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which voltage should I run this amp at?

Posted: Sat Sep 22, 2018 5:29 pm
by steamboat
Hello,

I'm in the U.S. and I'm just curious as to why this amp has the option of 110V and 118V ?
My other vintage oranges have 115V and the next available voltage is 200V 220V and 240V, so it's pretty easy to tell to just use the 115v.
I'm assuming use the 110V but I do know 115V is common here. Should I just measure the wall socket and use whatever is closer either 110v or 118v?
Or was 110V & 118V designed for another country?

Also, in the far bottom right in the picture, what does 100V Line mean? is that for the top 1/4 output jack or is that for the ohm selector? Should I only plug a speaker cab into the bottom of the two output jacks?

Image

Thanks

Re: which voltage should I run this amp at?

Posted: Sat Sep 22, 2018 5:48 pm
by bclaire
USA voltages are at least 118 volts. Use that one.

Re: which voltage should I run this amp at?

Posted: Sat Sep 22, 2018 6:13 pm
by steamboat
So use the 118V?

There is no 115V option. Like i said my other vintage amps have 115V as a choice.

I thought it was strange that this one had 110V & 118V as a choice.

Also in the far bottom right in the picture, what does 100V Line mean? is that for the top 1/4 output jack or is that for the ohm selector? Should I only plug a speaker cab into the bottom of the two output jacks?

thanks,

Re: which voltage should I run this amp at?

Posted: Sat Sep 22, 2018 7:21 pm
by Jondog
118. Some countries have 110, but NA is 115 or higher. I was measuring receptacle voltage at 125v the other day.

Re: which voltage should I run this amp at?

Posted: Sat Sep 22, 2018 7:34 pm
by steamboat
Thanks for clarifying that, much appreciated. I'll use the 118V.

Any idea what the 100V Line is all about?

Re: which voltage should I run this amp at?

Posted: Sun Sep 23, 2018 1:32 am
by fiveightandten
Definitely use the 118V. The amp will still run too hot on that tap, running off the 110V tap would run it WAY too hot.

The 100V line OT secondary tap won't really be of any use to you. It's to connect the amp to a 100V line speaker system. The PA system in, say, your high school, likely had a 100V line system. When you have long runs of wire, an amplifier can't power a large number of speakers with the wire creating resistance over large distances. So the speakers are powered off a 100V line and the amp drives them.

I'm not sure if that was ever even used for guitar amps back in the 70's. Maybe some of our older members may know. My '71 head (see sig pic) has this tap. I've never used it.

-Nick

Re: which voltage should I run this amp at?

Posted: Mon Sep 24, 2018 12:46 am
by steamboat
Nick,

Thanks for the info! I appreciate it.

This is also a Pics only Plexi amp. Whats the serial number on your 71 Plexi?

Re: which voltage should I run this amp at?

Posted: Mon Sep 24, 2018 3:16 am
by fiveightandten
steamboat wrote:
Mon Sep 24, 2018 12:46 am
Nick,

Thanks for the info! I appreciate it.

This is also a Pics only Plexi amp. Whats the serial number on your 71 Plexi?
Nice! I have #559