## Bottlehead Kits => Stereomour II => Topic started by: Adrian on April 02, 2017, 12:13:33 PM

Title: Gain into 4 ohm?
Post by: Adrian on April 02, 2017, 12:13:33 PM
The product page says the gain is 8 into an 8 ohm load.
I assume this is with the output transformers connected for 8 ohms.

What would be the approximate gain if the outputs are connected for 4 ohms feeding 4 ohm speakers?
Title: Re: Gain into 4 ohm?
Post by: Paul Joppa on April 02, 2017, 01:26:02 PM
The voltage gain would be about 0.7 times 8, or 5.6 - 0.7 being about the square root of 1/2.
Title: Re: Gain into 4 ohm?
Post by: Adrian on April 03, 2017, 03:06:31 PM
Got it:
assume power (watts) constant with v_1=8; R_1=8; R_2=4
w=v^2/R.
(V_1^2)/R_1 =(V_2^2)/R_2
v_2=v_1 √(R_2/R_1 )
v_2=8√(4/8)=5.66

(I think?)
Title: Re: Gain into 4 ohm?
Post by: Rocketman248 on April 03, 2017, 04:47:46 PM
....I understood some of those words.  :o
Title: Re: Gain into 4 ohm?
Post by: Paul Joppa on April 03, 2017, 05:56:18 PM
Got it:
assume power (watts) constant with v_1=8; R_1=8; R_2=4
w=v^2/R.
(V_1^2)/R_1 =(V_2^2)/R_2
v_2=v_1 √(R_2/R_1 )
v_2=8√(4/8)=5.66

(I think?)
Looks like you got it!