Michael_DK
New Member
With everybody talking about how loud this thing is, I'm starting to think this amp is not for me and my bedroom playing....
Yes, same with the 50.I use my Archon 100 at home levels. I'm sure the mt15 will do it.
With everybody talking about how loud this thing is, I'm starting to think this amp is not for me and my bedroom playing....
I had my volume control modded to an area control. Just one derivative...
For those talking about its loudness for only a supposedly 15 watt amp, don't forget that volume works on a logarithmic scale. For twice the volume you need 10 times the power! To get twice as loud as a 15 watt amp, you'd need 150 watts. For twice as loud as a 50 watter, you'd need a 500 watt amp!
In other words, this is potentially only half as loud as a 150 watt amp.
Actually, the multiplier is 8, not 10. A 120W amp is twice as loud as a 15W amp. It takes a 9dB increase in sound pressure for the human ear to perceive something as twice as loud. Sound pressure increases by 3dB every time we double power; therefore, we are looking at 2 to the 3rd power. Inversely, it takes an 9dB reduction in sound pressure for the human ear to perceive something as half as loud. If we want to reduce volume to that of 1/8th of a 100W amp, we need to reduce sound pressure by 27dB, which is equivalent to dividing power by 512 (2 raised to the 9th power). A 0.2W amp is 1/8th as loud as a 100W amp.
One thing that needs to be understood is that the average guitar speaker produces 100dB @ 1W @ 1 meter.
dB = 10 * log10(power)
Therefore, we have the following sound pressure levels are different wattage levels
100 + 10 * log10(1) = 100db@1W
100 + 10 * log10(2) = 103dB @2W
100 + 10 * log10(4) = 106dB@4W
...
100 + 10 * log10(15) = 111.76dB15W
...
100 + 10 * log10(100) = 120dB@100W
The human voice at three feet is 65dB. Needless to say, a 1W amp at full tilt through a loudspeaker with an efficiency of 100dB @ 1W @ 1 meter is significantly louder than the human voice. I love tube amps as much as the next guitarist, but, in my humble opinion, bedroom playing is best handled by a full quality analog solid-state setup or a digital signal processor combined with a solid-state power amp. We are dealing with a compromise situation where we want to achieve the best possible performance at the lowest possible volume. Solid-state circuitry is more linear and allows for a finer level of control over signal shaping. The beauty in a tube amp lies in how the power section pushes back at you when run at full tilt. This phenomenon is due to poor power amp damping and back EMF from the speaker. While I use a tube amp when I jam somewhere where I can open it up, I use a Tech 21 Trademark 60 at home. There are different tools for different jobs.
Actually, the multiplier is 8, not 10. A 120W amp is twice as loud as a 15W amp. It takes a 9dB increase in sound pressure for the human ear to perceive something as twice as loud. Sound pressure increases by 3dB every time we double power; therefore, we are looking at 2 to the 3rd power. Inversely, it takes an 9dB reduction in sound pressure for the human ear to perceive something as half as loud. If we want to reduce volume to that of 1/8th of a 100W amp, we need to reduce sound pressure by 27dB, which is equivalent to dividing power by 512 (2 raised to the 9th power). A 0.2W amp is 1/8th as loud as a 100W amp.
One thing that needs to be understood is that the average guitar speaker produces 100dB @ 1W @ 1 meter.
dB = 10 * log10(power)
Therefore, we have the following sound pressure levels are different wattage levels
100 + 10 * log10(1) = 100db@1W
100 + 10 * log10(2) = 103dB @2W
100 + 10 * log10(4) = 106dB@4W
...
100 + 10 * log10(15) = 111.76dB15W
...
