2. amps-preamps
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need help with impedance on SF power 2

I just get a Sonic Frontier power 2 and Genesis APM-1. On the manu, APM-1 impedance is 4 ohms and I am not sure what is the normal impedance for power 2. Is all SF power amp @ 8 ohms. I read on the manu said I have to make sure impedance match with speaker. What effect if I have 8 ohms on the amp and 4 ohms on the speaker? I felt like I need to turn up the volume quite high in order to get a good sound level. BTW, the APM-1 is 90db sensitivity.
waip7

Showing 3 responses by kana813

kana813
956 posts
 
How could you have purchased a tube amp without knowing it had output transformers? If you didn't know this, I recommend you carefully read the owners manual before you attempt to operate this or any tube amp. SF products have some of best manuals in the industry. If you didn't get one with amp, you can download it off their the website.

Agree with Gsselling, what you give up in bass control on the 8 ohm tap, is more than made up for in openness. You can tighten up the bass by replacing the stock 6550s with KT-90s. Talk with Kevin at Upscale Audio.
kana813
956 posts
 
You are very luckly to get an SE.

Using the 8 ohm tap will not shorten tube life.

Just make sure the tube bias is set correctly, which is very easy to do on SF amps.

If you decide you don't like the amp, please contact me.
kana813
956 posts
 
Waip7- I also have a SF Line 2, running a single-ended/RCA
source in and balanced XLR out to the amp is perfectly
fine.

A volume level between 60-70 for loud normal playback
is also fine. I normally listen between 55-65, but my amp's
input sensitivity is lower than the Power 2. It also depends on the output level of the source and the size of your room.
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