Jump to content


Please note: You can easily log in to MPN using your Facebook account!

matching speaker & amp wattage


awalsh

Recommended Posts

Hi,

I have some basic questions about matching amp & speaker wattage(s).

 

I have a Musicman 112 65 combo from 1974 and I'm looking into replacing the speaker (I got it used and it has an unmarked speaker that I'm looking to replace--if I remember what my amp tech said a 40 watt 8ohm speaker).

 

The amp has two power options, 65, and low power (aprox. 1/2 of 65). From reading the manual I saw online, the amp sounds best with the Master volume all the way up using the pre-amp volume to adjust loudness. What power rating should the speaker have? 65 watts? Will that be optimum for the low power setting? That's the one I'll use most as my gigs right now do not require the incredible loudness that this amp can generate.

 

I tried a 100 watt 8ohm JBL speaker but I think I'd have to turn it up all the way to get the right tone, at low volumes it just doesn't sound good to me.

 

How close should the amp and speaker wattages be?

would a 60 watt speaker be good? A 40 watt? If I always use the low power setting, a 30 watt speaker?

 

Thanks,

Alex

Link to comment
Share on other sites



  • Replies 13
  • Created
  • Last Reply

If it were me, I'd put in something like a Celestion Vintage 30 which ought to sound good at the low range but also handle the full power.

 

But that's just me.

 

And a very warm welcome to the forum - stick around and join in.

 

Geoff

"When the power of love overcomes the love of power the World will know Peace": Jimi Hendrix

http://www.soundclick.com/bands/default.cfm?bandID=738517&content=music

The Geoff - blame Caevan!!!

Link to comment
Share on other sites

Originally posted by awalsh:

Hi,

I have some basic questions about matching amp & speaker wattage(s).

 

I have a Musicman 112 65 combo from 1974 ...

 

From reading the manual I saw online, the amp sounds best with the Master volume all the way up using the pre-amp volume to adjust loudness.

Well, I don't agree with that at all. Takes away the entire point to having a master volume control. (Well, maybe the amp sounds 'best' without the master volume engaged, but it would be way too loud for my uses.) Mixing the blends between the preamp gain and the power amp level will give you your sound.

 

In fact, a part of why I have low power amps is that the three amp elements involving sound... preamp, amp, and speaker distortion... can all be brought into play.

 

And thus we arive at speaker choice. You can use any speaker with any amp, so long as the ohmage matches. What are the results? A speaker with high power handling capability is unlikely to break up at low volumes. A speaker with low power handling capabilities is likely to break up quicker, but will not handle large amounts of power so the possibility exists that the speaker may fry. Now, these are generalisations. That is why there are so many models of speakers and speaker manufacturers. And a lot of people wax poetic about various speakers... each guy has his favorite. And this is a false indicator too, because each guy is using a different amp/guitar/stompbox setup, in different situations, at different levels. Imagine Hendrix and Buddy Holly. Would you guess that they were both using the same guitar?

 

Back in the 70s it was popular to put Peavey Black Widow speakers in most amps. I don't know why, I never did it. My choice for your amp would probably agree with Geoff... a 30 watt speaker would do it for me with a reasonable safety margin... unless you play at full volume all the time. Some might even suggest a 20 or 25 watt speaker, depending upon your usual playing habits.

 

If you feel like experimenting, it is fun to stick cheap light fast-responding speakers in an amp just to see what happens. If they blow up, who cares?

 

And finally, check with Myles as to viable tube replacements for the amp. New tubes will revitalise your sound, and he is on top of the best choices.

 

Bill

"I believe that entertainment can aspire to be art, and can become art, but if you set out to make art you're an idiot."

 

Steve Martin

 

Show business: we're all here because we're not all there.

 

 

Link to comment
Share on other sites

A follow up question--

 

What determines the amount of power going to the speaker? The Master or pre-amp or combination?

 

If I have the Master on 10 to get the power tube distortion effect, and the pre-amp up just enough to get a reasonable volume (.5 in this case), will I blow the speaker? (is the speaker recieving the full amp wattage even though the volume isn't loud).

 

Thanks,

Alex

Link to comment
Share on other sites

Originally posted by awalsh:

A follow up question--

 

What determines the amount of power going to the speaker? The Master or pre-amp or combination?

 

If I have the Master on 10 to get the power tube distortion effect, and the pre-amp up just enough to get a reasonable volume (.5 in this case), will I blow the speaker? (is the speaker recieving the full amp wattage even though the volume isn't loud).

 

Thanks,

Alex

Alex,

 

you've got it backwards. You force the amp section into distortion by overdriving it with the preamp by turning the preamp up real loud.

 

In any case, the last thing in the chain before the speaker with be the final determiner (the master section), but they do inter-react. With both master and preamp set wide open, you deliver a lot more power to the speaker than any other combination.

 

Bill

"I believe that entertainment can aspire to be art, and can become art, but if you set out to make art you're an idiot."

 

Steve Martin

 

Show business: we're all here because we're not all there.

