Off Grid Amp Solutions?

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Dr.Ukenstein

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As a bass and guitar plucker and now solid body uke ubee, I have used many means to amplify my instruments beyond plugging into a fixed electrical outlet. Gas generators are noisy and defeat the whole non-polluting concept. Inverters have/had an annoying 60 cycle hum and require lugging a heavy battery around. The Crate Bass Buss 50 was a bust. I do have 2 Crate Tx30's that work well for guitar not bass but have very limited tonal spectrum. My present solution is the rig that I hope to post a pic of. Forgive the clarity of the photo. I am an impressionistic photographer. Is there a better solution to power a 12" to 15" speaker cabinet off grid? Thanks for previous solutions from past requests. Dr. U.
 

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This may not seem like much but for the price and simplicity it may suit your needs. I bought one for bass and it is loud enough for living room jamming with acoustic guitars. The other advantage is that is is a small PA so you can put a mic and/or guitar through it as well. For bass the speaker is not great but with light playing it will loosen up.

https://peavey.com/products/index.cfm/item/705/93630/

Bob
 
Thanks, Bob, I did not know Peavey had a portable rig for buskers. Certainly not enough power (10 watts on battery) or speaker size for my needs (ubass + bari-tenor) but might work fine around a campfire. Price is right. Adding this to the potential portable category for my fellow ukers. Again, Thank You for your new information.
 
Yes, Brad. I can now add the Vox DA5 and Carvin S400D to my inventory of potential portable amp/speaker combos. So far, I am sticking with my rig but checking if there was something better for my applications. Thanks for the info.
 
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I just got a Roland AC-33 a few days ago. It’s a 30w amp that runs on AC or battery power. I used it on battery power today for my open mic solo at my monthly uke jam. It has some nice features, and can be used with an instrument & a mic, or 2 instruments. Having the battery option was a life saver today. We were playing at a library we’ve never used before, and we had a bunch of amps & mics. Places to plug stuff in was at a premium. I was happy to just plunk my amp down on a table in a good position & play. No hassle. The amp is a nice size, weighs about 10 pounds, and has plenty of power for a meeting room filled with about 60 people.
 
Rafter, the Roland AC 33 really sounds like a good option for the higher range stringed instruments. Probably a very good choice for an off the shelf portable amp with lots of built in accessories. Do the batteries charge in the amp or must they be removed to place in a separate charger? Thanks in advance.
 
Bill, there are many ways to build a DC to AC power pack to power a whole band if necessary. Should anyone wish to do so, it is most important to choose an inverter that does not create a square sine wave. Otherwise, there will be an unremitting buzzing emanating from the speakers. The challenge I have is to find an off grid rig capable of ubass or uke that I can carry in one trip with two hands to the stage, guitar or uke case in one hand and speaker in the other. So far, the combo I posted does that best with just a few moments assembly. But, always looking for better... Thank You for the ideas. Charging from a battery can take amplified music far across the land (and sea).
 
Dr.Ukenstein said:
Rafter, the Roland AC 33 really sounds like a good option for the higher range stringed instruments. Probably a very good choice for an off the shelf portable amp with lots of built in accessories. Do the batteries charge in the amp or must they be removed to place in a separate charger? Thanks in advance.
Click to expand...

It can use 8 regular AA batteries or rechargeable AAs. Unfortunately, the rechargeable batteries don’t recharge in the amp when it’s plugged in.

On the subject of off the grid power sources. I use a cpap at night, and bring it on longer rafting trips. I use sealed 12V AGM deep cycle batteries. They aren’t very big size wise, but the little suckers weigh 13 pounds each. For all night cpap, I can get 2 - 3 nights per battery depending on outdoor temps. I did finally find a mega pow pop er lithium ion battery that gives the same amount of power but only weighs 3 pounds. 2 of those and a solar panel for recharging worked pretty well on weeklong trips. Recharging with a solar panel does require a bit of babysitting though.
 
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Thanks Rafter, too bad that Roland does not have a built-in amp charger like the Crate Tx30 did. Certainly, from the videos on-line, the Roland has a very clean sound. Charging lithium batteries from a solar panel probably requires a different solar panel charge controller than one designed for lead acid technology. Hmmm, another thing to Google...
 
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I can't speak to specific brands or models, but I think it's valuable to keep basic principles in mind.

Your AC-powered amplifiers all turn AC to DC inside the amp and use that DC to power the actual amplification circuit. If you use an inverter to convert DC to AC outside the amp, you're basically doing two conversions (one inside and one outside) with consequent losses and two chances to introduce noise.

So in principle at least the best solution should be to find an amplifier that is designed to bypass the whole AC-to-DC rectifier section when running off DC power.
 
Hooray Master Turf! You nailed it! The Vox Nu-tube series amplifier heads use a computer style 110v AC to 19v DC conversion cord to power their amps. Thus, no conversion circuit is required inside the unit. Lithium power tool batteries commonly come in the 20 volt range. So, the amp can easily be plugged into that style battery rather than the grid. And, the purity of DC (not referring to Washington DC) is maintained. With an attitude of gratitude, I honor your status as this thread's valedictorian.
 
I have the solution. This is my battery/inverter that I've been using with Carvin MB15 combo D 15" 250w amp and 115MBE ext. cab. There is no hum from the inverter because it's pure sine wave. It's extremely compact and light and lasts for hours. I stuck them together with Velcro™ and wiring.

