24V amp with MaxxBass + MiniDSP build |
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bitSmasher
Old Croc Joined: 23 June 2012 Location: Melbourne Status: Offline Points: 2296 |
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Posted: 01 December 2016 at 12:21pm |
It's been a while since I've had a new project, but here's something that's been on the "to do" list for way too long...
A stand-alone amp + battery box, that can take a few different inputs and spit out a decent amount of power on 4 speakons. MiniDSP as the brains, so I can use this for many purposes So far all my portable systems have had the amp and batteries built in, which means it's very much fixed to that usage As I'm closer to building a "proper" speaker stack, I'll need an amp setup that can run all sorts of combinations of top / sub / monitor / etc So far I have: Batteries and amp Sure AA-AB3318, which is a 4ch TK2050 based board, 30v max input, "100w" per channel output. Have used it briefly previously, and was very impressed with output for its size SLAs, have 2x 12ah (3.5kg ea) as well as 2x 7ah (2.5kg ea), plus a few bigger 30ah & 80ah (f'n heavy) if I ever wanted to have runtime measured in months MiniDSP and cheapo playback unit MiniDSP 2 in 4 out, the brains of the operation Have a cheapo Bluetooth / FM / MP3 thing, I expect it to sound awful but see it handy to have the option of a 32gb SD card full of music to fall back on if phones die, and also FM receiver (for radio linkup) Power bits Stepdown from 24v to 12v + 5v, having 12v on tap will be very great for adding to the system, and 5v will run the playback unit Have a 24v to 12v isolated stepdown, might stick that on the MiniDSP alone as I've read that it's a good idea to keep it isolated Also have a volt/amp meter, something I'm keen to add to battery packs for new builds So... what do I want out of this? Not quite sure yet, always wary of "scope creep" but will set a few goals:
Since working to a deadline seems to be a good motivator, I'm hoping to throw a rough working system together within 2 weeks - just for running small speakers at work christmas party. From there, I can decide on final refinements Right now it's the input section that needs attention - want a preamp and level meter in front of the MiniDSP as I'll be using anything between a measly phone headphone jack and a very hot mixer, primarily the latter Seeking input on the input any suggestions? Will have to spend some time trawling ebay and DIY projects to see what I can afford/build Also, what would you consider necessary or nicety given I essentially want an all-in-one solution for power, processing and amplification Let's see how I fare with productivity, being the silly season and all that ***edited topic title to add MaxxBass***
Edited by bitSmasher - 05 December 2016 at 9:45am |
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https://www.instagram.com/batteryacidsoundsystem/
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Ganon
Registered User Joined: 07 May 2014 Location: Denmark Status: Offline Points: 114 |
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if you can get your hands on a broken playstation 3 you can get a nice power supply.
It uses a 24v 23A powersupply inside, that could be a way to power it from mains :) |
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bitSmasher
Old Croc Joined: 23 June 2012 Location: Melbourne Status: Offline Points: 2296 |
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Uh oh, scope creep already!
Not sure how I forgot about the MaxxBass 103, which I have 3 of... bought them all discounted heavily, the first a few years ago which proved its worth on my trike system. Just picked up two on ebay since I know they're hard to find. This will run off the 12v step down, between preamp and MiniDSP Will result in a larger enclosure, so I'll have to get creative fitting it all in |
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slaz
Old Croc Joined: 27 November 2009 Location: London E2 Status: Offline Points: 2713 |
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If you need a pre-amp (by which I assume you mean a few db of signal gain) - I can more or less vouch for one of these :-
http://www.ebay.co.uk/itm/Car-Audio-Pre-Amp-RCA-Input-Output-Line-Driver-Signal-Amplifier-Module-/260745569341?hash=item3cb5a5a43d:g:a1MAAOxy66pRwDJV Very light weight, very low 12V power consumption and sounds OK. The 2 gain tweaks are bit clunky - but work - the spindles pull-out to leave a hexgonal socket. One down side is that it emits quite a nasty squawk at switch-on - so need to solve that - I just make its switched on a few seconds before everything else. |
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REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON
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bitSmasher
Old Croc Joined: 23 June 2012 Location: Melbourne Status: Offline Points: 2296 |
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Yep, not going to dub-style man the controls!
Just need a few db of gain for phone headphone output, and also to attenuate hotter signals where necessary Might get a little kit like this http://www.jaycar.com.au/champion-stereo-dual-channel-preamplifier-kit/p/KC5531 and perhaps even have facility for remote volume control (ie, external pot plugged in to a switching jack). uh oh, creeping again... |
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Sapro2
Registered User Joined: 31 January 2015 Location: Somerset Status: Offline Points: 354 |
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I too can vouch for that. I use one in Baby Sham. Mine doesn't squeek when i turn it on though. |
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Splat Soundsystem
Baby Sham pram Soundsystem Sapro - SoundCloud https://soundcloud.com/sapro DJ Sapro. West country free party DJ and Producer. |
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jerronimo
Registered User Joined: 11 July 2009 Location: Nederland Status: Offline Points: 438 |
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Maybe it's a good idea to use a step-up converter for the Sure amp, as ideal input voltage for full power is 30V.
Your batteries will have a nominal voltage of 23,76 volts when ''empty'' and 25,8 volts when fully charged, so the Sure amp will never ''see'' the full 30V on it's input rail. Another option would be to run the batteries in parallel on 12 volts, so no need for a step-down converter and only use the step-up converter for the Sure amp.
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bitSmasher
Old Croc Joined: 23 June 2012 Location: Melbourne Status: Offline Points: 2296 |
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Thanks for reviving the thread! This project has stalled, work and life went a bit silly over Christmas The more I think about it, this make more sense, and I've already checked out the Sure option: 500W BOOST Converter for CAR Audio - TL494 Losing a bit of efficiency is OK, when it keeps things flexible Will buy one and see how long it takes for me to get this together |
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_djk_
Old Croc Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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djk
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bitSmasher
Old Croc Joined: 23 June 2012 Location: Melbourne Status: Offline Points: 2296 |
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I'm pretty sure that style of "Bass Boost" is just a big parametric bump in the bottom end
The MaxxBass actually high passes, and creates fundamentals - different approach, more more speaker and power friendly When I eventually get time to start playing around and posting a blog, measuring the MaxxBass will be one of the first things I do. Will be interesting to see the result
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slaz
Old Croc Joined: 27 November 2009 Location: London E2 Status: Offline Points: 2713 |
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DC-DC converters like this can maybe work well, but can also cause complications. Unless there's some kind of soft-start going on, it can draw really high inrush current ar startup. One I had would go into protect/shutdown straightaway if the load (amplifier) was connected (as the amplifier itself itself also draws inrush current). I favour keeping things simple as possible .... I'd vote for using the 2 x 12V in series and maybe using another battery to power your "outboard" gear. I've used the naff "CCTV LiPo batteries" to power a small 12V DC DJ mixer (200mA or so) and sometimes a car 7-band equalizer (another CCTV battery) - also about 200mA - lasts the whole day with zero problems. a) It takes a bit of load off main batteries b) It neatly sidesteps any earth-loop type problems and any other hard-to-diagnose issues. c) Really minimal size/weight OK - it means remembering to charge em etc. .... but I reckon its worth it. |
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REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON
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RockBottom
New Member Joined: 09 February 2018 Location: az Status: Offline Points: 3 |
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Do you still have a MaxxBass 103 available? If so I want one.
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