DTS Audio ​Electronics

Audio Repairs, Sales, Mods and Upgrades

Conrad Johnson EV-1 Phono Preamp

Conrad Johnson designed this preamp with very few electrolytic capacitors. Opting for polypropylene and polyester films in filtration and coupling. However not only is it a bit long in the tooth, but the quality of some of the caps are very suspect. Also they used some very unusual sizes that don't make a lot of sense. Later models had some corners cut as well that may affect the sound. 

Some of the values originally used were even incorrect for they're use.
These were replaced with proper sized caps.

This particular unit received some very high quality parts.
Mundorf Supreme, bypassed by V-Caps at the output, V-Cap intermediate coupling, Solen Silver and Mundorf filtration. As well all series pass resistors were changed to Caddock. Even the filament supply was upgraded with Mundorf bypass and upsized Panasonic electrolytic (one of the few places electrolytics were originally used). 

You can see the V-Cap coupling caps off to the left and rear. The ones at the back bypass the large Mundorf caps just in front.

We've used M-Tubecaps for main filtration and Mundorf MKP just after the regulator.
The Solen Silver are used throughout as local filtration and Mundorf ZN as bypass.
In addition there are two Mundorf Silver/Oil caps used as high voltage bypass on the voltage references for the regulators.

All in all the preamp is quieter, and has detail in spades.
Bass response is deep and tight. Highs are clear and articulate.

The unit rivals (if not outperforms) Conrad Johnson's latest more expensive efforts and will outperform many, much more expensive phono stages.

Total cost of this spectacular upgrade is $1600.00