Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Phil_Tre on February 09, 2014, 02:11:58 pm
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Copy from my post on TDPRI...
Hi ! I will soon install a VVR in my 5E3. What I want is an internal pot
that I will set to a degree of attenuation that I like and forget about it.
I want to be able to just switch it on or off by the ground/standby switch
on the top of the chassis. see diagram...
(I will use a Dana/Hall design VVR but without pcb)
My question is not about VVR but more about the way to connect the toggle switch
to bypass the VVR and not loose the standby switch...
By the way, is this switch correct for the project: http://www.amplifiedparts.com/products/P-H527 (http://www.amplifiedparts.com/products/P-H527)
Can I do it like this ??
(http://www.tdpri.com/forum/attachments/shock-brothers-diy-amps/219382d1391972113-switching-vvr-vvr-jpg)
Thanks !
Phil.
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Can I do it like this ??
No. That DPDT switch does not operate the way you are thinking. Draw an imaginary vertical line down the center of the switch. The 3 lugs on the left make up one switch and the 3 lugs on the right make up another switch. They both switch at the same time. The lugs in the middle (you call them 2) are the wipers. In the top position the #2 lugs point up and connect to the #3 lugs. In the center position, the #2 lugs connect to NOTHING. And in the bottom position, the #2 lugs connect to the #1 lugs.
Now, the way you have it drawn, the switch does nothing. The VVR is always in the circuit. To do what you want, see pic...
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Thanks !!
Phil.
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I've had the same thought, but I've not put a lot of serious thought into it yet. I'm still trying to understand vvr
Not to hijack, but is there any reason this type of switch could not be used on, say, a higher voltag 6l6 amp (450+ volts) to run 6v6's?
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Is this DPDT switch day?
From another thread:
(http://www.el34world.com/Forum/index.php?action=dlattach;topic=16652.0;attach=41432;image)
The wiring shown will NOT work.
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A pair of years ago, for my job, I visited an old house
well, in the garret there was (and was still connected to the line) a switch like this
(http://lh5.ggpht.com/abramsv/SAbnkQ2ppjI/AAAAAAAAOmw/ENQzGfiZEz4/sdfhyewryhgfht55.jpg%3Fimgmax%3D512)
and you must pay a lot of attention when in the darkness you want to turn on the light :icon_biggrin:
K
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so if only one side of the switch is used, wouldn't a DPDT be overkill? I have a SPDT in my box, so that would work, right?
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yes
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Your plan puts raw high voltage on VVR module OUTput. It may not like that.
You could probably use a SPDT. Leave the VVR powered-up, but connect amplifier B+ to either VVR or to raw DC.
However with a DPDT in your hand, you may as well switch both ends of the VVR.
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Your plan puts raw high voltage on VVR module OUTput. It may not like that.
You could probably use a SPDT. Leave the VVR powered-up, but connect amplifier B+ to either VVR or to raw DC.
However with a DPDT in your hand, you may as well switch both ends of the VVR.
Ok, I like that... I will do it that way.
Update to come soon...
Thanks !