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I wanted to briefly thank Gary B for giving me the opportunity to hear and compare his fully decked, super modified Art to my stock. I was expecting a significant improvement in the area of +10. But I have been pleasantly rewarded with more! His Art is a silent killer of cd digititis. No smearing and no fatigue in our 3 hour session. Totally enjoyable afternoon.In summary, the modified Art is indeed French in character. It is suave yet firm, and can brush a musical note with ease and polish. It is revealing but not onstantious. To me it truly represents what this forum is all about. Exchange of information and the development of new friendships.
It feels great to spend very little money and be rewarded with a great performer. Meeting new friends just adds more rewards.
This is a plus 10 in my book.
Follow Ups:
YES I agree with you totally. I got my DI/O about 2-3 weeks ago and it just keeps getting sweeter and sweeter. I haven't done any of the board mods yet (just the simple ones), but look forward to doing (or have them done, as I'm not much of a bench tech.) Many, many thanks to all who have posted here on the ART!!! Without your input and threads, I would not have conjured up the guts to try this. For the first time in many years, I'm actually pulling out cd's I rarely or never listened to....hey , as trite as it sounds, I'm actually enjoying the music again. If you're thinking about getting a DI/O, just do it....you won't be sorryagram
and where to get stuffs/how-to's and put them in a review section or FAQ so people can attempt them. I'm trying to find information & having a tough time (with 200 message limits) going all the messages...Thanks,
Duc
Here's a summary of ART DI/O mods as far as I know, NOT in any order of priority. I don't know if I've missed any. Some may not make a difference you can hear, and many people are happy with the stock unit.
1. Getting the unit dis-assembled: There are two screws that need to be removed to take out the boards, one is on the bottom and the other is on the back panel. After they are removed, you need to take the nuts off the phone jacks in back and on the front remove the knobs, nuts, and washers from the pots. Then you need to lift the main and connector board at the same time in a kind of "jack knife" fashion to get everything to slide out. Once the main board is out the DAC board has to be separated from the mother board to get at U1 and U2. Pull it off carefully, and make sure to follow anti-static precautions doing all of this work.2. The analog output caps are on the connector board, they are C17 and C18. Some people have removed them and replaced them with jumpers. Some have replaced them with higher-quality caps of various values. There's really a lot of opinions on this one. The stock caps on my unit were Nichicon 22uf, 50V. Good sources for quality caps are welbornelabs.com and percyaudio.com. Black Gate caps have been getting some pretty good press. I removed mine and added shorting wires.
3. There are nine 1N4003 rectifier diodes, they are on the right hand side of the board in a row (when looking from the front) and they are black with a silver band. Replace them with 1 amp 90V IR schottky diodes from Digi-Key (Digi-Key item 11DQ09-ND, 38 cents each). Some people have only replaced the diodes associated with the D/A section, but I decided to replace all nine, they are cheap and once you crack the case you might as well.
4. If you are not going to use the A/D section, remove the tube and U2.
5. U1 and U2 are quad op amps, 14 pin DIPs. They are TL074's in the stock units. I removed U1 and U2 and added sockets, Digi-Key AE7302-ND. This is also controversial. There are those who feel that sockets could affect performance, so they solder the IC's directly to the board. I socketed mine because I plan to do "op amp rolling" and the board traces seem delicate to me, so I don't want to solder too many times.
6. Most people feel the stock op amps are not adequate. I replaced U1 with a a Linear LT1365 op amp. This is a quad amp with 70 Mhz BW and 1000V slew factor. It is also unity-gain stable and can drive loads with high capacitance. I don't know if the socket is detracting from the ultimate performance of this chip. This part is available from Digi-Key, LT1365CN-ND, $12.13 each. Once again, if you are only using D/A, then replace U1 (which is used by the D/A circuit) and remove U2 (A/D circuit). Other people have installed AD825 op amps with are mounted on little boards. These op amps are only available in SMT and are not available in a quad package. The boards are sold by audiocom-uk.com and lcaudio.com. If you go this way you'll have to do some pin mapping since there's not a 1:1 correspondence, and the sub board will "fly" beneath the DAC board. Both these companies are in Europe. Op amps are very subjective, and there may be other answers. I'm using the LT1365 for U1, it's a direct replacement and am happy so far.
7. The consensus is to replace the 100 ohm input resistor at the digital input (R10 on the connector board) with a 75 ohm metal film resistor. I used a Yageo from Digi-Key, 75.0XBK-ND. Other people like other mfgrs so pick your favorite brand.
8. Some people see improvements by grounding the case. I grounded the unit by replacing the bottom screw with a bare brass one, wrapping some wire around it, and screwing it down. I connected the other end to the cover plate screw on the wall outlet, which in my case is unpainted. It's important to use unpainted screws to ensure good contact, brass or copper(best).
9. The DI/O puts out over 7V at the analog outputs. This may cause a problem with some systems by overloading the preamp inputs. The "standard" value is 2-3 volts. My system doesn't have this problem. If you need to pad the signal, you can buy cables from boldercables.com or roll your own. See this post:
http://www.audioasylum.com/audio/digital/messages/30858.html
10. Most people replace the stock power supply. It puts out 9VAC at 800 ma. Most people use a Stancor STA-5790, 9VAC at 3.4 amps, alliedelec.com stock #928-9919, $18.29.
11. Some people are replacing the digital input connector with a Canare 75 ohm connector, and the analog output 1/4" phono connectors with quality RCA jacks like Cardas or Vampire. Once again, too many opinions on which parts are best, I'm still running stock right now. Welborne and Percy have many choices.
That's all I can think of.
Thanks
Could you please give some sonic impressions of the LT1365? I made some minor mods yesterday, but put the TL074 back in the U1 socket just to make sure everything still worked (some of those traces are incredibly thin, you never know). I won't get around to trying the LT1365 until next weekend, and am wondering what to expect.On another subject: Do you ever get the feeling that the power supply could use some more filtering, or something? Is it intrusive, do you think? I checked all the DI/O electrolytic caps, and except for the (large) 2200 uF ones, IMO they all checked out borderline to substandard to what I would choose for my tinkering, or even to what I'm used to (not talking audiophile grade here). Not sure if I'll do anything about it, see what others say...
Well, I really have not had time to do much serious listening so far. This morning though I played two of my "reference" disks, Kind of Blue and Take Five. I've been listening to these albums in vinyl and CD form for 30 years or so, I have a pretty good baseline. With the modified DI/O I hear the music with no distractions. When I'm done I'm not gritting my teeth. The same is true with a disk I have of Beethoven piano sonatas played by Rubinstein. Some of these pieces used to make my teeth chatter, but now the high end harshness is gone. I don't know if I attribute this to the LT op amps by themselves though. I first want to do more listening and then put the TL074 back in and see what happens.I bought the DI/O for $122 and I really wanted it to see what could be done with mods. It's a tremendous bargain for the price. It sounds head and shoulders better than the analog out on my DVD player, which uses drivers in the DAC chip - no op amps even! Talk about shrill sounding. I'm really glad to see the DAC board is a sub-board. I've been thinking of re-doing the power supply and analog sections totally, and just re-using the DAC board. The DAC's got differential outputs, so I'm thinking of going that way. I also want to try about twice the power supply capacitance that exists in the unit right now, bypassed. Who knows where it will end!
I also read a post from you where you state that anyone who doesn't worry about impedance matching at 3 mhz has never worked 80. Ain't that the truth. There are times when, based on what I read in the audio world, I wonder if the laws of physics and good circuit design principles apply. I won't get into another "75 ohm" SPDIF discussion again, people get too upset. Impedance matching = low return loss = signal integrity.
I'm also thinking about making a balanced digital connection between my DVD player and the ART. I'm using a Pioneer DV37 and it cost me close to a grand, so I'm not too keen about hacking it up. Don't know what I'm going to do yet. Maybe buy a cheap CDP with a good transport and use that as my vehicle.
Thanks. I like to compare the same way, removing the new item after a while and putting the original back. Not really convenient to do with parts, unless socketed. Will check a TL074B as well, since I have some. I'm thinking of leaving the TL074 in for a bit, and doing some of the caps first. I was in the mood, so I ordered filter caps from Digi-Key, most at least 50% larger in value than the originals and a little better quality (FC) + some NP for the analog I/O. I find good filtering of digital gear PS is noticeable, so we'll see how the DI/O responds. Also some metal film resistors just for the analog circuitry, though I'll save that for absolute last. I feel the same way about tweaking expensive gear, and that's why I'm going to town with the DI/O. So far, it seems hard to ruin it, but I haven't done much to the boards...A balanced analog output sounds interesting. I guess the DAC outputs require buffering? TIA
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