increasing the output of a bass

[bobbytodd]

ive recently got m hands on 90's samick bass so the first thing I did as swap the old pick ups for a spare set of Duncan design ones out of my vmj.thing is the output is still thin and weak sounding.so whats the best way to increase the output? the bass plays well and is so light my back loves it

Edited October 22, 2017 by bobbytodd

[M@23]

Preamp pedal? Or even just a boost pedal. Short of further modding the bass.

[bobbytodd]

would new pots and loom help?

[gary mac]

[quote name='bobbytodd' timestamp='1508670794' post='3393631']
would new pots and loom help?
[/quote]

If the existing ones are the cheap, nasty, tiny little things, it will certainly be money well spent changing them.

[geoffbyrne]

Are you sure they are not out of phase?

G.

[Grangur]

As we all know there is loads of discussion on here from time to time about tonewoods and different bridges etc. As a Warwick owner I'll be the first to defend the use of good materials, but being frank, if you're getting low output you need to look at more fundamental things.

If you're using your normal flavour of strings and pickups and getting low output, you need to look at:

1 - Set up - Check the distance from the string to the top of the pup, when fretted at the bottom of the neck, should be no more than about 5mm.
2 - Electrical losses - Check there are no losses between the pickup and the jack. A good check is to take the wires of the pup and solder them direct to the terminals of the jack and make sure you're getting a good output. I can see no reason why this won't give you something good as you're using good pups.

If the above all checks out and you're getting a fair output with the pups straight to the jack, then you need to take a look at the wiring loom. In which case I'd look to replace the whole loom if it's passive.

[Bassassin]

Might be worth experimenting with different pot values - if it has 250s (which I'd guess it probably does), maybe swap for 500s, which will tend to let a little bit more level through. Plenty of info out there if you google 250k vs 500k pots.

[Bigwan]

Try wiring straight to the jack with one pickup. That should rule out phase issues and the internal controls. If that's still weedy change pickups for something with a bit more oomph! Passive you could go to SD Quarter Pounders or Dimarzio Ultra Jazz, but the world's your oyster really!

[Grangur]

[quote name='Bassassin' timestamp='1508760095' post='3394178']
Might be worth experimenting with different pot values - if it has 250s (which I'd guess it probably does), maybe swap for 500s, which will tend to let a little bit more level through. Plenty of info out there if you google 250k vs 500k pots.
[/quote]

At full volume the resistance of a 500K ohm pot is Zero ohms in the path of the hot wire.
At full volume, the resistance of 250K ohm pot is Zero ohms in the path of the hot wire.

The resistance from the hot wire to earth, through the pot, will be the max resistance of the pot. Yet a negligible amount of signal will go through the pot main resistance to earth because it takes the path of least resistance. So I'd be interested to know the science behind this.

500K pots can make the sound more metallic/aggressive, but I can't see how it can be louder.

I would genuinely be interested to know. Not being funny, honest.

Edited October 23, 2017 by Grangur

[Bassassin]

[quote name='Grangur' timestamp='1508765549' post='3394255']
At full volume the resistance of a 500K ohm pot is Zero ohms in the path of the hot wire.
At full volume, the resistance of 250K ohm pot is Zero ohms in the path of the hot wire.

The resistance from the hot wire to earth, through the pot, will be the max resistance of the pot. Yet a negligible amount of signal will go through the pot main resistance to earth because it takes the path of least resistance. So I'd be interested to know the science behind this.

500K pots can make the sound more metallic/aggressive, but I can't see how it can be louder.

I would genuinely be interested to know. Not being funny, honest.
[/quote]

In fairness a bit speculative on my part - I swapped a 250k pot for 500 in a P copy fitted with a DiMarzio Model P, specifically to make it brighter and more aggressive - pleased with the result, and it does seem louder too.

Did a lot of reading about this beforehand - including accounts of people with P/J setups using combinations of different values to balance the output levels. That was of interest to me because I have a P/J equipped bass which has this problem, and was considering seeing if a 500 on the lower-output J would help even things out.

