Yeah, the Zapfilter is pretty expensive. I'm going to pursue all other options before I seriously consider this one, although in the end it is possible I will do it. I want to know how far I can go first..
I found the difference between the LT1570 and the oem BB2604 quite startling so hopefully my experiences may not be all that different from cotdt's.
I found the difference between the LT1570 and the oem BB2604 quite startling so hopefully my experiences may not be all that different from cotdt's.
Member
Joined 2003
My Zhaolu 2.5 has arrived today! My opinions:
Electronically it is of excellent quality, hence all the praises, but the build quality is very poor. The unit was missing a connection from ground to chassis, which was the first thing I attached having read about this problem in a previous post. Many of the screws are a bit mangled, as if that have been screwed in using an electric drill. The faceplate looks very nice, but the corners are sharp so watch out, and the volume knob drags on the faceplate making a quite unpleasant sound when you turn it. It always defaults to coaxial input, so if you use optical, you have to select it every time you turn it on.
The included optical cable looks to be a fine ordinary cheap cable. The end caps are attached to the cable so you can't loose them. The coaxial cable is junky, and I'd be surprised if it were actually a 75Ohm cable. The ends were corroded on mine, and one end had a puncture wound.
I bought the cheap AD1852 version. It came with upgraded op-amps, and I surely wasn't expecting to have 3 OPA2604 op-amps included as well. They were not shipped in any sort of ESD safe container, they were just placed in the package for the optical cable which was made of regular plastic. I'm exited to do some side by side listening to see if I can tell the difference between this fancy DAC and my Number Cruncher which cost less than half the price.
Electronically it is of excellent quality, hence all the praises, but the build quality is very poor. The unit was missing a connection from ground to chassis, which was the first thing I attached having read about this problem in a previous post. Many of the screws are a bit mangled, as if that have been screwed in using an electric drill. The faceplate looks very nice, but the corners are sharp so watch out, and the volume knob drags on the faceplate making a quite unpleasant sound when you turn it. It always defaults to coaxial input, so if you use optical, you have to select it every time you turn it on.
The included optical cable looks to be a fine ordinary cheap cable. The end caps are attached to the cable so you can't loose them. The coaxial cable is junky, and I'd be surprised if it were actually a 75Ohm cable. The ends were corroded on mine, and one end had a puncture wound.
I bought the cheap AD1852 version. It came with upgraded op-amps, and I surely wasn't expecting to have 3 OPA2604 op-amps included as well. They were not shipped in any sort of ESD safe container, they were just placed in the package for the optical cable which was made of regular plastic. I'm exited to do some side by side listening to see if I can tell the difference between this fancy DAC and my Number Cruncher which cost less than half the price.
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Joined 2003
I took some images of the chassis problems. This is a screw that is under the backplate. I found it odd because there are two screws under the backplate, but the other has a neat notch cut out to accommodate the screw. This image also shows a mangled screw. There are many in this condition on the bottom side of the Zhaolu.
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Finally, this image shows the puncture wound in my included coax cable, as well as the corrosion on it. All these are not things I would expect to see in a new commercially made product. Then again, I think this may be the first thing I have imported from China. I must stress that none of these things affect the acoustic performance which is excellent. I have also found a good use for the included OPA2604 IC's. I replaced the very cheap JRC4580s in the headphone amp with them!
I am loving the sound of this DAC
I am loving the sound of this DAC
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LT1570?
LT1570 is that a valid part number? I couldn't find it on www.linear.com
I guess you mean OPA2604 for oem BB2604.
kevinkr said:Yeah, the Zapfilter is pretty expensive. I'm going to pursue all other options before I seriously consider this one, although in the end it is possible I will do it. I want to know how far I can go first..
I found the difference between the LT1570 and the oem BB2604 quite startling so hopefully my experiences may not be all that different from cotdt's.
LT1570 is that a valid part number? I couldn't find it on www.linear.com
I guess you mean OPA2604 for oem BB2604.
Hi QSerraTico_Tico, I think it's the LT1057.
Hi DcibeL,
I've also received the D2.5 with the AD1852 chip. The
headphone volume knob on mine seems OK, though
I haven't actually used the headphone out. I'll be
trying it out later with some Grados and AKGs.
