It is currently Mon Mar 16, 2020 8:28 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 70 posts ]  Go to page 1, 2, 3, 4, 5  Next
Go to page 1, 2, 3, 4, 5  Next
Author Message
Post subject: While we are on the subject of speaker cabs - Wattage
Posted: Tue Sep 04, 2012 4:11 pm
Offline
Professional Musician
Professional Musician
User avatar

Joined: Thu Oct 14, 2010 8:54 am
Posts: 1179
Location: Florida
For Arjay or another with extensive experience working on power amp sections.

Once upon a time, there was a rule of thumb that speaker wattage should match the amps ratted output. In other words, enough to handle the amp, but not so much that the amp would be overloaded trying to drive the speakers.

Now we all know that Fender, among others, routinely put say, two 50 or 60 watt speakers in a cab for an amp rated around 50 watts. The reason is so that if one speaker dies, the other can safely handle the amp output.

Maybe that rule of thumb was for home stereo, maybe it was for solid state amps.

Your thoughts?

Art


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Tue Sep 04, 2012 5:24 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
The rule of thumb is the speaker should be rated at twice the power of the amp. Amp ratings are typically average power. Peaks can increase the power output momentarily by a significant amount. If you install a 30 watt speaker in a 30 watt amp that has 50 watt peaks, you might be picking speaker cone out of your grille cloth. :lol: Go with a 60 watt or greater speaker. Two 30 watt speakers will also work as amp power is divided equally between the two if they are connected in series and the impedance of each is the same. If the speakers are connected in parallel, you would probably want them both to be 60 watts because if one speaker fails, the other will see the full power output of the amp. Regardless of the power rating of the speaker, the speaker impedance and efficency must still be considered.

Contrary to what some people may think, putting a 60 watt speaker in a 30 watt amp will not "overload" the amp. :roll:

Note: Edited for clarity and to correct an error.

_________________
Bill

Image


Last edited by bluesky636 on Wed Sep 05, 2012 8:57 pm, edited 2 times in total.

Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Tue Sep 04, 2012 5:36 pm
Offline
Professional Musician
Professional Musician
User avatar

Joined: Thu Oct 14, 2010 8:54 am
Posts: 1179
Location: Florida
bluesky636 wrote:
The rule of thumb is the speaker should be rated at twice the power of the amp. Amp ratings are typically average power. Peaks can increase the power output momentarily by a significant amount. If you install a 30 watt speaker in an amp that has 50 watt peaks, you might be picking speaker cone out of your grille cloth. :lol: Go with a 60 watt or greater speaker. Two 30 watt speakers will also work as amp power is divided equally between the two if the impedance of each is the same. Regardless of the power rating of the speaker, the speaker impedance and efficency must still be considered.

Contrary to what some people may think, putting a 60 watt speaker in a 30 watt amp will not "overload" the amp. :roll:


This I understand. Two sixty watt speakers are great, when one blows, the second can handle that instantaneous high output until the power amp stabilizes at the higher impedance (figure a 50 watt power amp.)

Most ready made bass cabs are 500 watts or higher nowdays so I'd like to plug an old Bassman into one of these. Understanding of course that the old Bassman can't keep up with everything else today (but it can be mic'd)

Art


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Tue Sep 04, 2012 5:52 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
Art1 wrote:
bluesky636 wrote:
The rule of thumb is the speaker should be rated at twice the power of the amp. Amp ratings are typically average power. Peaks can increase the power output momentarily by a significant amount. If you install a 30 watt speaker in an amp that has 50 watt peaks, you might be picking speaker cone out of your grille cloth. :lol: Go with a 60 watt or greater speaker. Two 30 watt speakers will also work as amp power is divided equally between the two if the impedance of each is the same. Regardless of the power rating of the speaker, the speaker impedance and efficency must still be considered.

Contrary to what some people may think, putting a 60 watt speaker in a 30 watt amp will not "overload" the amp. :roll:


This I understand. Two sixty watt speakers are great, when one blows, the second can handle that instantaneous high output until the power amp stabilizes at the higher impedance (figure a 50 watt power amp.)

Most ready made bass cabs are 500 watts or higher nowdays so I'd like to plug an old Bassman into one of these. Understanding of course that the old Bassman can't keep up with everything else today (but it can be mic'd)

Art


If you manage to blow one 60 watt speaker out of two in a 50 watt amp, chances are you will blow the other in short order. :lol: Most people are not using the full output of their amps these days. :wink:

As long as the impedance of the speaker cab is suitable for the amp, you should be OK. However, the amp may sound louder or quieter then it would with a single 60 watt speaker if the efficencies are different. I assume you are talking about a multi-speaker cab so the sound dispersion would be different than a single speaker which may make it appear to sound louder.

