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Now I remember... Speaker magnetic circuit anomoly...


Boggs

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I tried out last night running the V22 Bugera into my 1x12 cabinet with the Carvin British Series speaker for comparison to the stock Bugera but the output of the Carvin was EXTREMELY low... It was as though the amp was putting out 0.1 watts... Clean and distortion channels worked as they were supposed to but just rediculously low output... :confused:

 

It struck me this morning why that may be and I will have to test the theory tonight. I haven't used it since putting on this type of steel speaker cover...

 

http://ecx.images-amazon.com/images/I/41B2PSOn-zL._SL500_AA250_.jpg

 

I remember in the past now putting one of them on and having the same thing happen. It is as though the steel cover messes up the "magnetic circuit" and wreaks havock with its performance. I will have to take the cover off tonight and try again. Last time, I remember that after removing the cover, the speaker performed just fine. Bizarre... If this is the case, I will have to find something like that cover in plastic. Of course, if I just remove the speaker and put it into the Bugera, that shouldn't be an issue since the cover is cloth. I'll let you know. I should record the Bugera followed by the Carvin with cover followed by the Carvin without the cover so you don't think I'm nuts... Well, maybe that won't change anything, but at least you would hear graphically how extreme the effect...

 

The cover is actually a 15" cover and it is secured into the front face of the enclosure and not directly coupled to the speaker basket as the speaker is a 12"... Last time, everything came out distorted as hell with the 12" steel cover. This time, cleans are still clean but just very quiet.

Check out my Rock Beach Guitars page showing guitars I have built and repaired... http://www.rockbeachguitars.com
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I'm sorry, I can't buy into your theory-

Take for instance, a 4x12 cab-, the speaker magnetss are all in close proximity of each other, and according to your thought, then there would be practically no sound output-

check your amp, cords, wiring.

"Who's gonna teach the children about Chuck Berry?"
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Absolutely. The speaker is mounted from the rear of the front panel and the cover is mounted to the front of the front panel. It is a 12" speaker and it is a 15" cover. Remember... I went through this before with a close proximity 12" metal cover only to worse effect. Only when I went to a full size grid not surrounding the speaker did it work propery. In a 4x12 configuration, the speakers are alongside each other and not surrounding the speaker itself. The protector grid resembles the one I made that goes around the periphery of the enclosure, not the speaker. I've been through this before with this speaker in this very enclosure. It is very real.
Check out my Rock Beach Guitars page showing guitars I have built and repaired... http://www.rockbeachguitars.com
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Weird; what else was different?

 

Loose output-tube?

 

Try it with another speaker, before even removing that grille?

 

Speaker cable known to be good?

 

Any other speakers connected in parallel or series or both, or just the one 1x12 cab?

 

If "yes" to additional speakers, could there have been somewhere that the positive and negative were reversed, causing inverse-phase cone actuation? THAT will result in a weird, tinny, strangled attenuation...

Ask yourself- What Would Ren and Stimpy Do?

 

~ Caevan James-Michael Miller-O'Shite ~

_ ___ _ Leprechaun, Esquire _ ___ _

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Not a tube. Cable tests good. Other speaker good. In parallel, both speakers (set to 4 ohm output now) lower output but standard Bugera speaker completely drowns out the Carvin. Individually, when the Bugera is very loud, the Carvin is barely audible at the same setting. Definitely not a polarity issue.
Check out my Rock Beach Guitars page showing guitars I have built and repaired... http://www.rockbeachguitars.com
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I have Carvin PA, Traynor PA, Squire PA, Fishman PA/amp, Fender Bass Amp and Pignose practice amp with what apppear to be metal screens on them and they will all play with plenty of volume...so I'm guessing it's not the grill that is causing the problem unless one of the mounting screws penatrated the speaker wire? Try the cab with another amp...
Take care, Larryz
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" It is as though the steel cover messes up the "magnetic circuit" and wreaks havock with its performance. "

 

only in Bizzarro World. Look for another problem.

"I believe that entertainment can aspire to be art, and can become art, but if you set out to make art you're an idiot."

