It is currently Mon Mar 16, 2020 1:09 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 14 posts ] 
Author Message
Post subject: What's a Watt?
Posted: Mon Feb 02, 2015 6:25 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Feb 02, 2015 6:16 pm
Posts: 2
First post so please be gentle!

I have two 'classic' Fender Princeton's circa 1974 - very nice and clean. I love these amps but they just can't keep up on stage with me. So I bought a Hot Rod Deluxe III last year and it sounds great and is fine on stage with our six piece band.

I understand my Princeton's are 12 watts and the HRD III is 40 watts. When I am on a gig I have the HRD III between 2 and 3 on the clean channel and it is loud enough. Why can't I get the same energy out of my Princeton's even at 9? It seems the Princeton's are great up to about 7 and then start to get less 'nice' and they sound a bit overwhelmed.

So it's got to be more than watts - educate me.

Thanks in advance.

-Don


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: What's a Watt?
Posted: Mon Feb 02, 2015 6:39 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Yes, a watt is a watt (whether tube or solid-state or whatever). However, the THD (total harmonic distortion) and IMD (intermodulation distortion) is just as important as the total output power of that amp. How clean or how "dirty" the amp reproduces that wattage --- effects the final tone as much as the power.

The speaker used also has a big effect on the final tone. A lousy 10-inch speaker will never sound good. No matter how good the amp is. An ok 12-inch is going to prolly sound cleaner to a louder volume, than this poor 10-inch. Which most SF Princeton Reverbs came equipped with, from the factory.

I have heard 2-watt SET amps through 100dB efficient speakers --- and they are great at full volume. I've heard borderline 50-watt amps through borderline speakers sound crappy at mid-volume.

Try the PR through a good speaker cab. This may solve a lot of the poor loud performance of the amp. A good 10-inch replacement speaker will help, too.

The HRDLx has 6L6GC's? Right? All things being equal, the 6L6GC will produce a cleaner "loud" than the 6V6GT. Higher power rating and the general nature of the two constructions.

One other thing about PR's. They have no bias pot to adjust the bias. Check the idle bias of the 6V6GT's. The bias circuit may need swapping-out resistors to get the 6V6GT's into proper idle bias range.


HTH! :)


Top
Profile
Post subject: Re: What's a Watt?
Posted: Mon Feb 02, 2015 6:47 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
Speaker efficiency plays a significant role in this equation. A 10-inch speaker only has 78 square inches of radiating surface while the 12-inch driver boasts 113 square inches. That differential demonstrates an increase of nearly 30%. As well, the HRD projects more efficiently due to the larger cabinetry. Coupled with the fact that your comparison is a slug-fest between the 15-watt Princeton Reverb platform and a HRD with nearly three times the output, that alone highlights the volume difference in the starkest of terms.

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: What's a Watt?
Posted: Thu Feb 05, 2015 4:55 pm
Offline
Hobbyist
Hobbyist

Joined: Mon Feb 02, 2015 6:16 pm
Posts: 2
Thanks for the replies. Very helpful and still a bit perplexing on the order of magnitude difference between the two systems. I am about to have the local Fender amp guru re-tube and check my Princeton's out - it's been a long time since they've been serviced so hopefully I gain a bit more energy from them after the service.

At rehearsal last night - my HRD was on 2.5 and can knock the wall down across the room - it still seems non-linear to a 12 watt system on 10.

Really appreciate the input folks

-D


Top
Profile
Post subject: Re: What's a Watt?
Posted: Thu Feb 05, 2015 6:48 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
For a practical demonstration contrasting and comparing output power in a less esoteric device, check out the difference in lumens between a 15-watt incandescent light bulb and that of a forty.

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: What's a Watt?
Posted: Fri Feb 06, 2015 2:27 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Fri Jan 02, 2015 6:57 am
Posts: 2238
Location: UK
Amp wattage is a bit like cubic capacity in a car. It is measure of the electrical dimensions of an amplifier not the power output.

Also sound pressure, or volume, isn't linear on a tube amp relative to the scale on the volume knob. Half way on the volume knob is unlikely to be 50% of the sound pressure the amp will produce. Some tube amps even get quieter once they go past a certain volume.

Also sound projection is very important - think of the speaker like a spot light. In a large venue without walls, or hard surfaces, to reflect the sound back, if you stand off axis (out of the speaker spotlight) it can be very quiet. With back line amps only I would sound check with a really long lead and walk around in front of the stage. The gutar might sound quiet where I was standing but be unbearable volume in front of the stage.

_________________
John

After all this time I should be better.