_________________
Bill

Image


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Tue Sep 04, 2012 6:22 pm
Offline
Professional Musician
Professional Musician
User avatar

Joined: Thu Oct 14, 2010 8:54 am
Posts: 1179
Location: Florida
bluesky636 wrote:
Art1 wrote:
bluesky636 wrote:
The rule of thumb is the speaker should be rated at twice the power of the amp. Amp ratings are typically average power. Peaks can increase the power output momentarily by a significant amount. If you install a 30 watt speaker in an amp that has 50 watt peaks, you might be picking speaker cone out of your grille cloth. :lol: Go with a 60 watt or greater speaker. Two 30 watt speakers will also work as amp power is divided equally between the two if the impedance of each is the same. Regardless of the power rating of the speaker, the speaker impedance and efficency must still be considered.

Contrary to what some people may think, putting a 60 watt speaker in a 30 watt amp will not "overload" the amp. :roll:


This I understand. Two sixty watt speakers are great, when one blows, the second can handle that instantaneous high output until the power amp stabilizes at the higher impedance (figure a 50 watt power amp.)

Most ready made bass cabs are 500 watts or higher nowdays so I'd like to plug an old Bassman into one of these. Understanding of course that the old Bassman can't keep up with everything else today (but it can be mic'd)

Art


If you manage to blow one 60 watt speaker out of two in a 50 watt amp, chances are you will blow the other in short order. :lol: Most people are not using the full output of their amps these days. :wink:

As long as the impedance of the speaker cab is suitable for the amp, you should be OK. However, the amp may sound louder or quieter then it would with a single 60 watt speaker if the efficencies are different. I assume you are talking about a multi-speaker cab so the sound dispersion would be different than a single speaker which may make it appear to sound louder.


Correct. I would be hooking it up to something like an Avatar B212 or something along those lines. For Guitar, the VT15 Bassman cabinet is great, but not for bass. Fender didn't know what a real bass cabinet was back in those days.

Art


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Tue Sep 04, 2012 6:30 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
Art1 wrote:
Correct. I would be hooking it up to something like an Avatar B212 or something along those lines. For Guitar, the VT15 Bassman cabinet is great, but not for bass. Fender didn't know what a real bass cabinet was back in those days.

Art


Sounds good.

Note that I made a few edits in my original response to you in order to clarify a few points.

Actually, the early single 15" Bassmans used a dual ported cabinet designed specifically for bass reproduction only. They were fine for that except the single speaker couldn't handle the power and kept blowing up! :lol: It wasn't until Fender started advertising the Bassman as BOTH a bass and guitar amp that they went to the open back, four speaker configuration. If one speaker failed, you just yanked its cable and continued on.

_________________
Bill

Image


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Tue Sep 04, 2012 6:38 pm
Offline
Professional Musician
Professional Musician
User avatar

Joined: Thu Oct 14, 2010 8:54 am
Posts: 1179
Location: Florida
These VT15 cabinets are wide enough to sit a Twin Reverb on top. Arjay has a few. They are awesome guitar cabs. They suck for bass. But the Bassman head looks so cool on them. 8)

I might try a Rumble 4x10 which also has the correct 4 ohm imdepance, but I think the Bassman head just sounds better with 2 x 12s. I don't know, I need to try a few out.

I guess the power handling really isn't a problem. My Champ 600 hasn't suffered from being hooked up to the big VT 15 cabinet. It's no louder that way but it sure sounds sweeter. :D

Art


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Tue Sep 04, 2012 6:50 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
Art1 wrote:
My Champ 600 hasn't suffered from being hooked up to the big VT 15 cabinet. It's no louder that way but it sure sounds sweeter. :D

Art


Heck, I have my Champ 600 connected to an 8-ohm, 75 watt, 12" Celestion cab. Works and sounds fantastic. :lol:

_________________
Bill

Image


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Tue Sep 04, 2012 6:58 pm
Offline
Professional Musician
Professional Musician
User avatar

Joined: Thu Oct 14, 2010 8:54 am
Posts: 1179
Location: Florida
I don't know what happened with those. Looks like they stopped selling them. But I don't know anyone that had a problem with them even though they are Chinese.

So, do we all now own collectors items? Not even two years old and it might be collectable before I get old? Errr, really old? :lol:


Art


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Tue Sep 04, 2012 8:56 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
Art1 wrote:
I don't know what happened with those. Looks like they stopped selling them. But I don't know anyone that had a problem with them even though they are Chinese.

