2. amps-preamps
  3. 190231-188464

Watts! How many do we need?

Got a new amp. Accuphase P-4600. It’s great. I love it. 
150 watts into 8 ohms, 300 watts into 4 ohms and it has meters so I can see wattage. Have them set on freeze so I can see the highest wattage during the session.

My Harbeth speakers are not very efficient. Around 86db. Their impedance is an even 6 ohms dipping no lower than 5.8 ohms. 

Playing HiRes dynamic classical recordings  ( Tchaikovsky , Mahler) at room filling volumes I have yet to exceed 1watt.. 

Amps today offer a lot of watts some going to 600 even 1200 watts. Even if you have inefficient speakers with an impedance that dips down to 2 ohms do we need all this wattage or should we be focusing on current instead? 

jfrmusic
westcoastaudiophile
274 posts
 

@jfrmusic spec with design details for p4600 https://www.accuphase.com/cat/p-4600_e.pdf 

jfrmusic OP
257 posts
 

@westcoastaudiophile

Yep that's what I was looking at. 6 transistors per channel. Now I would be happy if I was getting 10 watts per channel in Class A. Please direct to where this is noted.

westcoastaudiophile
274 posts
 

@jfrmusic it was noted here in my post above.. you may ask Accuphase support and update us on their  detailed spec details for this AB amp design! 

jfrmusic OP
257 posts
 

Ok I’ll send them an email. They’re very responsive

jfrmusic OP
257 posts
 

@weatcoastaudiophile

Still don’t understand how you calculated your number from those specs but you were on the money. Here’s the response from Accuphase. 
 

The actual amount of Class A bias for the P-4600 is not a fixed amount and will vary depending on the load of the speaker.  For most speakers it should have around 8W – 10W of class A bias but that could be less for speakers if they have less than 4 ohm impedance.  The exact method for how Accuphase applies bias to its output transistors is considered proprietary information and they do not allow us to publish more than that.

More to discover