Good to hear your sound quality is back! Yep, although the problem might have been small, we've all learned a lot 
.
Ehh, about the pot, my bad! Yep, switch the red and yellow wires, and you'll be good. Sorry about the mistake!
The easiest way to do this is to use something like a tweezer, to remove the pins from the white connector. They're locked in place, and with a tweezer it's easy to lift the locking part.
.Ehh, about the pot, my bad! Yep, switch the red and yellow wires, and you'll be good. Sorry about the mistake!
The easiest way to do this is to use something like a tweezer, to remove the pins from the white connector. They're locked in place, and with a tweezer it's easy to lift the locking part.
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That's good to hear. And as I said the first thing I try is different signal cable. That usually also reveals a faulty or dirty plug. I'd advice to use shielded or at least twisted cable from the jack plug to the amp. It may remove more noise. And as doctormord suggested also try decoupling the input signal.
Sure. The PHT407 sound best when crossed at about 2.1-2.3khz or more with a second other filter. But here we're crossing at 13.3-17.7khz with a 1st order filter. That means the equal output is around 400hz at -33dB for both filters, so for all frequencies above 400hz the used higher frequency low order filter attenuates the signal better electrically than the low frequency higher order filter. I really don't see the problem.
Sure Electronics have a headphone amp board that runs on 12V directly than can be used.
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Hello all
Many apologies for not chipping in earlier considering I am running the same setup as shortrope. I've been very busy with flood work at work and haven't checked the forum for a couple of weeks..... I'm not sure if I could've helped much because shortrope appeared to have done everything as I had..... My boominator sounds great but I have never tried to measure the SPL because I don't have the equipment. I certainly wouldn't trust any iPhone app to give an accurate result because a) the microphone isn't up to it, b) no calibration and c) those apps tend to be gimmicks......
I have driven the boominator to distortion with a laptop with a high end sound card but that is clipping the amplifier rather than some 'fault'.....
So I don't really know the output of my setup, sometimes I'd like it a little louder it I just think that's me being greedy......
On a different note.....
I've been reading some disturbing things about 41hz.... Shame because the amp6 is a lovely little amp and 41hz have so obviously been a big part of the boombox development scene...... So respect to 41hz but I will be using max amp in my next project......
BJ
Many apologies for not chipping in earlier considering I am running the same setup as shortrope. I've been very busy with flood work at work and haven't checked the forum for a couple of weeks..... I'm not sure if I could've helped much because shortrope appeared to have done everything as I had..... My boominator sounds great but I have never tried to measure the SPL because I don't have the equipment. I certainly wouldn't trust any iPhone app to give an accurate result because a) the microphone isn't up to it, b) no calibration and c) those apps tend to be gimmicks......
I have driven the boominator to distortion with a laptop with a high end sound card but that is clipping the amplifier rather than some 'fault'.....
So I don't really know the output of my setup, sometimes I'd like it a little louder it I just think that's me being greedy......
On a different note.....
I've been reading some disturbing things about 41hz.... Shame because the amp6 is a lovely little amp and 41hz have so obviously been a big part of the boombox development scene...... So respect to 41hz but I will be using max amp in my next project......
BJ
Well, there is one thing I know about the iphone internal mic and that is that it accepts 99dB max +/- 6dB at peak. So in other words, for high SPL measurements it's absolutely useless.
If you want to use it. Take the measurement at 4 or 10 meters distance and divide accordingly. That'll restore at least some degree of accuracy.
If you want to use it. Take the measurement at 4 or 10 meters distance and divide accordingly. That'll restore at least some degree of accuracy.
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I'm still not convinced that without proper calibration of the instrument itself is that likely to be any use. As dB follows a log scale, 1-2dB out is significant....
Thanks for the info anyway (and the inbox nudge)....
I'm limited on my knowledge here, I'm well out of my depth on the technical development side but I can follow instructions.... I'd like to understand in more depth but get lost in the physics....
BJ
An iphone SPL app is fairly accurate if the level is in the 70-80dB range or lower. Far from good enough for any real use but ok as an indication. At 90dB+ though it's pretty much useless.
