. One of the mods in the DIYAudio 'spec' is to change the LPF to the 4396 version.
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ak4393-6 dac scematic.pdf
DAC schematic
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little eddy
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#408

Post by little eddy »

Late to this subject but now that I've ditched my CD in favour of computer audio with my NAS and SBT, thought I should try something DIY to compete with my modified AudioNote DAC 1.2. So bought one of the CS4398 versions that is currently on some choppy ocean somewhere. Should be an interesting comparision given that some seem to like the AN DACs.

Going to try the stock DAC and have ordered one of these (although people say at these prices they are not genuine BB op amps): http://www.ebay.co.uk/itm/220994602890? ... 1439.l2649

Then have a scheme to try a pair of output transformers courtesy of SteveS, (no output valve stage so direct). Layout progressing as attached.
Attachments
IMG_8988.jpg
TD-125/RB250/MC25FL & 'Snail' phono, NAS/SBT with CS4398 DAC, 41MP pre & MoFo Power, still messing with OBs.
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Paul Barker
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#409

Post by Paul Barker »

I was advised not to buy the best BB opamps cheap but the second line BB opamps cheap are the real thing not counterfit. For the best you have to pay proper price.

Anyway I bought the second line stuff like you and it was an improvement.
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Paul Barker
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#410

Post by Paul Barker »

The one you linked to is the one I bought it sounds great.

It is the genuin part, because it is the cheap version not worth counterfiting. They only counterfit the quality one.

The BP is the higher grade. But these have got to be
the most counterfeited op-amps of all time, because of the cost, so beware.
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colin.hepburn
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#411

Post by colin.hepburn »

I have a feeling this eBay op-amp could well be a fake judging by the varies prices for a single chip but I also worrie about the wide variations in prices for this op-amp so if it the real thing It could well be a bargain though
http://www.head-fi.org/t/316937/fake-op ... e-wild/150


http://uk.rs-online.com/web/p/products/ ... _-OPA627AU

http://www.plccenter.co.uk/Shop/TEXAS%2 ... leShopping

http://www.google.co.uk/search?sourceid ... 80&bih=776
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little eddy
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#412

Post by little eddy »

Well mine's up and running in stock format other than the OPA627. Maybe not as smooth as my Audio Note but great detail, width and bass - altogether a more engaging listen.

Looking forward to getting the bits to try Steve's output transformers.

Must sort out the high def files that Chris The Stratmangler sent (but the cs4398 pcb doesn't have a high res LED like the 4393/6 board so can't see if its working). With a bit of luck I will be able to hear an improvment.
TD-125/RB250/MC25FL & 'Snail' phono, NAS/SBT with CS4398 DAC, 41MP pre & MoFo Power, still messing with OBs.
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Mike H
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#413

Post by Mike H »

Colin if it were me I'd pay the 'proper' price from a 'proper' supplier, forget about 'bargains'.

I think the problem here is the name, Burr-Brown, hence the fakes, but doesn't mean can't be made by somebody else under licence.

I notice RS are temporarily out of stock, but I'm thinking safer bet it's kosher having 'TI' printed on it rather than 'BB' and from eBay


Just IMHO :D
 
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little eddy
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#414

Post by little eddy »

Well impatience got the better of me, and fake OPA627 or not, I unplugged it and simply pushed leads from the output transformers into the appropriate pins on the vacated socket.

Still smiling and foot tapping. However saying that, the e-bay OPA627 sounded pretty good and I agree with Paul in that it is an improvement over the stock 5532.

The question now is whether to commit to a scratch build with better power supply and some of the recommended pcb components. Difficult to understand how better it could be in that I think this is the best digital has ever sounded through my system.
TD-125/RB250/MC25FL & 'Snail' phono, NAS/SBT with CS4398 DAC, 41MP pre & MoFo Power, still messing with OBs.
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Mike H
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#415

Post by Mike H »

Well if it seems to be OK, then use it :D
 
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little eddy
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#416

Post by little eddy »

Mike H wrote:Well if it seems to be OK, then use it :D
Well it is with mixed feelings that I have to report on the relative performance of the new budget DAC. I had the other half (who are sometimes said to have better hearing) listen to a few tracks, firstly with my old AN DAC and then the newcomer. First thing she said was "it's clearer". I had to agree. It also seemed to have more pace and better controlled bass, perhaps at the expense of 'liquidity' if that is the right term. But overall I would say an improvement so:

1. Do I commit to a new build with better power supply and some better components? - yes
2. What to do with my AN DAC that up to today I was quite proud of????????? At least it will stay until I have built another.
TD-125/RB250/MC25FL & 'Snail' phono, NAS/SBT with CS4398 DAC, 41MP pre & MoFo Power, still messing with OBs.
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Mike H
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#417

Post by Mike H »

Keep it as a spare? (2)
 
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little eddy
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#418

Post by little eddy »

Mike H wrote:Keep it as a spare? (2)
It's an expensive spare. I'll probably sell but doubt I'll get my money back for the upgrades I've done.
TD-125/RB250/MC25FL & 'Snail' phono, NAS/SBT with CS4398 DAC, 41MP pre & MoFo Power, still messing with OBs.
little eddy
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#419

Post by little eddy »

Might be a stupid question but feel free to shoot me down.

I am going to build a second cs4398 DAC but I want to replace all of the power supply section. I will be using transformer output so don't need the +12 and -12V supplies but there are three other voltages on the board that I need, 2 at 3.3V and 1 at 5V.

I was thinking using some type of power supply boards, possibly the 'heater' ones being developed by Andrew.

So I was going to try to find a e-bay seller that would supply a board without the 3 LM117 regulators fitted. If this is not possible then I could try to desolder them but have heard that the board is quite easily damaged.

If I have no components/supply to the supply side of the three LM117 regulators, could I simple just attach my new supplies to their output terminals without any damage or implications?
TD-125/RB250/MC25FL & 'Snail' phono, NAS/SBT with CS4398 DAC, 41MP pre & MoFo Power, still messing with OBs.
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Mike H
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#420

Post by Mike H »

I would say no, the input side of a LM317 must be kept positive relative to the output side. In situations where the input may become less positive, a reverse protection diode should be added across the chip so the reverse Voltage does not exceed about 0.6V

I think this is a substrate polarity issue, for example a negative regulator has the centre pin as the output (negative), which is also the tab (i.e. substrate, which is mounted onto the tab)

Safest is to break the circuit to isolate the existing regs or remove them. :?:
 
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