Fully admit I have no real understanding of the science involved - I just muck about with a soldering iron!

[Bigwan]

Da web say: Using higher value pots (500K) will give the guitar a brighter sound and lower value pots (250K) will give the guitar a slightly warmer sound. This is because higher value pots put less of a load on the pickups which prevents treble frequencies from "bleeding" to ground through the pot and being lost.

I can neither confirm nor deny... But my thoughts are that this only comes into play if you turn your volume down from max, otherwise how could it make any difference as you're shorting out the pot's resistance with the volume all the way up? Perhaps it's why passive diehards say their basses sound better with the volume at 90%?

Edited October 23, 2017 by Bigwan

[Grangur]

[quote name='Bassassin' timestamp='1508773571' post='3394310']


In fairness a bit speculative on my part - I swapped a 250k pot for 500 in a P copy fitted with a DiMarzio Model P, specifically to make it brighter and more aggressive - pleased with the result, and it does seem louder too.

Did a lot of reading about this beforehand - including accounts of people with P/J setups using combinations of different values to balance the output levels. That was of interest to me because I have a P/J equipped bass which has this problem, and was considering seeing if a 500 on the lower-output J would help even things out.

Fully admit I have no real understanding of the science involved - I just muck about with a soldering iron!
[/quote]

It could, of course, be the replacement pots were better quality. This wouldn't surprise me as you look out good quality pots and the manufacturer wouldn't.

[Woodinblack]

[quote name='Grangur' timestamp='1508765549' post='3394255']
At full volume the resistance of a 500K ohm pot is Zero ohms in the path of the hot wire.
At full volume, the resistance of 250K ohm pot is Zero ohms in the path of the hot wire.

The resistance from the hot wire to earth, through the pot, will be the max resistance of the pot. Yet a negligible amount of signal will go through the pot main resistance to earth because it takes the path of least resistance. So I'd be interested to know the science behind this.
[/quote]

Not quite the path of least resistance, more the path determined by the current flow of the whole circuit. With a passive input in an amplifier the input is generally like 1M upwards (much lower on active), a pot of 500k means that more of the power of the pickup is going through the volume pot then down the cable. With 250, obviously even more is going through the pot, so it does make a huge difference. Because of the power going through the pickup there is loss in the pickup and there is loss in the long cable on the way to the amplifier (I like treble, that is why I always have an active bass, I would rather remove the treble by choice later).
I don't know what a ballpark figure of an unloaded voltage output of your average pickup is, the internet shows just various amounts of crazy to figures. Might measure it tonight and work it out.

When you draw the whole circuit out there is more going on then you would think.

[Grangur]

[quote name='Bigwan' timestamp='1508777971' post='3394368']
Da web say: Using higher value pots (500K) will give the guitar a brighter sound and lower value pots (250K) will give the guitar a slightly warmer sound. This is because higher value pots put less of a load on the pickups which prevents treble frequencies from "bleeding" to ground through the pot and being lost.

I can neither confirm nor deny... But my thoughts are that this only comes into play if you turn your volume down from max, otherwise how could it make any difference as you're shorting out the pot's resistance with the volume all the way up? Perhaps it's why passive diehards say their basses sound better with the volume at 90%?
[/quote]
With a VVT set up I've generally found if you turn both volumes to full, the output dips. If you back one or both off a little, the output comes back up. Never worked out why that is, but I've also never thought about it much as I don't own one.

[Grangur]

[quote name='Woodinblack' timestamp='1508781615' post='3394395']


Not quite the path of least resistance, more the path determined by the current flow of the whole circuit. With a passive input in an amplifier the input is generally like 1M upwards (much lower on active), a pot of 500k means that more of the power of the pickup is going through the volume pot then down the cable. With 250, obviously even more is going through the pot, so it does make a huge difference. Because of the power going through the pickup there is loss in the pickup and there is loss in the long cable on the way to the amplifier (I like treble, that is why I always have an active bass, I would rather remove the treble by choice later).
I don't know what a ballpark figure of an unloaded voltage output of your average pickup is, the internet shows just various amounts of crazy to figures. Might measure it tonight and work it out.

