Hello all!
I have a quick question for all of you builders out there. For my amp build, I am planning on using two 6L6GC output tubes in My output section. However, down the road I may want to double the output power, which I believe I can just add A couple of extra tubes in a specific configuration to get the extra power.
My intention is to buy components that I could use for the expansion if I want to do that, but not really sure how that would all come together.
If someone can provide a general explanation of how one would go about that, I would appreciate hearing your suggestions!
Double the tubes, double the power?
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martin manning
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Re: Double the tubes, double the power?
Both the output transformer and the power transformer (the whole power supply, really) will need to be sized for four tubes, so if you think you will be going there you might as well build it that way to start. You can run it at half power by removing or switching two tubes off, and you will need a multi tap OT to miss match the speaker load when you do that.
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Stevem
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Re: Double the tubes, double the power?
Three big things need to be taken into consideration when you have a power supply that has enough current to run 4 tubes, but your only running 2.
First off the near 100% less current draw will kick up the power supply voltage by maybe as much as 20%, so all of your power supply filters need to have a voltage rating to deal with that.
2nd, all of this added voltage powering the preamp section will have a impact on the tone, as in, as in more gain and more bottom and high end.
3rd, the excess current will keep the output tubes from going into clipping at the volume level that they would when the amp has all 4 output tubes in.
This can be a good thing or a bad thing depending on your playing needs.
Also twice the wattage output does not make for double the volume that your ear's precive!
If I where you I would be looking into a power scaling set up from London power to place into your build while your at it.
Another option is to get or build a attenuator box to go in line with the speaker(s)
First off the near 100% less current draw will kick up the power supply voltage by maybe as much as 20%, so all of your power supply filters need to have a voltage rating to deal with that.
2nd, all of this added voltage powering the preamp section will have a impact on the tone, as in, as in more gain and more bottom and high end.
3rd, the excess current will keep the output tubes from going into clipping at the volume level that they would when the amp has all 4 output tubes in.
This can be a good thing or a bad thing depending on your playing needs.
Also twice the wattage output does not make for double the volume that your ear's precive!
If I where you I would be looking into a power scaling set up from London power to place into your build while your at it.
Another option is to get or build a attenuator box to go in line with the speaker(s)
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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Dr Tony Balls
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Re: Double the tubes, double the power?
Yep. If volume is what you're after you'd be better off just using an extra cab or more efficient speakers.
I build effects and amps and do custom builds to order. Boom.
Site: http://ballseffects.com/
Site: http://ballseffects.com/
Re: Double the tubes, double the power?
+1 to the comments that just double the tubes does not mean double the power, and especially it does not mean twice the loudness. Double the power needs double the entire power handling chain; power transformer, rectifiers, capacitors, tubes, output transformer. Twice the perceived loudness needs maybe ten times the amplifier power.
From the Tube Amp FAQ, 1999 at geofex.com:
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How can I modify my Blender Tweety Bird amp to be as loud as a Marshall Major/AC30/Tweed Bassman/SVT/etc.?
(Alternatively, how can I make my amp twice as loud/more power/ etc.?)
You can't do this in a low power amp, at least not electronically. To put out the power the big amps put out, you need the entire power train to be as beefy as the big amps. This means bigger power transformer, rectifiers, filter capacitors, output transformer, more power tubes, bigger chassis, more ventilation to carry off the heat, lots of things. You can't just add a couple of tubes.
An amplifier is properly thought of as primarily a big power supply that has some extra junk tacked onto it to carefully let a little of the power out to the speakers under special, controlled circumstances.
You might be able to just pull a couple of tubes OUT of a high power amp to make it quieter, under some conditions.
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From the Tube Amp FAQ, 1999 at geofex.com:
====
How can I modify my Blender Tweety Bird amp to be as loud as a Marshall Major/AC30/Tweed Bassman/SVT/etc.?
(Alternatively, how can I make my amp twice as loud/more power/ etc.?)
You can't do this in a low power amp, at least not electronically. To put out the power the big amps put out, you need the entire power train to be as beefy as the big amps. This means bigger power transformer, rectifiers, filter capacitors, output transformer, more power tubes, bigger chassis, more ventilation to carry off the heat, lots of things. You can't just add a couple of tubes.
An amplifier is properly thought of as primarily a big power supply that has some extra junk tacked onto it to carefully let a little of the power out to the speakers under special, controlled circumstances.
You might be able to just pull a couple of tubes OUT of a high power amp to make it quieter, under some conditions.
====
"It's not what we don't know that gets us in trouble. It's what we know for sure that just ain't so"
Mark Twain
Mark Twain
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Stevem
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Re: Double the tubes, double the power?
The only thing that doubling the output tubes is guaranteed to get you? Assuming the output tubes test the same ) is double the clean head room in the output stage.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Double the tubes, double the power?
Only if it actually increases the output power. And without modifications to power supply it doesn't.
And what's double clean headroom anyway? In terms of loudness doubling the output power only results to slightly audible increase in loudness (ca. 1.3x "louder"). I wouldn't regard that as marvelous increase in "headroom", not even significant increase. It's just barely louder than previously. Much easier to invest in more sensitive speakers, IMO.