Rewiring a bass cab...help

[CMOR]

I'm looking to rewire or load a bass cab. The drivers are 32 ohms each, as far as I can tell, thanks to the multimeter. Don't know what the wattage is but is really relevent? Anyway, is there a way to wire it so the cab is 4 ohm total load? There are no other toys like tweeters or horns, so it's just the drivers. By the way, its a 4x10 cab. I believe it's wired parallel now to 8 ohms total load. If anybody knows how to do it, your help would be great. Even if you know where I can take it for the work in the Altoona area, that would be cool.

[lonewolf]

I'm looking to rewire or load a bass cab. The drivers are 32 ohms each, as far as I can tell, thanks to the multimeter. Don't know what the wattage is but is really relevent? Anyway, is there a way to wire it so the cab is 4 ohm total load? There are no other toys like tweeters or horns, so it's just the drivers. By the way, its a 4x10 cab. I believe it's wired parallel now to 8 ohms total load. If anybody knows how to do it, your help would be great. Even if you know where I can take it for the work in the Altoona area, that would be cool.

32 ohms is pretty rare. Are you sure that isn't 3.2 ohms? That would make sense with a 4ohm speaker.

To answer your question, 8 ohms is the lowest number you can get with four 32 ohm speakers. To get 4 ohms with 4 identical speakers, you need 4ohm or 16ohm speakers.

Are you trying to squeeze more power out of your amp?

[CMOR]

I'm not trying to get more power,just run the amp at the optimal numbers. Besides, it would be nice to switch heads for different sounds if I wanted to. I guess I'll just get new speakers so I don't have to worry about wattage or ohms. Thanks.

[Ron]

Unless you are running a tube amp, going from 8 to 4 ohms is not going to make a distinct difference in the sound of your rig, aside from gaining some headroom.

If you are running a tube amp, then your speaker impedence should match the output impedence of the amp or it could cause problems with the output transformer, which can be an expensive fix.

Is there an impedence switch on the back of the amp? Tube amps are a bit different than solid-state amps, they should only be operated with the output/speaker impedences matched, and they shouldn't be operated without a speaker/load connected.

If you plan on swapping tube amps on the same cabinet, it's best if your heads all have the same output impedence, or else you'll run into the same problem again with the new speakers.

[CMOR]

Both heads are 4 ohm rated. Neither are tube, I'm not big on tube bass heads, unless they say Mesa. Mine don't, I'm po'. Headroom is what I'm looking for, not sound. I love the sound of sealed cabs(which it is). Do you know where I might be able to get wiring schematics for two output jacks? Thanks for your help.

[Ron]

If it's just headroom you're after, you're spending a lot of money for 3dB.
Remember too that it's only headroom if you don't use it.

If you were after better tone, then swapping speakers could make sense, as long as the new ones sound better. If you are satisfied with your current tone, and are simply after volume/headroom, you will be dissappointed and could possibly ruin the tone of the cabinet in the process. Older speakers that are broken in mechanically (and are undamaged) will normally have better tone than the same speaker off of the shelf.

I'm not sure if 2 output jacks can work. It depends on what you want to do with them. If it can work, I can draw you a wiring diagram.

[bassist_25]

If you're looking for more head room, it would make more sense to purchase a higher wattage head/power amp. Lowering your impedance from 8 ohms to 4 ohms is only going maximize your output by about 10%. If your volume is sufficient, but you're clipping your amp by EQing, a higher wattage amp would allow you to keep the same volume while maintaining whatever EQing you'd desire.

If volume is an issue, you should add another cabinet to your rig. It's easier to gain volume by "pushing more air" rather than adding wattage (granted you still need to have enough watts to push two cabinets). It takes twice as much wattage as whatever you have now to gain an increase in volume by 3db.

If you do decide to reload your cabinet, keep in mind speaker efficiency. If your replacing efficient speakers with inefficient ones, you might as well not reload the cab.

What kind of rig are you running, Steve?

[CMOR]

Quite honestly, it's my secondary rig. An old Crate B150 head and a Crate 4x10. I wanted to use my main head(BBE preamp and Mackie power amp)on the Crate cab without blowing it up. I love my Acme 4x10, but sometimes I want a different sound without completely changing the EQ, you know? The speakers in the Crate are old as dirt. I think they've been overloaded a few times and are breaking up alot even with lower watts at lower volumes.

[bassist_25]

If the speakers have been overloaded, they may be creased or have blown voice coils. Creased speakers will work for a period of time, but will eventually fall apart completely. Speakers with blown voice coils will give a farty distorting sound, almost like they're clipping, and have lower output.

If you're still shopping for speakers, I'd recommend sending Dave at www.avatarspeakers.com an email. The prices aren't quite wholesale, but they've been the cheapest that I've ever found, even cheaper than the big online speaker outlets.

It's awesome to see a fellow BBE user. When I was shopping for a preamp, my choices came down to either a Bmax or a SansAmp. I bought the Bmax and have never looked back.

[lonewolf]

If you're looking for more head room, it would make more sense to purchase a higher wattage head/power amp. Lowering your impedance from 8 ohms to 4 ohms is only going maximize your output by about 10%.

Actually, it depends on the amp design. Linear power amps generally will double the power as the impedance is halved. This results in 3db more gain. Switching power amps generally go up about 1.414x as the impedance is halved. You will get almost 2db more gain out of that-not worth bothering with.

CMOR:

You won't have any problem running either of those amps at 8 ohms. In fact, solid state amps run cooler and with less stress at 8ohms than at 4ohms. Sure, 4 ohms will maximize the power output, but you won't notice that much difference.

If you want to go 4 ohms, I'd suggest getting an 8-ohm, 18" cab to go under those 10"s and run the cabs in parallel.

If the crate speakers are shot, you may as well get 16 ohm replacements, but they may not be readily available. Most (but not all) bass speakers come stock at 8 ohms and a few of them have 4 or 16 ohm versions. Many times, that means, gulp ... $PECIAL ORDER$.

[CMOR]

I love the BBE, but I didn't go with the tube model. I like pristine bass tone. If I want a little fuzz, I have pedals. I'm kicking around the the idea of speakers, maybe just to match the Acme cab. As far as adding another cab, I used to run the crate with 1x15 and a different head(old peavey mark 7 or . Wish I still had the head... Personally, 18's have too much flutter or lag time for me. Keep it tight and punchy, not boomy.

[bassist_25]

Yeah, I went with the solid state BBE too. I had to A/B them on basstasters.com before ordering one. While the tube preamp had more warmth, it still didn't justify paying twice the price of the solid state model. For that price, I probaly could have scored an Eden Navigator off of Ebay.

If you want to fill up the bottom while still keeping a punchy and tight sound, you may want to look into 12 inch speakers. Many cabinet companies are offering 2x12 enclosures at very affordable prices. I'd like to put a 2x12 under my 4x10, but it wouldn't make much sense because I DI to the board and my cabinet is just there for us up on stage. Don't carry more shit than what you need is my motto.

Or you could look into Accugroove who probaly has whatever speaker configuration you have in mind already build into a single box.