Percieved Power outputs Tube vs Solid State

IbanezPlayer · 4th April 2011, 11:35 AM

Hi All
I have just completed my first build, a 15w guitar amplifier with 2x EL84 output valves working in the push-pull configuration. Having powered it up for the first and the bugs all sorted out, I was amazed at the beautiful tone that I created on such a limited budget and skill set. However what really got my attention was that the power dwarfed my store bought solid state 15w amp. Why is this?

mastodon · 4th April 2011, 12:13 PM

Maybe the 15W transistor job wasn't really capable of putting out 15W.
Maybe you used a much more efficient speaker with the tube amp than with the transistor amp.
Maybe you never pushed the transistor amp as hard as the tube amp.
Or maybe you experience a difference that isn't really there.

It's hard to say. But 15W = 15W, no matter where it comes from. With the same speaker in the same room etc. etc. (ceterus paribus), the sound pressure level at 15Wrms should be the same regardless of the method of amplification.

bigwill · 4th April 2011, 12:29 PM

The perceived difference may be down to the differences in harmonic content of each amplifier, but yes, 15W is 15W regardless of it coming from a tube, transistor, lightning strike, etc

mastodon · 4th April 2011, 12:48 PM

Quote:

Originally Posted by bigwill

15W is 15W regardless of it coming from a tube, transistor, lightning strike, etc

Modulated lightning strikes sounds like an exciting way to boost the bass response of a valve audio system. There may be practical drawbacks though. I guess the fact that you need a medium-sized volcano as a driver to modulate the discharges might be an issue.

bigwill · 4th April 2011, 12:55 PM

DF96 · 4th April 2011, 01:30 PM

Valves tend to do peak clipping more smoothly than transistors, especially if there is little or no feedback. This means that you can drive a valve amp more than SS without it sounding harsh. If you measure output voltages, you will find that your average valve output is higher than the SS average, even though the peaks will be about the same. Set them to the same non-clipping gain and they will sound about the same volume.

Having said that, there is an alternative explanation. Below clipping, a valve amp will probably have higher distortion than SS and this can add to a perception of loudness even if it does not sound unpleasant.

IbanezPlayer · 4th April 2011, 02:09 PM

Having read your replies I think it might be a combination of a bigger (12" as opposed to 8") and the transistor job not producing 15w RMS as mastadon stated, still hooked on the tube sound though. Thinking of building a bigger one in the near future any suggestions as to nice sounding amps you have built in the past?

4th April 2011, 11:35 AM	#1
IbanezPlayer diyAudio Member Join Date: Apr 2011 Location: South Africa	Percieved Power outputs Tube vs Solid State Hi All I have just completed my first build, a 15w guitar amplifier with 2x EL84 output valves working in the push-pull configuration. Having powered it up for the first and the bugs all sorted out, I was amazed at the beautiful tone that I created on such a limited budget and skill set. However what really got my attention was that the power dwarfed my store bought solid state 15w amp. Why is this?

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4th April 2011, 12:13 PM	#2
mastodon diyAudio Member Join Date: Jan 2011	Maybe the 15W transistor job wasn't really capable of putting out 15W. Maybe you used a much more efficient speaker with the tube amp than with the transistor amp. Maybe you never pushed the transistor amp as hard as the tube amp. Or maybe you experience a difference that isn't really there. It's hard to say. But 15W = 15W, no matter where it comes from. With the same speaker in the same room etc. etc. (ceterus paribus), the sound pressure level at 15Wrms should be the same regardless of the method of amplification.

4th April 2011, 12:29 PM	#3
bigwill diyAudio Member Join Date: Dec 2004 Location: UK	The perceived difference may be down to the differences in harmonic content of each amplifier, but yes, 15W is 15W regardless of it coming from a tube, transistor, lightning strike, etc

4th April 2011, 12:55 PM	#5
bigwill diyAudio Member Join Date: Dec 2004 Location: UK

4th April 2011, 01:30 PM	#6
DF96 diyAudio Member Join Date: May 2007	Valves tend to do peak clipping more smoothly than transistors, especially if there is little or no feedback. This means that you can drive a valve amp more than SS without it sounding harsh. If you measure output voltages, you will find that your average valve output is higher than the SS average, even though the peaks will be about the same. Set them to the same non-clipping gain and they will sound about the same volume. Having said that, there is an alternative explanation. Below clipping, a valve amp will probably have higher distortion than SS and this can add to a perception of loudness even if it does not sound unpleasant.

4th April 2011, 02:09 PM	#7
IbanezPlayer diyAudio Member Join Date: Apr 2011 Location: South Africa	Having read your replies I think it might be a combination of a bigger (12" as opposed to 8") and the transistor job not producing 15w RMS as mastadon stated, still hooked on the tube sound though. Thinking of building a bigger one in the near future any suggestions as to nice sounding amps you have built in the past?

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