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High B+ voltage on export version

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Christophe Le Crom (vignau)
Username: vignau

Registered: 08-2010
Posted on Wednesday, June 01, 2011 - 06:51 am:   

Hi,
This is something I already talk about on the help topic concerning the high B+ voltage measure on my 210HD130 (2275 EX). I measure 770 V. Amp works fine on low and high position but I am use to select the low position, far enough for gigs. Input AC is 237V . Any idea on how to decrease B+ voltage ? (a resitor somewhere in the power section, ie the power switch ?). Some guys in France are use to decrease voltage on princeton by using 5U4G as rectifier instead of GZ34. Any expriences from this forum on B+ voltage with EX model in Europe or Australia ?
Lars Verholt (lmv)
Username: lmv

Registered: 11-2009
Posted on Wednesday, June 01, 2011 - 05:02 pm:   

I wouldn't worry too much - the voltage is only about 6% over the 725V nominal voltage in the schematic. That voltage was probably created with a reference input voltage of 220V.
If memory serves, the EX models have a voltage input tap for UK power (nominal 240V back in the day). If you use that tap (which may be marked 250V in the schematic), you would get a slightly lower B+ and keep you further away from the 800V maximum voltage for EL-34.

Cheers,
Lars Verholt
Christophe Le Crom (vignau)
Username: vignau

Registered: 08-2010
Posted on Thursday, June 02, 2011 - 07:53 am:   

Not sure Lars I understand, you mean there is a available wire to be connected for 240 V ?, which color ? probably you don't know as you are in Canada, I have to open it again... Any guys around with EX version (Europe, Australia...) ?
Lars Verholt (lmv)
Username: lmv

Registered: 11-2009
Posted on Saturday, June 04, 2011 - 06:06 am:   

The 250/240V tap is red-black.

-Lars Verholt
Christophe Le Crom (vignau)
Username: vignau

Registered: 08-2010
Posted on Saturday, June 04, 2011 - 06:41 am:   

Thank's Lars,
I will have a look around when I will open the amp.
Regards,
Chris