leo
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Post by leo on Nov 13, 2007 1:06:31 GMT
This is the next project, will post pictures as its built in stages Its basically a TDA1541A based dac designed by Pedja Rogic called the AYA, it uses Asynchronous reclocking, separate supplies with discrete regulation, I/V conversion is done by an I/C implemented as a common base with NFB I already built his first TDA1541A based dac which was very good so will be interesting to try this newer one Reclocker is underneath the pcb
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mrarroyo
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Post by mrarroyo on Nov 13, 2007 1:51:30 GMT
Leo, I look forward to your impressions. I am looking for a 2nd DAC and base on my experience w/ the Lite DAC-AH I would like it to be NOS. Hopefully it would be an inexpensive one to build! BTW are you going to use standard, or premium, or boutique parts? Hopefully a combination based on your experience. Thanks.
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leo
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Post by leo on Nov 13, 2007 2:21:54 GMT
Miguel, Regarding parts, I will first use what Pedja recommends including BG caps in certain places, after its had a good run in and I'm familiar with it I'll probably try some different parts depending how it sounds. I'm afraid it won't be a cheap dac to build if your starting from scratch but I already have a lot of the parts (thanks to a friend, he knows who he is ) including the rare TDA1541S2 double crown and a custom wound screened transformer with 8 x pairs of secondarys Only boutique resistors will be used in the I/V section as these are the most critical
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Post by fanboi on Nov 13, 2007 8:20:07 GMT
Hi Leo, interesting to hear your comment re resistor quality in the I/V stage. I have a kit for the Rudolf Broertjes I/V gain stage for my Monica2 NOS DAC - have not yet gotten around to soldering it up. Are there any particular resistors in this circuit diyparadise.com/ssiv.html that might be usefully substituted with better quality (and if so do you have any recommendations) TIA Tony G
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Post by minivan on Nov 13, 2007 8:33:59 GMT
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leo
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Post by leo on Nov 13, 2007 8:49:38 GMT
Hi Tony,
The 1k5 resistor and the cap across it are the ones I'd fit a good quality low noise low inductive type, going for non magnetic too is a good idea as magnetic ones can add a glassy signature to the highs. Good ones I've tried are Caddock TF020, Riken and Vishay VTA-55.
All sound noticeably different, the Caddocks are more forward than say the Vishay. I did not like the Welwyn RC55 series used in the I/V , for dirt cheap the MRS25 are not bad
for the cap a small polypropylene,polystyrene etc should be fine, I wouldn't use polyester or ceramic there
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leo
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Post by leo on Nov 13, 2007 8:58:08 GMT
is this diy dac any good? i interested in getting one, only $300 aud It looks very good value for money if that is for a complete kit, I can see it uses TDA1541A but can't comment on it as I don't know what circuit they are using, I'll have a browse on their site. Problem with the TDA1541A is that they are hard to get right, you can throw the best components you want at it and implement in a complex circuit but you can't guarantee top results as I found out the hard way ;D Also the track layouts and grounding is really hard with these dacs, they have more supplies than the the usual chips only needing single ones
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leo
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Post by leo on Nov 13, 2007 9:02:25 GMT
BTW I like the case, wish I could find something similar over here
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Post by fanboi on Nov 13, 2007 9:59:38 GMT
Hi Tony, The 1k5 resistor and the cap across it are the ones I'd fit a good quality low noise low inductive type, going for non magnetic too is a good idea as magnetic ones can add a glassy signature to the highs. Good ones I've tried are Caddock TF020, Riken and Vishay VTA-55. All sound noticeably different, the Caddocks are more forward than say the Vishay. I did not like the Welwyn RC55 series used in the I/V , for dirt cheap the MRS25 are not bad for the cap a small polypropylene,polystyrene etc should be fine, I wouldn't use polyester or ceramic there Thanks for that Leo, will see what I can find of what you suggest.
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Post by dc on Nov 13, 2007 10:43:24 GMT
how to buy kits
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leo
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Post by leo on Nov 14, 2007 21:44:00 GMT
Hi Tony, The 1k5 resistor and the cap across it are the ones I'd fit a good quality low noise low inductive type, going for non magnetic too is a good idea as magnetic ones can add a glassy signature to the highs. Good ones I've tried are Caddock TF020, Riken and Vishay VTA-55. All sound noticeably different, the Caddocks are more forward than say the Vishay. I did not like the Welwyn RC55 series used in the I/V , for dirt cheap the MRS25 are not bad for the cap a small polypropylene,polystyrene etc should be fine, I wouldn't use polyester or ceramic there Thanks for that Leo, will see what I can find of what you suggest. No probs, glad to be able to help, have fun! the Rudolf Broertjes I/V stage looks a nice circuit, feed it a good quality supply
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leo
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Post by leo on Nov 14, 2007 21:45:25 GMT
There does not seem to be a lot of full dac kits about at the moment, I personally prefer to source my own parts tbh although this can take more time and get expensive
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leo
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Post by leo on Nov 14, 2007 22:07:36 GMT
Fitted some bits that arrived from Farnell, thanks to a mate for sticking them on his order
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mrarroyo
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Post by mrarroyo on Nov 15, 2007 1:47:08 GMT
Leo, can't wait for it to be finished! Then impressions!!!
