100 volt input on PT

All about iron and copper.

Moderator: VelvetGeorge

Post Reply
danman
Senior Member
Posts: 680
Joined: Tue Sep 10, 2013 9:09 pm
Just the numbers in order: 13492

100 volt input on PT

Post by danman » Thu Sep 19, 2013 11:27 pm

Hello everyone, I am starting a new build on a JMP 50 watt (68 lead spec) and I am trying to decide on which PT I should get. I notice that on some of the PT's listed for this model have an extra 100 volt primary tap along with the standard 120/220/240 inputs. What is the purpose of this? Is this simply for areas that have 100 volt service (which I didnt know existed) or can you use this tap with a variac to achieve a lower voltage on the secondary? I have been searching for several days now and can not seem to find an answer so I thought I would check with you guys first before making a purchase. Thanks for any info you can provide on this.

danman
Senior Member
Posts: 680
Joined: Tue Sep 10, 2013 9:09 pm
Just the numbers in order: 13492

Re: 100 volt input on PT

Post by danman » Sat Sep 21, 2013 5:24 pm

I finally found my answer on the Classictone site today. It turns out that the 100volt winding is for use in Japan. Guess I wouldn't need that option!

rockgod212
Senior Member
Posts: 1169
Joined: Wed Mar 03, 2010 11:47 pm
Just the numbers in order: 7
Location: U.S.A.
Contact:

Re: 100 volt input on PT

Post by rockgod212 » Sun Mar 29, 2015 2:20 pm

but does the 100volt tap lower the plate voltage at all compared to 120volt, I have the same transformer and I just got a variac and I want to lower it. right now im at 436vdc unbiased@120vac, so will the 100volt tap variaced to 100vac input lower the plate voltage, or will it still be the same as the 120vac input?
"purple power rules"

User avatar
Brian Wallace
Supporting Advertiser
Posts: 873
Joined: Thu Mar 03, 2005 10:45 pm
Just the numbers in order: 7
Location: Michigan
Contact:

Re: 100 volt input on PT

Post by Brian Wallace » Sat Apr 04, 2015 12:32 pm

Using the 100VAC primary tap with the US 120VAC wall voltage will raise all the secondary voltages.
Patience is a virtue.

Wallace amps

Wallace forum

User avatar
syscokid
Senior Member
Posts: 618
Joined: Mon Oct 27, 2008 2:25 pm
Just the numbers in order: 13492
Location: Groovy Beach, CA.

Re: 100 volt input on PT

Post by syscokid » Sat Apr 04, 2015 4:49 pm

Can any part of the amp get damaged if you use the 220vac tap with an actual 120vac supply?
:scratch:
"When I'm on stage and first plug in, and I feel a rush of air in my balls... That's when I know my guitar is sounding good!" -Leslie West

Haze13
Senior Member
Posts: 413
Joined: Tue Oct 16, 2012 10:33 am
Just the numbers in order: 13492
Location: Israel. Bat-Yam

Re: 100 volt input on PT

Post by Haze13 » Sat Apr 04, 2015 11:06 pm

If there is enough voltage for the heaters than probably not. Every thing just will be lower... B+, bias, heaters...
ADA preamps run this way. ~4vdc for heaters and less than 200 volts for B+.

Post Reply