β22 amplifier
(AMB prototype shown, actual appearances vary depending on case used)DIY design developed by
AMB.
Inquire about having one prebuilt by
MisterX or
thrice.
Assembled and tested circuit board modules are also available from
SFT.
-Amp name/model: β22 ("beta 22")
-In production? Yes
-List price: DIY: varies; Prebuilt: contact builders for pricing info
-Current "street" price: n/a
-Type of amp: Solid state class A, all-discrete fully complementary, JFET input stage, BJT voltage amplification stage, high current MOSFET output stage. All stages dynamically cascoded. 2-channel passive ground, 3-channel active ground or 4-channel fully balanced options.
-Stock tubes: n/a
-Crossfeed: None
-Other processors: None
-Portable? No
-Power supply: Companion
σ22 ("sigma 22") all-discrete, complementary dual rail tracking regulated PSU, ±24V to ±30VDC.
-Detachable power cord? Yes
-Number of headphone jacks: 1 or more
-Jack output impedance (per jack, if more than one): < 0.01Ω
-Jack output (per jack, if more than one -- include @ #Ohms) n/a
-Jack type: 1/4" phone (unbalanced) or dual XLR (balanced)
-Inputs: Line in (unbalanced RCA or balanced XLR)
-Other outputs: Speaker output (optional)
-Output power (unbalanced): 18Wrms/ch into 8Ω, 5.6Wrms/ch into 32Ω, 0.75Wrms/ch into 300Ω
-Output power (balanced): >50Wrms/ch into 8Ω
-Possible upgrades/upgrade path: See websites
-Input Sensitivity: n/a
-Maximum Gain: 8 (20.8db) default, can be built to other gain settings
-Input Impedance: 47.6KΩ (depends on volume pot/attenuator used)
-Output Impedance: < 0.01Ω 20Hz - 20KHz
-Total Harmonic Distortion: 0.0010% (RMAA)
-Intermodulation Distortion: 0.0072% (RMAA)
-Frequency Response: 0Hz - 2.5MHz, +0, -3dB
-Slew rate: 198V/µS @ 43Vp-p output, 100KHz square wave
-Rise time: 175nS 10%-90%, 100KHz square wave
-Signal to Noise Ratio: 90dBA (RMAA)
-Stereo Crosstalk: -86dB (RMAA)
-Housing material: Various choices
-Size (dimensions): Various choices
-Weight: n/a
