Brian
Joined: Feb 25, 2006
Posts: 19194
Des Moines, Iowa, USA
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Posted on Jan 21 2020 10:27 AM
Asking for someone else
I just wanted to ask a question about my Alamo 2570,,,,it has two 10 inch speakers and an extra speaker jack in front ,,,,what omm speaker should I use for the extra speaker help with this would appreciated
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Surf_Skater
Joined: Sep 06, 2012
Posts: 1288
Lawrenceville , GA
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Posted on Jan 21 2020 06:20 PM
https://surfguitar101.com/forums/topic/19170/?page=1#p250762
You might want to ask Bill aka remora1. He said he had one in this old thread and he still is active on the site.
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MC
Joined: Aug 23, 2017
Posts: 47
Atwater California
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Posted on Jan 22 2020 07:27 PM
I'm guessing he has the early 1960's tube model. From looking at some pics on the internet and doing a little research the amp should have two 10 inch speakers, 16 ohms each wired parallel. The output transformer would see a 8 ohm load. The wires from the OT to the ext speaker jack look to be a parallel circuit to the speakers. If your friend plugs a 8 ohm speaker cab into the jack the OT would see a 4 ohm load. Looking at some pics on the internet the output tubes have 20 uf caps above the tube sockets indicating cathode bias. This should allow for an 8 or 4 ohm load to self adjust with out stressing the output circuit. Fender amps have the same circuit where there is a speaker and ext speaker out although not using cathode bias. Fender amps OT can handle + - 100%. I suspect they were not the only ones using well built OT's. Plug a 8 ohm speaker in and see what happens. If the volume is the same or a little louder you should be ok.
Here is a link to the pics I'm referencing to
https://el34world.com/Forum/index.php?topic=13041.0
Also he could submit a question to Skip Simmons TAVA pod cast
podcast@fretboardjournal.com
Or he could call or email Skip from his web sight http://www.skipsimmonsamps.com/
Last edited: Jan 22, 2020 19:37:22
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