BobM said:
Hi Bob,
Always good to hear a confirmation. I'm still happy with the mods after listening for more than 5 hrs yesterday - the latest definitely addressed the issue I was trying to solve. I found improvements across the board, deep bass sounds much tighter and more dynamic, the mids are open and detailed, and the highs smoother, more extended and cleaner. As I said in an earlier post the sound is just more integrated overall as well, it sounds tonally balanced. Sound is warm without being euphonic, and there is lots more low level detail.
One area where performance while better, still leaves something to be desired is on actual 24 bit 96kHz material. I believe the Benchmark handled that better overall. Fortunately I don't have much music recorded at this native resolution. I am going to look for other potential causes for this issue in the digital board.
I played a little more with the op-amps and can say that I think the changes work better with the LM4562 over the OPA2107. The 2107 is now lacking detail on the top end that the 4562 brings out. I thought the 4562 was too "tingy" on the top before, but now it definitely sounds more balanced overall.
Thanks again. I'm liking what I'm hearing also, but need to put in more time overall to make any final judgements.
Bob
Thanks again. I'm liking what I'm hearing also, but need to put in more time overall to make any final judgements.
Bob
Does anyone have an older model?
I picked up a 1.3 recently and it already has a couple of mods but I find the output level a bit too high.
It doesn't clip but it causes my tube-pre to clip so I have to play with volumes...I would like it to be a couple dB lower.
Also, am I the only one who finds it strange that it has two DACs on board?
I just found the jumper today and switched from the CS8414 to the AD1852...I think I like the AD chip better so far...only played Norah Jones though.
Here is a pic of my DAC's innards:
You can see the OPA627s...what should I upgrade the 2604s to?
I picked up a 1.3 recently and it already has a couple of mods but I find the output level a bit too high.
It doesn't clip but it causes my tube-pre to clip so I have to play with volumes...I would like it to be a couple dB lower.
Also, am I the only one who finds it strange that it has two DACs on board?
I just found the jumper today and switched from the CS8414 to the AD1852...I think I like the AD chip better so far...only played Norah Jones though.
Here is a pic of my DAC's innards:
You can see the OPA627s...what should I upgrade the 2604s to?
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Interesting dac... I don't have any information on this early model, but I can tell it has an added clock module and a lot of other changes.
The CS8414 is actually the spdif receiver IC, and the AD1852 is the dac - unless you have something like the CS4397/98 I would assume this unit has a single dac.
Which jumper did you change, you might have changed something else or do you actually have two separate dac boards?
The gain probably can be lowered, but without seeing an actual schematic it is hard to tell you what to do.
The CS8414 is actually the spdif receiver IC, and the AD1852 is the dac - unless you have something like the CS4397/98 I would assume this unit has a single dac.
Which jumper did you change, you might have changed something else or do you actually have two separate dac boards?
The gain probably can be lowered, but without seeing an actual schematic it is hard to tell you what to do.
Member
Joined 2003
Order is in for parts to upgrade the Zhaolu 2.5A DAC. I needed to order some more parts to make my Digikey order large enough to not have a handling fee, so I will be replacing all the electrolytic caps in the power supply with better ones, and of proper voltage rating for the ones that were too close for comfort.
billnchristy said:
Do you use this dac with a pc or just a cd player or transport? I'm assuming for use with a cd based source you might want the 48/96K setting. I assume this is messing with the sample clock FS. See what sounds best I guess.. I have no idea what they (or you) are doing..
Is the jumper on the tcxo board or the dac board - I couldn't find it based on the information provided.
billnchristy said:I have no idea what I am doing either...at least we are on the same page.
It is on the DAC board. Look at the bottom Op-amp...pass the resistors to its right...see that purple cap? Right next to it is a 2 pin jumper set.
Thats the one.
I guess the best thing to do is set it to whatever sounds best with the source hardware you are using. I'm assuming 96kHz is probably fast enough. I've noticed that 24/96 reproduction in my 2.5A is just ok - it seems that the dac really performs much better at the lower sample rates.
Hi Thomas,
I delighted to hear that it worked as well for you as it did for me. The really unfortunate thing about all of this is the engineers at Zhaolu could have and should have done all this work - there was so much potential that could have been unlocked right from the get go and for no really significant increase in cost.
This would have pushed it from: "Zhaolu - a good value DAC" to "Zhaolu - an unbelievably good sounding DAC." Sad really...
I delighted to hear that it worked as well for you as it did for me. The really unfortunate thing about all of this is the engineers at Zhaolu could have and should have done all this work - there was so much potential that could have been unlocked right from the get go and for no really significant increase in cost.
This would have pushed it from: "Zhaolu - a good value DAC" to "Zhaolu - an unbelievably good sounding DAC." Sad really...
Servo
I spent several hours implementing the servo shown in post #302 and I would recommend that you NOT use this circuit.
While it worked exactly as predicted on the bench and the output offset settled to less than 1mV after a couple of minutes, in actual use bursts of distortion started to occur on musical crescendos that were not previously present.
I suspect because of the physical size of the film caps used and some lead lengths required by this mod that the integrator was not really stable.. It was an extremely kluggy implementation and the LM4562 might not be the best low frequency integrator due to stability considerations.
Funny that it took over an hour to implement the mod and just a few minutes to remove it..
The servo was definitely the source of distortion - as I listen to it now it's back to being clean.
This is probably the end of the line for me and the Zhaolu.. I've ordered a pair of COD pcbs, an IVY pcb, and an assembled and tested spdif module based on the Wolfson WM8804 from Twisted Pear.
The Zhaolu will continue serving in my system until the Twisted Pear stuff is tweaked enough to surpass its performance. In the mean time it sounds very good and I will probably reapply it somewhere else.
I spent several hours implementing the servo shown in post #302 and I would recommend that you NOT use this circuit.
While it worked exactly as predicted on the bench and the output offset settled to less than 1mV after a couple of minutes, in actual use bursts of distortion started to occur on musical crescendos that were not previously present.
I suspect because of the physical size of the film caps used and some lead lengths required by this mod that the integrator was not really stable.. It was an extremely kluggy implementation and the LM4562 might not be the best low frequency integrator due to stability considerations.
Funny that it took over an hour to implement the mod and just a few minutes to remove it..
The servo was definitely the source of distortion - as I listen to it now it's back to being clean.
This is probably the end of the line for me and the Zhaolu.. I've ordered a pair of COD pcbs, an IVY pcb, and an assembled and tested spdif module based on the Wolfson WM8804 from Twisted Pear.
The Zhaolu will continue serving in my system until the Twisted Pear stuff is tweaked enough to surpass its performance. In the mean time it sounds very good and I will probably reapply it somewhere else.
Member
Joined 2003
If they were BYV28 as marked on the PCB then they would be good diodes, but the diodes themselves clearly say BY228 on them, which is a slow high voltage diode. I'm replacing them with MUR210.BobM said:
My parts arrived today (haven't picked them up yet), so I'll be modifying over the weekend. Wish me luck.
Member
Joined 2003
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