We have measured all devices (oscillators and frequency doublers) with 3 different power supply:
- TWRPS-LBS LiFePo4 battery supply at 16.5V (series of 5 batteries)
- TWRPS-pp push-pull regulator at 16.5 V
- TWRPS-UGL linear regulator at 15V
The phase noise performance of all the devices are almost the same for all the above power supply, the LiFePo4 power supply is slightly better so we recommend this for the ultimate performance.
Exotic parts would be a wast of money, these are RF devices and we have used the best parts available for such that application (NP0-C0G capacitors, low flicker noise active devices, ceramic core Coilcraft and Epcos single layer inductors for the highest self resonant frequency as possible)
And moreover we had taken the maximum care to the PCB layout.
We had taken care of components tolerance, the components listed in the BOMs were chosen with the right tolerance, you can find 1% capacitors and 2% inductors.
We recommend to get exactly the components listed in the BOM, no replacement parts at all.
A switch board would be awesome to get the best out of the 5 and 6 mHz clocks for 44.1-48khz files and switch to the doublers for 192khz.
Thanks for confirming this Andrea. I had decided to implement your innovation exactly as specified. I respect your performance measurements. Why fix it if it is not broken?
This is another thing.
If you would get the best form the 5/6 MHz oscillators I suggest to wait for the new discrete DAC Lite.
The board I was talking about would be designed with the following features:
- Input: 2 sine wave oscillators, one for each sample rate families)
- sine to square converters (LTC6957)
- double output (fanout, 2 output for each sample rate families to distribute the clock)
- or swithed output, single sample rate family at a time with parallel output (fanout to distribute the clock)
Double output and switched output would be alternatives to each other.
Switched output would require external control with the following options:
1) fixed High/Low control (Hiigh x48, Low x44.1)
2) 2 x fixed enable controls (high enabled, low disabled)
) 2 x pulsed enable controls, 30 ms min. (one for x48 + one for x44.1)
Please, let me know if there is enough interest on the above board (at least 10 pcs to start the design and the production).
Sorry, with "replacement parts" I meant "cross reference" in the BOM if some components were not in stock from Mouser.
In other words I meant that no parts in the BOM should be replaced with similar, you should get exactly the listed parts.
I am interested. (would use 2 x fixed enable controls, high enabled, low disabled)
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i did not mean any fix, what i actually mean is, say you need two (not just one) 1K 1% R, i can buy 20 of them and it should not be difficult to hand pick just two which is well within 0.1%.
but as Andrea has confirmed, just stick with specified. thanks Andrea.
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