But you can just take the measurement further away. At 2 meters you add 3dB to get the SPL at 1 meter distance, at 4 meters add 6dB, at 10 meters add 10dB and so on.
But you can just take the measurement further away. At 2 meters you add 3dB to get the SPL at 1 meter distance, at 4 meters add 6dB, at 10 meters add 10dB and so on.
As also can be seen in this video:
https://www.youtube.com/watch?v=RWjBS5hT3ZU
According to the details, it's only playing at ~70% and reaches near 100dB peak.
I have a Dayton microphone on the way that plugs straight into the 3.5mm socket of a iPhone/Android phone:
Dayton Audio iMM-6 iDevice Calibrated Microphone* | 390-810
Had more parts on the way and thought, why not, its getting good reviews so it should be quite good for the money. Will report back when I have some results
I'm also taking my Boominator(s) to a few guys with somewhat more professional equipment after finishing them, which should also yield some nice results, especially in tuning the MiniDSP to the right settings
https://www.youtube.com/watch?v=RWjBS5hT3ZU
According to the details, it's only playing at ~70% and reaches near 100dB peak.
I have a Dayton microphone on the way that plugs straight into the 3.5mm socket of a iPhone/Android phone:
Dayton Audio iMM-6 iDevice Calibrated Microphone* | 390-810
Had more parts on the way and thought, why not, its getting good reviews so it should be quite good for the money. Will report back when I have some results
I'm also taking my Boominator(s) to a few guys with somewhat more professional equipment after finishing them, which should also yield some nice results, especially in tuning the MiniDSP to the right settings
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Exactly. Notice the SPL numbers are exactly the same when he moves the iphone from about 2 meters distance to about 50 centimeters distance. It jumps up 1-2dB when moved to 5 centimeters (it should have been 16dB up from the 2 meter distance measurement).
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Not long now..
Hi guys, greetings from a long time lurker.
I am super excited about the new mini boominator!
I built a Sp60 / nd16fa based boombox for last Roskilde festival which I love but want to try a properly tuned bipolar boominator.
Me and a friend will build one each.
I have a Hobby King 4s LifePo4 8.4Ah battery from my last project which I would like to try to use to save cash though its dimensions may be problematic at 145mm long.
ZIPPY Flightmax 8400mAh 4S2P 30C LiFePo4 Pack
The alternative would prob be a 10 Ah 4s Headway 38120s pack but sadly they are a little long too. (152mm long) (though there may be a tabbed instead of screw terminal version available)
I currently use a Imax B6 balance charger which although works well, I would love to have an on board solution to make charging that bit easier.
IMAX B6 Charger/Discharger 1-6 Cells (GENUINE)
So I have some questions for you all:
A - If I were to use a cheap 4s pcm/bms could I just use a laptop PSU to supply the DC voltage and would the pcm/bms act like a balance charger? Would it be set and forget? (and can someone recommend one)
B - Would the DC voltage need to be specific or within a parameter? (say 14 to 17v or what PSU i can find lying around?)
C - Could i leave it plugged into the wall and could i run the system while charging? (The Maxamp 20 is rated to 14.4v so it will be near a Lifepo4 charging current)
D - If I were to install a sure bluetooth board, how would I switch between bluetooth and aux? (can i run them in parallel or is that a no no..)
E - If I were to install a sure pre amp, is it possible to bypass it when not needed to save power?
F - Is a preamp recommended with an iphone/maxamp combo and although besides the gain advantage, does it have a negative effect compared to just the distortion (THD) from the maxamp?
G - Does the sure Bluetooth receiver benefit from a preamp? Does it sound good alone and does it add much value to the project? (I used a cheap external one briefly but it needed to be paired with a mechanical button and made awful sounds coming in and out of range)
H - How much of a battery runtime hit would I lose by using the pre or bluetooth or combo?
WeslyK, you mentioned Accusafe? has become a dealer for Monacor and Dayton, will you be able to supply the SP60 and Nd16fa and when?
