Tube amps for 5 string bass frequencies.

[Raybob]

Area bass player has combo SWR bass amp w/2x10s and wants me to see if it can be helped. His complaint, "Amp had a resistor changed, and a rubber bumper put in to try to remedy a breakup that happens, primarily on the B string, at volume. Didn't fix issue. Maybe new tube and cleaning?"

My initial thought is that there must not be a 10" speaker designed to put out notes with frequencies of that low B string.. around 31hz. If anyone has been there, done that, with trying to fix something that can't be fixed, I'd sure love to hear about it.

[Leo_Gnardo]

Area bass player has combo SWR bass amp w/2x10s and wants me to see if it can be helped. His complaint, "Amp had a resistor changed, and a rubber bumper put in to try to remedy a breakup that happens, primarily on the B string, at volume. Didn't fix issue. Maybe new tube and cleaning?"

My initial thought is that there must not be a 10" speaker designed to put out notes with frequencies of that low B string.. around 31hz. If anyone has been there, done that, with trying to fix something that can't be fixed, I'd sure love to hear about it.

If you gang together a collection of 10's, say two SVT 8x10 cabs, you may be able to satisfy the need to hear a clean low B at volume. With only two? I don't think so.

SWR owner better invest in an 18" cab, and get used to hauling it around. Like a hippopotamus for Christmas, "nothing but a hippopotamus will do."

You could try a couple of car-subwoofer speakers, ones with a large Xmax figure, that's the distance the cone will move from its rest point. But those speakers generally have low efficiency, and by the time you have a satisfactory volume, everything in the SWR combo cab will be shakin', quakin' & rattling something awful. FWIW Parts Express has a good choice of car subwoofers. Good luck. We'll be watching the seismometer.

[J M Fahey]

As is? Forget it. Forget combos.

Get separate Head/Cabinet and the latter at least 4x10" or 2x15" .
Single 15" won't do either and although an 18" in a *large* cabinet will do wonders for the low B , won't excel at mid/high punch and attack, bass will sound like a distant summer storm thunder or a subway passing underground: felt in your pants but easily lost under guitar/drums/etc.

Reggae Bass players love 18" in their Acoustic 361 or 371 cabinets, just look at the size/weight of them.

As a stopgap solution add a good 15" (Eminence/FaitalPro/RCF/Beyma) in its`own (largish) cabinet.
Even an 18" in an even larger one, if he pairs it with the existing 10" for definition.

Your friend will physically destroy present speakers with overexcursion, no rubber bumper will help him.

It's not an amp/tube/dirt/whatever problem, just needing more cone surface and more cabinet cubic inches to push a lot of air at very low frequencies.

He must also forget "smile curves" in graphic equalizers, bass boosters, parametric equalizers, etc. , you can't actually "fake" a Bass`response which is not there.

Or a Plan B: keep the amp but add a DJ/PA type powered subwoofer, drive it from his amp Line out or even better if he has a Biamp out.

[Enzo]

2x10 bass cabs are more for definition and punch, not bottom. Stack one on a big cab.

Maybe new tube and cleaning

Total guess, meaningless suggestion from someone who lacks knowledge of amp technology.

[Leo_Gnardo]

<new tube & cleaning>

Total guess, meaningless suggestion from someone who lacks knowledge of amp technology.

Exactly, like if I brush my teeth & comb my hair (both of them... ) that will enable me to lift 450 pound barbell....

No substitute for power, & big speakers for low notes.

[nsubulysses]

It's a delicate balance to listen to the customers valuable information vs. knowing what is a meaningless suggestion that will mislead you and waste your time.

I once told a guy with a Gibson Super Gold Tone that his 10" speaker was the cause of the ugly distortion he was experiencing. When playing the speaker by itself the note attack was alright but it would honk out during the sustain. Checking all through the amp that was the only thing I could find that was causing a bad sound. It's a 4xEL84 amp and was doing 36W at clipping. He insisted he needed me to overnight ship a whole new set of tubes so he could play a show on saturday...........................uh, so I did it. Give the people what they want?

[The Dude]

Tell him to get one of these.

[potatofarmer]

Most bass guitars don't put out much fundamental; it's primarily the second harmonic. Still, ~60Hz is going to be difficult for most commercial bass cabs, especially combos.

You most certainly can get there with a single 15, though it probably won't be cheap. I built (well, modified) a cab around a Dayton Audio PA380-8 - ~2.5 cu. ft. and tuned to 48Hz with a shelf port. Wound up excursion-limited to ~300W, -3dB at ~50Hz. Lots of tildes but how much can you trust WinISD and manufacturer tolerances? Only downside of that woofer is that it drops off around 2kHz, even on-axis. If I had the money though, the Eminence 3015 is pretty hard to beat.

