501+ PreAmp
501+ Preamp
Shape your tone from the very first stage.
The 501+ Preamp is a fast, detailed, and highly responsive microphone preamplifier designed to cover a wide sonic range.
By balancing the input gain against the output attenuator, it can move effortlessly from clean, open amplification to richer tones with greater harmonic character and personality.
M.S.R.P.
$799.00
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At its input, a proprietary Quagliardi permalloy-core transformer provides excellent noise rejection while preserving clarity, detail, and transient response.
Together with a discrete 2520-style operational amplifier and custom output transformer, it forms a fully analog signal path that can remain remarkably transparent or be deliberately driven to introduce depth, texture, and coloration.
A front-panel Neutrik combo connector accepts both low-impedance microphone signals and high-impedance instruments in DI mode.
The FRONT selector lets you switch between the front-panel input and the rear 500 Series rack connection, allowing two sources to remain connected simultaneously and making the 501+ easy to integrate into changing studio workflows.
Additional controls include polarity reversal, +48 V phantom power, and a −20 dB pad. The proprietary X-REL function changes the configuration of the input transformer windings, offering an alternative transformer response and expanding the tonal possibilities available from the preamp.
The 501+ Preamp follows a deliberately minimal signal-path philosophy.
Only the essential components stand between the source and the output, allowing its sonic character to come from the quality and interaction of its transformers and discrete operational amplifier rather than from unnecessary circuitry.
Technical Specifications
Connections
Front-panel combo input connector: balanced XLR microphone input and unbalanced 1/4” Hi-Z instrument input.
Gain Range
Mic: 38 dB to 78 dB
Mic with Pad: 18 dB to 58 dB
Hi-Z: 17 dB to 57 dB
Maximum Input Level
Measured at 0.1% THD at the output
Mic: -11.8 dBu
Mic with Pad: +8.5 dBu
Hi-Z: +9.7 dBu
Input Impedance
Mic: 450 Ω / 750 Ω with Pad (with 150 Ω source impedance)
Hi-Z: 1 MΩ
Output Impedance
Less than 10 Ω (with variable output attenuator)
Maximum Output Level
+30 dBu
Frequency Response
+0.45 dB @ 20 Hz / -1.3 dB @ 20 kHz
+0.6 dB @ 20 Hz / -0.3 dB @ 20 kHz (with XREL)
THD
0.003% @ +4 dBu output (unweighted)
0.015% @ +26 dBu output (unweighted)
Equivalent Input Noise (EIN)
-130 dB with 160 Ω input load (unweighted)
Power Consumption
±16 V DC @ 60 mA
Dimensions
230 × 200 × 50 mm
9” × 7.8” × 2”
Weight
0.410 kg (0.88 lb)
