Review: StereoCoffee LDR preamp with updated 2021j Control board

[Densel]

I have been listening to a 2019 model Stereo Coffee LDR preamp for a year and a half, and have found it transparent and revealing. When I first installed the Stereo Coffee “it” sounded quite bad, but with Chris Daly’s generous help, I quickly discovered faults elsewhere in the chain, and fixed them - tremendously improving my system.

The effect of every change is laid bare by the Stereocoffee and it is very easy to make stepwise improvements using the comparative method. One of the things most destructive to good sound turned out to be a small-value silver mica cap in the signal path of my Brook 2A3 amp. Changing it to a Corning glass capacitor vastly improved my system and the Stereo Coffee drove me to find and fix many similar bottlenecks.

For at least 4 months I’ve been waiting, with growing impatience, for a long heralded improvement to the Stereo Coffee’s control board. I’ve finally installed the new board, (2021j), and it is wonderful... When the source material is well recorded things are spooky good.

I should add that I sum stereo channels to listen in mono. This “ghosts”, or greatly reduces the loudness of, sounds at the edges of the Stereo soundstage - suppressing ambience cues. And now, with the new board, and despite the reduction of ambience cues, I can clearly hear the distinctive acoustic spaces around each instrument. This instrumental separation isn’t over-etched. It doesn’t distract from the music - as hypertrophied imaging does IMHO (the reason that I listen in mono despite the drawbacks of summed Stereo). Multitrack confections sound organic and musical.

I can now hear very deeply into quiet passages: bells and cymbals and the like shimmer delicately and tantalizingly. The sound is big, fat, and juicy on good recordings. Harmonically rich instruments are ravishing. Instrumental color is also amazing, and the new StereoCoffee beautifully complements the Spendors’ strong suite: their extraordinary tonal and timbral accuracy.

However, the increased lucidity of the new Stereo Coffee board is exposing strengths and shortcomings of my system that I hadn’t previously noticed. This will undoubtedly help me to bring my system to yet greater heights, but it highlights the fact that the Stereo Coffee probably shouldn’t be thrown into lesser systems - or at least not unless the owners are willing to follow its promptings in their quest for better sound.

For example, the observations I made above only apply to my LP rig. CD’s - which had sounded better than LP’s with the original control board - now sound somewhat coarse/unsubtle by comparison.

I am also more aware of the congestion and clipping of my underpowered 10W push-pull 2A3 amp (a heavily modified Brook 12a) as it attempts to drive the 84db/W Spendors - and of the inability of those Spendors to move enough air to portray the heft and scale of drum sets and pianos.

This new board has been worth the wait. It is once again guiding me to new heights of music reproduction. The StereoCoffee with this new regulator board is very fine, and an insane bargain, but it demands attention to ancillaries and careful system tuning. Highly recommended.

[Barry]

Nicely written review Aron. Well done.

I wonder if the subjective improvement you found was due to the very low dielectric absorption of Corning glass capacitors (~ 0.012%), compared with that of silver mica capacitors?