When you draw the whole circuit out there is more going on then you would think.
[/quote]

Thank you for that. It's very true, it's easy for us to look only at the bass circuit in isolation, bit elections don't see it that way.

[LITTLEWING]

[quote name='Bassassin' timestamp='1508760095' post='3394178']
Might be worth experimenting with different pot values - if it has 250s (which I'd guess it probably does), maybe swap for 500s, which will tend to let a little bit more level through. Plenty of info out there if you google 250k vs 500k pots.
[/quote]

Careful, 500k's will also add possibly unloved harsh middly tones which means a new lot of amp fiddling.

[MoonBassAlpha]

In passive circuits, the value of the potentiometer is always connected between the signal (hot) and the ground, so even when the pot wiper is set to max volume, the 250 or 500k of the pot track is still connecting the pot to the ground.

[Woodinblack]

[quote name='Grangur' timestamp='1508783797' post='3394418']
With a VVT set up I've generally found if you turn both volumes to full, the output dips. If you back one or both off a little, the output comes back up. Never worked out why that is, but I've also never thought about it much as I don't own one.
[/quote]

Because a VVT is wired backwards to a single pickup, such as a P bass. In a P bass, the volume pot is placed in parallel with the pickup so the load on the pickup is (for sake of argument ignoring those other things I said to ignore) the same and the volume just gives you some fraction of it.

In a jazz bass, the output is in parallel with both of the volumes (so half the resistance of the pots at the output) and the variable part of the pot is connected to the pickup, which means the tone actually changes from the pickup as the load on it increases as the volume is turned down, but at both being at full volume, the resistance, or in this case the impedance, is half as much as both of the coils are in parallel with the output.

[Marc S]

Lots of good, useful suggestions on here. But as Grangur says, first, check the set-up. Especially the distance between pickups and strings. However, don't make that distance too small, because that can cause the magnets to exert a force which "attracts" the strings, choking the output. Definitely try different strings too. Then you should be looking at wiring & pickups, and electrics.....
EDIT: KiOgOn on this forum does some nice solder-free wiring kits. I've used one and it was great - he'll answer any questions you have, as he's ever such a helpful BC'er
He'll know which pots and capacitors will be best, and does several versions of each kit to suit what you're after

Entwistle make some very inexpensive pickups that are really good. The PBXN and JBXN pickups are amazing. I see you have a pair of Jazz type pickups there. Two JBXN's would give you a much louder output - the magnets they contain are very deep - so you'd need to rout out a deeper centre channel within the pickup cavity...

However, before you start all that, someone did suggest a PreAmp pedal - this is also a good idea. Not only will it boost your output, but you will have more control over your EQ.
It's relatively inexpensive, as many Pre amp pedals are cheaper than some pickups. Try a 2nd hand one - you could even sell it for the same money if you don't get on with it.
Behringer do one for around £30. I've got one and it's not bad at all. It's certainly good value for that money, and even better for me cos I only paid a tenner 2nd hand for it

Good luck in your quest

Edited October 24, 2017 by Marc S

[Woodinblack]

[quote name='Woodinblack' timestamp='1508781615' post='3394395']
I don't know what a ballpark figure of an unloaded voltage output of your average pickup is, the internet shows just various amounts of crazy to figures. Might measure it tonight and work it out.
[/quote]

I did tonight. The average figure on the front pickup of my Ibanez 5005 is 350mVpp after the initial hit dies down*. Much harder to measure on the P Bass, as the P Bass doesn't really have much sustain. However, measuring the overall on the P, including the hit it seems to be in the same ballpark as the ibanez (which makes sense) but the initial pluck on the E string is over 2Vpp for the first cycle.

* and it appears that the reason my back pickup sounds so quiet is that it produces exactly half the voltage - I think there is a coil problem there

[Conan]

With our tying to sound glib or obvious, can you not just turn your amp up?