• Model 625 S2 Stereo Amplifier
      • Model 625 S2 Stereo Amplifier
      • Model 625 S2 Stereo Amplifier

      Jeff Rowland

      Jeff Rowland Model 625 S2 Stereo Amplifier



      In stock (0) - 10 - 20 days Available in store: Check availability

      The 625 Series 2 incorporates many of the same technical features of the 725 amplifiers. Similar to the 725, the 625 S2 signal circuitry is built upon a Rogers ceramic circuit board laminate material for lower dielectric absorption and energy storage.

      Product description

      Jeff Rowland Model 625 S2 Stereo Amplifier

      Precision LED based current sources have been implemented throughout the amplifier circuitry, along with 0.1% thin film SMD resistors for more stable operating points and lower noise. Custom designed Lundahl input transformers are implemented with a higher turns ratio and wound with Cardas high purity copper wire.

      Input circuitry includes an additional linear phase 2 pole filter to effectively attenuate all out-of-band signals from any source, including DSD spurious noise.Cardas gold/teflon/rhodium XLR input connectors are carried over from the 725. Newly developed error-correction circuitry has been incorporated around the entire amplifier, making a total of three independent error-correction techniques used to decrease all forms of distortion throughout the entire audio bandwidth.

      The Model 625 S2 delivers a sensuous grain-free musicality of unparalleled transparency and low level resolution that blossoms from a rich velvety silence and blossoms into the pure enjoyment of your listening experience.

      Machined Aluminum Chassis

      Precision-machined chassis with integrated heat-sinks, milled from a solid block of aircraft grade aluminum, provides exceptional thermal heat transfer/dissipation, RFI/EMI shielding, and resonance control.

      Composite Circuit Architecture

      Unique composite circuit architecture incorporating separate Class AB voltage and current gain blocks with no overall negative feedback, delivers a sensuous grain-free musicality of unparalleled transparency and low level resolution.

      Balanced Topology

      Inherent cancellation effects of balanced topology implemented throughout all power and input/output circuits ensures greatly reduced distortion and noise under dynamic signal conditions.

      High-Current Copper Bus-Bars

      High-current, dual polarity, ultra low impedance copper bus-bars distribute both power supply input current and signal output current, virtually eliminating intra-circuit EMI signal contamination, greatly reducing internal wiring, while increasing circuit board rigidity.

      High Precision Surface Mount Components

      Extensive use of Lead (Pb)-free, low temperature coefficient, active and passive surface-mount components results in significantly smaller loop areas, reduced circuit capacitance and inductance, and introduces less noise than conventional leaded components.

      Transformer-Coupling and Isolation

      Transformer coupled input circuitry provides universal component compatibility and virtually eliminate ground loop noise and RFI/EMI. Transformer coupling ensures identical amplifier overall gain when using unbalanced input adapters.

      Power Factor Correction

      Power Factor Correction (PFC) in the power supply reduces AC line harmonic noise pollution and increases AC line power utilization to 99%.

      High-Efficiency Switch-Mode Power Supply

      Highly efficient, compact, light weight, 1500 watt DC switch-mode power supply provides optimum voltage regulation for all circuits and operating conditions, and allows for quiet operation over a wide range of AC mains power sources.

      Dual-Position Speaker Terminals

      Dual CE approved speaker output terminals, in both horizontal and vertical orientation, require no tools for secure, low resistance connections, and allow for easy bi-wiring applications.

      Flexible 20 Amp AC Power

      20 amp AC power inlet accepts a wide variety of after-market high-performance power cables.

      Front Panel Standby Button

      Illuminated front panel push-button switches the amplifier into standby mode (<1 watt consumption).

      Rear Panel Remote Jack

      12V 3.5mm jack on rear panel permits amplifier power on/standby switching in remote and home theater applications.

      Self-Leveling Supports

      Removable 3-point self-leveling Delron chassis supports provide high frequency mechanical noise isolation.

      Jeff Rowland Model 625 S2 Stereo Amplifier User's Manual


      Output Power

      325 watts @ 8 ohms / 600 watts @ 4 ohms

      Frequency Response

      10 Hz – 150 kHz, -3 dB

      S/N Ratio

      95 dB, ref. 1.0 watt @ 8 ohm load

      Output Noise

      < 100 µv, A-wtd


      > 91 dB @ 1 kHz, 74 dB @ 20 kHz

      Input Impedance

      40k ohms

      THD + Noise

      < 0.001% @ 1 kHz, 8 ohms

      Damping Factor

      > 200, 20 Hz – 20 kHz

      Overall Gain / Bal. or Unbal.

      26 dB

      Common Mode Rejection Ratio

      > 90 dB, 20 Hz – 20 kHz

      Absolute Phase Non-inverting

      Pin 2 Positive


      1 pair balanced (XLR)


      2 pair parallel binding posts per channel

      Power Consumption Idle

      100 watts

      Power Consumption Standby

      < 0.5 watt

      Amplifier Weight

      54 lbs. 

      Amplifier Shipping Weight

      64 lbs.

      Amplifier Dimensions 

      5.75”  ( H ) x 15.5” ( W )  x 16.25” ( D ) 

      Available in store


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