Owner’s Reference
BHK Signature Amplifiers
Introduction
4826 Sterling Drive, Boulder, CO 80301
15-070-01-1
PH: 720.406.8946 [email protected] www.psaudio.com
Rev A2
©2015 PS Audio Inc. All rights reserved.
Introduction
®
Thank you for your purchase of the PS Audio
®
BHK Signature Amplifier.
Designed by master engineer and audiophile, Bascom H. King, the BHK Signature Series of amplifiers
represents one man’s decades long pursuit of perfection. Nothing was spared, no shortcuts were
taken.
Power amplifiers are the make-or-break component in a music reproduction chain. Everything in your
system funnels into this critical component and anything lost can never be recovered. To solve this
problem, the BHK Signature was designed as a hybrid amplifier featuring a zero-loss vacuum tube
input stage coupled to a high bias differentially balanced MOSFET output.
There are two dedicated models in the Signature Series, the 250 stereo and the 300 monoblock.
Each model is housed in the same chassis with the identical circuit components; the stereo has two
channels, the mono one. In the stereo 250 one input tube is used for each of the two channels, in the
mono 300 both tubes are used in parallel to lower noise and double current. The same methodology
of parallel connection is employed in the MOSFET output stage as well.
Output speaker connectors are custom machined out of copper, then gold plated. There are two pair
per channel on the stereo 250, and two pair on the mono 300. Each of the connectors was engineered
specifically to benefit the performance qualities of the BHK Signature.
The unit is shipped with a pair of hand matched Gold Lion 6922 vacuum tubes, installed in their proper
sockets and ready for use. If you wish to experiment with different tubes, you may use most 6 or 7
Series triode without changing the bias, which is adjusted automatically. Tube rolling, as it is known,
is common practice and an entirely different sound quality can be achieved by changing tube types.
There are 6 fuses on the BHK Signature. 4 of the fuses are for the high voltage power supply rails.
The remaining two are AC input fuses, one each for the two power transformers. The smaller AC input
fuse passes power to the separate vacuum tube power supply, the larger fuse for the massive power
output stage transformer. It is possible to replace the supplied fuses with high-end versions, but we
recommend care be taken to use H-Rated fuses, specifically tailored for high current, high transient
in-rush conditions.
Power cords matter. We recommend using a high-end power cord to replace the courtesy stock
power cord supplied with the BHK Signature.
Break in matters. The BHK Signature should sound quite good out of the box, but far better with a
hundred or so hours of on-time. It is not necessary during the on-time to play music. Simply leaving
the amplifier in the ready position will help the MOSFET power section improve its performance over
time. The tubes also need break in, but that time should be limited to 24 hours of constant on-time to
preserve their life.
Thank You
Zero Loss
Connectors
Break In
Two Models
Vacuum Tubes
Fuses
Power Cords
v