Top
Profile
Post subject: Re: What's a Watt?
Posted: Fri Feb 06, 2015 9:40 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
Rated amp wattage is exactly clean power output (minimal THD), as measured with a purely resistive load (not with a speaker). WTF is "electrical dimensions"?

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: What's a Watt?
Posted: Fri Feb 06, 2015 11:52 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
shimmilou wrote:
WTF is "electrical dimensions"?


C'mon, shimmilou......that's the "new-age" paradigm.


Get with the program, will ya!

:lol:

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: What's a Watt?
Posted: Sat Feb 07, 2015 1:38 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Fri Jan 02, 2015 6:57 am
Posts: 2238
Location: UK
shimmilou wrote:
Rated amp wattage is exactly clean power output (minimal THD), as measured with a purely resistive load (not with a speaker). WTF is "electrical dimensions"?


I think you will find it is established through calculation based on the components employed and by design.

_________________
John

After all this time I should be better.


Top
Profile
Post subject: Re: What's a Watt?
Posted: Sat Feb 07, 2015 2:56 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
However you arrive there, it is "power output", which is measured at some point to verify.

So, for a DRRI for example, 4x5.5 = 22, that's 22 watts rated power output. <-----( electrical dimensions) :lol:

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: What's a Watt?
Posted: Sat Feb 07, 2015 4:12 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Fri Jan 02, 2015 6:57 am
Posts: 2238
Location: UK
shimmilou wrote:
However you arrive there, it is "power output", which is measured at some point to verify.

So, for a DRRI for example, 4x5.5 = 22, that's 22 watts rated power output. <-----( electrical dimensions) :lol:


Indeed. And, once you have finished laughing, if you consider the concept in trying to explain the difference in why one amp 50 Watt amp is louder than another 50 Watt amp the analogy works reasonably well IMHO.

The amp is rated based on its electrical design ( 4x5.5 =22 is as good example as any other). However, there are a vast array of variables which will establish how loud it is perceived (or measured in decibels) as compared to its stated wattage. In the same way that you can have 2 2.0 ltr cars but one may be faster than the other.

As a simple person myself I try to explain things in simple terms. I accept that "Power Output" was the wrong term because it is ambiguous in this context, and can be confused with watts, and would have been better stated as "loudness" perhaps.

"Watts" is a minefield when you try to relate it to loudness. As was stated previously, in the same way "Watts" is a pretty poor way to measure the light of a light bulb.

I used the term "electrical dimensions" because that relates to the electrical functionality of the amp."Loudness" has become associated with Watts (as in a 100 Watt amp must be "louder" than a 50 Watt amp) but the relationship to Watts and loudness is as irrelevant as Watts to light.

I think we are getting better with light bulbs as they are now more commonly specified including Lumens. Perhaps one day amps will be rated in decibels.

_________________
John

After all this time I should be better.


Top
Profile
Post subject: Re: What's a Watt?
Posted: Sat Feb 07, 2015 4:49 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Fri Jan 02, 2015 6:57 am
Posts: 2238
Location: UK
John Sims wrote:
...Perhaps one day amps will be rated in decibels.


And, because its seems being pedantic seems to have become the style of this thread, I should note that statement should be related to combos only not amps in isolation. Amplifiers don't produce sound in isolation they need to be in a system with speakers. Amplifiers in isolation only output an electrical current and thus the output can be expressed as watts.

_________________
John

After all this time I should be better.


Top
Profile
Post subject: Re: What's a Watt?
Posted: Sat Feb 07, 2015 5:42 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
" if you consider the concept in trying to explain the difference in why one amp 50 Watt amp is louder than another 50 Watt amp the analogy works reasonably well IMHO. "

"Loud" not only takes into account how much power the amp produces. But, also the character of the tone. How much distortion. What type of distortion. Harmonic characteristics. The transient slew-rate or how fast the amp responds to input changes. Headroom.

Two amps can make, say, 40 watts. Say, a 6V6GT push-pull pushed to its upper limits of Class B. And a 6L6GC push-pull running its tubes at moderate levels, in Class AB. The 6L6GC amp will prolly sound better under these conditions.

That's my take on the power thing. :)


Top
Profile
Post subject: Re: What's a Watt?
Posted: Sat Feb 07, 2015 6:00 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
"Loud", as pointed out already, has a lot to do with speaker efficiency.

The example of two amps, say two identical HRDlx 40 watt amps, one with a 98db speaker and one with a 102db speaker, the latter will be louder, yet both produce 40 watts of output power.

Rated wattage is output power, nothing more, nothing less. It doesn't have anything to do with loud, and however you want to phrase it, rated wattage is output power, period.

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 14 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: Google [Bot] and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: