RAAL Requisite

HSA-1b Headphone & Speaker Amp

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  • Reference class headphone amp
  • Run ribbon headpohones, normal headpohones and speakers from the one desktop box
  • True balanced design
  • Precision 24-step attenuator for rock-solid left/right balance at all listening levels
  • Pro Audio heritage
  • 5 year local warranty


Simply put, the HSA-1b delivers the most enjoyable, immersive, engaging and outright addictive listening experience I’ve had with the SR1a, short of spending more than double the asking price on high-end speaker amplification!

In fact, I like the HSA-1b so much with the SR1a that I would have had no qualms about buying it just to drive them, even though that wouldn’t be taking full advantage of what it offers. But since I found it similarly compelling with almost every other regular headphone I tried it with, and it reduced my desktop box-count into the bargain, it was an even easier decision - and better value as a result.

Ian Dunmore (@Torq) on Headphones.com


Direct drive amplifier for True-Ribbon Earfield Monitor headphones, speakers, conventional dynamic, and planar magnetic headphones.


Load Impedance: 0.3 Ohm – infinity
Output Power (one chanel driven): 10W /8Ω, 20W/4Ω, 40W/2Ω, 55W/1Ω @ 1khz/sine
Ribbon & Headphones Drive: RAAL-requisite SR-1a, Dynamic & Planar Magnetic
Speaker Drive: 8Ω, 4Ω, & 2Ω Loads
Freq. Response: 100mv/ in/sin. 15hz – 500kHz
Power Bandwidth: 100kHz (-3db) at 1khz
Distortion: < 0,5% at 1khz
Signal to Noise Ratio: Better than 90dB
Input Impedance: 40 kOhm
Sensitivity: 0,5V /40kOhm
Input: IN1- 2 RCA, IN2 – 2 XLR
Max Power Consumption: 150W , without signal 25W
Dimensions: H 90, W 218, D 320mm (3.54 x 8.58 x 12.60 inches)
Weight: 5,3kg (11.68 pounds)



  • HSA-1b amp unit
  • Power cable
  • Manual
  • 5 year warranty


Some stock is kept on hand but due to the large number of model and colour combinations speakers are only made once ordered. If it says "In Stock" or "Buy Now" then it's good to go. It it says "Pre-Order" then it is made to order and delivery times are 6-8 weeks.

Free shipping in Australia. 



HSA-1b Headphone &amp; Speaker Amp
HSA-1b Headphone &amp; Speaker Amp
HSA-1b Headphone &amp; Speaker Amp

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