 

Steve Martin

 

Show business: we're all here because we're not all there.

 

 

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Apparently, in this case, the low output was due to the fact that the 25' commercial grade 14ga speaker wire I used to test the satellite was too much load for the amp. I went to a 3' length of 16ga and it worked fine... The 25' wire worked just fine on the PA... That would explain why the speaker volume was so low and not low and severely distorted like last time I went through this... Last time, I simply took off the cover and left everything else and it all came back which is why I made the incorrect assumption this time. This was tested with a CD player going into the amp input at constant volume and all was at low levels. I still have to plug a guitar into it and crank it up after my wife gets up and goes to work to be absolutely certain. Y'all can say "I told you so" now...
Check out my Rock Beach Guitars page showing guitars I have built and repaired... http://www.rockbeachguitars.com
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Apparently, in this case, the low output was due to the fact that the 25' commercial grade 14ga speaker wire I used to test the satellite was too much load for the amp. ....

 

That doesn't make any sense either. 14 gauge is thicker than 16 gauge, which translates to less of a load on the amp, foot for foot. (basically a bigger pipe....) Any amp should be able to drive a 25 foot load through 14 guage cable. Granted, 3 feet of length is even better, but 25 feet should not have compromised the performance that much. How many watts is this amp?

 

Could there be a connector wiring issue?

"I believe that entertainment can aspire to be art, and can become art, but if you set out to make art you're an idiot."

 

Steve Martin

 

Show business: we're all here because we're not all there.

 

 

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Well, somethin's fishy here, and it seems to be that cable- somethin' to do with it, or the connectivity at one end or the other.

 

I've used longer heavy-duty speaker-cables than that with tube guitar-amps before, primarily for stereo or multi-amp set-ups, and once used a 50' one in a pinch between a head and 4x12 cab (one of those stupid last-minute-emergency kinda things). And I never had any problems like you describe here.

 

You should really thoroughly check that cable out; and when you check for continuity, double check to be sure that it's tip-to-tip and sleeve-to-sleeve, and NOT tip-to-sleeve, etc. Can't hurt to be sure; at least you'll have ruled that out.

 

I have experienced similar enough symptoms when a speaker was out of phase with others connected to the same amp, when a tube was bad, and when an amp that used four output-tubes was being run on two, but one of the two had been mistakenly put in the wrong socket so that the amps output-section was working in a weird manner.

Ask yourself- What Would Ren and Stimpy Do?

 

~ Caevan James-Michael Miller-O'Shite ~

_ ___ _ Leprechaun, Esquire _ ___ _

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Apparently, in this case, the low output was due to the fact that the 25' commercial grade 14ga speaker wire I used to test the satellite was too much load for the amp. I went to a 3' length of 16ga and it worked fine... The 25' wire worked just fine on the PA...

 

No, that's really not a plausible explanation. Even with a crap 18 gauge wire or worse you would have to get into the hundreds of feet of cable before the resistance was a significant enough factor to effect volume noticeably. I'm guessing you had a high resistance connection caused by some tarnish or corrosion on one of the contacts at either end. The point of contact on each conductor on a 1/4" plug/jack is a straight blade touching the edge of a cylinder, i.e. an extremely tiny area of contact. This is why we no longer use 1/4" connections for speakers in pro audio. Any time I plug a 1/4" connector into a jack I rotate it back & forth about a half dozen times. I'm obsessive, I know, but doing so cleans any corrosion off the point of contact & ensures a clear connection. 1/4" plugs/jacks are an inherently flawed design which come to us from the old telephone industry, and which in most parts of the pro audio industry have been replaced with XLR & Speakon formats which have vastly larger points of contact. Anyway, that's my analysis of your experience.

 

Scott Fraser

Scott Fraser
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Could be some sort of flaw in the cable's wires at some point in it's length, where there is minimal contact, possibly a frayed point inside the insulated covering?

 

+1 Have a cable that I finally found the flaw in accidently by stepping on it, took it out of line and "voila" problem solved...

Take care, Larryz
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