DC bucking convertor noise

[trobbins]

The hassle with Li-Ion is similar to lead-acid, the battery needs a low-voltage cutout somewhere in the system, as irreversible cell damage occurs if the cell voltage drops too far. Li-Ion also need there own special charger (just like lead-acid, and like Ni-Cad). Li-Ion also needs specialist balancing circuitry if multiple cells/strings are in place, as cell capacities can diverge, and lead to a lower capacity cell or string developing, and cause poor performance - that requirement goes for portable power tool battery packs just as much as Tesla's and large 'grid size' battery plant.

It appears that some, not all, commonly seen 'portable power tool' Li-Ion battery packs have the low voltage cutout in the battery (ie. not in the tool), which would make a very practical portable battery and charger system for other equipment like pedals. The battery is neatly packaged, and comes with its own charger, and Li-Ion packs the most capacity for size and weight and has a commendable service life where energy capacity just gradually falls away.

Ni-Cad can exhibit a memory effect, whereby if they are consistently only discharged to a certain level (<100% depth of discharge), then over time , if the next discharge requires the battery to discharge further than it has been before, then the battery doesn't deliver capacity down to 100% rated depth of discharge. A periodic maintenance regime is often used that fully discharges the battery, and then recharges, as a way to 'erase' any memory effect.

[nickb]

Aren't rechargeable AA's still NiCad?

I'd say NiMH is more common nowadays. They still have limited life and 1.2V cell voltages but are still easy to charge and do not have a memory effect.

But just stepping back to look at the big picture, given you need AC power for your amplifier, isn't the simplest solution of an multiple output AC to 9VDC power supply also the best? Some the digital effect pedals and draw a big chunk of current and batteries, especially lithium, are so expensive.

[Chuck H]

I'd say NiMH is more common nowadays. They still have limited life and 1.2V cell voltages but are still easy to charge and do not have a memory effect.

But just stepping back to look at the big picture, given you need AC power for your amplifier, isn't the simplest solution of an multiple output AC to 9VDC power supply also the best? Some the digital effect pedals and draw a big chunk of current and batteries, especially lithium, are so expensive.

When I gigged I just used the ubiquitous rechargeable 9V's in each pedal. Granted I only used three pedals most of the time. A small hassle with the need to change them out in each units battery box but really, how hard is it? Something we do here is creative solutions for problems that don't exist Everyone likes their own clever novelty. On that note I'd say that something like this for me would just be to use larger cells rather than more smaller ones. 8 D cells is good for 10Ah and really, how much space does it take up? To me a more clever device would be an 8 D cell battery pack with a built in momentary button and LED to demonstrate the charge level. That way I could just press a button and know if I'm good to go for a gig. But I don't wan't to take the thread off topic.

[HaroldBrooks]

When I gigged I just used the ubiquitous rechargeable 9V's in each pedal. Granted I only used three pedals most of the time. A small hassle with the need to change them out in each units battery box but really, how hard is it? Something we do here is creative solutions for problems that don't exist Everyone likes their own clever novelty. On that note I'd say that something like this for me would just be to use larger cells rather than more smaller ones. 8 D cells is good for 10Ah and really, how much space does it take up? To me a more clever device would be an 8 D cell battery pack with a built in momentary button and LED to demonstrate the charge level. That way I could just press a button and know if I'm good to go for a gig. But I don't wan't to take the thread off topic.

I wished I would have purchased the "D" cells instead, and I still can. It's just that I went on a buying spree (LED lights from IKEA) around the holidays, and bought more AA rechargeable cells than I needed. The proper solution would be to relegate those to other uses, and purchase proper NiMH 10A D cell rechargeable with a charger. Those would go a few gigs with ease. I might just do that and scrap the fancy buck converters.

[loudthud]

... But it also seems my Boss Chorus and Compressor need the absolute highest voltage to not distort, and the type of distortion they yield on even a half done battery does not generally sound good...

Some Boss pedals were originally designed to run from a slightly hummy Boss unregulated 12V wall wart. They have additional filtering that drops the voltage from the external supply jack and lowers the hum. I ran into this on a Boss CE-2. Had to add a jumper on the PCB. You can find this info on the web if you search enough.

[g1]

Some Boss pedals were originally designed to run from a slightly hummy Boss unregulated 12V wall wart. They have additional filtering that drops the voltage from the external supply jack and lowers the hum. I ran into this on a Boss CE-2. Had to add a jumper on the PCB. You can find this info on the web if you search enough.

Also results in the LED not working right with the lower voltage 9V type adapter.
I think this is the mod page you may be referring to: http://stinkfoot.se/archives/1019

[HaroldBrooks]

Some Boss pedals were originally designed to run from a slightly hummy Boss unregulated 12V wall wart. They have additional filtering that drops the voltage from the external supply jack and lowers the hum. I ran into this on a Boss CE-2. Had to add a jumper on the PCB. You can find this info on the web if you search enough.

Thanks ! If I can mod the one pedal (the ST-2) to filter the power, then I am set I believe. I will look that up and see if I can make it work.

[HaroldBrooks]

Does anyone know what a practical upper limit is for the voltage on Boss Pedals ? Will they take a running voltage of perhaps 10.5vdc ? I realize there must be some leeway, and it would make things easier to use 8 rechargeables instead of 7. When I fully recharge the IKEA Ladda AAs they are about 1.42vdc, but that quickly settles back to aroun 1.35 or so. 8 x 1.35 = 10.8vdc and that's why I am hesitant for using 8 batteries in a series holder "brick".

[Chuck H]

Does anyone know what a practical upper limit is for the voltage on Boss Pedals ? Will they take a running voltage of perhaps 10.5vdc ? I realize there must be some leeway, and it would make things easier to use 8 rechargeables instead of 7. When I fully recharge the IKEA Ladda AAs they are about 1.42vdc, but that quickly settles back to aroun 1.35 or so. 8 x 1.35 = 10.8vdc and that's why I am hesitant for using 8 batteries in a series holder "brick".

Just make a battery shaped jumper for the 8th battery space.