JohnH
Well-Known Member
hi @RoadShow
Just to try to get to the bottom of the volume discussion, Im just wondering about the 18W amp. How loud is it usually, if not attenuated? and how compared to the JTM45?
So far as I know, a JTM45 puts out just under 40W RMS clean. If the 18W was doing 18W, then the difference in level between them is somewhere 3 to 3.5db if similarly cranked. This is a small step in volume, about the same as the smallest step available on the attenuator. Does that match up to what you experience?
You could also check by measuring AC voltage at the amp output, ie at the input to the attenuator or across the speaker if no attenuator. (needs some care to clip test leads securely). Nominally, at 18W into 8 Ohms, you expect 12V ac at the output. A measurement made by a meter using a guitar or other signal will be much more variable, but you should get 'several' volts there.
With the JTM45, which attenuation setting gets you down to about that nice conversation level of volume?
Just to try to get to the bottom of the volume discussion, Im just wondering about the 18W amp. How loud is it usually, if not attenuated? and how compared to the JTM45?
So far as I know, a JTM45 puts out just under 40W RMS clean. If the 18W was doing 18W, then the difference in level between them is somewhere 3 to 3.5db if similarly cranked. This is a small step in volume, about the same as the smallest step available on the attenuator. Does that match up to what you experience?
You could also check by measuring AC voltage at the amp output, ie at the input to the attenuator or across the speaker if no attenuator. (needs some care to clip test leads securely). Nominally, at 18W into 8 Ohms, you expect 12V ac at the output. A measurement made by a meter using a guitar or other signal will be much more variable, but you should get 'several' volts there.
With the JTM45, which attenuation setting gets you down to about that nice conversation level of volume?