Go Back   UG Community @ Ultimate-Guitar.Com > Instruments > Guitar Gear & Accessories
User Name  
Password
Search:

Reply
Old 05-01-2013, 08:37 AM   #1
garfo
Registered User
 
garfo's Avatar
 
Join Date: Mar 2013
amp/speaker impedance

So, my amp works 55 watts at 4 ohms.
I can select from 4/8/16 ohms working operation.
If I use a speaker that is rated 35 watts 8ohms, does it take the load of the amp working on 8 ohms?
garfo is offline   Reply With Quote
Old 05-01-2013, 09:43 AM   #2
red.guitar
Imagine All The People
 
red.guitar's Avatar
 
Join Date: Mar 2007
Location: Saskatchewan
I guess it would work, but you risk blowing the speaker... As long as you make sure to select 8ohms on your amp.

If you play at really low volumes, it should be fine tho.

If it was me, I wouldn't risk it.
__________________
Guitars:
Gibson Les Paul 60's Tribute
MIJ Contemporary Strat
Snake Pit Les Paul
MIM Fender Tele

Amps:
Jet City JCA 50H
Randall 212+115
Mesa Boogie 212

Check out my band CITIES GATEWAY
red.guitar is offline   Reply With Quote
Old 05-01-2013, 10:01 AM   #3
311ZOSOVHJH
G G & A - B A B Y
 
311ZOSOVHJH's Avatar
 
Join Date: Mar 2008
Location: Offline
This is your V55 right?

You would set the amp to 8 ohms to match up your new speaker but I agree that a 35 watt speaker is not ideal. Ideally you want to be at 55 or even a bit higher. I'd be looking at 60 watt speakers and higher. I think you were interested in cleans and using pedals for dirt no? What speaker did you find that was 35 watts?
__________________
311ZOSOVHJH is offline   Reply With Quote
Old 05-01-2013, 10:13 AM   #4
gumbilicious
beginner
 
gumbilicious's Avatar
 
Join Date: Oct 2007
Location: on the road... again
yes, set the amp to 8 ohms with your speaker.

the 35 watt rating on the speaker can potentially be inadequate at some point. i am pretty adventuresome with my speakers, to me a 55 watt to 35 watt mismatch something to be wary of but i may still run it depending on the situation.

mind you, i am so adventuresome because:
1) i have dealt with a bunch of speakers
2) i have mismatched speaker power handling before
3) i can generally tell (from the sound of the speaker) if it is becoming stressed
4) i won't be heart broken if a blow the speaker

if that doesn't describe you, then maybe you should consider another speaker with a higher power handling.
__________________
punk isn't dead, it's always smelled that way.

"A perfection of means, and confusion of aims, seems to be our main problem."
-ae

Last edited by gumbilicious : 05-01-2013 at 10:14 AM.
gumbilicious is offline   Reply With Quote
Old 05-01-2013, 10:14 AM   #5
red.guitar
Imagine All The People
 
red.guitar's Avatar
 
Join Date: Mar 2007
Location: Saskatchewan
Take a look at the Eminence c-rex. Its got a hemp cone and has louder breakup. Really smooth all around.


Cheap too. Like $85 new
__________________
Guitars:
Gibson Les Paul 60's Tribute
MIJ Contemporary Strat
Snake Pit Les Paul
MIM Fender Tele

Amps:
Jet City JCA 50H
Randall 212+115
Mesa Boogie 212

Check out my band CITIES GATEWAY
red.guitar is offline   Reply With Quote
Old 05-01-2013, 11:00 AM   #6
311ZOSOVHJH
G G & A - B A B Y
 
311ZOSOVHJH's Avatar
 
Join Date: Mar 2008
Location: Offline
Quote:
Originally Posted by gumbilicious
yes, set the amp to 8 ohms with your speaker.

the 35 watt rating on the speaker can potentially be inadequate at some point. i am pretty adventuresome with my speakers, to me a 55 watt to 35 watt mismatch something to be wary of but i may still run it depending on the situation.

mind you, i am so adventuresome because:
1) i have dealt with a bunch of speakers
2) i have mismatched speaker power handling before
3) i can generally tell (from the sound of the speaker) if it is becoming stressed
4) i won't be heart broken if a blow the speaker

if that doesn't describe you, then maybe you should consider another speaker with a higher power handling.


I agree with the bolded part and I've mismatched before too but based on some prior threads by this TS and the fact he is talking about a Bugera V55 that has had known power section/heat sink issues I decided to post the 'safe' answer
__________________
311ZOSOVHJH is offline   Reply With Quote
Old 05-01-2013, 02:03 PM   #7
garfo
Registered User
 
garfo's Avatar
 
Join Date: Mar 2013
Quote:
Originally Posted by 311ZOSOVHJH
This is your V55 right?

You would set the amp to 8 ohms to match up your new speaker but I agree that a 35 watt speaker is not ideal. Ideally you want to be at 55 or even a bit higher. I'd be looking at 60 watt speakers and higher. I think you were interested in cleans and using pedals for dirt no? What speaker did you find that was 35 watts?

The Jensen C12Q 8 ohms.Thge reason why I was looking at this is because the 50 and 100 watts versions are double the price.Also, I don't know why, but I've always been under the impression that the load of the amp also had connection with the power consumption.WIMWT is, if an amp is 55watts at 4 ohms, then at 8 ohms should be somewhere arround 25watts..!?!But maybe that's just a silly idea, honestly, I don't know where it came from.

Last edited by garfo : 05-01-2013 at 02:09 PM.
garfo is offline   Reply With Quote
Old 05-01-2013, 02:17 PM   #8
Dave_Mc
Chirp and Swirl
 
Dave_Mc's Avatar
 
Join Date: Mar 2005
Location: Northern Ireland
the load only affects the power in solid state amps, as far as i'm aware.
__________________
Quote:
Originally Posted by Cathbard
We had a guy in the band admit that he liked Nickelback. We immediately started looking for his replacement.


Dave_Mc is offline   Reply With Quote
Old 05-01-2013, 02:35 PM   #9
Roc8995
Moderator
 
Roc8995's Avatar
 
Join Date: Nov 2005
Location: Madison, Wisconsin
It affects power in tube amps, but differently. It's a less linear relationship. With a 2:1 mismatch on a tube amp you lose (officially) 10.5% efficiency. So instead of a SS amp where it's rated for 200 watts at 4 ohms and 100 at 8, with a tube amp you'd get 55 watts at 4 ohms and 49 point something at 8.

These are 'spherical cow' numbers so they'll be different in real life, but they're good enough for our purposes.
__________________
rr, pe&a
Roc8995 is offline   Reply With Quote
Old 05-01-2013, 02:53 PM   #10
garfo
Registered User
 
garfo's Avatar
 
Join Date: Mar 2013
Quote:
Originally Posted by Roc8995
It affects power in tube amps, but differently. It's a less linear relationship. With a 2:1 mismatch on a tube amp you lose (officially) 10.5% efficiency. So instead of a SS amp where it's rated for 200 watts at 4 ohms and 100 at 8, with a tube amp you'd get 55 watts at 4 ohms and 49 point something at 8.

These are 'spherical cow' numbers so they'll be different in real life, but they're good enough for our purposes.

oh yeah, it means I need a 100watts speaker
garfo is offline   Reply With Quote
Old 05-01-2013, 05:05 PM   #11
Arby911
Finding the Pattern
 
Arby911's Avatar
 
Join Date: Jul 2010
Quote:
Originally Posted by Roc8995

These are 'spherical cow' numbers so they'll be different in real life, but they're good enough for our purposes.


Abstract Physicist humor FTW!!!
__________________
The man who holds to a belief because of tradition, or hides it because he fears he may be shown to be wrong, does not love the truth but manifests a coward’s faithfulness to his prejudices.
Arby911 is offline   Reply With Quote
Old 05-02-2013, 12:47 PM   #12
gumbilicious
beginner
 
gumbilicious's Avatar
 
Join Date: Oct 2007
Location: on the road... again
Quote:
Originally Posted by garfo
The Jensen C12Q 8 ohms.Thge reason why I was looking at this is because the 50 and 100 watts versions are double the price.


a 'higher wattage' speaker pretty much means three things:
1) beefier voice coil
2) heftier suspension parts
3) bigger permanent magnet

the bigger magnet is usually the thing that drives up the price.

Quote:
Originally Posted by garfo
Also, I don't know why, but I've always been under the impression that the load of the amp also had connection with the power consumption.


tube amps use an output transformer to match the impedance of the circuit with the speaker, it allows for optimal performance when the impedance is matched.

solid state amps have circuits loaded directly by the speaker.

in both of these cases changing the impedance from what is expected has consequences on the sound output, but the two types of amps react quite differently when you change the impedance.

Quote:
Originally Posted by garfo
WIMWT is, if an amp is 55watts at 4 ohms, then at 8 ohms should be somewhere arround 25watts..!?!But maybe that's just a silly idea, honestly, I don't know where it came from.


that is similar to how a solid state amp works. like this the specs on a crown power amp

550W, Stereo, 2 Ohms
350W, Stereo, 4 Ohms
215W, Stereo, 8 Ohms

tube amp's aren't really assigned a variable output because the output transformer effectively corrects for different speaker impedances when 'matched' to the cabinet (the output transformer isn't perfect though, see colin's/roc's post).
__________________
punk isn't dead, it's always smelled that way.

"A perfection of means, and confusion of aims, seems to be our main problem."
-ae
gumbilicious is offline   Reply With Quote
Old 05-02-2013, 01:40 PM   #13
Dave_Mc
Chirp and Swirl
 
Dave_Mc's Avatar
 
Join Date: Mar 2005
Location: Northern Ireland
Quote:
Originally Posted by Roc8995
It affects power in tube amps, but differently. It's a less linear relationship. With a 2:1 mismatch on a tube amp you lose (officially) 10.5% efficiency. So instead of a SS amp where it's rated for 200 watts at 4 ohms and 100 at 8, with a tube amp you'd get 55 watts at 4 ohms and 49 point something at 8.

These are 'spherical cow' numbers so they'll be different in real life, but they're good enough for our purposes.


oh yeah, of course with mismatches you don't get the full power transfer (you know more than me about this, obviously), I was just assuming the impedances would be matched.
__________________
Quote:
Originally Posted by Cathbard
We had a guy in the band admit that he liked Nickelback. We immediately started looking for his replacement.


Dave_Mc is offline   Reply With Quote
Reply


Thread Tools Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -4. The time now is 06:32 PM.

Forum Archives / About / Terms of Use / Advertise / Contact / Ultimate-Guitar.Com © 2014
Powered by: vBulletin Version 3.0.9
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.