Sunn SL260 questions

[robbymiseries]

So back in December I acquired a Sunn SL260, I've got two WGS Vet 30's wired for 8 ohms in her at the moment. I recently bought an Avatar 2x12 to run with the SL, this cab is also 8 ohms. Since the load without an extension cab is already 8 ohms, am I safe running the Avatar with it? I'm not too sharp on impedance and have no access to any sort of owner's manual. Any insight is greatly appreciated!

[EdBass]

I think most transistor Sunns are stable to 4 ohms, which would mean another 8 ohm cab in parallel should be fine. I think I read somewhere that the SL260 was a descendant of the Beta series of amps, which I believe were rated at 100 watts with a 4 ohm load.

[robbymiseries]

Thanks a ton! I really appreciate the info, finding most anything on this amp has been a chore so far.

[loudthud]

I don't have a schematic for the SL260, but I do have a schematic for the SB160. The catalog info on the SL160, SL260 and SB160 is the same, all listed as 60W RMS with an 8 ohm load.

The SB160 schematic shows that the External Speaker jack is wired in series with the internal speaker so anything connected to the External Speaker jack raises the impedance seen by the power amp and will reduce power. Connecting an 8 ohm external speaker cabinet, while safe for the amp probably won't increase the volume.

[robbymiseries]

I don't have a schematic for the SL260, but I do have a schematic for the SB160. The catalog info on the SL160, SL260 and SB160 is the same, all listed as 60W RMS with an 8 ohm load.

The SB160 schematic shows that the External Speaker jack is wired in series with the internal speaker so anything connected to the External Speaker jack raises the impedance seen by the power amp and will reduce power. Connecting an 8 ohm external speaker cabinet, while safe for the amp probably won't increase the volume.

Thanks so much for the reply thud, gives me total peace of mind. I'm not so much after a volume increase as I am just a more filled out sound, so as long as it's safe I'm more than stoked! 

[ejudasf]

I am new here, and am hoping to get a descent copy of the schematic for the SB160. 

I don't understand where the op amp voltages originate from.  I may have more troubles as well.  I hope you can help.

Thanks.

ed