None of the screws on the outside on mine is mangled like
that one in your pic. I haven't opened mine up to see
what it's like inside.
Can you point to where you put the chassis to ground
connection?
My cheapie coax has corroded connectors like yours
though I didn't spot any punctures. I too was suprised
to see opamps floating in the optical cable packaging.
(Actually I'm surprised to see cables since I had not
heard they were included.)
Did yours come with an owner's manual? Mine didn't.
The D2.5 locked onto my Marantz CD52 but not my CD63.
I don't use a DAC normally so I might be doing something
funny here...
Cheers,
Dennis
Hi DcibeL,
I've also received the D2.5 with the AD1852 chip. The
headphone volume knob on mine seems OK, though
I haven't actually used the headphone out. I'll be
trying it out later with some Grados and AKGs.
None of the screws on the outside on mine is mangled like
that one in your pic. I haven't opened mine up to see
what it's like inside.
Can you point to where you put the chassis to ground
connection?
My cheapie coax has corroded connectors like yours
though I didn't spot any punctures. I too was suprised
to see opamps floating in the optical cable packaging.
(Actually I'm surprised to see cables since I had not
heard they were included.)
Did yours come with an owner's manual? Mine didn't.
The D2.5 locked onto my Marantz CD52 but not my CD63.
I don't use a DAC normally so I might be doing something
funny here...
Cheers,
Dennis
No mangled screws or dragging volume control knob on mine either..
Still using the LT1057 op-amps. I did try the Burr Brown 2134A I got a few days ago, and have to say that they aren't audio nirvana. Very smooth and laid back - much of the dimensionality and snap of my dac was lost. LT1057 went right back in..
Still using the LT1057 op-amps. I did try the Burr Brown 2134A I got a few days ago, and have to say that they aren't audio nirvana. Very smooth and laid back - much of the dimensionality and snap of my dac was lost. LT1057 went right back in..
Member
Joined 2003
Adding ground connection was actually very easy to do. I tucked the wire under a standoff that holds up the AC input board (RF filter?). Just loosen the screws, wrap the wire around the screw, and tighten them back up.Dennis Hui said:
The dragging volume knob is no problem, I just pulled the knob off and sanded the bottom a bit.kevinkr said:
I'll have to investigate the aforementioned grounding issue - I haven't removed the shield covering the ac power circuitry so I have not seen an unconnected ground wire.
I received the owner's manual with mine, but it is in Chinese and there is almost nothing useful to be learned from it.
I wasn't expecting the cables that came with the dac, mine are just fine - no corrosion of the spdif coax. I was surprised that the 2604 op amps were tossed in with the optical cable. OTOH I think they sound mediocre at best and won't be using them. AFAIK they aren't particularly static sensitive.
The real disappointment was in the substitution of the 2134A's in the analog output section - it was almost as if a veil descended over the sound. It was really lacking in HF detail and energy, sounded literally like the top octave was gone.. The mids were butter smooth, and the bass muddy. It was polite and uninvolving, sort of like a really bad tube pre-amp. (Don't flame me, my system is all tube.) Despite negative comments about the BB jfet op amps on other threads I really expected better. The electrical specs of this op amp
left me believing it would sound much better than it did. I like the sound quality achieved with the "upgrade" to LT1057 but hope for some further improvement with the LM4562. As it stands I could live quite comfortably with the Zhaolu 2.5A - it makes my reference dac, a PS Audio Ultralink II sound broken by comparison.
My employer unfortunately folded this week so any plans to explore the Zapfilter are now on hold..
I received the owner's manual with mine, but it is in Chinese and there is almost nothing useful to be learned from it.
I wasn't expecting the cables that came with the dac, mine are just fine - no corrosion of the spdif coax. I was surprised that the 2604 op amps were tossed in with the optical cable. OTOH I think they sound mediocre at best and won't be using them. AFAIK they aren't particularly static sensitive.
