BTW, I have been meaning to share this here and over on the mini thread.
I use my mini on the beach a lot and I have a plastic tub that I use to haul fire wood down to the beach for campfires. After I dump the wood onto the beach, I flip the tub over and put my mini on it.
The tub acts as a resonating chamber and deepens the bass considerably. I even drilled a port into the tub to tune it. Unfortunately, that tub eventually cracked and I had to discard it. My new tub is smaller and does not perform as well, so I think size matters.
I'll try this with the full sized boominator as well.
I use my mini on the beach a lot and I have a plastic tub that I use to haul fire wood down to the beach for campfires. After I dump the wood onto the beach, I flip the tub over and put my mini on it.
The tub acts as a resonating chamber and deepens the bass considerably. I even drilled a port into the tub to tune it. Unfortunately, that tub eventually cracked and I had to discard it. My new tub is smaller and does not perform as well, so I think size matters.
I'll try this with the full sized boominator as well.
May I ask what mixer you used?
We occationally use 1 acoustic gitar as well as the electrics but then we either use phase switch or sound hole cover to avoid feedback.
Do you think feedback will be a problem for guitars or mic's? I mean where we used to practice we had stage monitors speakers and the only feedback problem we had was with some acoustic guitars until we started using sound hole cover.
To the guys and gals looking for an amplifier for the next build.
I tried this and i an VERY pleased!
Sure Electronics' webstore 2 x 50 Watt 4 Ohm Class D Audio Amplifier with Bluetooth 4.0 APT-X - JAB2-50
I bought it with the additional frontpanel and cable package.
Pros:
Loud, clean sounding, easy to use with the cable package. Auto Switching when plugin in mini-jack. Includes charging port for USB devices on frontpanel. Can be used as a solar charging manager(Not tried myself)
Cons:
Bluetooth antenna is not great. Small wire-gauge used in cable package.
I tried this and i an VERY pleased!
Sure Electronics' webstore 2 x 50 Watt 4 Ohm Class D Audio Amplifier with Bluetooth 4.0 APT-X - JAB2-50
I bought it with the additional frontpanel and cable package.
Pros:
Loud, clean sounding, easy to use with the cable package. Auto Switching when plugin in mini-jack. Includes charging port for USB devices on frontpanel. Can be used as a solar charging manager(Not tried myself)
Cons:
Bluetooth antenna is not great. Small wire-gauge used in cable package.
Hi guys, I'm new here, was lurking for a while, and just started planning my boominator build!
Today I was browsing the Internet for hours, looking for viable solar cells. I found some good offers for CIGS cells, but they have an Umpp of only 0.45 V per cell. I could fit 10 of those on the Boominator to get an Umpp of 4.5 V. Is it possible to use an DC to DC boost converter in this case? I'm afraid it won't work in combination with an MPPT charge controller. Or maybe there are charge controllers with an integrated boost converter?
I'm aware that I will lose power in the conversion process, but those cells would provide 26 W.
Today I was browsing the Internet for hours, looking for viable solar cells. I found some good offers for CIGS cells, but they have an Umpp of only 0.45 V per cell. I could fit 10 of those on the Boominator to get an Umpp of 4.5 V. Is it possible to use an DC to DC boost converter in this case? I'm afraid it won't work in combination with an MPPT charge controller. Or maybe there are charge controllers with an integrated boost converter?
I'm aware that I will lose power in the conversion process, but those cells would provide 26 W.
Last edited:
Found the solution, I will try to cut those raw cells in 4 parts and put them in series to get 18V.
Oh dear
Had a beach party last night and after 8 hrs my boominator started to sound bad, I checked the voltage and my voltage reading was about 5 volts..... Oh dear, my 2 X 7ah SLA's must have been stuffed before to only last 8hrs but they were holding 13v for a week beforehand. Anyway, they are stuffed now.... I'm thinking of replacing them with lifePo4's, any advice on the best place to buy them from in the UK?
Thanks
BJ
Had a beach party last night and after 8 hrs my boominator started to sound bad, I checked the voltage and my voltage reading was about 5 volts..... Oh dear, my 2 X 7ah SLA's must have been stuffed before to only last 8hrs but they were holding 13v for a week beforehand. Anyway, they are stuffed now.... I'm thinking of replacing them with lifePo4's, any advice on the best place to buy them from in the UK?
Thanks
BJ
I got a Battery discharge tester recently to check Lipo's from ebay(5000mAh
), the thing is it has a battery low voltage cut off function, as it must, but you can actually select the lower cut off, so if you were to install this in your boombox permanently you can monitor the capacity of your battery and how it changes over time, have an idea of run time and protect the battery at the same time.1 5V 12V Battery Capacity Meter Discharge Tester 18650 Li ion Lithium Lead Acid | eBay
I use PBQ 10-12 LiFePO4 (12.8v / 10Ah Lithium Ferro Phosphate) : Euro Energy. Silly expensive (£110), but has built in battery protection and seems to drive 2 Maxamps and MiniDSP fine as will as 1.6m of SPI LED strip and controller.
Dupe...
Yeah it's interesting that LiFePO4 batteries have resisted in coming down in price, I don't know the manufacturing details, so there maybe good reason for this, but it seems that if they don't find a way to reduce costs in great haste they risk in really being steamrolled by the Li-ion industry, especially when Tesla are getting ready to ship from their battery factory.