There are 10s that can handle the 50-60Hz range without issue, but the downside is they tend not to have much midrange. And of course there are 12s and 15s that will handle it with ease.

Anyway!

Will this combo accept an external cab? Many bass combos are rated for a 4 ohm load but only have an 8 ohm load built in. This would be a relatively cheap way to get a +6dB bump in output, and assuming he keeps his volume the same as before, it should accommodate his EQ preferences better.

[Mick Bailey]

Those 300W KRK subs have single 10" glass-fibre coned drivers and they handle 30Hz and lower with ease. Sealed cabs with plenty of wadding. I'm pretty impressed at the performance and Xmax is huge. I thought a pair of those speakers may make a decent small bass cab for bottom-end 'plummy' 5-string use. The main downside is there's not much mid and very little overload capability - get even close to their limit and they burn out pretty sharpish.

I've just been working on an Acoustic Image combo with a single 10" Eminence driver that handled that low B pretty well. Similar speaker construction to the KRKs.

[tedmich]

Most people don't hear the low B fundamental, they may feel it a bit but its the harmonics you hear. What the OP customer needs to stop the clipping of the very low signal on the 10s and that can't be after the power amp (lets roll a couple 74mH inductors for a 4th order highpass at 50Hz, where'd I put that 422uF cap??) so a tunable highpass upstream would help. A simple 2nd or 4th order high pass upstream before the preamp should allow him to dial out the clipping.

The Eminence Lab12 will happily go to 25Hz in a small ported cab and handle 250w, but produce very little above 500Hz, which luckily the typical 10" handles quite well.

[Mike Sulzer]

Most people don't hear the low B fundamental, they may feel it a bit but its the harmonics you hear. What the OP customer needs to stop the clipping of the very low signal on the 10s and that can't be after the power amp (lets roll a couple 74mH inductors for a 4th order highpass at 50Hz, where'd I put that 422uF cap??) so a tunable highpass upstream would help. A simple 2nd or 4th order high pass upstream before the preamp should allow him to dial out the clipping.

The Eminence Lab12 will happily go to 25Hz in a small ported cab and handle 250w, but produce very little above 500Hz, which luckily the typical 10" handles quite well.

The Lab 12 has a sensitivity 89.2 db. The Kappalite 3015 mentioned earlier has 100.8 db. This discussion is about using a tube amp, you know, like 40 watts. The K3015 will be quite impressive with 40 watts in a reasonable box and you cannot melt it with that little power. The Lab 12 will be somewhat less impressive with 400 watts, and it might not last forever. Anyway, who carries around a 400 watt tube amp?

[mhuss]

Anyway, who carries around a 400 watt tube amp?

Mine's only 300...

[tedmich]

I have a Eminence Kappa-15LFA that I quite like, and its 99db/watt efficient. It will be flat to 40Hz and handle ~250w but the box has to be...6.9 cu ft
it currently in a (still big) Peavey 115BX at 4.5 cu ft and makes 45Hz. while the original 1502-4 Blackwidow did close to 40Hz, but burned out.

Home sub guys loved the Kappalites especially with http://www.billfitzmaurice.com/ handing them some good box designs, and then the Chinese started ramping up the price of neodymnium...

Efficiency, Xmax or price, pick any two.

[Justin Thomas]

What I read in the OP was "New TUBE?" Is this a "hybrid" with a "tube preamp?" I highly doubt it's only 40W... I'd be very surprised if it wasn't at least 200W.

To the OP, can we get a specific model?

Justin

Edit: @mhuss: if I had one, I'd carry it around. Nice amp!

[Leo_Gnardo]

The Lab 12 has a sensitivity 89.2 db. The Kappalite 3015 mentioned earlier has 100.8 db. This discussion is about using a tube amp, you know, like 40 watts. The K3015 will be quite impressive with 40 watts in a reasonable box and you cannot melt it with that little power. The Lab 12 will be somewhat less impressive with 400 watts, and it might not last forever. Anyway, who carries around a 400 watt tube amp?

Hi Mike, I'm not so sure the SWR in question is all tube. Haven't seen the model number mentioned. SWR has a habit of building in a preamp tube, y'know for that "magical tube sound", with transistor power amps ranging from 100 to 400W. 12AX7 pre tube run off the transistor supply rails.

So, a question for Raybob our OP, what model SWR amp is it? Do it have the typical tube pre/SS power?