Opamp inquiry

Hello Everyone how are you. The seller of the Lampucera dac kit I bought yesterday has suggested buying other things to improve things like a opamp he sells 🙂. He is saying he can put everything in one package to save on postage 😀. He is a salesman trying to get more money which is a good thing if your buying something good. What do you think of this op amp.

https://www.ebay.com/itm/186781815445
 
Do you have the Lampucera schematic you can post?

Regarding HDAM modules, IIRC there are various types. Some can sound good if well designed and well powered. Don't know about this guy's take on it.

Regarding a USB card, that one isn't great. It depends on how the dac will be clocked if connected to a USB card, and how USB bus noise might affect dac operation. For that we would need to take a closer look at the dac circuit.
 
Okay, looks like its SPDIF/TOSLINK input only. No I2S. There is going to be probably more than minimal jitter.

Cheap Chinese stuff, maybe some fake caps. If the Wima are real, they are probably not the lower distortion dielectric type. Chinese tubes may not be as good as some of the Russian ones.

Its a toy to play around with, maybe worth $150 of fun. Wouldn't spend too much on upgrades though as it looks like the whole thing could use a redesign.

Also, its a good opportunity to learn how to sketch up a schematic from visual inspection and maybe a little work with a ohmmeter.

Most important thing would probably be to be very, very careful with the uninsulated soldered 220vac connections. Very dangerous. It needs a fuse too. Also probably needs a hum breaker circuit for safety if the AC power where you are has an earth ground pin.
 
Here is an example hum breaker circuit:

1741542761439.png


Regarding the youtube video, its useless for judging sound. Try more complex music that also contains spatial information. Its going to be too distorted and or blurred together sounding with excess 2nd harmonic, and probably no longer very spatial. Again, its a cheap $150 toy dac to play around with and have fun. If you buy two HDAM modules and a USB board then maybe it will be closer to a $300 toy. I would be careful about making into a $500 toy or something like that. It just not well designed enough in ways that you can't easily change to invest too much money in.