The real disappointment was in the substitution of the 2134A's in the analog output section - it was almost as if a veil descended over the sound. It was really lacking in HF detail and energy, sounded literally like the top octave was gone.. The mids were butter smooth, and the bass muddy. It was polite and uninvolving, sort of like a really bad tube pre-amp. (Don't flame me, my system is all tube.) Despite negative comments about the BB jfet op amps on other threads I really expected better. The electrical specs of this op amp
left me believing it would sound much better than it did. I like the sound quality achieved with the "upgrade" to LT1057 but hope for some further improvement with the LM4562. As it stands I could live quite comfortably with the Zhaolu 2.5A - it makes my reference dac, a PS Audio Ultralink II sound broken by comparison.
My employer unfortunately folded this week so any plans to explore the Zapfilter are now on hold..
Member
Joined 2003
I am also surprised that the OPA2134's did not sound good. I have used the OPA2134 and OPA2132's in other gear and thought they were just great. Maybe it's just all that old-fashioned tube gear muddying the sound 
. Flame on! 
hehe.
After listening to a lot today, my system has never sounded better. It's like I have a new stereo and have to listen to all my old albums again. I don't know if I will ever replace the LT1057's with something else. I can't imaging how this could possibly sound better, but I'll probably buy a couple LM4562's and try them just because they are all the rage these days...
Sorry to hear about your loss of a job.
. Flame on! hehe.After listening to a lot today, my system has never sounded better. It's like I have a new stereo and have to listen to all my old albums again. I don't know if I will ever replace the LT1057's with something else. I can't imaging how this could possibly sound better, but I'll probably buy a couple LM4562's and try them just because they are all the rage these days...
Sorry to hear about your loss of a job.
With all due respect, I don't see how anyone could find the LT1057 sounding good. I listen mostly with headphones where small differences in sound can be perceived easier and to me the LT1057 sounded muddy, with no high frequencies at all and bloated bass. Even the OPA2604 sounded a lot better in comparison. And as for chips like the OPA2107, OPA627 and LM4562, they are so much better it isn't funny. I guess on a mediocre speaker system where resolution isn't important the LT1057 might not sound that horrible.
Oh, and happy new year!
Oh, and happy new year!
I guess we are probably listening for different things. I'm not a headphone listener, and my choices are dictated by other interactions with system components and my room. Also no two people upon hearing the same thing are likely to react exactly the same way. Perhaps your nirvana is different than mine. I'm still awaiting the arrival of the LM4562, and hopefully those will address some of the concerns I do have with the LT1057.
Apparently the guys who sell this dac also think the LT1057 sounds better than the stock 2604s that Zhaolu installs in this dac.
Funny your observations through the headphone outputs are the exact oposite of mine. I thought the 2604 sounded muddy, boring and uninvolving, however despite slightly preferring it I also thought the 1057 sounded hard, flat, and clinical, however I don't listen to headphones for serious music listening. Through the analog outputs my impressions were somewhat different.
I have a pair of homebrew Onken speaker cabs with Iconic 165-8G woofers, JBL 4333 Alnico midrange horns with diffusers, and 2402H annular ring horn tweeters so I guess compared to some high end systems these might qualify as cheap and mediocre... Electronics are all tube, and mostly dht based (26 line stage and 300B power amp) System has dedicated analog, digital, and auxiliary branch circuits for ac power. Digital music is from my media server and is all flac encoded. (Details in another thread.) I listen to a fair amount of analog as well.
Through the analog outputs I found the 1057 to be the most extended at the extremes, much faster and the airiest of the current choices available and not muddy at all. Perhaps a bit hard sounding, a little excessive bass emphasis and somewhat 2 dimensional overall. However both the 2604 and 2134 sounded very soft and rolled off in my system, none of the specific attributes I like about this dac being well served by these choices. Bass control on the bottom end was lacking with both the BB choices, and more bottom end extension was missing with the 2604. Not just my impression either, I've had several people over to listen to this dac.
Some people like the BB sound and some apparently don't - I guess I fall into that category, but I'm not deaf either. The LT1057 is simply the least offensive choice I have for the moment.
I haven't tried the 2107, but based on its specs I would not expect it to trounce the 2134A, and should have the BB house sound in any case which I apparently don't like much. (to my admitted surprise)
The AD627 are excellent (for an op amp) from prior experience, but this will have to wait for the acquisition of brown dog adaptors and the chips - I've had the dac for less than 2 weeks..
Personally I think all op amps s*ck and I would seriously consider the Zapfilter, but that will have to wait a bit.
