I went over and over all the websites and talked to people about doing the same thing with my Blues Jr.

Here is what I did instead:








I am running 2 16 ohm speakers in parellel to get 8 ohms.

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Chet Feathers

Authorized TonePros Dealer
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F/A Official Southpaw Compliance Certification Tester http://faamps.com/

http://www.facebook.com/cafeathers


I didn't Lose my mind, I traded it for this guitar.

dear Lord!
im just speachless bill. amazing craftsmanship brother.

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63supro
"The good thing is in a club situation, most of the patrons are trashed and really can't tell the difference."

hell even my g.friend just flipped out bill.
it takes a lot to get her moved on anything guitar related.

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63supro
"The good thing is in a club situation, most of the patrons are trashed and really can't tell the difference."

It was over a year ago and I can't remember for sure how long, so perhaps my question and his response are no longer on file. However, I would just re-ask the question. You see, I asked the question because he had one mod for the extension jack only, and another mod that had an upgraded OT in conjunction with the additional jack. I asked why the upgraded OT with the ext. jack and was give the "not too frequent nor @ too high a volume qualifier.

_________________
The quintessential sound of 60/70's R&R:
Fender Tube Amps
Gibson Guitars

what it OT if i may ask?

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63supro
"The good thing is in a club situation, most of the patrons are trashed and really can't tell the difference."

Output Transformer

BTW, Bet you can't get a Fender tech. to tell you a 4 ohm load is OK. Is your BJ still under warranty?

_________________
The quintessential sound of 60/70's R&R:
Fender Tube Amps
Gibson Guitars

nope im the second owner.
why wont the fender tech tell you that the 4 ohm is ok??

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63supro
"The good thing is in a club situation, most of the patrons are trashed and really can't tell the difference."

That means bypassing the internal speaker since its 8 ohms. I do the same for my Princeton, bypass the internal speaker and run it into 2 16 ohm loads. IMO I don't think another speaker of the same make and model will make a noticeable difference. You would need to buy two speakers, 16-ohm each, etc. One option is go to http://www.avatarspeakers.com and look at their 2 X 12 cabinets; But before you buy anything listen to the speakers at http://www.celestion.com, http://www.jensentone.com, and http://www.eminence.com. And, my favorite, the Rivera speaker shootout video:
http://www.youtube.com/watch?v=jWK0sa7tlfI

Then decide which type of speaker(s) best helps to achieve that "tone" in your head.

Use headphones.

Enjoy your adventure into speakerdom.

Because the OT is an 8 ohm ONLY OT and does not have more than one tap which is the case for tube amps designed to use ext. cabs.

_________________
The quintessential sound of 60/70's R&R:
Fender Tube Amps
Gibson Guitars

no no no, i want to still be able to use the amps speaker as well. its a must.
i just bought a avitar 1X12 cab with celestion greens in it. i love it. good move on my part. the kid didnt like toting around a amp and a speaker. it still even has the tags on it lol.

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63supro
"The good thing is in a club situation, most of the patrons are trashed and really can't tell the difference."

cool speaker link 1982. i still like the clestion vintage 30's best.

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63supro
"The good thing is in a club situation, most of the patrons are trashed and really can't tell the difference."

Man that amp looks fantastic! I'm envious CAFeathers. I bet that it sounds great too, I like the 2x12 idea.

If you all are interested, here is a pretty thorough explanation of tube amp impedance, and matching of amp and speaker (link below). It does seem to be commonly accepted that impedance matching for an amp is important, and it is important, but simply for efficiency, in order to get the best sound and most power out of the amp. We all know that using a tube amp without a speaker will damage the amp, however, using the amp with a very low impedance speaker will not do any damage, even down to zero ohm load. Notice that many newer amps have a shorting output jack, so that if the speaker is unplugged, the OT will be shorted, which protects the amp from the "no speaker" condition. Here is an exerpt, it is about half way down the page on the site.

"Q: What does the "impedance" of my output transformer mean?

A: Transformers don't have impedances, they have impedance RATIOs. This is an important distinction.

