I have an opportunity to test out a better pair of speakers for my desktop system, and felt I needed a change from the dulled character of the TubeCube 7.
As an experiment, I used the DSP in Roon to kick up the highs quite a bit, like by 12 or 18 dB. It resulted in almost no change to the sound. And on stronger material, the amplifier was actually overloading in the highs.
I’ve chalked this up to a poor amplifier design. As per my original review of the TubeCube 7, there is another review out there exhibiting the same rolloff. I would think twice about buying this amp or at the very least, hoping for a good return policy. It appears this amp also goes under the APPJ model designation elsewhere.
Being eternally stupid, I decided to try another chi-fi amp, although this one was favorably reviewed by Steve Guttenberg. Again, it’s no perfect amp, and I’ve read of a couple of them arriving dead or having an early capacitor failure. But the version of the Reisong A10 I ordered is point-to-point wired, and is a version shipped without tubes, so I could use my own.
I figure if the amp fails or I want to improve the sound, I can order up a set of Nichicon caps and give it a good going-over. It really is a simple circuit, like amps in the old days. And it’s easy to apply any further modifications down the road, including changing the output transformers (with a little bit of case work). It looks like a decent enough chassis to build on.
The tubes I have on hand are a pair of Electro Harmonix 6CA7 (EL34 equivalent) and a pair of Voshkod 6N2 input tubes. I am awaiting the rectifier tube.
At least if this one doesn’t do it for me, I can resell it, and would probably lean towards an NAD 7050 or PS Audio Sprout100, which would also give me a DAC upgrade.