Originally Posted by HiFlight /img/forum/go_quote.gif Yes, I have tried it and it works OK, but IMO there are better choices for the DAC, such as the AD8656, LT6234, LMH6643. All are more lifelike with better imaging.
Originally Posted by souperman /img/forum/go_quote.gif What's the sound signature of the AD746?
It is the dual version of the AD744 as used in the LaRocco amps. Detailed with superb soundstage and imaging. Very neutral. Nothing is overemphasised. The datasheet specs do not reflect the sound quality of this opamp. The noise specs are higher than most others I have used, but this is not at all apparent in actual use. I do not find it boring in the least.
Many have as me what method I use to evaluate the performance of various opamps in the D1. Not a big secret, here it is....
I use about 4 different very high-quality CDs that are played thru the optical out of my CD player to the optical in of the D1. That way, all of the opamps in the D1 are able to be evaluated as a set, so to speak, rather than just focusing on the DAC or amp sections by themselves.
I try to select cuts with various intrumentations, especially with lots of transients, such as snares, cymbals, etc. I also use at least several cuts that include female vocalists and applause. I always use at least one cut that has a male vocalist to see if there is unnatural coloration in the higher bass registers.
Applause is one of the best sources to get a sense of image and the realism of an actual performance. The volume is set to approximate what I would hear if the performance was attended in person at the distance away that I usually try to sit.
Some opamps seem to work better together than others, that is why I try to evaluate the opamp package as an entity rather than focus on individual opamp characteristics.
It is useless to try to make meaningful evaluations if using a mediocre sources; for that reason, I always try to use the best player, CDs and cables I have available.
When I find a combo that sounds like it has potential for better performance in the D1, I then compare it to my Earmax Pro, Dared MP-5 (both tube) and Xin Reference amps. If it stand up well in these comparisons, I then post the results with my comments as a possible choice for the D1.
There have been MANY opamps and combinations of opamps that I have tried that did not meet these criteria so I have not mentioned them on the forum.
How difficult is this really? I have a pretty good selection of tools in my home shop - bench drlll press, good soldering gear (Weller temperature controlled iron), Optivisor for close in work, some Dremel stuff for smaller work etc. and some experience putting together laboratory instrumentation and building DIY audio kits from the past like the Dynaco stuff that was sold 25 years ago. My electrical engineering is a little fuzzy - it has been a long time since I studied this theory.
My plan would be to drill out the through holes for the existing caps described in these threads and then replace them with the Black Gates that people have had success with in this thread.
Originally Posted by ehlarson /img/forum/go_quote.gif How difficult is this really? I have a pretty good selection of tools in my home shop - bench drlll press, good soldering gear (Weller temperature controlled iron), Optivisor for close in work, some Dremel stuff for smaller work etc. and some experience putting together laboratory instrumentation and building DIY audio kits from the past like the Dynaco stuff that was sold 25 years ago. My electrical engineering is a little fuzzy - it has been a long time since I studied this theory.
My plan would be to drill out the through holes for the existing caps described in these threads and then replace them with the Black Gates that people have had success with in this thread.
Any thoughts?
This would destroy any 'through hole plating' of the mounting hole and could cause real problems.
Maybe I missed the post, but I don't seem to be able to find whether there is a big difference between using USB and optical for the D1. I'm currently using it through USB, and I'm thinking about connecting it through optical out of the Micro.
Also, I lost the adapter of my TBAAM from mini to optical. Would something like this work too? I think this is the same thing.
Originally Posted by xnothingpoetic /img/forum/go_quote.gif Please don't drill it.
Why not just desolder the caps?
Yes, the caps are desoldered, but because of the very hard solder used in the D1, it is nearly impossible to remove the residue remaining in the holes by using wick, etc. The high temperatures involved will certainly damage the traces. Use of a proper circuitboard drill works very well. I used an appropriately-sized circuitboard bit mounted in a handheld chuck that resembles a mini-screwdriver and the residue carefully drilled out by finger-power. I have experienced no damage whatever to any of the plated holes.
