Blues Jr into a cab with missing speaker?

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Hey all, I have a blues jr that I kinda took a part a while ago and put the internal speaker in a 2x12 cab. I was wondering if i could hook the blues jr up to that cabinet without the internal speaker in the blues jr? would that be ok? or just asking for trouble? I see two speaker cable jacks on the chasis and im confused how to go about this...first time messing with an amp. any help would be great, thanks
 

ASC67

Member
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373
There is only one speaker jack on the Blues Junior , the other one is for the foot switch.
 

ButchR

Komet Player
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Use to run mine with an external speaker cabinet all of the time. No problems.
 

DeaconBlues

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Yeah, unplug the internal speaker and plug the extension speaker into that jack. Like ASC67 said, the other one is for a foot switch.
 

IM4Tone

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3,773
It's recommended that the Blues Jr. have an 8 ohm load. If you've paired the original speaker (which is 8 ohms) with another speaker, the total impedance of the pair cannot be 8 ohms. Many will tell you it's OK, but I won't mismatch due to possible damage to the amp.

If the original speaker is by itself in the 2X12, no problem.
 

Billm

Member
Messages
574
From long experience with many Blues Juniors, I can assure you that the amp will drive two 8 ohm speakers in parallel all day and night without problems. It will handle a 16 ohm load without difficulty, too.

There are several mods you can do to make the Blues Junior far more flexible and better at driving multiple speakers.
 

IM4Tone

Member
Messages
3,773
From long experience with many Blues Juniors, I can assure you that the amp will drive two 8 ohm speakers in parallel all day and night without problems. It will handle a 16 ohm load without difficulty, too.

There are several mods you can do to make the Blues Junior far more flexible and better at driving multiple speakers.
I certainly recognize you have a wealth of experience with the Blues Jr., BUT, several years back I posed this same question to you as I wanted to use a splitter and drive the internal speaker and an external 8 ohm cab. I had considered the OT upgrade you offer which is designed to handle 4 ohm or 8 ohms. I was trying to decide if the upgraded transformer was really necessary and the answer you gave at that time was 'it's OK stock as long as it wasn't played at high volume, frequently'.

Your creditability with me is now in question. Sorry to be so blunt, but what has changed in the interim? And, what would Fender's response be to this question?
 

Billm

Member
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574
Your creditability with me is now in question. Sorry to be so blunt, but what has changed in the interim? And, what would Fender's response be to this question?
Several years and you're still dithering? Or did you buy a 4/8 ohm OT? :)

Fender's answer is printed on the label inside: 8 ohms minimum.

When you go off spec in impedance, you lessen the efficiency with which the output tubes can transfer power to the speaker(s). The inefficiency causes the tubes to run hotter, which is why I recommend adjustable bias--so you can ratchet the whole thing down a couple of notches. I have never, however, encountered a failed output transformer. That's not the weak link. The heat kills the tubes faster, and if you play with heavy distortion, the screen grids in the EL84s take a beating.

And to the OP, your forum name says you're for tone. Me, too. And upgrading the output transformer is an excellent way to improve BJr tone, as thousands of users can attest to. Using an improved OT with 4 and 8 ohm taps gives you the best of both worlds.

My previous reply stands. :)
 
Last edited:

IM4Tone

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3,773
Several years and you're still dithering? Or did you buy a 4/8 ohm OT? :) I bought a Weber Z-matcher, converted my Blues Jr. to a head, and now have many options. The Z-matcher is, of course, not dedicated to the Blues Jr. either.

Fender's answer is printed on the label inside: 8 ohms minimum. in essence not recommending two parallel 8 ohm speakers.

When you go off spec in impedance, you lessen the efficiency with which the output tubes can transfer power to the speaker(s). The inefficiency causes the tubes to run hotter, which is why I recommend adjustable bias--so you can ratchet the whole thing down a couple of notches. I have never, however, encountered a failed output transformer. That's not the weak link. The heat kills the tubes faster, and if you play with heavy distortion, the screen grids in the EL84s take a beating.

And to the OP, your forum name says you're for tone. Me, too. And upgrading the output transformer is an excellent way to improve BJr tone, as thousands of users can attest to. Using an improved OT with 4 and 8 ohm taps gives you the best of both worlds.

My previous reply stands. :) But the question is which reply? the one you gave me in the past or the one on this thread? Not dithering, nor questioning that the dual tap OT gives better results than the stock one, just have a fairly good memory and recognize contradictions. I'd prefer to rely on advice from more experienced and technically savvy people (than myself) such as you, but you've brought out the skeptic in me with these contradictions.
:nono
 




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