Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: EKDENTON on May 13, 2016, 09:01:37 am
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On mark's power supply he has the 5k5watt resistor + the choke. Should the resistor stay when using the choke? I see on the updated schematic hoffman version, that has several changes and the 5k5watt is removed. I am using a tube rectifier on this one. Also I am using the JJ filter can Doug sells 40/20/20/20. That leaves me one 20u section left over on the can cap when wiring the amp by the huss schematic. Would it be of any benefit to use the unused 20u? If yes what would be the best way to use it? Would it be simply be jumpering the last two 20u's together? Is a resistor needed if I do? Probably silly questions, I know.
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It says on the updated mhuss schematic (rev c) to wire 40/20/20/20 cap so that first two 20 are parallel so that it makes 40/40/20 cap.
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Okay thanks, now I see the note below the caps on the schematic.
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You did notice that Mark's schematic has a total of 5 B+ nodes??? You could use the can for nodes A, B, C, and D. Then you only need one additional filter cap.
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You did notice that Mark's schematic has a total of 5 B+ nodes??? You could use the can for nodes A, B, C, and D. Then you only need one additional filter cap.
Thats on the Hoffman 6v6 plexi schematic you drew up.
Mark's only has 3 B+ nodes the two preamp tubes and PI share node C.
He has the two additional 22u 450v radial filter caps with 10K cap resistors on the board.
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Mark's only has 3 B+ nodes the two preamp tubes and PI share node C. He has the two additional 22u 450v radial filter caps with 10K cap resistors on the board.
Yes, and three plus two equals five. :icon_biggrin:
If you are building this in a 12" chassis like Doug and I did, then space is a premium. If you can eliminate 1 cap from the board, your board can be shortened 1 inch. That's a lot of real estate in a 12" chassis.
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Yes, and three plus two equals five. :icon_biggrin:
Haha ... Okay so I Had that comming!
Yes I like that layout and having it all in a smaller chassis is really nice. I want to try that one soon. I have this one to finish and two others first though.
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I think you will like the sound of this amp, I know I do. :icon_biggrin:
Doug's uses a SS rectifier, what tube are you going to use GZ34?
With the tube rectifier have you tried making that in PSU?
With SS we can use bigger filter caps with no problems.
I found out that the tube rectifiers are a little more finicky about how big of filter caps you can use early in the PS.
I ran some simulations with tube rectifiers that didn't like my bigger 40-50uF caps, even when I had a small 10uF before the choke.
I think it would be worth the time to put your PS in PSU and see if it complains about 40/40uF for the first 2 filter caps. :dontknow:
IMO, that is much better than building it and smoking your tube rectifier when you try it out. :icon_biggrin:
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Yes the GZ34 is what i want to try this time. I have diodes on the board if I decide i dont like the tube rectifier.
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I just mentioned that filter cap issue in case you were unaware of it like I was not too long ago. :BangHead:
If you are using a vintage GZ34 with their insane prices, you definitely don't want to kill that tube. :sad2: