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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 8:08 am
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Guitarist1983 wrote:
stratele52 wrote:
+1 aclempoppi.

With two tubes removed, the amp won't play at half level, and 50 watts is a very loud too.


+1

Theoretically, (if memory serves me/someone please correct if this is wrong):
10 watts will give approximately 1/2 the volume of 100 watts. It would take 1000 watts to achieve approximately 2 times the volume of 100 watts. So pulling 2 tubes from a 4 tube amp cuts the watts in half, which doesn't cut the volume in half.
(Theoretical of course, your mileage may differ :)


Every doubling of power is a 3 dB increase in power. Doubling volume is a 10 dB increase in sound pressure level (SPL).

Assume you have a speaker with an effiicency of 100 dB SPL at 1 watt input measured at 1 meter (standard method to measure speaker efficiency). This is a pretty common value for a guitar speaker:

1 watt power in = 100 dB SPL

2 watts power in (+3 db, power doubled) = 103 dB SPL

4 watts power in (+3 db, power doubled again) = 107 dB SPL

8 watts power in (+3 db, power doubled again) = 110 dB SPL (volume has now doubled)

Continuing on using this speaker and an 80 watt Twin Reverb gives you:

16 watts power in (+3 dB, power doubled again) = 113 dB SPL

32 watts power in (+3 dB, power doubled again) = 116 dB SPL

64 watts power in (+3 dB, power doubled again) = 119 dB SPL

80 watts power in (approximately +1 dB) = 120 dB SPL (volume has been doubled again).

So yes, it takes about 10 times the amount of power to double the volume level.

It works the same way reducing power to reduce volume. However, the amount of power reduction achieved when going from 4 tubes to 2 tubes really depends on the circuit design. It can be approximated mathmatically, but a measurement would be better.

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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 8:41 am
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bluesky636 wrote:
Guitarist1983 wrote:
stratele52 wrote:
+1 aclempoppi.

With two tubes removed, the amp won't play at half level, and 50 watts is a very loud too.


+1

Theoretically, (if memory serves me/someone please correct if this is wrong):
10 watts will give approximately 1/2 the volume of 100 watts. It would take 1000 watts to achieve approximately 2 times the volume of 100 watts. So pulling 2 tubes from a 4 tube amp cuts the watts in half, which doesn't cut the volume in half.
(Theoretical of course, your mileage may differ :)


Every doubling of power is a 3 dB increase in power. Doubling volume is a 10 dB increase in sound pressure level (SPL).

Assume you have a speaker with an effiicency of 100 dB SPL at 1 watt input measured at 1 meter (standard method to measure speaker efficiency). This is a pretty common value for a guitar speaker:

1 watt power in = 100 dB SPL

2 watts power in (+3 db, power doubled) = 103 dB SPL

4 watts power in (+3 db, power doubled again) = 107 dB SPL

8 watts power in (+3 db, power doubled again) = 110 dB SPL (volume has now doubled)

Continuing on using this speaker and an 80 watt Twin Reverb gives you:

16 watts power in (+3 dB, power doubled again) = 113 dB SPL

32 watts power in (+3 dB, power doubled again) = 116 dB SPL

64 watts power in (+3 dB, power doubled again) = 119 dB SPL

80 watts power in (approximately +1 dB) = 120 dB SPL (volume has been doubled again).

So yes, it takes about 10 times the amount of power to double the volume level.

It works the same way reducing power to reduce volume. However, the amount of power reduction achieved when going from 4 tubes to 2 tubes really depends on the circuit design. It can be approximated mathmatically, but a measurement would be better.

No wonder my hearing is going


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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 9:48 am
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tbazzone wrote:
bluesky636 wrote:
Guitarist1983 wrote:
+1

Theoretically, (if memory serves me/someone please correct if this is wrong):
10 watts will give approximately 1/2 the volume of 100 watts. It would take 1000 watts to achieve approximately 2 times the volume of 100 watts. So pulling 2 tubes from a 4 tube amp cuts the watts in half, which doesn't cut the volume in half.
(Theoretical of course, your mileage may differ :)


Every doubling of power is a 3 dB increase in power. Doubling volume is a 10 dB increase in sound pressure level (SPL).

