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Double Bass K&K Bass Max - bit quiet?

kevteop

kevteop

Feb 12, 2008
4,452
513
York, UK
#1
Hi all, newbie DB botherer here,

I've just fitted a K&K Bass Max and given it a quick trial going straight into a Hartke 200W head. It seems to be doing a good job of reproducing the sound of my bass (some cheap German ply thing) but I have to really crank the amp even to get "home practice" levels out of it.

Is this normal? If so, what do you guys do to get more grunt out of your amp?

Do I need a preamp?

The pup isn't an especially tight fit (towards the edge of the bridge it's tight, but further in it isn't, if you see what I mean), could that be the issue? Or is it running a high impedance piezo straight down 20ft of instrument cable that's the problem?

The instruction sheet says the pickup has "high output signal" so I'm assuming I am the source of the problem!

Oh: I've got active and passive inputs on the amp, I'm using the passive one, I'm guessing that's the most appropriate?
 
#2
The Bass Max is the hottest pickup I've used, compared to the Realist, Fishman, and Underwood. No problems here plugging into any old BG amp. Like other wing pickups, it is sensitive to fitting though - too tight will choke the tone and too loose will drop the output IME. Maybe you need to fine tune the fit for more even contact over the whole pickup?
 
#3
red_on_red said:
The Bass Max is the hottest pickup I've used, compared to the Realist, Fishman, and Underwood. No problems here plugging into any old BG amp. Like other wing pickups, it is sensitive to fitting though - too tight will choke the tone and too loose will drop the output IME. Maybe you need to fine tune the fit for more even contact over the whole pickup?
Click to expand...

+1! The K&K Bassmax usually provides a super-high output level. That's coupled, unfortunately, with what I find to be a very unrefined sound.
 
#5
Piezo pickups like the Bass Max have high impedance, and need to be plugged into a high impedance input. A lot of bass guitar amps have fairly low input impedance so the output of piezo is dragged down. A high input impedance preamp (1-5 Megaohm) may be necessary, not for the amplification, but for impedance matching. For example, the spec on the Hartke HA2500 says the input impedance is 100 kiloohms, which might not be quite good enough.

More info here.
 
#6
Shim it, get the fit right. The volume is there. The pickup is as high output as I have ever used. Will a preamp help? Maybe, but I wouldn't suggest you NEED one. Just get the pickup to fit fairly tightly. A sax reed works great for this.
 
#8
Adrian Juras said:
Shim it, get the fit right. The volume is there. The pickup is as high output as I have ever used. Will a preamp help? Maybe, but I wouldn't suggest you NEED one. Just get the pickup to fit fairly tightly. A sax reed works great for this.
Click to expand...

True - proper fit is the first thing to do. However, if the impedances are poorly matched you won't get the full signal out of the pickup. And poor match tends to kill off the lows. Depending on the bass/pickup/amp, it may sound fine even without a preamp. It's worth a try if you can borrow a preamp prior to buying one.
 
#9
cavemusic said:
True - proper fit is the first thing to do. However, if the impedances are poorly matched you won't get the full signal out of the pickup. And poor match tends to kill off the lows. Depending on the bass/pickup/amp, it may sound fine even without a preamp. It's worth a try if you can borrow a preamp prior to buying one.
Click to expand...

Right, I've had a proper go at it, tried it in both sides of the bridge, tighter, looser, it actually sounds best to me without any shim material wedged in there. The more shim I added, the more nasal the sound got.

I also tried switching to the active input on this old Hartke and the signal got quieter, so I think it is an impedance issue and I will have to try a preamp. I've got a bassist coming over next week so I'll see if he can bring a pre I can try, but I'm fairly convinced that will solve the problem.

Thanks for the help guys.
 
#10
cavemusic said:
Piezo pickups like the Bass Max have high impedance, and need to be plugged into a high impedance input. A lot of bass guitar amps have fairly low input impedance so the output of piezo is dragged down. A high input impedance preamp (1-5 Megaohm) may be necessary, not for the amplification, but for impedance matching. For example, the spec on the Hartke HA2500 says the input impedance is 100 kiloohms, which might not be quite good enough.

More info here.
Click to expand...

Well, this is sort of correct. Piezos need a high-impedance to avoid rolling off the low end response. A 100k input will not drag down appreciably the output of the BassMax. There is another problem here.
 