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leo
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Post by leo on Nov 15, 2007 19:36:34 GMT
Few more bits fitted, just need to wait for some other stuff on order
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leo
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Post by leo on Nov 29, 2007 22:45:52 GMT
Standard TDA1541A fitted for testing, no way I'm fitting the double crown until I'm sure everthings ok Will need some time to run in for a while, initial listening tests are more than promising
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Post by Deleted on Nov 29, 2007 22:57:03 GMT
Leo What kind of capacitors are you using in the TDA1541A "ladder ? Are they closely matched for each channel ? Alex
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mrarroyo
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Post by mrarroyo on Nov 29, 2007 23:09:45 GMT
Leo, will the PSU be an external type of wallwart? If so, send me a PM on how much it would cost to get one made.
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leo
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Post by leo on Nov 29, 2007 23:27:32 GMT
Leo What kind of capacitors are you using in the TDA1541A "ladder ? Are they closely matched for each channel ? Alex The caps I fitted for the ladder are the same as Pedja uses, BG NX Hi-Q, once I have evaluated it etc I will be replacing those with matched SMD PPS, one of my favourite caps in certain area's
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leo
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Post by leo on Nov 29, 2007 23:33:56 GMT
Leo, will the PSU be an external type of wallwart? If so, send me a PM on how much it would cost to get one made. The transformer is custom wound from Antrim, it has 8 x pairs of secondary windings as the supplies in this dac are all separated, the transformer is also shielded. Unfortunately it wasn't cheap, infact the most expensive part for this project
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leo
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Post by leo on Nov 30, 2007 0:56:03 GMT
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mrarroyo
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Post by mrarroyo on Nov 30, 2007 3:37:02 GMT
Leo, I looked at the site and I am extremely surprised. It states that the price of a fully assembled unit is 650 euros, fine. But to ship to the USA the total cost is 829.8 euros. So the total S&H to the USA is 179.8 euros or the equivalent of $265 dollars.
I would like to be respectful but I have to wonder WTF are they shipping the DAC in? The listed weight of the unit is 3 Kg so lets add 1 Kg for the shipping materials. I am sorry, I find it hard to believe that it costs $265 dollars to ship 4 kg or 8.82 lbs from Serbia to the USA.
I just checked in the US Postal Service and to ship a 9 lb box w/ Priority Mail Flat Rate Box (6 -10 days) the cost is $35.15 buying the shipping label on line. My point is that there has to be a cheaper way to ship from Serbia to other countries.
At that rate there is not way in hell I would buy one of their units, no matter how good it is.
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leo
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Post by leo on Nov 30, 2007 21:10:40 GMT
Miguel,
I did not look at the shipping just posted the link to their kits, as I mentioned before I only brought the pcb before kits was offered and sourced my own parts including the custom transformer Problem is sourcing your own parts does tend to be more hassle and works out quite expensive so buying a kit or a ready built unit would be a lot easier. I already had a lot of the bits spare anyway
I have mailed Audial regarding the P&P and they sent me this The 829.8 EUR includes 150 EUR for shipping by FedEx and 29.8 EUR is for credit card processing.
Shipping by registered airmail to USA is 80 EUR. The postage itself costs 60 EUR and 20 EUR covers customs tax which applies to any export from Serbia (yes, I also don't understand this country but it is thus).
Processing fees again apply for the payments by credit card, but this 650 + 80 = 730 EUR is the final amount if you pay by bank transfer.
This 650 EUR offer is valid until 15 December.
Pedja
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rowuk
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Post by rowuk on Nov 30, 2007 21:14:16 GMT
I think 650 Eur will feed a typical Serbian family for 2 or 3 months!
Boy have they learned fast!
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leo
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Post by leo on Nov 30, 2007 21:46:05 GMT
I said before the TDA1541A based dacs are not cheap but tbh I'd rather have a design like this than risk some other cheap unknown from China, TDA1541A's are still one of the hardest parts to implement.
I honestly thought 650 euro is very good price for a dac of this caliber, if you add up the amount of work, parts etc they actually are not making a lot on it
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