Xuelin 1969 tube player
Xuelin 1969 tube player was upgraded from beginning to end on the basis of the original 1969. In the digital part of the headend, the asrc asynchronous phase-locked loop is used to increase the frequency and the tcxo temperature-warming clock is used to reduce the system jitter to a very low state.
The end of the simulation part, using the jan5636 military standard hot thumb tube amplification and dual ad8397 current drive, from beginning to end, the concept of fever throughout.
Let's put some debugging photos below for everyone to enjoy.
Only good sounds are not enough. The two bile ducts light up and instantly warm the heart.
Beautiful spectrum display window. Someone asked me why it is not 20khz but 15khz? When debugging, I found that the energy above 15k is very small, not enough to drive the display, so the overall beat rhythm is not beautiful, so that's it. Others say that this is useful? Actually it didn't work, but it's cool.
This photo is not taken well, the brightness is not enough, and there is too much noise.
This is the engineering prototype in the commissioning, and it has been going back and forth for half a year. The dispersion of the electron tube is large, and it is not easy to do it well.
Coordinate with the early 960 player for digital clock section. Flying a lot of hair-like connections, compare the test of welding work, a little carelessly, the previous work is abandoned.
Jitter is a natural enemy of digital circuits. Players are prone to cold, hard, and dry problems. At the source, they are caused by clock jitter. The human ear is not sensitive to amplitude errors, but is very sensitive to frequency errors.
We redesigned the asrc design for the global clock. It is not the usual 96k/192k, but we specially designed the unconventional 2**k supersampling. The specific technical details will be detailed later.
Some friends have some misunderstandings about asrc. It feels like the camera interpolation is a trousers fart, which actually brings two benefits.
1: Pushing the audible noise caused by aliasing to a more inaudible high frequency band, can push most of the noise to a frequency of several hundred K, and can be easily cut off in the output LPF circuit at the back without accidentally injuring the friendly army. Simplifies the design of lpf.
2: Asynchronous clock asynchronos We use +-0.5ppm tcxo Taiwan crystal technology txc crystal, (unit price exceeds 100 yuan) to reduce the overall jitter by several orders of magnitude, bringing a very clean sound. Until now, asrc has been the most effective way to reduce jitter. ess has integrated the asrc module in the full range of decoding, so it is the leader in high-end decoding. (It can be said that the ess series is already an audio subsystem integrated with asrc, not a separate dac)
In the commissioning of the forest to customize the tcxo crystal, of course, the actual use of this full-size product is not possible, but a smaller patch tcxo crystal.
The oscilloscope observes the digital signal. The lrck, bck, and mck in the iis are not independent. They must be synchronized with the sdo sampling. Therefore, many clock processing methods are derived from this. Many of them are unique and are the hardest to do in the audio system. part.
At the same time, with the frequency meter monitoring, some frequency drift phenomena can be accurately detected, such as the frequency drift after heating with the air cylinder.
Analog circuit We use the jan5636 bile voltage amplification plus two-way ad8397 driver structure. It is still very rare to apply bile ducts in the body at present. This is the first one to use a fully conventional thumb glass tube. The tone of the bile duct has a "warm simulated taste" compared to the stone machine, but there are also some drawbacks. The bottom noise level of the bile duct is relatively large (this is also one of the sources of simulated flavor), the actual audition comparison, unless very few Multi-unit moving iron does not affect the sense of hearing. The unique sense of tube reverberation can be called the gospel of female drug lovers.
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