#12
Thanks Francois but I've tried that too. It just never goes very loud.

The level I've got the amp set at, if I plugged in a bass guitar it would wake up my neighbours. With the Bass Max it's quiet enough to have a conversation over.

Edit: Just had a nosey at some specs and it appears my Boss LS-2 has a 1 Mohm input impedance, going to try running the pickup into that... No, no improvement. :(
 
#13
I have two thoughts:

1. Did you buy the pickup used? Perhaps it's damaged.

2. Is the surface of the bridge leg parallel to the bridge wing? And is the surface of the bridge wing flat instead of rounded? I am suspecting that you are not achieving full contact since a) you are not getting full volume and b) the pickup gets tighter / looser as you move it around.

If you are able to post photos of both the bridge and the installation, maybe it will help with "diagnosis".

PS - I love the Bassmax, it's my favorite pickup. Maybe not great for some people, but I play in a surf band and the "unrefined" sound works for me.
 
#14
Bass said:
I have two thoughts:

1. Did you buy the pickup used? Perhaps it's damaged.
Click to expand...

Yes I bought it from a bassist on a UK forum. The regulars there are trustworthy and I don't think he would've knowingly sold me a lemon, but maybe it is damaged. I fitted it very gingerly when it first arrived so I don't think I could've damaged it during installation, maybe it got damaged in the post but he sent it in its original packaging.

One side of the pickup looks a bit roughed-up - the silver sticker is torn off and the rubber surround looks a bit scratched up where the sticker should be, it also looks like there's been adhesive on it at some point (the rubber is shiny at either side of the scratched-up area). So perhaps it was quite firmly attached to its previous host and got damaged during removal? Obviously I can't see the piezo elements themselves, nor would I know how to tell if they were damaged unless they were shattered into bits...

Bass said:
2. Is the surface of the bridge leg parallel to the bridge wing? And is the surface of the bridge wing flat instead of rounded? I am suspecting that you are not achieving full contact since a) you are not getting full volume and b) the pickup gets tighter / looser as you move it around.
Click to expand...

Initially it wasn't a snug fit all the way across the pickup - the very edge of the wing slot was a good fit but it was easy to move the pickup around in the rest of the slot. It was still in contact throughout, just not a tight fit. During my experiments this evening I wedged it in pretty tight with a piece of card for a shim and that didn't really improve matters; not much more volume, just a more nasal sound.

I hope it's not a duff pup. :(
 
#15
OK I've had another bash at fitting this tonight, it's a very snug fit, but I'm still not really seeing a great deal of volume. I'm assuming the pickup is in full working order because it's not misbehaving in any way; no distortion, no crackles or pops or anything out of the ordinary, it's just quieter than I'd expect.

But this is the first pup I've ever fitted to a double bass, so maybe I'm just phrasing my question wrong: Is it typical for a Bass Max (sans preamp) to generate about half the volume of a typical passive bass guitar?

I'm requiring roughly twice the power from the amp to create a signal of equivalent (perceived) volume. I might seem unnecessarily concerned with this ("Just throw more power at it" would be my usual solution) but it's because I was intending to take this bass out busking with a small portable amp for a little reinforcement, so I'd like to be able to squeeze whatever I can from the amp.
 
#20
kevteop said:
OK I've had another bash at fitting this tonight, it's a very snug fit, but I'm still not really seeing a great deal of volume. I'm assuming the pickup is in full working order because it's not misbehaving in any way; no distortion, no crackles or pops or anything out of the ordinary, it's just quieter than I'd expect.

But this is the first pup I've ever fitted to a double bass, so maybe I'm just phrasing my question wrong: Is it typical for a Bass Max (sans preamp) to generate about half the volume of a typical passive bass guitar?

I'm requiring roughly twice the power from the amp to create a signal of equivalent (perceived) volume. I might seem unnecessarily concerned with this ("Just throw more power at it" would be my usual solution) but it's because I was intending to take this bass out busking with a small portable amp for a little reinforcement, so I'd like to be able to squeeze whatever I can from the amp.
Click to expand...


Hi. I tried comparing my passive electric bass against my u/r bass with K&K BassMax plugged directly into a GK MB150. The electric bass is definitely louder than the BassMax at the same volume/tone settings. I know a lot of people don't use a preamp and have good results. However, I have always preferred using one. It seems to me I get a fuller sound. That's just my opinion though.
 

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