ABOUT THE SLP-05 PREAMPLIFIER
We have had numerous requests from customers for many years regarding possible upgrades to the SLP-05 preamplifier. For the past couple of years, we have made it a project to find the appropriate combination of components to take the SLP-05 to another level. Finally, we believe we have achieved our goal. We are incredibly happy with the results of these upgrades which can be installed in any SLP-05, no matter the vintage. The “Ultimate Upgrade” consists of changes to the power supply as well as the line stage circuit.
The power supply portion of the upgrade consists of “maxing out” the filtering capabilities along the entire power supply chain, all the way into and including the preamplifier. Purifying DC voltages is extremely important to providing a clean, clear, smooth sound quality that is free from grain, noise and strident artifacts. This also improves imaging qualities as it provides a much blacker background. The type and quantity of capacitance are important as we are not just adding an extra 1200uf of UCC electrolytic capacitance into the main B+ (high voltage) supply but also an additional total of 125uf of Polypropylene capacitors throughout the B+ line. This includes a huge 100uf Polypropylene capacitor right at the line stage PC board. The rest of the additional capacitors are used as bypass capacitors across each UCC electrolytic filter capacitor. This provides a dramatically smooth, sweet sound quality.
In the line stage circuit, we change the resistors to high quality 1% Vishay metal film plate load and cathode resistors. This parts change improves the midrange and bass substantially for a fuller, more textured midrange. You will notice more body and texture to vocals and acoustic instruments, etc. Bass is more authoritative and tight. Highs are smoother yet detailed.
And finally, for the pièce de résistance. We are removing all of the coupling capacitors and installing (10) Mundorf MCap coupling capacitors throughout the entire line section. This is the final addition that completely allows the sound qualities of the SLP-05 to shine through, resulting in a sweet, fluid, full bodied yet delicate delivery of every single instrument and natural vocal detail. It is done without adding brightness, and yet delivers an amazing amount of air and detail revealing the acoustics of the room and instruments with breathtaking natural realism. There is body, texture and fullness to instruments that break through with such ease and delicacy no matter the complexity of the music.
The “Ultimate Upgrade” is not just an upgrade. It elevates the SLP-05 to a whole other level of sound quality. It retains the attributes of the SLP-05 that you know and love but gives you more of everything.