Topping D70 vs the passage of time.

A few days ago, I bought a Topping D10 (presumably barely) used locally for $55. Something about the orange display and overall design really caught my eye. I also wanted to mess around with DSD, as I am lucky enough to have one of those special ;) Sony Blu-ray players and a couple SACDs. I have been very impressed with its operation so far. I am using it connected to my JDS Labs Element, using just the headphone amplifier part of it to drive my HD650s. I have never been great at hearing differences between DACs, but I have to say that it sounds excellent, and has the added benefit of accepting much higher quality files than the Element DAC's 96 kHz upper limit. If I'm not mistaken, it measured somewhat better than it too on a certain Audio Science website. This definitely has me interested in their other models now! I wonder if the D70 would be an improvement over my very early production Gungnir :rolleyes:
 
GaryB, very interesting your RC snubbers suggestion to improve Topping D70 sounds. Concerning 0,022uf capacitor, could i use 275v/AC?Thanks in advance for your response
 
All the voltages in the D70 are low - less than 25v. So a 275v capacitor is overkill. For me the biggest consideration in choosing the capacitor was its physical size and whether or not it was sitting in my parts box. There isn't a lot of space for parts on the bottom of the board because the spacers used to mount the board to the chassis are quite short. So you need a thin capacitor. The ones I use are about 2.5mm thick and work fine. They're polyester film caps rated at 100v. I don't recall exactly what the model number is but if you go to digikey or mouser and look up polyester film caps, you'll find models of roughly that size. While I didn't use these caps, they seem similar in size to the Vishay MKT370 or Wima MKS2 polyester caps.
---Gary
 
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JohnVF

Administrator
Staff member
I have turned on the main stereo for the first time in awhile. It wasn't for a lack of interest, but for a lack of time. That and I was hanging out with the bedroom system, ripping CDs.

Just a note to say the Topping doesn't suffer from absence. In fact, I like it as much or better than I did before. This is a truly excellent DAC. Again, I didn't love it as a pre/DAC..but as a component in a system with a great pre/amp already? It's a stunning value.
 
John,
Glad to hear that the D70 continues to satisfy.
I haven't commented much about my impressions so I thought I'd chime in. A couple of weeks back I posted some mods to the D70 and those made a big difference in my system. Before I did the modifications, I admired the sound quality out of the D70 but I didn't love it. After the mods I have become quite taken with it and agree that it's a keeper. This is all in the context of my current system - Squeezebox streamer to D70 via coax to Slagle AVC to Flying Mole digital amps to Ref 3A mm de capo i speakers.
Comparing it to the Berkeley DAC using exactly the same system down to the power cords and interconnects, I find that the Berkeley DAC is ever so slightly better. A touch more natural and detailed in the highs. But it's not a big difference.
Being an inveterate tweaker, I'm thinking about a few more mods that might help further close the gap. Stay tuned.
---Gary
 
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JohnVF

Administrator
Staff member
John,
Glad to hear that the D70 continues to satisfy.
I haven't commented much about my impressions so I thought I'd chime in. A couple of weeks back I posted some mods to the D70 and those made a big difference in my system. Before I did the modifications, I admired the sound quality out of the D70 but I didn't love it. After the mods I have become quite taken with it and agree that it's a keeper. This is all in the context of my current system - Squeezebox streamer to D70 via coax to Slagle AVC to Flying Mole digital amps to Ref 3A mm de capo i speakers.
Comparing it to the Berkeley DAC using exactly the system down to the power cords and interconnects, I find that the Berkeley DAC is ever so slightly better. A touch more natural and detailed in the highs. But it's not a big difference.
Being an inveteratre tweaker, I'm thinking about a few more mods that might help further close the gap. Stay tuned.
---Gary
I look forward to seeing what you do with it. I'm really happy with it out of the box, it just sort of gels with the rest of what's here. When I used the Berkeley in this setup, it was slightly too clinical but had more whiz-bang imaging..everything was HUGE.
 
I look forward to seeing what you do with it . . .
I think that the output circuit in the D70 is very similar to what's shown in the AKM4497 datasheet, which I've copied below. Some of the values look different but the topology seems similar. Two op amps for filtering + and - signals and one op amp for balanced to single ended conversion. What caught my eye is that the akm4497 dac chips are cap coupled to the output stage. Topping uses 100uf 25v Nichicon Muse ES bipolar caps, which I suspect aren't the most transparent in the world. So upgrading those coupling caps is first on my list. One can also bias the op amp outputs into Class A, which is supposed to warm up the sound a bit. More extreme would be to try transformer coupling but I don't think that would fit in the same case anymore.
---Gary
 

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