Bill Fitzmaurice

Not that old of a school, I'm afraid. Real old school is when you don't have to remove a single board to replace any parts, let alone having to replace a board. It's not as bad as current amps, but it's still bad enough that the labor charges alone may exceed the value of the amp. I wouldn't toss it, it has value to someone, but probably as parts.

If it was an SVT I'd say find a good man with valves to fix it. The point to point wiring makes it very easy to fix if you know your way around them. But the SVT4 Pro only has a valve pre-amp, the power amp is SS, and it's not point to point wired, but is built on circuit boards. That makes them easier and less expensive to build, but much more difficult and expensive to repair. Based on that I'm inclined to agree with John Gee's assessment.

The only way you'll get specs on those is if Celestion still makes them, and even then maybe not. They still don't publish Greenback specs, not that it matters all that much with guitar drivers.

It depends how old they are. Prior to roughly the mid 1990s they may not be available. They can be measured, but you need the tools to do so. Celestion is one of the worst. They approached me circa 2005 about recommending their drivers in my designs, but were unable to provide any specs. I don't have any specs on file from them prior to 2008, while I have specs on JBL going back to the mid 70s.

50 years ago a 4x12 bass cab and 4x12 guitar cab were the same thing. If you run a bass through a 4x12 guitar cab today the result will be the same as running it through a 4x12 bass cab 50 years ago: it won't go as low or as loud as a modern bass 2x12. Next: Why? It's a form factor that hasn't made sense since 50 years ago. If you need more output than what a modern 2x12 can deliver, which isn't likely but that's a different topic, get a pair of 2x12.

The article is titled A Case Against Subwoofers. Don't blame the subs for the actions of those who abuse them. This quote in particular tells me the author isn't well versed in gear: "If certified low-end experts like O’Malley and Carlson don’t use subwoofers to listen to music, why does anyone?" If I didn't use the subwoofer in my home or car systems when listening to music there wouldn't be anything to hear below 100Hz. He doesn't know diddly about recording studios either. The use of subs didn't end with Pretzel Logic. They're standard issue, and have been for forty years. And he's off with what he says about vinyl. Records do have narrow grooves, to prevent needle jump, and for that reason their bass content is rolled off. That rolloff is compensated for by the RIAA equalization of phono pre-amps. Needle jumping during payback from high bass content can happen, but not when the turntable is adequately isolated.

And there's the reactionary flip side. Where subs are concerned the only time they're counter-productive, either in a club, a stadium, a car or a home, is when they're used to reproduce low frequency sounds that shouldn't be there. To say they shouldn't be used to reproduce what should be there is just as silly as the opposite view.

Nothing catastrophic. But if your desire is the best sound possible (isn't it always?) mixing cabs is not the way to get it.

You could use it in a dual amp setup, along with a regular bass amp and speakers. Turn the bass EQ on the Marshall all the way down, and the mid and high EQ on the bass amp all the way down.

I'm reluctant to make a reply, as this is one of those questions that always ends up at ten pages of bickering back and forth, like the difference between tube watts and SS watts. For an example go to Talkbass.com. The subject comes up at least once a week and it never ends well.

The tweeter isn't the problem, the woofer is horn loaded.

Mixing cabs is seldom a good idea. Mixing direct radiators with horn loaded cabs is a particularly bad idea.

Impressive if true, but I doubt it. It would require driver specs that are unattainable. You can get -3dB at 33Hz with 96dB sensitivity, but not from a cabinet less than twice the size of the Ampeg.

Play it at war volume and your Bluesbreaker will be a Bluesbroken. It won't bother the amp but the speakers won't take it.

https://media.music-group.com/media/PLM/data/docs/P0742/BXR1800H_P0742_M_EN.pdf There's not much that you can't find a manual for, you just have to look, even for gear no longer in production. For that matter it's become common for items to come with perhaps a quick start guide, with the full manual only available on line. I've gotten into the habit of downloading the manual for a potential purchase before buying, to be sure it meets my needs.

What? Read the manual? And risk this?

Respect for James Watt demands nothing less. 👌

IME British cars of the 60s were paragons of reliability compared to Italian cars. Still, having owned an MG Midget it's a damn good thing you did a better job with Hurricanes and Spitfires.

So long as they're working it makes no difference. If series wired and one toasts a coil neither will work, so that would be a problem at a gig. If parallel wired and one toasts a coil the other will keep working, so it might get you through a night, but if that happens the cab tuning will be upset and there will only be one driver doing all the work, so it might die before the end of the set anyway.

They're well known for playing fast and loose with specs.

That's a safe bet...unless it's a Behringer.

That's not particularly helpful, since neither watts nor impedance define how well a driver will function in a given cab. It's not even a correct answer, as two 4 ohm drivers series wired also gives an 8 ohm load. In any event chances are if this isn't an exact match it's probably close enough: http://store.gallien-krueger.com/mm5/merchant.mvc?Screen=PROD&Product_Code=082-0460-C

There's a difference between within spec and optimal. Besides, amps aren't intentionally designed to give maximum power at their minimum rated impedance load, it just works out that way.

Heat. 100 watts into 8 ohms is 28.3 volts at 3.5 amperes, 100 watts into 4 ohms is 20 volts at 5 amperes. Where creation of heat in the amp components is concerned the primary source of heat isn't voltage, it's current. The same is true of driver voice coils. The lower the current the less heat generated. That's why power lines transmit at very high voltage, typically well over 100 kilo volts. Doing so minimizes current, which minimizes heat in the transmission lines, which minimizes the wire gauge required. It's also why you can run a 500 watt amp with a 16 gauge power cord. At 220 volts and 50% efficiency the amp will never draw more than 5 amperes. Put an amp with the same specs into a car with a 12v power supply and you need a massive mains cable, because you're now maxing out at 80 amperes.

Doubling the excursion of a driver results in a doubling of SPL. That requires doubling the voltage to the driver, which equals a four fold increase in power, which gives a 6dB level increase. One can realize that same 6dB by doubling the driver count driven with the same voltage. One may also realize a 6dB increase in SPL in an open space by halving the distance from the source to the listener. You also realize 6dB when you halve the space that the speaker radiates into, for instance when a speaker is mounted in a wall as opposed to being in an open field. The need for at least a 6dB difference to be meaningful is why going from, say, a 50 watt amp to a 100 watt amp is underwhelming. Sheer disappointment was my reaction when I went from s 50 watt Fender Bassman to a 100 watt Fender Dual Showman. That was when I was still in secondary school, it would be another two years before I learned the reason why I should have gone straight to the SVT.