So, do we all now own collectors items? Not even two years old and it might be collectable before I get old? Errr, really old? :lol:


Art


Yeah, Fender appears to have dropped it for those weird Greta and Excelsior amps. What a shame. :(

_________________
Bill

Image


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Wed Sep 05, 2012 2:58 am
Offline
Professional Musician
Professional Musician

Joined: Fri Jun 26, 2009 6:53 pm
Posts: 2252
Location: Harvard IL
Art, I know it's not spot on. But our bass player used a BF Bassman for years. Usually through a 2X10(8ohm) and a 15(8ohm). Sometimes he'd haul in the 2X12cab. In the tavern venue, I thought it was great. Very soulful !!! Art

_________________
None of Us are free, if One of Us is chained !


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Wed Sep 05, 2012 4:48 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Thu Oct 14, 2010 8:54 am
Posts: 1179
Location: Florida
aclempoppi wrote:
Art, I know it's not spot on. But our bass player used a BF Bassman for years. Usually through a 2X10(8ohm) and a 15(8ohm). Sometimes he'd haul in the 2X12cab. In the tavern venue, I thought it was great. Very soulful !!! Art


Exactly my point Art! Nothing, and I mean NOTHING, sounds like a 60's Bassman. Well, I take that back, the brand new pro Bassman series does, but at a price. I can pick up a pair BF and early SF Bassman heads (needing minimal work) for the price of a single 100T head. (need a backup no matter how good the amp is constructed.)

And yeah, "soulful" might just be the word I'm looking for. Talk about "The Soul of Tone" :D

Art


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Wed Sep 05, 2012 7:02 am
Offline
Hobbyist
Hobbyist

Joined: Sun Nov 06, 2011 5:47 am
Posts: 78
bluesky636 wrote:
Two 30 watt speakers will also work as amp power is divided equally between the two if they are connected in series and the impedance of each is the same. If the speakers are connected in parallel, you would probably want them both to be 60 watts as each speaker is seeing the full power output of the amp.


If I'm plugging one speaker into my 60s Bassman's main speaker out, and a second speaker is connected in to the extension speaker out, am I running them in parallel?

Concerned because I have one 50-watt speaker and one 30-watt speaker, and the amp is rated at 50-watts, so I'll need to be sure to rewire to series if this is the case.

I thought I'd done my research but it looks like I got my wires crossed somewhere!


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Wed Sep 05, 2012 7:18 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Thu Oct 14, 2010 8:54 am
Posts: 1179
Location: Florida
demaria.daniel wrote:
bluesky636 wrote:
Two 30 watt speakers will also work as amp power is divided equally between the two if they are connected in series and the impedance of each is the same. If the speakers are connected in parallel, you would probably want them both to be 60 watts as each speaker is seeing the full power output of the amp.


If I'm plugging one speaker into my 60s Bassman's main speaker out, and a second speaker is connected in to the extension speaker out, am I running them in parallel?

Concerned because I have one 50-watt speaker and one 30-watt speaker, and the amp is rated at 50-watts, so I'll need to be sure to rewire to series if this is the case.


The two jacks on the Blackface/Silverface amps are in parallel. So, you need to take several things into consideration.

Both speakers need to be 8 ohm so that the amp will "see" a total of 4 ohms (if you don't make modifications.)

You could rewire the cabinets so that one plugs into the amp, and the other feeds into the first cab. The problem here is, if you loose the first cab, no signal will get to the second cab (think cheap Christmas tree lighting.)

Parallel is really the way to go. At least if one goes, you might be able to finish the song.

But Personally, I would save those speakers for another project and get a pair of 60 or preferably 100 watt speakers for the Bassman. As Bluesky noted earlier, the 50 watt rating on the Bassman is RMS or "average" output. The peaks can be much, much higher, even if the volume is not turned all the way up. Typical problem with a lot of "student" or practice amps back in the day was low priced speakers that could not handle the peaks of the little 5 watt amps. The speakers began to break up way too early and eventually, no clean sound was ever generated. Of course, the materials in those practice amp speakers were crap to start with. :lol:

Art


Top
Profile
Post subject: Re: While we are on the subject of speaker cabs - Wattage
Posted: Wed Sep 05, 2012 7:19 am
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
demaria.daniel wrote:
bluesky636 wrote:
Two 30 watt speakers will also work as amp power is divided equally between the two if they are connected in series and the impedance of each is the same. If the speakers are connected in parallel, you would probably want them both to be 60 watts as each speaker is seeing the full power output of the amp.


If I'm plugging one speaker into my 60s Bassman's main speaker out, and a second speaker is connected in to the extension speaker out, am I running them in parallel?

Concerned because I have one 50-watt speaker and one 30-watt speaker, and the amp is rated at 50-watts, so I'll need to be sure to rewire to series if this is the case.

I thought I'd done my research but it looks like I got my wires crossed somewhere!


I have no idea. Which 60's Bassman? What does the schematic show for the speaker output? What impedance is the amp designed to drive? 2, 4, 8, 16 ohms? What are the speaker impedances? Not enough information in your question to provide an answer.

_________________
Bill

Image


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 70 posts ]  Go to page 1, 2, 3, 4, 5  Next
Go to page 1, 2, 3, 4, 5  Next

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


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: