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What can I screw up?

PostPosted: Sat May 26, 2012 4:16 pm
by dylanger
So as some of you might know my bassman caught fire last night for a few seconds. I need an amp to use until I can get some cash together to get it fixed. I have a pro Junior with a bad speaker and what I thought I could do is take one of the really nice speakers out of my bassman and put it in my Pro Junior. Is there anything that should be done to the amp when swapping out speakers, and is it bad to use a 15 watt speaker with a 15 watt amp?

Thanks

Dylan

Re: What can I screw up?

PostPosted: Sat May 26, 2012 5:05 pm
by Scott DeVarenne
Find out the impedance of the speaker that you are thinking about putting in. Does the amp have an impedance switch? Recommended optimum impedance? What's the story with the bad speaker that's in JR now?
I have a
http://www.eminence.com/pdf/Ramrod.pdf
and a
http://www.eminence.com/pdf/Lil_Buddy.pdf
They are both 8ohms, 10", rated for 75 and 50 watts respectively, and both are available for loan or purchase.
But answer the impedance questions and I will chime in regarding risk of screw up.

Re: What can I screw up?

PostPosted: Sat May 26, 2012 6:00 pm
by dylanger
8ohm was in the JR. and a 8ohm came out or the bassman

Re: What can I screw up?

PostPosted: Sat May 26, 2012 6:22 pm
by Mathieu Benoit
Bring the Bassman in at least to see what the damage is first. I'm curious to see what an amp that caught fire looks like.

Re: What can I screw up?

PostPosted: Sat May 26, 2012 7:06 pm
by Scott DeVarenne
You are replacing an 8 ohm, 10" speaker with another one so it's going to work. If it was my amp I would go easy on the volume, probably wouldn't turn it up much past half. You could crank it and be fine, but maybe not, and the way things are going for you lately, is that a chance you want to take?
There is nothing that needs to be done to the amp other than ensuring it is off and unplugged. Make note of the polarity of the speaker leads, disconnect them, remove old speaker, install new speaker, attach leads.

Re: What can I screw up?

PostPosted: Sat May 26, 2012 10:02 pm
by dylanger
Scott DeVarenne wrote:You are replacing an 8 ohm, 10" speaker with another one so it's going to work. If it was my amp I would go easy on the volume, probably wouldn't turn it up much past half. You could crank it and be fine, but maybe not, and the way things are going for you lately, is that a chance you want to take?
There is nothing that needs to be done to the amp other than ensuring it is off and unplugged. Make note of the polarity of the speaker leads, disconnect them, remove old speaker, install new speaker, attach leads.



Seems to work, I'll take it over to the studio tomorrow and see if it handles volume that isn't aloud in an apartment building

Re: What can I screw up?

PostPosted: Sat May 26, 2012 10:23 pm
by Scott DeVarenne
Cool, but be careful with that see if it can handle it approach. My understanding of power rating for a speaker is that it's a measure of how much signal the voice coil can tolerate before it heats up to an unsafe level. Unsafe meaning increased malleability and possibly burning out. I don't know if there are any obvious warning signs such as pronounced, unpleasant distortion. Also, if the replacement speaker has a relatively low sensitivity (relative to what you are used to in that amp) you may be inclined to turn it up, and up. If you have any doubts, borrow a speaker from me. It is also permissible to put a mic in front of your amp even though you aren't recording or on stage, I checked.

Re: What can I screw up?

PostPosted: Sat May 26, 2012 10:56 pm
by Malcolm Boyce
Scott DeVarenne wrote:...It is also permissible to put a mic in front of your amp even though you aren't recording or on stage, I checked.
Love this. Really.

I don't really know much about drivers matching gtr amps. As Scott mentioned, efficiency plays a big part in how a driver will perform in a given combination.

Re: What can I screw up?

PostPosted: Sat May 26, 2012 11:55 pm
by Scott DeVarenne
Malcolm Boyce wrote: efficiency plays a big part in how a driver will perform in a given combination.

Oh yeah. With my speaker that's rated as a sensitivity of 100db, I've been using a Hot Plate to attenuate 8db of the speaker output so I can set my master volume to the point where things are getting warm and squishy and nice, without the destructive volume (that 8db really makes a difference). I've lately been considering purchasing a Jensen Mod 1235 which has a sensitivity of 93.7db. Theoretically, with that speaker I could drop the attenuator from my rig. However, not knowing how it sounds and not being able to source one closer to home (yet), I've decided against buying one.

Re: What can I screw up?

PostPosted: Mon May 28, 2012 4:52 pm
by Scott DeVarenne
Hey Dyl Pickles,
How's the JR Pro with the replacement speaker?

Re: What can I screw up?

PostPosted: Mon May 28, 2012 7:14 pm
by Alain Benoit
Turns out it wasn't the issue if I remember correctly.

A.

Re: What can I screw up?

PostPosted: Mon May 28, 2012 7:36 pm
by Scott DeVarenne
I don't understand. Somebody, tell me something. I'm dying, here.

Re: What can I screw up?

PostPosted: Mon May 28, 2012 11:28 pm
by Malcolm Boyce
Scott DeVarenne wrote:I don't understand. Somebody, tell me something. I'm dying, here.
I'm with Scott. Update? I was curious to hear about the result of the speaker swap as well.

Re: What can I screw up?

PostPosted: Wed May 30, 2012 4:34 pm
by Mathieu Benoit
Malcolm Boyce wrote:
Scott DeVarenne wrote:I don't understand. Somebody, tell me something. I'm dying, here.
I'm with Scott. Update? I was curious to hear about the result of the speaker swap as well.


We fixed the Bassman on Sunday. Took about 90 minutes in total. I have no idea about his Blues Jr though...

Re: What can I screw up?

PostPosted: Wed May 30, 2012 4:35 pm
by Mathieu Benoit
Mathieu Benoit wrote:
Malcolm Boyce wrote:
Scott DeVarenne wrote:I don't understand. Somebody, tell me something. I'm dying, here.
I'm with Scott. Update? I was curious to hear about the result of the speaker swap as well.


We fixed the Bassman on Sunday. Took about 90 minutes in total.

I have no idea about his Blues Jr though... I'm not sure if he continued on with the swap since we fixed the Bassman.

Re: What can I screw up?

PostPosted: Wed May 30, 2012 6:01 pm
by dylanger
Sorry, the email that I would of got to tell me someone posted must of slipped through the cracks on my part.


The speaker swap didn't cure anything..........I thought it was a bad speaker because I plugged the Pro Junior into another cab a while back and it seemed to work much better. I guess I'll know more when I get it over to Fluid.

Dylan

Re: What can I screw up?

PostPosted: Thu May 31, 2012 8:48 am
by Scott DeVarenne
Thanks yous guys. What caused the Bassman to catch fire? Is it known?

Re: What can I screw up?

PostPosted: Thu May 31, 2012 12:43 pm
by Alain Benoit
It is known, I do not however know if I am a liberty to say.

A.

Re: What can I screw up?

PostPosted: Fri Jun 01, 2012 1:21 am
by Malcolm Boyce
What? Was someone smuggling contraband across the border in it or something? :-D

Re: What can I screw up?

PostPosted: Sat Jun 02, 2012 11:05 am
by Alain Benoit
Funny you should say that cause it does look like an old suitcase!

A.