[Soundsgoodtome]

I'm new into the speaker world and am currently going to need a preamp for an amp that runs full on. I'm hoping some headphone amp enthusiasts who know speaker amps can chime in here. First, it's weird to see requirement voltages be 1.5v for a speaker amp to output 150w into an 8ohm load (1.5V from the preamp would be max volume for amp - is this the correct thinking?)... but then again I'm new to the speaker world. My understanding is these super low voltage requirements are more for units that output low voltage - preamps that output in 1.5v realm.

I'm looking at some of the requirements and was wondering if it's possible to use my Audio GD SA31SE as a preamp? DAC outputs at 2.7V but my AGD SA31SE does 4V line out (when fed 2.5V). Since the SA31SE goes to 99 on the volume/preamp and outputs 4V at max, now correct me if I'm wrong here, with this curve below and the 4V output - would I be able to use 0-30 on the volume to get from 0-1.5v the speaker power amp needs?
 

 

[Sodacose]

 First, it's weird to see requirement voltages be 1.5v for a speaker amp to output 150w into an 8ohm load

 
Nah, that's not too strange.  Most modern amps want 1-2V input to reach full rated output.  This is also about the output of most sources (CDP, DAC, etc).
 
Volume knobs are not normally linear with respect to output voltage (they work on a logarithmic scale), so you'll probably be able to get a lot more turn out of it before you get 1.5V.  
 
You should be fine.  If your speakers aren't rated to take the full 150W, just be careful with the volume control.  Unless they're real inefficient, you will probably have more than enough volume before you clip the amp anyways.

 

[Soundsgoodtome]

   
Nah, that's not too strange.  Most modern amps want 1-2V input to reach full rated output.  This is also about the output of most sources (CDP, DAC, etc).
 
Volume knobs are not normally linear with respect to output voltage (they work on a logarithmic scale), so you'll probably be able to get a lot more turn out of it before you get 1.5V.  
 
You should be fine.  If your speakers aren't rated to take the full 150W, just be careful with the volume control.  Unless they're real inefficient, you will probably have more than enough volume before you clip the amp anyways.

Thanks for the input! I'm powering some hungry KEF from the late 70s/early 80s. I'll be getting an amp that does 150wpc (rms) into 8ohms but worried about the output of my dac at 2.7V... which I'll be needing a preamp of course, that's where my Audio-GD comes in. I've gotten word directly from Kingwa himself that I should be able to use up 0-30 (up to 50) before full power is sent to the amplifier as you're correct it's non-linear.

 

 

[Sodacose]

My pleasure.  Some of the old KEF stuff is very nice.  Enjoy!

 

[Pharmaboy]

Some of the old KEF speakers are quite amazing. Back in the early 1980s, when I was transitioning from mass market audio gear to high end stuff, I made the rounds of NY/NJ audio salons, listening to the best gear. I heard some KEFs that knocked me out. I heard a symphony (Brahms?), and these big floor-standing KEFs put me right in Symphony Hall @Row M. I couldn't afford them, but they sounded beautiful.
 
Even the smaller KEF "bookshelf" speakers from the late '70s/early '80s were remarkably rich & "big."
 
Audio GD + KEF sounds like a combination made in heaven!

 

[Soundsgoodtome]

  Some of the old KEF speakers are quite amazing. Back in the early 1980s, when I was transitioning from mass market audio gear to high end stuff, I made the rounds of NY/NJ audio salons, listening to the best gear. I heard some KEFs that knocked me out. I heard a symphony (Brahms?), and these big floor-standing KEFs put me right in Symphony Hall @Row M. I couldn't afford them, but they sounded beautiful.
 
Even the smaller KEF "bookshelf" speakers from the late '70s/early '80s were remarkably rich & "big."
 
Audio GD + KEF sounds like a combination made in heaven!

They're the KEF 105.2 Reference floorstanding. They're a little rough in shape but very good for a 30yo cabinet/speaker --  but yes they do sound quite amazing.