Assume you have a speaker with an effiicency of 100 dB SPL at 1 watt input measured at 1 meter (standard method to measure speaker efficiency). This is a pretty common value for a guitar speaker:

1 watt power in = 100 dB SPL

2 watts power in (+3 db, power doubled) = 103 dB SPL

4 watts power in (+3 db, power doubled again) = 107 dB SPL

8 watts power in (+3 db, power doubled again) = 110 dB SPL (volume has now doubled)

Continuing on using this speaker and an 80 watt Twin Reverb gives you:

16 watts power in (+3 dB, power doubled again) = 113 dB SPL

32 watts power in (+3 dB, power doubled again) = 116 dB SPL

64 watts power in (+3 dB, power doubled again) = 119 dB SPL

80 watts power in (approximately +1 dB) = 120 dB SPL (volume has been doubled again).

So yes, it takes about 10 times the amount of power to double the volume level.

It works the same way reducing power to reduce volume. However, the amount of power reduction achieved when going from 4 tubes to 2 tubes really depends on the circuit design. It can be approximated mathmatically, but a measurement would be better.

No wonder my hearing is going


WHAT?????

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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 11:25 am
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howardken52 wrote:
Toppscore wrote:
Hi, I own the following four amps, each with four power tubes:
1964 Fender Twin Reverb 85w 2x12 combo
1968 Fender Dual Showman Reverb 100w amp head
1984 Fender Twin Reverb II 105w amp head
1994 Fender Tone Master 100w amp head

Question:
Within an amp that has four power tubes, what are your thoughts about removing
two power tubes to reduce the wattage output for better home practice volumes?
or small club or show volumes?

Good idea or bad idea?

Which two to remove? Inner two? Outer two?
Any two? does it make a difference?
I've read that the inner or outer two would do the job.
To learn something here, why are some tubes not to be removed?

Also, I've purchased a Weber Mass 200 attenuator and it is great.
But, we've all read about how some of the older amps (I have several)
might have output transformer issues with attenuator!!! True or not,
would it be better to remove two of four tubes rather than attenuate all four?

Does the bias need to be constantly reset?
Say you are practicing at home in the morning
with 50w two tubes, then go to practice later, and re-install to 100w four tubes.
Does going back and forth require bias setting or not?

Thanks for your ideas, experiences and technical know-how :shock:
Toppscore 8)


Why do I get the feeling you don't own any of the amps you listed?

Howard, why?
These are just amps with four power tubes. Reason for this thread.
Wonder why, Howard, keep wondering.

Howard, why do I wonder why you are here?
Are your thoughts without thought? Are you "thinking", Howard?
Go deep, Howard, and find that "inner feeling". Express it to someone who cares.
Maybe you'll find out, "why". Why, howard, why? Go deep.

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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 11:54 am
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We got a new member in the club. Welcome Howard :D


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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 12:29 pm
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tbazzone wrote:
We got a new member in the club. Welcome Howard :D

Howard is a good man!
Just has some "feelings" and "why's".
Sensitivity is good. Right Tabby?

At least Howard is a bit advanced as he get's some sort of an inquiry or question in there :lol:

Take care. Toppscore 8)

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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 7:35 pm
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Thanks for the 6V6 info, Beemer! Might be something fun to try. Good breadown on the watt-db relationship, Bill!!! Art

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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 7:53 pm
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" Hi, I own the following four amps, each with four power tubes:
1964 Fender Twin Reverb 85w 2x12 combo
1968 Fender Dual Showman Reverb 100w amp head
1984 Fender Twin Reverb II 105w amp head
1994 Fender Tone Master 100w amp head "



I know this is a crazy question & maybe I'm taking a big bite of the BIG bait-- but why do you own four 85-100 watt amps? Just sell one and get a Princeton Reverb or DR. Then, your "attenuator issue" will be solved. Or is this too old school?

Thanks!