Thanks to everyone in advance and a massive thanks to Saturnus for making the designs public.
If anyone is interested in my experiences with the LifePo4 packs, I can say they work really well and you would need a good reason to not go LifePo4.
Though some sort of bms/pcm would be recommended (esp with the hobby packs) as I think I ruined a battery pack by accidentally leaving the amp on over a long period of time.
Its worth having a hard to turn on switch too..
The Imax charger is amazing but its a hassle unplugging every time.
Oh and I have posted this on both Speakerplans and Diy Audio as its getting confusing following both threads reg. the mini now..
Cheers!
Hi guys, greetings from a long time lurker.
I am super excited about the new mini boominator!
I built a Sp60 / nd16fa based boombox for last Roskilde festival which I love but want to try a properly tuned bipolar boominator.
Me and a friend will build one each.
I have a Hobby King 4s LifePo4 8.4Ah battery from my last project which I would like to try to use to save cash though its dimensions may be problematic at 145mm long.
ZIPPY Flightmax 8400mAh 4S2P 30C LiFePo4 Pack
The alternative would prob be a 10 Ah 4s Headway 38120s pack but sadly they are a little long too. (152mm long) (though there may be a tabbed instead of screw terminal version available)
I currently use a Imax B6 balance charger which although works well, I would love to have an on board solution to make charging that bit easier.
IMAX B6 Charger/Discharger 1-6 Cells (GENUINE)
So I have some questions for you all:
A - If I were to use a cheap 4s pcm/bms could I just use a laptop PSU to supply the DC voltage and would the pcm/bms act like a balance charger? Would it be set and forget? (and can someone recommend one)
B - Would the DC voltage need to be specific or within a parameter? (say 14 to 17v or what PSU i can find lying around?)
C - Could i leave it plugged into the wall and could i run the system while charging? (The Maxamp 20 is rated to 14.4v so it will be near a Lifepo4 charging current)
D - If I were to install a sure bluetooth board, how would I switch between bluetooth and aux? (can i run them in parallel or is that a no no..)
E - If I were to install a sure pre amp, is it possible to bypass it when not needed to save power?
F - Is a preamp recommended with an iphone/maxamp combo and although besides the gain advantage, does it have a negative effect compared to just the distortion (THD) from the maxamp?
G - Does the sure Bluetooth receiver benefit from a preamp? Does it sound good alone and does it add much value to the project? (I used a cheap external one briefly but it needed to be paired with a mechanical button and made awful sounds coming in and out of range)
H - How much of a battery runtime hit would I lose by using the pre or bluetooth or combo?
WeslyK, you mentioned Accusafe? has become a dealer for Monacor and Dayton, will you be able to supply the SP60 and Nd16fa and when?
Thanks to everyone in advance and a massive thanks to Saturnus for making the designs public.
If anyone is interested in my experiences with the LifePo4 packs, I can say they work really well and you would need a good reason to not go LifePo4.
Though some sort of bms/pcm would be recommended (esp with the hobby packs) as I think I ruined a battery pack by accidentally leaving the amp on over a long period of time.
Its worth having a hard to turn on switch too..
The Imax charger is amazing but its a hassle unplugging every time.
Oh and I have posted this on both Speakerplans and Diy Audio as its getting confusing following both threads reg. the mini now..
Cheers!
Hi, I have distortion problems in boombox. Maxamp distorts and Sure Amp 2x25w with Sure headphone preamp clips/pops and distorts in about same volume. Maxamp goes little bit louder. 8 ohm speakers and 12v battery.
Multimeter shows like 0.03 A when it distorts. So 0.03 A in 12v is 0.36W. Can't believe that amp does not go louder than that.
Does that distorts because mp3 player/phone needs so much gain to go loud and that gain before amp distorts it?
Have heard that those amps should go about 4-8 watts in 8 ohms without distortion.
Do i need bigger sound source like laptop to go louder which does not need so much preamp gain which distorts it? Or do i need more voltage than 12 ? 12v should put out like 10 watts so can't believe that there is the problem.
