[deuginthesky]

I have measured that the resistors at least on the analogn board are actually sometimes more than 1% tolerant.
Is there any better to do with some types of resistors ?

Would carbon resistors sound better (Read that elsewhere) ?

 

[SonicDawg]

Man, I have been thinking about making the final upgrade to my source lately. Can someone give me an idea the comparison between the zapfiltered Zhaolu and the LM4652s opamped Zhaolu? I really love the LM4652s, and I think it's improved the stock sound by quite a degree. From the general impressions I get with the Zapfilter, the main improvements come from dynamics, soundstage and the general tonal timbre. But how exactly is the result comparable to the 4652s? I also really like the idea of opamp rolling for different sound flavor. Would I be missing too much when I opt for zapfilter?

 

[Zenja]

I haven't listened to the LM opamps, but I had OPA627s on browndogs in mine. I really did notice a big improvement going to the zapfilter, but that must be at least partially due to no longer using the built-in amp (and maybe rewiring the headphones).

I should also point out, in case some people are interested, that the latest zapfilters (like the one I got) are slightly different than the older ones that people have posted in this thread. The PCB is blue and seems nicer, the transformer is now a different Amveco one (this caused me some delays trying to figure out which wires hook up where on the zapfilter now since the coloring is different than the old transformer's), and the ribbon cable between the power section and the zapfilter board is different too. Those are just the differences I noticed right away, I didn't take a closer look to find more.

 

[SonicDawg]

Can you be a bit more specific with the terms of improvement? I know that the OPA627s are known for having a big, warm and musical sound. How has the zapfilter improved upon the sound?

 

[Zenja]

Quote:

Originally Posted by SonicDawg /img/forum/go_quote.gif Can you be a bit more specific with the terms of improvement? I know that the OPA627s are known for having a big, warm and musical sound. How has the zapfilter improved upon the sound?

I've never before tried to describe sound, and like I said, I don't know what can be attributed directly to the zapfilter, but I'll try. The bass definitely seemed to improve, going deeper and feeling more solid and accurate. It keeps up with fast bass beats really well too, always sounding proper rather than generic. The sound cleaned up and got smoother at all frequencies. The thing that struck me the most is how more resolving and dynamic it is now. I had fast, complex music before (like Slayer - Reign In Blood) that seemed kind of crappy quality, but now I would have to say that that album is actually really good quality. It sounds much better and everything is clean and separated, not harsh, muddy, and smearing together. On the other hand, slow, quiet music has better ambiance, making it seem more real and improving soundstage. Cymbals definitely seem more real, crisp and separated too.

I don't guarantee that this stuff isn't placebo, but this is really the first time in audio (other than switching headphones) that I've noticed a difference that I can say really seems to be there.

 

[SonicDawg]

Seems like you have the D2 version. Does the chasis provide enough room for everything to be installed properly?

 

[Zenja]

Quote:

Originally Posted by SonicDawg /img/forum/go_quote.gif Seems like you have the D2 version. Does the chasis provide enough room for everything to be installed properly?

Once the headphone amp is taken out, then it's an easy fit. The tightest was to lay the transformer and power board side by side to the right of the power switch, but there's still enough room to do it. One issue I had was the chassis feet being in the way of where screws are supposed to go. You'd have to drill the holes for the feet elsewhere and move them (and change the screws used and add a nut to the other end). I didn't want to do more drilling at the end so all I did for now was move one of the feet to one of the bolts which the stock transformer is bolted down with, and removed the other foot entirely. This leaves me with just one foot at the front in the middle but it's an easy solution. Also, the metal sticks up a bit where the old feet used to be, and I had to place the new transformer on top of that. It's not a big deal but it would be better to first grind that down to be flat so the transformer rests on a flat surface. This way it's still relatively flat and secure though because the bottom of the transformer is a soft, foamy surface.

 

[SonicDawg]

My, I am really sold on this one, as it might be the last thing I will do for my source upgrade. I might call them up tomorrow for availability. Wish me luck

 

[Zenja]

Quote:

Originally Posted by SonicDawg /img/forum/go_quote.gif My, I am really sold on this one, as it might be the last thing I will do for my source upgrade. I might call them up tomorrow for availability. Wish me luck

Good luck. I hope my impressions don't result in disappointment for you. At least you shouldn't have to do anything more DAC-related after this.

 

[SonicDawg]

One more question: did you follow the guide provided here in installing the zappy? Was there anything particularly difficult for, say, a soldering novice( I have done some basic soldering before, in fact, I modded my K340s myself)? Also, you mentioned that they have new circuit boards now, how does that affect the installation process?

 

[Zenja]

Quote:

Originally Posted by SonicDawg /img/forum/go_quote.gif One more question: did you follow the guide provided here in installing the zappy? Was there anything particularly difficult for, say, a soldering novice( I have done some basic soldering before, in fact, I modded my K340s myself)? Also, you mentioned that they have new circuit boards now, how does that affect the installation process?

I definitely skimmed parts of this thread for stuff like pictures and instructions on some specific things, but I didn't really see a step-by-step guide or anything to follow. I just mostly went off the few pictures posted and a couple of diagrams. The new boards won't affect installation (except which direction the ribbon cable exits on but this doesn't matter). The different transformer affects installation in that you have to know what color wire to put where. Frankly I'm not sure if I connected the wires to the right places exactly but it works.

The scariest part is obviously soldering to those 4 SMD resistors but I actually thought this was pretty easy. It was quick and trouble-free. The most annoying part for me was to solder the power wire from the zapfilter power board to the IEC power socket. I'm not sure why I had so much trouble with that, but I did. I also melted the plastic around one of the pins in the process so one of the power pins is now a little loose. I'm also fairly new to soldering, having only done a couple of interconnects before mostly, but it's not hard stuff as long as you know the theory behind it.

 

[SonicDawg]

Quote:

Originally Posted by Zenja /img/forum/go_quote.gif The different transformer affects installation in that you have to know what color wire to put where. Frankly I'm not sure if I connected the wires to the right places exactly but it works.

This is pretty reassuring

... Is there anyway to know exactly what color wires to go with what?

 

[Zenja]

Quote:

Originally Posted by SonicDawg /img/forum/go_quote.gif This is pretty reassuring ... Is there anyway to know exactly what color wires to go with what?

You could ask some people that know more here

I didn't just guess with the wiring either though, heh. I'm pretty sure I did it right.

What I did was google the number that's written on the transformer to find Amveco's page for the transformer. They have a diagram with the colors there. That'll tell you which ones are primary and secondary, and which ones are paired with which. I'm guessing that that's all you really need to know, and that the exact order of the wires isn't important. If I still had the online diagram for the transformer, I'd tell you what I did. Basically, the two + wires on the primary go on one outer pin on the power board and the other two go to the other outer pin (so pins 1 and 4 on the primary connector). The secondaries are paired up, so there'll be a +, -, +, -. The + and - pairs go next to each other on the secondary connector (pin 1 and 2, then pin 3 and 4 for the other + - pair). I'm pretty sure this is right but I'm not entirely sure if the order of the pairings matters (when connecting to the power board). That is, I'm pretty sure that knowing which wires are paired up is important (there's two two separate secondary windings, so two pairs of wires), but I don't know if it matters whether one pair is connected to pin 1 and 2, or to pin 3 and 4.

 

[SonicDawg]

Thanks a lot for all the info. I will call them tomorrow. Hopefully they will have some in stock finally.

 

[Rakukojin]

I just changed the op-amps on my Zhaolu D2C but now it won't start up. I think maybe I put one in wrong or something and fried it. Is there anything I can do to fix it?