Yearly Archives: 2020

A few months with the KEF LS50

Just before the shitshow shutdown, I was debating improving my desktop system with a new amp and set of speakers.  I’ve gotten the amp taken care of, as a previous article mentions.  I looked at a handful of smaller speakers to see what would fit my desk and still sound good.  I finally narrowed it down to two KEF systems, and the LS50 won out.

Appearance-wise, they’re a cool combination of black cabinet and rose gold speaker.  My only minor concern is that there are no grilles to deflect damage.  Not that we have a rough household, but accidents happen.

As I’m using them near a rear wall, I’ve installed the included port plugs.  These seem to match nicely with the small subwoofer I use under the desk–the way the sound disperses under and behind the desk, it coincidentally provides a seamless match with the speakers.  The LS50s themselves are a nice system.  The coherency is amazing–the concentric tweeter is really something special here.  What amazes me even more is now inert the cabinet is.  Under moderate volume, you can’t feel anything from the cabinets whatsoever.  No doubt this is a key to their uncolored performance throughout the mids and upper bass.

They still need to break in a bit, as I’ve also been playing my main system in the evenings.  I want to get proper stands so I can hear the LS50s correctly in my main system, rather than trying to find random bits and pieces to set them on.

I still have a dullness in my desktop system, though. Could I possibly have another dud amp?  I’ve changed both analog and digital interconnects.  The tubes I chose for the amp are not known to be dull.  I plan on trying it in my main system soon, as that’s ultimately what will tell me the most about how well it is reproducing music.  (I even went with 6CA7 tubes to try to avoid that mushy EL34 sound.)  Jury’s still out on the amp, but I really didn’t spend all that much on it either.  I could easily get a PS Audio Sprout100 or NAD D3020 (or similar model) that would work out well, and either would provide a better DAC than the DacMagic I’m using now.

TubeCube heading to retirement; Reisong A10 replacement on the way

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.