So if buy bigger 2x50w amp. Does it distorts in same volume than when 2x25w distorts because it's the preamp gain what distorts it ? Not the amplifier itself?
Multimeter shows like 0.03 A when it distorts. So 0.03 A in 12v is 0.36W. Can't believe that amp does not go louder than that.
Does that distorts because mp3 player/phone needs so much gain to go loud and that gain before amp distorts it?
Have heard that those amps should go about 4-8 watts in 8 ohms without distortion.
Do i need bigger sound source like laptop to go louder which does not need so much preamp gain which distorts it? Or do i need more voltage than 12 ? 12v should put out like 10 watts so can't believe that there is the problem.
So if buy bigger 2x50w amp. Does it distorts in same volume than when 2x25w distorts because it's the preamp gain what distorts it ? Not the amplifier itself?
You get nothing out of buying a bigger amp before you find out what your problem really is. It's most likely your power supply. And if not, then your signal chain.
What does your battery measure? Do you use short relatively thick power cables?
What's your signal chain? Do you have a preamp, eg. a fiio, if so the signal is much too powerful for a maxamp which has very high input sensitivity. Have you tried changing signal cables? Are you sure you have connected everything correctly?
Etc etc.
Try to isolate the problem by testing each separately.
What does your battery measure? Do you use short relatively thick power cables?
What's your signal chain? Do you have a preamp, eg. a fiio, if so the signal is much too powerful for a maxamp which has very high input sensitivity. Have you tried changing signal cables? Are you sure you have connected everything correctly?
Etc etc.
Try to isolate the problem by testing each separately.
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A,B. No. Unless the BMS has a integrated charger. In that case, you should check the specs of the used BMS to see the allowed input voltage and use a suitable power brick.
C. Depends, a PSU usually has a "cleaner" output, resulting in less noise. It is possible though, but it might increase the noise level of the amplifier.
D. Either a switch, or a 3.5mm socket with a integrated switch. A 3.5mm with switch usually has 5(common ground) to 6(separate ground) pins. You connect both the amplifier and the bluetooth module to the switch, and the switch automatically disconnectes bluetooth module when a plug is inserted.
E. You do not necessarily need a pre amp with maxamp or an other amplifier with a high input gain. You could probably bypass the preamp with a switch, but it's power consumption will be low anyways, so I would save yourself the trouble(and maybe not get a pre amp at all).
F. Not needed. The Maxamp has 2 gain settings, it ships with the high setting selected. This will increase the noise floor a bit over the low setting, but it's not really noticeable. With a good pre-amp this noise floor will probably be lower, but again, you'll probably not notice the difference.
G. I believe not. The Sure Bluetooth module is quite good.
H. Bluetooth consumes something like 20mA, not that much.
Yep, I already have some SP60s in stock at the moment, along with some 6.8µF MKT(or MKP) capacitors, and I expect to receive the ND16FA this Friday. If all goes well they should be added to the webshop by the end of this weekend.
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Everybody is ready with parts and waiting for Saturnus' design haha! No pressure When the mini design is unveiled I will actually decide if I'm doing the small closed box or the larger ported box. I hope you can comment on the differences, Saturnus, when you are ready. I'm sure there are tradeoffs!
When the mini design is unveiled I will actually decide if I'm doing the small closed box or the larger ported box. I hope you can comment on the differences, Saturnus, when you are ready. I'm sure there are tradeoffs!For you that live in sweden, Ljudia.se have lots of P.audio HP-10W
https://www.facebook.com/photo.php?...1797196934.132157.198849756934&type=1&theater
https://www.facebook.com/photo.php?...1797196934.132157.198849756934&type=1&theater
Boominator MINI DIY sketchUp
https://3dwarehouse.sketchup.com/model.html?id=uf5f8321a-4d1c-49be-a4a5-2bea1a6618da
https://3dwarehouse.sketchup.com/model.html?id=uf5f8321a-4d1c-49be-a4a5-2bea1a6618da
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