Beresford TC-7510 DAC modding?

[Sranang_Boi]

I don't know if any or many of you have heard of this budget DAC that has been around for a while and getting good reviews for its sound.
I got two of them: an older one and a more recent one. Both use identical chips so I searched the net for any info on how to mod this DAC. The output opamp is a surface mount NJM4558, the clock IC is a CS8414, the DAC is a PCM1716. These are surface mount. The headphone amps are LM386.
From that list I identified the NJM4558 as a prime candidate for replacement. I was thinking of the NE5532, but any other suggestions are welcome.
I did a deep search on the net and found that the Wolfson WM8716 is a direct drop in replacement for the PCM1716. It has a higher output and better specs.
The LM386 is however my Achilles heel. The IC is quite noisy and has a less than respectable profile out there. But I just can't find anything as a direct replacement. I did find the TBA820 that is almost similar and I made a veroboard based circuit that I then dropped in the TC-7510 as a replacement, with the necessary mods. But the noise level of the TBA820 was identical to the LM386 . Weeks of research and circuit building just to end up with the same result as before.

So here is my question to the community: with a line voltage of just 10V to the headphone circuit, what practical headphone amp cct could I design to take the place of the LM386? Maybe I could design a voltage inverter in order to also give me a negative supply? Then maybe use a modified CMoy amp cct with a NE5532 to replace the LM386 cct? Or has anyone ever done a headphone amp to replace a LM386?

Maybe other folks here have modded a TC-7510? It has loads of possibilities and seems to be popular all over the net, but it must be one of the few DACs that has no modders working on it. So I am kind of out there on my own I feel. Any suggestions are most welcome.

[pftrvlr]

Had one 7510 before. sounded pretty ordinary to my ears. Modded the power supply, still did not like it. And I don't like to mod SMD board. So I sold the 7510.

Any of my cheap DIY DAC sounds better than the 7510, no regret selling it.

[Bgt]

Originally posted by Sranang_Boi
The output opamp is a surface mount NJM4558, the clock IC is a CS8414, the DAC is a PCM1716. These are surface mount. The headphone amps are LM386.
From that list I identified the NJM4558 as a prime candidate for replacement. I was thinking of the NE5532, but any other suggestions are welcome.
I did a deep search on the net and found that the Wolfson WM8716 is a direct drop in replacement for the PCM1716. It has a higher output and better specs.

Do you have some pictures of the inner hardware. Was thinking of trying 1 also. Modding the SMD board would be instant. The NJM4558 should be the 1st object and modding the power supply will also be neceserry I think. With cheap stuff thats always a must.

[jackinnj]

Here are some of the pix of the MCM DAC -- guess what's really inside:

CS8414


Headphone amplifier:


On board power regulators:


Output Stage:

[jackinnj]

Originally posted by Sranang_Boi

The LM386 is however my Achilles heel. The IC is quite noisy and has a less than respectable profile out there. But I just can't find anything as a direct replacement. I did find the TBA820 that is almost similar and I made a veroboard based circuit that I then dropped in the TC-7510 as a replacement, with the necessary mods. But the noise level of the TBA820 was identical to the LM386 . Weeks of research and circuit building just to end up with the same result as before.

So here is my question to the community: with a line voltage of just 10V to the headphone circuit, what practical headphone amp cct could I design to take the place of the LM386?

Probably should first consider cleaning up the 10V line -- this uses an LM7810 regulator. If you pop in an LM317 with 120R/820R and 1uF/16V bypassing the adjust pin you'll knock the noise down immensely. Note that the LM317 and LM7810 are not pin-for pin. The fixed value regulator is "Input Gnd Output", the LM317 is "Adj Output Input" (Not trying to be pedantic...).

The next thing to do is attend to the 5V regulator...