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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 8:46 pm
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BMW2002Ti wrote:
" Hi, I own the following four amps, each with four power tubes:
1964 Fender Twin Reverb 85w 2x12 combo
1968 Fender Dual Showman Reverb 100w amp head
1984 Fender Twin Reverb II 105w amp head
1994 Fender Tone Master 100w amp head "



I know this is a crazy question & maybe I'm taking a big bite of the BIG bait-- but why do you own four 85-100 watt amps? Just sell one and get a Princeton Reverb or DR. Then, your "attenuator issue" will be solved. Or is this too old school?

Thanks!

I think it could be called "compensation" for something lacking. :mrgreen:


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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 8:50 pm
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BMW2002Ti wrote:
" Hi, I own the following four amps, each with four power tubes:
1964 Fender Twin Reverb 85w 2x12 combo
1968 Fender Dual Showman Reverb 100w amp head
1984 Fender Twin Reverb II 105w amp head
1994 Fender Tone Master 100w amp head "



I know this is a crazy question & maybe I'm taking a big bite of the BIG bait-- but why do you own four 85-100 watt amps? Just sell one and get a Princeton Reverb or DR. Then, your "attenuator issue" will be solved. Or is this too old school?

Thanks!


You don't know the half of it. Here are some more amps he claims to own. I think there is an even longer list floating around out there too.

1954 5D6
4x10 1960 6G4 2x10
1962 6G4 2x10
1963 Tremolux
1964 Bassman Blackface
1964 Super Reverb

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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 9:07 pm
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You know what they say about a fool and his money......and he talks and mentions all this constantly,but not one picture of any two together..... :roll:


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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 10:31 pm
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bluesky636 wrote:
You don't know the half of it. Here are some more amps he claims to own. I think there is an even longer list floating around out there too.

1954 5D6
4x10 1960 6G4 2x10
1962 6G4 2x10
1963 Tremolux
1964 Bassman Blackface
1964 Super Reverb


I think Walter Mitty's "list" also included a CS Tonemaster stack or half-stack, Bill.

(I wonder how many Dumbles he'll "own" once he learns about them on the web?)

:lol:

Arjay

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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 11:29 pm
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bluesky636 wrote:
BMW2002Ti wrote:
" Hi, I own the following four amps, each with four power tubes:
1964 Fender Twin Reverb 85w 2x12 combo
1968 Fender Dual Showman Reverb 100w amp head
1984 Fender Twin Reverb II 105w amp head
1994 Fender Tone Master 100w amp head "



I know this is a crazy question & maybe I'm taking a big bite of the BIG bait-- but why do you own four 85-100 watt amps? Just sell one and get a Princeton Reverb or DR. Then, your "attenuator issue" will be solved. Or is this too old school?

Thanks!


You don't know the half of it. Here are some more amps he claims to own. I think there is an even longer list floating around out there too.

1954 5D6
4x10 1960 6G4 2x10
1962 6G4 2x10
1963 Tremolux
1964 Bassman Blackface
1964 Super Reverb

Pretty good score keeping, Bluesky! I AM very impressed :!: :P
You can take out the words "claims to own." and replace with "owns."

The 1962 Super Amp has been sold :cry: . . . wishing it was not gone with what I know today.
There are several "1960s" missing from your inventory.

But, thanks for the reminder :lol: :lol: :lol:

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Last edited by Toppscore on Wed Jul 11, 2012 11:47 pm, edited 1 time in total.

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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Wed Jul 11, 2012 11:45 pm
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Retroverbial wrote:
bluesky636 wrote:
You don't know the half of it. Here are some more amps he claims to own. I think there is an even longer list floating around out there too.

1954 5D6
4x10 1960 6G4 2x10
1962 6G4 2x10
1963 Tremolux
1964 Bassman Blackface
1964 Super Reverb

I think Walter Mitty's "list" also included a CS Tonemaster stack or half-stack, Bill.
(I wonder how many Dumbles he'll "own" once he learns about them on the web?) :lol:
Arjay


Interestingly enough . . . . . . the Tone Master "stack" sold tonight on EBay.
Just the gorgeous amp head remains 8)

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Post subject: Re: 4-Power Tubes * 2-Power Tubes or Attenuate All Power Tub
Posted: Thu Jul 12, 2012 12:10 am
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Toppscore wrote:
You can take out the words "claims to own." and replace with "owns."


The only thing we're *pretty certain* you own is a computer.

:lol:

Arjay

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