PR5 Tube Phono Preamp
Do you want to play Vinyl? If so, you need an RIAA Phono Preamplifier.
An RIAA phono preamplifier amplifies the millivolt signals from the phono cartridge to a level suitable for driving a stereo power amplifier to full volume. It also applies the RIAA frequency correction which is the inverse of the frequency response applied during the disk production process. The result is accurate and sufficient sound from your system.
Use with any Power Amplifier. The Red Roo PR5 phono preamplifier kit is a perfect partner for our SE5 power amplifier or any other power amplifier if you want to upgrade your system to play vinyl records.
Circuit Line-up. The tubes used are four 12AX7/ECC83/7025 configured as two constant current draw (CCDA) amplifiers. Cathode followers in the output of each CCDA provide a low-impedance drive for the RIAA equalisation network (to maintain RIAA accuracy as tubes age), and a low output impedance (for driving low input-impedance power amplifiers or long/high-capacitance cables).
Switch Between Two Inputs. The phono preamplifier kit has, as standard, two switchable moving-magnet (MM) phono inputs. Great if you have two turntables and want to queue music.
Moving-Coil Option. If you have a moving-coil (MC) cartridge, one of the inputs can be converted to moving-coil by inserting two Lundahl cobalt-based amorphous core LL9226 step-up transformers onto the PC Board, or by using external step-up transformers (both options are an additional cost). You would then be able to switch between an MC cartridge for really serious listening and a MM cartridge for everyday music.
Step-up transformers are a low-noise way to amplify the tiny microvolt level signals of a moving coil phono cartridge without having to resort to solid-state circuitry in the audio path.
Small Footprint. The PR5 phono preamplifier kit is very compact: a perfect partner to our SE5 stereo amplifier. It doesn't take up nearly as much shelf space as other tube preamplifiers that are often large, heavy, and cumbersome.
User Functionality. The front panel holds a large solid-metal Balance knob, and attractive toggle switches for power on-off and phono input selection.
The rear panel holds the input and output connectors and a turntable earth wire connection (if your turntable has one). Blue LEDs shine up under the tubes when the power is on (can be changed to any other LED colour).
Easy to Build. The PR5 tube preamplifier is very easy to build. For a trouble-free build, order the solderless kit which is supplied with fully assembled and tested PC boards. Alternatively, if you want the full kit building experience, order the full kit of parts which comes with individual components that need to be soldered into the PC boards.
The 'solderless' option will save you a lot of time and will guarantee success. If you can use a screwdriver you can build the solderless option.
Power Supply Design. Mains power does not enter the chassis and the unique power supply design, DC heaters, and an earth-loop breaker all help to eliminate power supply-induced hum or buzz from the speakers.
Care is required as the circuit contains hazardous voltages up to 280V DC.
The SE5 dimensions are 154mm wide, 240mm deep, and 115mm high.