100 + 10 * log10(100) = 120dB@100W
The human voice at three feet is 65dB. Needless to say, a 1W amp at full tilt through a loudspeaker with an efficiency of 100dB @ 1W @ 1 meter is significantly louder than the human voice. I love tube amps as much as the next guitarist, but, in my humble opinion, bedroom playing is best handled by a full quality analog solid-state setup or a digital signal processor combined with a solid-state power amp. We are dealing with a compromise situation where we want to achieve the best possible performance at the lowest possible volume. Solid-state circuitry is more linear and allows for a finer level of control over signal shaping. The beauty in a tube amp lies in how the power section pushes back at you when run at full tilt. This phenomenon is due to poor power amp damping and back EMF from the speaker. While I use a tube amp when I jam somewhere where I can open it up, I use a Tech 21 Trademark 60 at home. There are different tools for different jobs.
There is nothing wrong with using a tube amp at home as long as you can let the power amp breath a little bit. I own a 2-Channel "H" (I have also designed and built tube amps at several power levels), and it in no way performs as well as the Tech 21 Trademark 60 at bedroom volume. It sounds and feels like it is being starved to death. In a room where I can open the 2-Channel up, there is absolutely no comparison. However, I stand by my assertion that bedroom and spouse-approved volume levels and tube technology are basically mutually exclusive. It is a compromise situation. The Archon suffers from the same problem when run at bedroom volume. Even if we generate a lot of distortion in the preamp, the phase inverter (PI) and the power tubes are part of tube amp tone and feel. Some of this magic can be maintained by using a post-PI master volume, but back EMF does not come into serious play until the amp is opened up.
We can use an attenuator, but good attenuator design is a black art because impedance is not a synonym for resistance. Resistance is a measure of resistance to the flow of direct current. Impedance is the resistance to the flow of alternating current, and alternating currents have frequencies (e.g., the power at a U.S. power receptacle has a frequency of 60Hz). A guitar signal is an alternating current that is induced in pickup coils when the ferrous strings cut magnetic lines of force in a magnetic field. Anyone who has taken an ohm meter to an 8-ohm speaker knows that it does not read 8 ohms. That is because speakers are rated at nominal impedances, and impedance is frequency dependent due to impedance equaling the SQRT(R^2 + X^2), where SQRT equals the square root function, R = resistance, X = reactance, and the symbol "^" meaning raised to the power of. Reactance (X) is the difference between inductive reactance (Xl) and capacitive reactance (Xc). Inductive reactance is 2 * Pi * f * L, where Pi = 3.14, f = frequency, and L = inductance in henries. Capacitive reactance is 1 / ( 2 * Pi * f * C), where Pi = 3.14, f = frequency in hertz, and C = capacitance in farads. Speakers are both inductive and capactive. As output power is the square of voltage divided by impedance, the power delivered by the amp to the load changes with respect to frequency because speaker impedance changes with respect to frequency due to speakers being inductive devices. Tube amp power is rated by measuring output transformer secondary voltage into an 8-ohm dummy load, which is a non-inductive resistor bank; therefore, its resistance to the flow of alternating current is not frequency dependent like a speaker. Add in the fact that a speaker is a magnetic transducer that can also produce electrical current when the voice coil moves through the magnetic field that flows back through the power transformer into the power tubes (a.k.a. back EMF), and we have a very difficult real-world design problem on our hands.
I find that neither my tube amps or my axe fx sound or feel great at bedroom volume. But they get the job done.
And I play loud whenever I can.
1965
“Turn down that noise!!”
“But Mom, it sounds best when it’s loud!”
1970
“Turn down that noise!!”
“WTF, man! Never trust anyone over 30!”
1979
“Turn down that noise!!”
“If it’s too loud, you’re too old!”
1988
“Turn down that noise, the baby’s sleeping!!”
“Aw, grumble...”
2000
“Turn down that noise!!”
“But. My. TONE!”
2018
“Turn down that noise!!”
“Never trust anyone over...uh....If it’s too loud you’re...umm...”
There is nothing wrong with using a tube amp at home as long as you can let the power amp breath a little bit. I own a 2-Channel "H" (I have also designed and built tube amps at several power levels), and it in no way performs as well as the Tech 21 Trademark 60 at bedroom volume. It sounds and feels like it is being starved to death. In a room where I can open the 2-Channel up, there is absolutely no comparison. However, I stand by my assertion that bedroom and spouse-approved volume levels and tube technology are basically mutually exclusive. It is a compromise situation. The Archon suffers from the same problem when run at bedroom volume. Even if we generate a lot of distortion in the preamp, the phase inverter (PI) and the power tubes are part of tube amp tone and feel. Some of this magic can be maintained by using a post-PI master volume, but back EMF does not come into serious play until the amp is opened up.