 

 

Link to comment
Share on other sites

There's also the issue of getting the output transformer saturated. This produces another type of distortion and is just as much a part of the tube amp sound as power tube distortion.

 

Just remember that when an output transformer is saturated, it is putting out it's maximum power. So a speaker hooked up to that that is rated at a lower power handling capability than the amp can cook the voice coil relatively quickly.

 

It's best to use a driver that is rated for at least 15% (25% is better) more than the RMS power rating for the amp. Otherwise expect to have to replace speakers rather often if you play the amp at close to maximum output.

Born on the Bayou

 

Link to comment
Share on other sites

Originally posted by G. Thomas O'Byrne:

I understand that the Celestion Vintage 30 will actually handle about 80-ish Watts.

 

G.

That's pretty close. I just went and looked it up. According to their online specs it should handle 60 watts and it's probably a little higher than that. That's usually an RMS power rating rather than max, too. So he should be okay with the Vintage 30.

 

http://professional.celestion.com/guitar/products/classic/spec.asp?ID=4

 

The Greenbacks (G12M) are the ones you have to be careful with since they are only rated at 20 watts. They sound sweet but a 60 watt amp can burn one out pretty quickly.

Born on the Bayou

 

Link to comment
Share on other sites

awalsh.........(is the speaker recieving the full amp wattage even though the volume isn't loud).
No.

 

Just think of it this way. The more "work" being done the more watts you use. So if you are doing less work (low volume) your amp produces fewer watts.

Link to comment
Share on other sites

Originally posted by Bill@Welcome Home Studios:

Originally posted by awalsh:

Hi,

I have some basic questions about matching amp & speaker wattage(s).

 

I have a Musicman 112 65 combo from 1974 ...

 

From reading the manual I saw online, the amp sounds best with the Master volume all the way up using the pre-amp volume to adjust loudness.

Well, I don't agree with that at all. Takes away the entire point to having a master volume control. (Well, maybe the amp sounds 'best' without the master volume engaged, but it would be way too loud for my uses.) Mixing the blends between the preamp gain and the power amp level will give you your sound.

 

In fact, a part of why I have low power amps is that the three amp elements involving sound... preamp, amp, and speaker distortion... can all be brought into play.

 

And thus we arive at speaker choice. You can use any speaker with any amp, so long as the ohmage matches. What are the results? A speaker with high power handling capability is unlikely to break up at low volumes. A speaker with low power handling capabilities is likely to break up quicker, but will not handle large amounts of power so the possibility exists that the speaker may fry. Now, these are generalisations. That is why there are so many models of speakers and speaker manufacturers. And a lot of people wax poetic about various speakers... each guy has his favorite. And this is a false indicator too, because each guy is using a different amp/guitar/stompbox setup, in different situations, at different levels. Imagine Hendrix and Buddy Holly. Would you guess that they were both using the same guitar?

 

Back in the 70s it was popular to put Peavey Black Widow speakers in most amps. I don't know why, I never did it. My choice for your amp would probably agree with Geoff... a 30 watt speaker would do it for me with a reasonable safety margin... unless you play at full volume all the time. Some might even suggest a 20 or 25 watt speaker, depending upon your usual playing habits.

 

If you feel like experimenting, it is fun to stick cheap light fast-responding speakers in an amp just to see what happens. If they blow up, who cares?

 

And finally, check with Myles as to viable tube replacements for the amp. New tubes will revitalise your sound, and he is on top of the best choices.

 

Bill

Remember that the MM amps where some of the first hybrid amps ss pre/tube output- I can see why they recommended turning the master up- to get the full tube effect-

Peavey BW's were popular because they were a high-power handling speaker, had something like a 103db SPL- and could be re-coned in about ten minutes.

Although a Celestion V30 is a great speaker- it ain't everyone's cup of coffee, some say it sounds best in a closed cab- some say best in an open backed cab-and it does have that upper mid thing going on. If you decide to get a V30- give it plenty of break-in time before you decide if you like it or not- I hated mine at first, but after awhile, I started liking it.

"Who's gonna teach the children about Chuck Berry?"
Link to comment
Share on other sites

Originally posted by marvar:

Why did this post twice?

You did not wait and hit add reply a second time.

 

I will delete the duplicate.

Myles S. Rose

www.guitaramplifierblueprinting.com

www.la-economy.blogspot.com

www.facebook.com/mylesr

www.twitter.com/myles111us

 

Link to comment
Share on other sites

Thanks. I actually work nextdoor to Guitronics in SF and Hal was nice enough to let me check out a used Celestian Vintage 30. I put it in last night and played for 4 hours. Big difference. Since the speaker was used I think it had been broken in a little bit. It sounded better as the night progressed, made the low power setting sound as good as the high power setting. The guitar was crystal clear, and it felt like the amp and guitar were working together, rather than a little off, if that makes sense. Did not blast it because of neighbors but will when I bring it to my rehearsal studio.

Alex

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...