It is probably worth mentioning that I have done this type of operation hundreds of times, not always successfully!
I would suggest practicing on a scrap circuit board that one can pick up from most any TV or computer repair service until the necessary skill and confidence level has been reached; only then will you want to apply your skills to the D1.
A good temperature-controlled iron is a necessity, as is the use of a very high-quality solder. My iron tip is a pencil tip with one flat side.
I personally use Kester silver solder .020 in diameter. You need a spot of solder on your iron about the size of a pinhead to safely solder one SOIC leg. Any larger and it is likely that 2 legs will be shorted together by a solder bridge.
Originally Posted by HiFlight /img/forum/go_quote.gif It is the dual version of the AD744 as used in the LaRocco amps. Detailed with superb soundstage and imaging. Very neutral. Nothing is overemphasised. The datasheet specs do not reflect the sound quality of this opamp. The noise specs are higher than most others I have used, but this is not at all apparent in actual use. I do not find it boring in the least.
AD744/46 for sure are noisy, but it's only apparent with IEM's or other extremely sensitive phones. They're the noisiest opamps I've heard. LISAIII and PRII are known to be noisy amps when used with IEM's.
Use AD746 constantly for a couple of weeks and then tell me it's not boring. The first days I used it, I found it to be the perfect opamp, but then...
Originally Posted by souperman /img/forum/go_quote.gif Maybe I missed the post, but I don't seem to be able to find whether there is a big difference between using USB and optical for the D1. I'm currently using it through USB, and I'm thinking about connecting it through optical out of the Micro.
Also, I lost the adapter of my TBAAM from mini to optical. Would something like this work too? I think this is the same thing.
As both USB and optical are digital signals, I hear no difference between the 2 when inputting to the D1. If you are using the TB, you can either feed an analog or digital signal to the D1, but the USB directly out of your PC to the D1 is a higher quality signal than that processed by the TB even via the optical. The TB is not an audiophile-quality DAC.
I would suggest just going straight to the D1 USB input via one of your computer USB ports and avoid going thru an extra unnecessary device, unless you are using the TB equalizer software.
If your cable is toslink-toslink, the adapter shown in your link above will work. The D1 input is toslink. The output of the TB, most CD players, and the iriver H120/140 is mini.
Originally Posted by NelsonVandal /img/forum/go_quote.gif AD744/46 for sure are noisy, but it's only apparent with IEM's or other extremely sensitive phones. They're the noisiest opamps I've heard. LISAIII and PRII are known to be noisy amps when used with IEM's.
Use AD746 constantly for a couple of weeks and then tell me it's not boring. The first days I used it, I found it to be the perfect opamp, but then...
I have used the AD744 both bypassed for Class-A output or without bypassing for a couple of years using my circumaural as well as my Westone and ER IEMs. I never experienced hiss or audible noise problems with any of these configurations. Datasheet specs do not always relate to audible performance. Much also depends on other circuit design factors as well as the opamps when considering hiss or noise issues.
Even after this period of time spend with the AD744/746, I personally do not find it boring. YMMV!
If one places noise specifications above all else, the LT6234, ADA4841-2 and AD8599 are all extremely low-noise, with input noise densities less than 2 nV/SqRt/HZ. That in itself does not, however, automatically make them the best choice for overall audio performance. Good, yes, absolute best..no.
Originally Posted by HiFlight /img/forum/go_quote.gif
I would suggest practicing on a scrap circuit board that one can pick up from most any TV or computer repair service until the necessary skill and confidence level has been reached; only then will you want to apply your skills to the D1.
Good idea about practicing with a scrap board. I have a box of old PC cards from my computer upgrades and builds that will be just the thing.
As far as SOIC soldering I find application of a wick to the tops of the legs results in a good looking joint with no possibility of bridges.