We can use an attenuator, but good attenuator design is a black art because impedance is not a synonym for resistance. Resistance is a measure of resistance to the flow of direct current. Impedance is the resistance to the flow of alternating current, and alternating currents have frequencies (e.g., the power at a U.S. power receptacle has a frequency of 60Hz). A guitar signal is an alternating current that is induced in pickup coils when the ferrous strings cut magnetic lines of force in a magnetic field. Anyone who has taken an ohm meter to an 8-ohm speaker knows that it does not read 8 ohms. That is because speakers are rated at nominal impedances, and impedance is frequency dependent due to impedance equaling the SQRT(R^2 + X^2), where SQRT equals the square root function, R = resistance, X = reactance, and the symbol "^" meaning raised to the power of. Reactance (X) is the difference between inductive reactance (Xl) and capacitive reactance (Xc). Inductive reactance is 2 * Pi * f * L, where Pi = 3.14, f = frequency in hertz, and L = inductance in henries. Capacitive reactance is 1 / ( 2 * Pi * f * C), where Pi = 3.14, f = frequency in hertz, and C = capacitance in farads. Speakers are both inductive and capactive. As output power is the square of the output transformer secondary voltage divided by impedance, the power delivered by the amp to the load changes with respect to frequency because speaker impedance changes with respect to frequency due to speakers being inductive devices. Tube amp power is rated by measuring output transformer secondary voltage into an 8-ohm dummy load, which is a non-inductive resistor bank; therefore, its resistance to the flow of alternating current is not frequency dependent like a speaker. Add in the fact that a speaker is a magnetic transducer that can also produce electrical current when the voice coil moves through the magnetic field that flows back through the power transformer into the power tubes (a.k.a. back EMF), and we have a very difficult real-world design problem on our hands.
Maybe I’ve missed it somewhere but what’s you’re history with building amps? This tech talk is awesome!!Actually, the multiplier is 8, not 10. A 120W amp is twice as loud as a 15W amp. It takes a 9dB increase in sound pressure for the human ear to perceive something as twice as loud. Sound pressure increases by 3dB every time we double power; therefore, we are looking at 2 to the 3rd power. Inversely, it takes an 9dB reduction in sound pressure for the human ear to perceive something as half as loud. If we want to reduce volume to that of 1/8th of a 100W amp, we need to reduce sound pressure by 27dB, which is equivalent to dividing power by 512 (2 raised to the 9th power). A 0.2W amp is 1/8th as loud as a 100W amp.
One thing that needs to be understood is that the average guitar speaker produces 100dB @ 1W @ 1 meter.
dB = 10 * log10(power)
Therefore, we have the following sound pressure levels are different wattage levels
100 + 10 * log10(1) = 100db@1W
100 + 10 * log10(2) = 103dB @2W
100 + 10 * log10(4) = 106dB@4W
...
100 + 10 * log10(15) = 111.76dB15W
...
100 + 10 * log10(100) = 120dB@100W
The human voice at three feet is 65dB. Needless to say, a 1W amp at full tilt through a loudspeaker with an efficiency of 100dB @ 1W @ 1 meter is significantly louder than the human voice. I love tube amps as much as the next guitarist, but, in my humble opinion, bedroom playing is best handled by a quality fully analog solid-state setup or a digital signal processor combined with a solid-state power amp. We are dealing with a compromise situation where we want to achieve the best possible performance at the lowest possible volume. Solid-state circuitry is more linear and allows for a finer level of control over signal shaping. The beauty in a tube amp lies in how the power section pushes back at you when run at full tilt. This phenomenon is due to poor power amp damping and back EMF from the speaker. While I use a tube amp when I jam somewhere where I can open it up, I use a Tech 21 Trademark 60 at home. There are different tools for different jobs.