Interesting voltage drops

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Normster
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Re: Interesting voltage drops

Post by Normster »

I'm not sure what PT you're using, but the D'Lite 325-0-325 needs a 1K as the first dropping resistor to maintain correct V3 plate voltage. If you're using a more traditional 345-0-345, then use a 2.2K as Scott suggested.

BTW, Preamp tube brands WILL effect voltages. EH 12AX7's seem to run in the 195-210V range while JJ's run about 180-200V.

Oh, and Scott...no lecture on the PT please. Moss has the 345's coming in. :lol:
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dogears
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Re: Interesting voltage drops

Post by dogears »

Actually with the 457V you have on the B+, you should have a 3.3K wirewound after the screens. Also, use a single 150K for the FET simulator. It is neater than the paralle thingy.... LOL
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odourboy
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Re: Interesting voltage drops

Post by odourboy »

dogears wrote:... It is neater than the paralle thingy.... LOL
Bite me! I said it was just as a test! :D
"Let's face it, the non HRMs are easier to play, there, I've said it." - Gil Ayan... AND HE"S IN GOOD COMPANY!

Black chassis' availble: http://cepedals.com/Dumble-Style-Chassis.html
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DaveBo32
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Re: Interesting voltage drops

Post by DaveBo32 »

You guys rock, It's amazing how much the pwr supply effects the sound. I'm using a 325-0-325 180mA Fender replacement P-TF22723 from tubes and more. I currently have a 1K 3W at the first dropping resistor(between B+2 and B+3). Dogears, When you said I should have 3.3k wirewounds after the screens, are you refering to the 1k 5W cerment resistors that are connected to pin 4 of each pwr tube(screen grids)? Is the goal here, to knock down that voltage so I don't burn my tubes out?:oops: I need to go shopping for parts..

Thanks again guys, your suggestions are constantly improving this amp.

Dave
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dogears
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Joined: Wed Feb 01, 2006 1:29 pm

Re: Interesting voltage drops

Post by dogears »

Just change the 1K to a 2.2K or 3.0K (depending on what voltage you wind up at). Not the screen resistors. I merely mean you should replace the 1K with a wirewound resistor (cement is fine) of 2.2K or 3.0K value. Dumble used wirewounds there 100% of the time (as far as I know). Maybe he wanted the inductance. You can custom size too. 2.5K, 2.7K, etc....
DaveBo32 wrote:You guys rock, It's amazing how much the pwr supply effects the sound. I'm using a 325-0-325 180mA Fender replacement P-TF22723 from tubes and more. I currently have a 1K 3W at the first dropping resistor(between B+2 and B+3). Dogears, When you said I should have 3.3k wirewounds after the screens, are you refering to the 1k 5W cerment resistors that are connected to pin 4 of each pwr tube(screen grids)? Is the goal here, to knock down that voltage so I don't burn my tubes out?:oops: I need to go shopping for parts..

Thanks again guys, your suggestions are constantly improving this amp.

Dave
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DaveBo32
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Joined: Sat Feb 24, 2007 3:44 am
Location: Salem, NH

Re: Interesting voltage drops

Post by DaveBo32 »

Cool, I'll do that..Thanks again
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