Blues Junior Amp Modifications

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Blues Junior Amp Modifications

Postby eline » Wed Feb 20, 2008 4:40 am

How much trouble is it to modify a Blues Jr. amp? Can the wattage be increased, say from a 15watt to a 30watt? Also, I have a blown speaker...a little vibration in the tone; do any of you have any recommendations for a particular speaker or is the stock speaker the best thing to go with?
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Re: Blues Junior Amp Modifications

Postby thebluesbox » Wed Feb 20, 2008 5:59 am

I might get flogged for this but I cant resist.
Here is a gritty mojo mod for it.




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Re: Blues Junior Amp Modifications

Postby ricochet » Wed Feb 20, 2008 1:01 pm

Doubling the power would be a pretty major mod. And you'd have a hard time noticing the difference. That's 3 dB difference in sound level, less than 1 notch on the volume knob, just noticeable.
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Re: Blues Junior Amp Modifications

Postby eline » Wed Feb 20, 2008 4:12 pm

A couple of weeks ago, I was jammin' at one of our local lounges here in Riverside (CA). I was playin' through my Blues Junior and it wasn't quite loud enough. There was another harp player and he was playing through a Peavy Classic 30, and his amp was loud enough. Ultimately I ended up using his rig. But it seemed like his amp was a lot louder. My thought was that the difference was in the wattage and the bad speaker. I didn't really notice my speaker until the next day; I might have blown the speaker that night...most likely. Any ideas about the speaker mod.? Or would it be best to stick to a Fender replacement speaker?
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Re: Blues Junior Amp Modifications

Postby ricochet » Wed Feb 20, 2008 6:34 pm

15W vs. 30W is almost unnoticeable if the speakers are of equal efficiency. That's surely the difference. A 5W amp with a highly efficient speaker can easily be noticeably louder than a 100W amp with an inefficient speaker. When looking at speakers' specs, look for the sensitivity figure; higher numbers mean higher efficiency. Make sure the units are the same. The standard rating is in dB/1W/1M, the sound level in dB recorded by a calibrated mic 1M in front of the baffle the speaker's mounted in, on the axis of the speaker, with a 1W pure tone fed into it (usually of 400 Hz.) Sometimes they'll use bogus things like a 2.86W signal or move the mic in to 1M from the dust cap of the cone instead of the face of the baffle, move the mic off axis to find a louder point or change the test frequency to hit a response peak.

Another curious thing is that speakers rated for higher power levels are often MORE sensitive than lower power models. Bigger magnets and voice coils, and more flexible surrounds.
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Re: Blues Junior Amp Modifications

Postby angerboy » Wed Feb 20, 2008 9:21 pm

Here are some ideas...

1. Go to the Weber forums at http://www.tedweber.com and ask Ted Weber on the speaker forum or pose the question on the harp forum. You'll get a good speaker recommendation there. The best way to get more volume out of that amp might be to buy an Anti-Feedback box from Kinder.

2. You are unlikely to get huge amounts of volume out of a Blues Junior. You might be better suited to buy a replacement speaker, sell it and put the money towards a larger harp amp. You will have a difficult time wringing a tremendous amount of volume out of that amp for harp. The cabinet is small and they tend to feedback early.

I played a Pro Junior for the past year. It had the same problem. It sounded good, but it just didn't have enough volume. I ended up selling it and buying a more usable amp.

You can spend a lot of money on modding that amp or you can sell it and buy something more harp friendly. The good news is that Blues Junior holds it's value pretty well. Guitar players love those amps.

To get more useful volume, you may have to step up to a larger amp like a Bassman or drop some dough on a harp specific amp like a Harpgear Double Trouble. I ended up buying a Harpgear. I think every one of those 18 watts is usable. It's way louder than a Blues Junior. It's almost Bassman loud. It's one of the nicest midsize amps around.
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Re: Blues Junior Amp Modifications

Postby thebluesbox » Sun Feb 24, 2008 2:09 pm

there is one on ebay now being sold by its previous owner that only played it twice, hmm wonder why?
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