I've been generally using a 0.020 Kester lead/tin eutectic. I can see though the lower melting point of the silver fomulations would be very good for this kind of work. I will have to get some.
Hello, I listen to a lot of classical music and would like to know if the D1 adds any static or hiss to the recording when using a sensitive IEM. Does anyone use the D1 with the E500 and classical music? When you plug in the IEM without a source connected, is there any audible hiss?
I don't think the D1 has a low gain option, and the default gain is 6dB, so I am worried it will cause a lot of static.
Originally Posted by HiFlight /img/forum/go_quote.gif As both USB and optical are digital signals, I hear no difference between the 2 when inputting to the D1. If you are using the TB, you can either feed an analog or digital signal to the D1, but the USB directly out of your PC to the D1 is a higher quality signal than that processed by the TB even via the optical. The TB is not an audiophile-quality DAC.
I would suggest just going straight to the D1 USB input via one of your computer USB ports and avoid going thru an extra unnecessary device, unless you are using the TB equalizer software.
If your cable is toslink-toslink, the adapter shown in your link above will work. The D1 input is toslink. The output of the TB, most CD players, and the iriver H120/140 is mini.
(trying to post from cell, sorry if the error causes a duplicate post)
I've posted many of these before as test music, but not listed all in the same place.
I MOST like Arne Domnerus "Jazz at the Pawnshop" for the great recording mastering, applause and small live venue with clinking dishes and talkers, with accoustic instruments lke drums bass piano vibraphone sax clarinet - all of which if the source, amp and phones do their job will help you "be there" in the moment.
I also use Tord Gustavsen "Being There" for the drum solo in "Karmosin" and more piano/string bass elsewhere.
I listen to The Rippingtons "20th Anniversary" to get a feel for bass impact and quickness of response to snappy music.
Dianna Krall "Girl in the Other Room" for female voice and piano in a small venue or intimate studio, and "Live in Paris" for a Female vocal in large venue with ambience.
Jack Johnson "In Between Dreams" for male vocals and acoustic guitar.
"Lord of the Rings Return of the King" soundtrack for classical with good bass (sometime's Sibellius Kullervo) and occ Christopher Hogwood condcting Handel's Messiah for soundstage and presence in a large venue (with poor bass).
Picking Rock is harder, and I'll usually test with U2 "Achtung Baby", Boys Like Girls "The Great Escape, and Good Charlotte "Good Morning Revival", and Dave Matthews & Tim Reynolds "Live at Radio City".
Larry
Quote:
Originally Posted by HiFlight /img/forum/go_quote.gif Many have as me what method I use to evaluate the performance of various opamps in the D1. Not a big secret, here it is....
I use about 4 different very high-quality CDs that are played thru the optical out of my CD player to the optical in of the D1. That way, all of the opamps in the D1 are able to be evaluated as a set, so to speak, rather than just focusing on the DAC or amp sections by themselves.
I try to select cuts with various intrumentations, especially with lots of transients, such as snares, cymbals, etc. I also use at least several cuts that include female vocalists and applause. I always use at least one cut that has a male vocalist to see if there is unnatural coloration in the higher bass registers.
Applause is one of the best sources to get a sense of image and the realism of an actual performance. The volume is set to approximate what I would hear if the performance was attended in person at the distance away that I usually try to sit.
Some opamps seem to work better together than others, that is why I try to evaluate the opamp package as an entity rather than focus on individual opamp characteristics.
It is useless to try to make meaningful evaluations if using a mediocre sources; for that reason, I always try to use the best player, CDs and cables I have available.
When I find a combo that sounds like it has potential for better performance in the D1, I then compare it to my Earmax Pro, Dared MP-5 (both tube) and Xin Reference amps. If it stand up well in these comparisons, I then post the results with my comments as a possible choice for the D1.
There have been MANY opamps and combinations of opamps that I have tried that did not meet these criteria so I have not mentioned them on the forum.
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