Krell KRS-1a - 4 Piece Reference Preamp with Phono Module
Designed and built in the late 80’s, the golden age of high end audio, the KRS-1a was a “no expense spared” flagship reference preamp from Krell.
This is a dual mono design and I mean DUAL MONO. Not just two separate signal paths in one box, but actually two completely separate unconnected boxes. One for each channel. It was common to have a two piece reference preamp, one housing the power supply and the other the preamp section - but a 4 box version was unheard of.
In addition, the KRS-1a uses the highest quality components available at the time. It is fully analogue without any complicated integrated circuits or proprietary components. This makes the unit super easy to service and likely to last for decades.
When the unit arrived at our shop we quickly got to replacing every single capacitor in the preamp section. That is no small feat as there are over 120 capacitors. Unfortunately most capacitors will age, bulge, and leak over time and this unit showed some signs of it being a problem in the future. So, we went all out and replaced them all. We even serviced the phono boards.
This is a laborious and tedious endeavor but well worth the investment for a piece of audio history of this caliber and rarity. Do not buy a unit like this that has not been fully serviced as you will cringe when you get the bill for service. We used the highest quality Nichicon capacitors we could get our hands on.
As expected this unit comes with super high quality Krell phono modules internally installed. There are micro switches located on the boards that allow for no less than 10 loading values. There are also adjustments for a feature we have never seen before on a preamplifier. Internally you will find micro switches to select the correct type of CD player that is being connected. They call it a 3-pole phase correcting filter which is set to match the type of CD laser used in your unit like Phillips or Sony. Very cool option.
After service the unit was thoroughly tested on the workbench before making its way into our dedicated listening room where it blew the doors off any preamp we have ever had the pleasure of using. Yes the dual volume adjustments take a bit more effort than a single potentiometer, but the extra trouble results in the best imaging and channel separation we have ever experienced.
Cosmetically the unit is in amazing shape considering the age. There are no noticeable or deep scratches or dents. There are a few light marks here and there but nothing worth mentioning and only visible upon very close inspection. All the writing and engraving is in perfect shape and there are no signs of use or abuse. The gold plated connectors are super clean and the knobs all operate precisely and responsively.
Don’t miss the opportunity to own this piece of history sure to appreciate over time as more and more audiophiles realize the benefits of a full analogue preamp.
Included are the 4 pieces as pictured, the two umbilical cords, two power cables, and original manual.