Did someone try that already? I'm not sure if it would work with the built in step-up and step-down converters (3.7V to 5V USB) at output and input.. Not to mention the power loss caused by those conversions.
My boominator is "clipping"
I think clipping probably isnt the accurate term but lacking a better one I will use it for the phenomenon in this post. My problem is when i increase the volume to a certain point, the boombox goes silent for a couple of seconds, then plays a few seconds, then silent, then play and so on.
The parts I'm currently using are:
4 x HP10w speakers
4 x DAP Piezo QLM-1005 tweters
1 x maxamp20 with 3.5mm input, no volume control (but the jumper as it was when delivered, see picture) and in hi gain setting (unmodded)
2 x 12v 12aH Biltema sealed lead acid batteries Blyackumulatorer - Batteri Gräsklipparbatteri Blybatteri 6volt 6 volt 6v - Biltema
I did not put any resistors before the tweeters, and the wiring is as shown on this image (but with the parts mentioned above)
So a background of the problem. Last year i was using a lepai lp2020a amplifier in the same box. No matter if i powered it with the batteries or an 12v adapter from a wall socket, it started clipping at volumes way lower (volume cranked to about 2/3 of max on the amp) then I could play on my previous boominator with the exact same parts. Since that happened with different power inputs, i figured the amp was the problem. Therefore i switched to a maxamp20 this year.
Well, the problem still remains. One battery was destroyed after being short circuited last year (9.9 volts when fully charged), but the other one seems to be working acceptable and has a current of 12.8 volts when fully charged so I'm only using that one now.
So what could cause this? A theory is that the working battery also got damaged and thats the problem. Or could the lack of resistors be the problem?
Since the max voltage of the maxamp is 14, do you think it's possible to fix it with a dc/dc converter that make sure it gets 14 volts constantly? Like this one DC/DC boost converter, input 2.9V to 32V, output 5V to 36V
Or could a headphone preamp help?
As a matter of fact, i experience the max volume to be lower with the maxamp then with the lp2020, even thought i can crank the cellphone up to 16/20 steps before it starts clipping.
I really want this build to become as amazing as my last one so all help is greatly appreciated!
I think clipping probably isnt the accurate term but lacking a better one I will use it for the phenomenon in this post. My problem is when i increase the volume to a certain point, the boombox goes silent for a couple of seconds, then plays a few seconds, then silent, then play and so on.
The parts I'm currently using are:
4 x HP10w speakers
4 x DAP Piezo QLM-1005 tweters
1 x maxamp20 with 3.5mm input, no volume control (but the jumper as it was when delivered, see picture) and in hi gain setting (unmodded)
2 x 12v 12aH Biltema sealed lead acid batteries Blyackumulatorer - Batteri Gräsklipparbatteri Blybatteri 6volt 6 volt 6v - Biltema
I did not put any resistors before the tweeters, and the wiring is as shown on this image (but with the parts mentioned above)
So a background of the problem. Last year i was using a lepai lp2020a amplifier in the same box. No matter if i powered it with the batteries or an 12v adapter from a wall socket, it started clipping at volumes way lower (volume cranked to about 2/3 of max on the amp) then I could play on my previous boominator with the exact same parts. Since that happened with different power inputs, i figured the amp was the problem. Therefore i switched to a maxamp20 this year.
Well, the problem still remains. One battery was destroyed after being short circuited last year (9.9 volts when fully charged), but the other one seems to be working acceptable and has a current of 12.8 volts when fully charged so I'm only using that one now.
So what could cause this? A theory is that the working battery also got damaged and thats the problem. Or could the lack of resistors be the problem?
Since the max voltage of the maxamp is 14, do you think it's possible to fix it with a dc/dc converter that make sure it gets 14 volts constantly? Like this one DC/DC boost converter, input 2.9V to 32V, output 5V to 36V
Or could a headphone preamp help?
As a matter of fact, i experience the max volume to be lower with the maxamp then with the lp2020, even thought i can crank the cellphone up to 16/20 steps before it starts clipping.
I really want this build to become as amazing as my last one so all help is greatly appreciated!
Won't work because of the current limit of the converters. Also pretty inefficient. If you want a '12V' lithium pack I'd just buy one of these: 10.8V 11.1V 12V : Lithium Rechargeable Batteries, Battery BMS, Pack Assembling or something similar from another site.
Or better yet, LiFePO4.
I've tested it with just one 20Ah 3.6A(2 Outputs connected parallel) Xiaomi Powerbank, a 5V to 10V Step up converter and a 4700uf cap. Even with the additional power loses caused by the external step up converter it was pretty impressive.
The current limit is a thing, but the capacitor helps a lot to match max. output power of the Power bank with rms power. So you actually get 30Wrms power of 3 2A Powerbanks if you add some capacitance and 30W should be enough for a boombox.
I guess the conversion efficiency of the internal step up converter is very high(>90% maybe) and its just a minor downside considering how cheap they are compared to DIY Lion Packs with proper protection/charging circuit and high quality cells
Lifepo4 is what I'm after. In my original post I was asking where the best place to get them was.
BJ