Active bass - 9v to 18v voltage doubler circuit

[roman_sub]

hi guys

Would appreciate BC's collective wisdom.... I rather liked how the EMG's and active pre-amps sounded in my Warwicks when running at 18v (as opposed to the usual 9v). More headroom, less compressed top end, etc etc. It's all subjective but I want to pursue this further.

I don't want to route out another battery compartment (or have an extra battery in the control cavity), so was thinking of adding a voltage doubling circuit. This one seems to be pre-made:

[url="http://www.mojotone.com/Accessories_x/Pedalboards-Pedal-Parts_x/Mojotone-Micro-9v-to-18v-Voltage-Doubler_2"]http://www.mojotone.com/Accessories_x/Pedalboards-Pedal-Parts_x/Mojotone-Micro-9v-to-18v-Voltage-Doubler_2[/url]

Any reason not to do this? any concerns? anyone aware of cheaper / UK-based equivalents?

thanks
Roman

[roman_sub]

If anyone is interested, I found this UK-alternative (have to self-build though)

[url="http://shop.pedalparts.co.uk/Power_Pump/p847124_11037989.aspx"]http://shop.pedalparts.co.uk/Power_Pump/p847124_11037989.aspx[/url]

[Mottlefeeder]

[quote name='roman_sub' timestamp='1470312364' post='3104994']
If anyone is interested, I found this UK-alternative (have to self-build though)

[url="http://shop.pedalparts.co.uk/Power_Pump/p847124_11037989.aspx"]http://shop.pedalpar...4_11037989.aspx[/url]
[/quote]

This designer does not recommend its use on battery circuits - presumably it draws more current that other designs.

David

[roman_sub]

He had originally recommended this circuit himself, but later transpired it would be unlikely to provide enough current.. so yes the Fuzz dog one is out.

[4stringslow]

Think in terms of power, which is voltage x current (amps) rather than just voltage alone.

A 9v battery can provide only so much power and it can't be increased by doubling the voltage. If the voltage is doubled then the current will be halved.** This may or may not be a problem depending on the application, but it's something that has to be considered in the overall design.


** in theory. In practice the voltage doubling circuitry will not be 100% efficient so the total power out will be slightly less than the total power in.

[Grangur]

[quote name='4stringslow' timestamp='1470395883' post='3105699']
Think in terms of power, which is voltage x current (amps) rather than just voltage alone.

A 9v battery can provide only so much power and it can't be increased by doubling the voltage. If the voltage is doubled then the current will be halved.** This may or may not be a problem depending on the application, but it's something that has to be considered in the overall design.


** in theory. In practice the voltage doubling circuitry will not be 100% efficient so the total power out will be slightly less than the total power in.
[/quote]
^This

Also there's the other thing we haven't considered is "what will happen when we connect the 2 circuits, in the bass, in parallel?"
While WE like to think they work on their own and won't see each other, that's not how they see it.

For example, if each circuit has a smoothing capacitor across the beginning of the circuit, valued at say 300uF, the total capacitance across the beginning of the combined circuit will be 300+300, Then there will be other complications we can only imagine.

I say drop the idea before you damage something if you ask me.

Edited August 6, 2016 by Grangur

[Chienmortbb]

By going to 18v rather than 9v, assuming the current state the same (unlikely) the available Power is doubled.

Some circuits nay use low vintage ICs and 18V may be too much. However most circuits will run happily on 9 or 18V. You need the Circuit Diagram (schematic for those of you that spend too much time on Talkbass). If you can't read a circuit diagram, leave it alone!

[Dood]

If your on board electronics are all EMG, maybe this a go:

http://pages.ebay.com/link/?nav=item.view&alt=web&id=191917878998&globalID=EBAY-GB

EMG electronics will happily take 27v, so this 24v mod could be just the ticket!

[rmorris]

[quote name='dood' timestamp='1470509803' post='3106504']
If your on board electronics are all EMG, maybe this a go:

[url="http://pages.ebay.com/link/?nav=item.view&alt=web&id=191917878998&globalID=EBAY-GB"]http://pages.ebay.co...lobalID=EBAY-GB[/url]

EMG electronics will happily take 27v, so this 24v mod could be just the ticket!
[/quote]

And I was just going to suggest investigating different physical battery sizes - such as lithium type batteries that might usually be used for photographic eqpt etc...

[4stringslow]

Smaller batteries is an interesting idea, especially if it meant being able to fit two of them into the existing cavity. One thing to consider with DC voltage doubling circuits is switching noise. Not necessarily a problem with a well designed circuit but it's something to be dealt with whereas a couple of batteries are intrinsically noise free and provide rock steady DC. Just a thought.

Edited August 10, 2016 by 4stringslow

[luckydog]

The one in the OP should work in the vast majority of active guitar circuits. Might have noise problems picked up in the PUs I suppose, but if you check reviews or recommendations it will prob be OK.

LD