Epicurean which version of the Zhaolu dac are you listening to?
Edit: content
Apparently the guys who sell this dac also think the LT1057 sounds better than the stock 2604s that Zhaolu installs in this dac.
Funny your observations through the headphone outputs are the exact oposite of mine. I thought the 2604 sounded muddy, boring and uninvolving, however despite slightly preferring it I also thought the 1057 sounded hard, flat, and clinical, however I don't listen to headphones for serious music listening. Through the analog outputs my impressions were somewhat different.
I have a pair of homebrew Onken speaker cabs with Iconic 165-8G woofers, JBL 4333 Alnico midrange horns with diffusers, and 2402H annular ring horn tweeters so I guess compared to some high end systems these might qualify as cheap and mediocre...
Electronics are all tube, and mostly dht based (26 line stage and 300B power amp) System has dedicated analog, digital, and auxiliary branch circuits for ac power. Digital music is from my media server and is all flac encoded. (Details in another thread.) I listen to a fair amount of analog as well.Through the analog outputs I found the 1057 to be the most extended at the extremes, much faster and the airiest of the current choices available and not muddy at all. Perhaps a bit hard sounding, a little excessive bass emphasis and somewhat 2 dimensional overall. However both the 2604 and 2134 sounded very soft and rolled off in my system, none of the specific attributes I like about this dac being well served by these choices. Bass control on the bottom end was lacking with both the BB choices, and more bottom end extension was missing with the 2604. Not just my impression either, I've had several people over to listen to this dac.
Some people like the BB sound and some apparently don't - I guess I fall into that category, but I'm not deaf either. The LT1057 is simply the least offensive choice I have for the moment.
I haven't tried the 2107, but based on its specs I would not expect it to trounce the 2134A, and should have the BB house sound in any case which I apparently don't like much. (to my admitted surprise)
The AD627 are excellent (for an op amp) from prior experience, but this will have to wait for the acquisition of brown dog adaptors and the chips - I've had the dac for less than 2 weeks..
Personally I think all op amps s*ck and I would seriously consider the Zapfilter, but that will have to wait a bit.
Epicurean which version of the Zhaolu dac are you listening to?
Edit: content
Looking at the specification for the LT1057 I don't see anything offhand that would make it particularly bad for audio applications, true it is a bit noisy at 13nVrtHz, but given the signal levels this is reasonable.
Slew rate, bandwidth and loop gain are all within reasonable values for audio use.
Call me confused, I don't think it sounds that bad??
The LM4562 specs a lot better, so I'll soon know how much, if any of that improvement is actually audible.
Obviously there is no ideal op-amp, the fact that they sound audibly different indicates that there are significant deficits from ideal performance. Since such is obviously the case consideration needs to be given to how these deficits might complement other components in a given associated circuit or even components within a hifi system.
Slew rate, bandwidth and loop gain are all within reasonable values for audio use.
Call me confused, I don't think it sounds that bad??
The LM4562 specs a lot better, so I'll soon know how much, if any of that improvement is actually audible.
Obviously there is no ideal op-amp, the fact that they sound audibly different indicates that there are significant deficits from ideal performance. Since such is obviously the case consideration needs to be given to how these deficits might complement other components in a given associated circuit or even components within a hifi system.
I've heard the LM4562, and it doesn't remotely hold a candle against the Zapfilter in the Zhaolu 2.5A application. I've also found that with either the LM4562 or the Zapfilter, the AD chip sounds better than the CS chip. The AD chip just needs some burn-in time and good opamps (or a discrete). Why do people pay extra money for the CS version when it's a significant downgrade?
Spartacus said:
Are you asking me? I completely agree with these guys, who say it better than I can:
http://www.head-fi.org/forums/showthread.php?t=215759
I notice that the better the opamp (or discrete circuit) you use, the better the AD is in comparison with the CS. It seems as if the CS was designed to overcome the shortcomings of the typical opamp, by overemphasizing the upper midrange and other such things, overall a more forward presentation. But the AD is more neutral and has better resolution, better frequency extremes, and has more bass impact. The AD also has lower noise floor, a more "analogue" sound, better transparency, wider soundstage, and is smoother-sounding.The CS is a couple dB louder than the AD, so it's hard to compare directly though.
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