Wagan EL2600 Elite Pro 200W Pure Sine Inverter for $55 from Amazon and Universal UB1280 AGM 12v 8Ah battery that measures 6.25" wide x 8" tall x 2.75" deep, weighs 6.4 lbs for $38 plus charger for $30 from my local hardware and audio parts stores. It has two a/c outlets and one USB and lasts for about 5 hours running my Carvin MB15 200/250w 15" speaker bass amp. I put together the wires and Velcro straps.

battery rig w hand 400.jpg


This is Michael Kohan in Los Angeles, Beverly West near the Beverly Center
9 tenor cutaway ukes, 5 acoustic bass ukes, 11 solid body bass ukes, 11 mini electric bass guitars (Total: 35)

• Donate to The Ukulele Kids Club, they provide ukuleles to children in hospital music therapy programs. www.theukc.org
• Member The CC Strummers: YouTube: www.youtube.com/user/CCStrummers/video, Facebook: www.facebook.com/TheCCStrummers
 
turf3 said:
I can't speak to specific brands or models, but I think it's valuable to keep basic principles in mind.

Your AC-powered amplifiers all turn AC to DC inside the amp and use that DC to power the actual amplification circuit. If you use an inverter to convert DC to AC outside the amp, you're basically doing two conversions (one inside and one outside) with consequent losses and two chances to introduce noise.

So in principle at least the best solution should be to find an amplifier that is designed to bypass the whole AC-to-DC rectifier section when running off DC power.
Click to expand...
This is why I did some research on which brand of cpap I got ahead of time. Because I spend a good bit of time in the backcountry, I wanted one that did not require an inverter. I need to squeeze every bit of power out of each battery as possible. The Li-Ion batteries are awesome, but it can be hard to find one that has enough power to run a cpap. The one I found on Amazon that I liked, disappeared from Amazon after about a year. Luckily I bought 2 of them, as did my cpap using rafting buddy. He did an 18 day Grand Canyon with 2 Li-Ion batteries & a solar panel.
 
turf3 said:
I can't speak to specific brands or models, but I think it's valuable to keep basic principles in mind.

Your AC-powered amplifiers all turn AC to DC inside the amp and use that DC to power the actual amplification circuit. If you use an inverter to convert DC to AC outside the amp, you're basically doing two conversions (one inside and one outside) with consequent losses and two chances to introduce noise.

So in principle at least the best solution should be to find an amplifier that is designed to bypass the whole AC-to-DC rectifier section when running off DC power.
Click to expand...

Mike and Rafter, Master Turf, got to the root of the issue. DC only is the most efficient amp for portability. So, now the quest becomes: What amplifiers or cpap machines are available that run from a 19 volt computer style power adapter cord? 20 volt power tool lithium batteries are very common and can be found with enough storage to equal Mike's lead acid battery, but much, lighter, no inverter necessary, and capable of thousands of charge cycles before needing replacement. The Vox Nu-tube series are the only amps that meet the 19v DC parameters. Any others out there? P.S. - I have no affiliation with Vox other than being a satisfied customer. Thanks for your thoughtful replies.
 
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If I'm not mistaken, my Phil Jones Bass Double Four 70w amp is DC19v, I use a lithium laptop battery that is set for 19v and it lasts for many hours. Don't be swayed by the bass designation, it's sounds great with any instrument. It's really small but on the expensive side.

PJD4 & Battery.jpg
 
Thanks, Mike. That Phil Jones amp looks like a top flight grab and go rig for the bassman wanting to do a quick sit in in a small or volume restricted venue. Bass in case on one hand, amp in the other, drop it on a chair or table, plug in guitar cord and play. With more watts out than the old Fender Bassman heads, should have power to spare. Can an additional cabinet be plugged in? I have a 16 ohm half metal cone Hartke in a small cabinet that might be worth a second trip back to the car. The reviews look good. This is a true off-grid portable rig. I have learned something new, here. Muchas Gracias.
 
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The Li-Ion battery I have is a Qi-Infinity 52,800 mAh that has 9V, 12V, 16V, 19V, 20V output + USB. These batteries are no longer available on Amazon. I need to recharge them, but then I'll see if they will power my Roland amp. The batteries came with a bunch of different adapter plug-ins, and there appears to be one that matches the Roland power cord.
 
Rafter, sounds like your Roland is a DC amp as well which is likely why it sounds so sweet on the demo videos. Hopefully you can match your power cord output and specific input plug from the lithium battery that you already own. Won't it be wonderful not having to remove and replace batteries! How many years did I lug around monster amps with huge heavy transformers? Too many is the correct answer. Have a joyful day and every moment forevermore.
 
Hi there - I’m a bit late to this discussion. Anyway, I have used a Roland AC-33 to busk three or four times a week for the last 3 years, and it is a great amp for both voice and uke (the AC stands for ‘acoustic’). I use 8 AA 2600mAh Lithium batteries which last at least 12hrs and 600 plus recharges. These batteries run the amp at the same volume as the 240vAC/9.6vDC adaptor and I wouldn’t use any other battery. Yes I recharge them every night or second night, but the light weight and simplicity of using AA batteries can’t be beaten.

I use a Mainland cedar topped tenor with a Zoom MS50G as a DI/Effects pedal and a Shure M58 microphone and this very simple rig sounds fabulous. No feedback issues, heaps of volume, light weight and super reliable.
 
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