PR41 Passive Preamp / Stepped Attenuator
46 Step precision main volume control.
Totally passive design.
23 step balance control.
Selector for 6 inputs.
All metal film resistors.
Optional phono preamp (Solid State or Tube) inside.
Optional remote control with motor on each knob.
The PR41 passive preamp provides a volume and balance control and input selector of the highest quality.
The passive preamp / stepped attenuator volume control has 46 steps of attenuation of 1.25 dB each. This level control is assembled using a high quality mil-spec rotary switch and presision metal film resistors. The balance control also uses a stepped attenuator with 0.6 dB steps. In one direction only the left channel gets attenuated and in the other direction only the right channel gets attenuated. The input selector switch on the passive preamp can select from 6 input channels.
The front panel of the passive preamp has the 3 controls. The rear channel has the 6 pair of input connectors and the output connectors. There is no power cord or power supply of any kind. All connectors are heavy duty brass and gold plated with teflon insulation. The cabinet is black with white lettering. Knobs are black aluminum.
The PR41 passive preamp is compatible with most any component with line level outputs, like CD player, tuner, tape recorder, etc, and with most power amplifiers, tube or solid state. Most power amplifiers have an input impedance in the range of 10KOhm to 100KOhm. The PR41 front panel is calibrated for a load impedance of 25 KOhm, but using an amplifier with a different input impedance only changes the calibration by a small amount (less than 1.5 dB) and is generally not a problem. The PR41 can also drive any of our electronic crossover networks.
An uptional remote control feature is also available. The
motorized remote on the passive preampwill turn any of the 3 knobs
using an IR remote control.
A Balanced version with XLR connectors is also available.
Please consult factory for details: email@example.com or
We also have an optional phono-preamp available. This
phono-preamp can be mounted inside the PR41 passive preamp
cabinet. Two versions are available: The LN106
is a solid state phono-preamp and the LN108
is a tube phono-preamp. Both have the same specifications (see
below). Both have a subsonic filter that rejects all frequencies
below 8Hz. Accurate metal film resistors and polypropylene
capacitors in the filters assure great sound. Both preamps use an
external wall transformer for power. The LN106 solid state
phono-preamp uses a two stage op-amp design. We now use the
OPA2134 op-amp with good results. The tube LN108 uses 3 12AX7
tubes, zero feedback and passive RIAA filter.
A Dual-mono version of the PR41 passive preamp is also available. Other options include balanced (XLR connectors) , H and bridged-T ladder configurations.Resistance values other than the standard 20K are also available. Please consult factory for details: firstname.lastname@example.org or (585) 423-0462
Volume control: rotary 46(PR41) step stepped attenuator
Balance control: rotary 23(PR41) step stepped attenuator
Source selector: rotary 6 channel selector
Inputs: 6 pair of heavy duty gold RCA connectors.
Output: 1 pair of heavy duty gold RCA connectors.
Frequency response: DC - 100KHz +/- 0.25dB
Input impedance: 20 KOhm
Step size, attenuator PR41: 1.25 dB
Step size, balance PR41: 0.6 dB
Optional phono-preamp: RIAA +/- 0.25dB
Subsonic filter at 8Hz.
gain 40dB at 1KHz
Output load: 10KOhm or more (25 KOhm typical).
Dimensions: 17" X 2.8" X 8.5 "
For these versions/options consult factory:
PR41-BAL Balanced inputs/outputs
PR41-REM Remote control feature
PR41-ATT1-A 46 Position stepped attenuator only , mono
PR41-ATT2-A 46 Position stepped attenuator only, stereo
46 position heavy duty attenuator inside the passive preamp.