soundcheck's - audio@vise

RPi kernel developments - 2023

Hi folks.

The foundation has updated its kernel tree a short while ago. It seems they plan to switch to kernel version 6.1 during the year. Usually the foundation goes for LTS (long term support) kernel versions.

A lot of RPi related stuff had been merged into the so called mainline kernel tree of 6.1 over time. That's the master tree maintained by Linus Torvalds. The more stuff the foundation can transfer to mainline the less effort they and the developers will have to maintain two kernel trees. And the users should greatly benefit by getting much faster newer kernel versions and related features. Especially accessing performance relevant developments asap are of great value for embedded system like the RPi.

What's new on 6.1 ?

A lot.

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RPI4 - All Lights OFF - Update

Not much going in RPi land these days. It's unbelievable that a whole industry branch gets dragged down currently.

However. Many of us still run and maintain RPis. I'd like to make you, the tweakers, aware of a recent change in the RPI firmware.

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RPi Power Gadget - UcPi

IanCanada recently released a new gadget called UcPi.

It's basically a supercap power buffer for the RPi. It follows a to me new approach - I just called it "HAB" -- Hardware Attached to Bottom. To accomplish it IanCanada makes use of spring contacts to connect to the soldered GPIO power pins at the bottom of the PI board.

Over at github you'll find the manual that also lays out this or that application:

https://github.com/iancanada/DocumentDownload/blob/master/UltraCapacitorPowerSupply/UcPi/UcPiManual.pdf

Audiophonics sells the product:

https://www.audiophonics.fr/en/single-board-computers-et-hats/ian-canada-ucpi-universal-ultracapacitor-power-supply-board-for-raspberry-pi-p-16717.html

I do use cap buffers to improve the RPi power rails for years with good results.
Therefore I consider the UcPi a promising gadget. However. @ $/€79 plus feet on top I consider the pricing a bit steep.

Further it seems to take a while to get the supercaps charged, which might make operation of the module slightly annoying, especially if you don't run an AlwaysOn system.

Beside that it's recommended to use a quality PS for charging. Another argument that weakens the UcPi proposition. Of course - the lack of a case is another bummer.

Anyhow. I do think for those who run quality RPi implementations with PS like Allo Shanti, iFi iPower or alike the UcPi should enhance the overall performance of the setup without being too complex.

If anybody out there have already tested the UcPi, please let us know.

Enjoy.

soundcheck's Purifi amplifier

Let's talk a bit about amplifiers. I owned numerous devices. Commercial and DIY. Jeff Rowland, Anaview Abletec, Hypex, T-amps, SMSL and the list goes on and on. I tried many of those ebay Class-D modules. I tried all kind of power supplies (connex/hypex/linears, ...), I tried several full digital amps. and I compared these to even more amps owned by audiophile friends of mine.

Oh dear. What a career. I swapped Class-D output transformers with Mundorf coils, replaced rectifiers, cabling, fuses connectors, power cables and the tweak list goes on and on.

And finally I got hooked up to a Purifi Audio Eigentakt 1ET400A Stereo Eval1 amp integrated into a Ghent Audio case.

I am running this amp for more than a year by now. Puh. What a journey.

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Gustard V18 vs. Allo Katana - a 2022 assessment

For almost a year or so I am running an IMO excellent Gustard A18 DAC. The Gustard builds around the top of the line AKM AK4499 and Accusilicon clocks. The DAC received quite some nice reviews confirming my experience with it. Most reviewers saw that DAC challenging much pricier rivals. Until now I was never in doubt about the overall DAC performance...

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