plate voltage effect on tone

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frankly
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Re: plate voltage effect on tone

Post by frankly »

Hi all,

Just wanted to see if any amp guys out there have any thoughts on this:

Just hauled out my old "the ultimate tone 1" book and read in "the preamp basics" section (p4-5) that shows that increasing plate voltage by a lot only increases gain by a little.
20230306_133728.jpg
Look at lines 5 and 10. Doubling plate voltage (v+) apparently only increases gain (Av) by about 4%.

I wonder why a lot of amps are made nonetheless with really high plate voltages. Is it just to eke out the extra bit of power for marketing purposes or does it really make that much of a difference in tone?

Could it just be tradition and using tried and true voltages? I would think that running higher voltages would shorten tube life over time.

Frank
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pdf64
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Re: plate voltage effect on tone

Post by pdf64 »

frankly wrote: Mon Mar 06, 2023 5:46 pm
Just hauled out my old "the ultimate tone 1" book and read in "the preamp basics" section (p4-5) that shows that increasing plate voltage by a lot only increases gain by a little.

20230306_133728.jpg
Is the unbypassed cathode on which that table is based relevant here?
Bear in mind that compared to bypassed, it greatly increases anode source impedance, thereby reducing loaded gain.
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Reeltarded
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Re: plate voltage effect on tone

Post by Reeltarded »

Ehh.. brighter. Moves the harmonics, and if you have a plan to develop a specific sound it is pretty much where to start.

If you increase 100k to 220k it's facey and zippy. You can use a bigger cathode bypass and.. well, everything is a balancing act.
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WhopperPlate
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Re: plate voltage effect on tone

Post by WhopperPlate »

Reeltarded wrote: Tue Mar 07, 2023 3:04 am
If you increase 100k to 220k it's facey and zippy. You can use a bigger cathode bypass and.. well, everything is a balancing act.
Why I don’t like high plate amplifiers . 102 comes to mind.
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Reeltarded
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Re: plate voltage effect on tone

Post by Reeltarded »

For high gain amp it can reveal too much attack that is very hard to hide without some sewious expewience.
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
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