Transformers transform impedances as a pure ratio. That is, a 4400 PP to 8 ohm transformer makes any load on its secondary look like it's 550 times bigger to a tube at the primary. An 8 ohm secondary load then looks like a 4400 ohm load at the primary. It also makes a 16 ohm load look like an 8800 ohm load if you hook 16 to it, 2200 if you hook a 4 ohm load to it, and similarly for all values in between. Power tubes have a power output that depends on matching - that is, they have sweet spot load that they do best on, most power out, and other loads will get less power because the tube itself limits how much power it will transfer out. [Actually there are two sweet spots, one for highest power, one for lowest distortion; the two spots are not the same for any known tube. From zero ohms loading up to some ill-defined number of ohms higher than the optimum power load, power tubes do not destroy themselves, they merely change how much they transfer to the load. So - if you have a tube amp with a tap for 8 ohms, you will get the nominal power of the amp only with a "matched" 8 ohm load. If you hook 16 ohms there, the power tubes "see" a proportionately higher ohmage on their plates, and can only put out about half the nominal power. If you hook up a 4 ohm load to the 8 ohm tap, the power tubes "see" a load about half of the matched one, and again will put out only about half of the nominal power. This "half the nominal" power is not fixed because of the 2:1 change in load, but varies from amp to amp and tube to tube, and may not be exactly 2:1. In addition, speakers are NOT single impedance loads. It is convenient to think of "8-ohm" speakers, but the plain fact is that the speaker's impedance varies with frequency and also with the acoustic loading (cabinet and other things) that the speaker sees. That impedance meter is not going to be a huge help, because you have to specify the frequency being tested as well as the impedance to have something meaningful.

Q: Why do I have to match speakers to the output impedance of the amp?
A: You'll get the most power out of the amp if the load is matched.

Q:Will it hurt my amp/output transformer/tubes to use a mismatched speaker load?
Simple A: Within reason, no.
Say for example you have two eight ohm speakers, and you want to hook them up to an amp with 4, 8, and 16 ohm taps. How do you hook them up?

For most power out, put them in series and tie them to the 16 ohm tap, or parallel them and tie the pair to the 4 ohm load.

For tone? Try it several different ways and see which you like best. "Tone" is not a single valued quantity, either, and in fact depends hugely on the person listening. That variation in impedance versus frequency and the variation in output power versus impedance and the variation in impedance with loading conspire to make the audio response curves a broad hump with ragged, humped ends, and those humps and dips are what makes for the "tone" you hear and interpret. Will you hurt the transformer if you parallel them to four ohms and hook them to the 8 ohm tap? Almost certainly not. If you parallel them and hook them to the 16 ohm tap? Extremely unlikely. In fact, you probably won't hurt the transformer if you short the outputs. If you series them and hook them to the 8 ohm or 4 ohm tap? Unlikely - however... the thing you CAN do to hurt a tube output transformer is to put too high an ohmage load on it. If you open the outputs, the energy that gets stored in the magnetic core has nowhere to go if there is a sudden discontinuity in the drive, and acts like a discharging inductor. This can generate voltage spikes that can punch through the insulation inside the transformer and short the windings. I would not go above double the rated load on any tap. And NEVER open circuit the output of a tube amp - it can fry the transformer in a couple of ways.

Extended A: It's almost never low impedance that kills an OT, it's too high an impedance.

The power tubes simply refuse to put out all that much more current with a lower-impedance load, so death by overheating with a too-low load is all but impossible - not totally out of the question but extremely unlikely. The power tubes simply get into a loading range where their output power goes down from the mismatched load. At 2:1 lower-than-matched load is not unreasonable at all."


http://www.geofex.com/tubeampfaq/tubefaq.htm#transformers

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---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.

shimmilou,
Bet you can't get a Fender tech. to tell you it's OK to use a 4 ohm load on the BJ. If he/she will, I'll start start using an ext. cab. with mine. I already know it sounds great. And why do you think that Billm said it should not be done frequently and at high volumes?

_________________
The quintessential sound of 60/70's R&R:
Fender Tube Amps
Gibson Guitars

im kinda reserved at the fender techs on this amp.
if they were in the know they wouldnt have made the amp with so many flaws. IMHO.

_________________
63supro
"The good thing is in a club situation, most of the patrons are trashed and really can't tell the difference."

What are you refering to?

_________________
The quintessential sound of 60/70's R&R:
Fender Tube Amps
Gibson Guitars