Description
Our most esoteric product is THE 300B PREAMPLlFIER. This is the first and only preamp to feature these classic tubes. We had been designing the 300B into small power amps for many years and have always had great respect for the smooth natural sound of this tube. However, a single 300B provides truly appropriate power and voltage swing for headphones and makes a remarkable line driver. Here is where the impedances are not too low and the power requirements are not too high: ideal for this kind of tube in a single-ended configuration. This was the genesis of a new preamp.
We combine the historic 300B with another classic, the large octal based 6SL7GT, for the input stage- all triodes running in pure Class A operation. To complement this ‘retro’ feel, we implemented vacuum tube rectification and regulation in the power supply along with plenty of capacity. We also developed an additional (and innovative) ripple rejection circuit to filter out power supply noise making this an incredibly low-noise preamplifier- especially critical for headphone users.
Complementing this lovely and rich sounding line-driver is the ALPS audiophile volume control, gold plated RCA connectors, high purity silver wire, mil-spec printed circuit boards with extra thick copper and plating, and custom designed output transformers which we wind right here in our own magnetics department. It all adds up…
For 2002, we returned to our classic and elegant “Manley-Blue” pewter grey color and the chassis was reworked to accommodate a few updates we had in mind – and in 2022, we added Black and Silver faceplates as custom-order options.
Whether you use headphones or loudspeakers this preamp will deliver the goods and spoil you for any other preamplifier.
Notes for current version not covered in the manual:
The transformer switch puts the output transformer in or out of circuit. You HAVE TO have it switched to “IN” to use the headphone jacks. It is recommended, in the spirit of “less is more”, to switch to “OUT” when using the main line outputs.
The SUB out is a post-volume control output which can be used to drive a powered subwoofer unit so that the level of the subwoofer follows the volume level of the preamplifier.
