The Boominator - another stab at the ultimate party machine - Page 84 - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 17th February 2011, 10:19 AM   #831
Wubbaz is offline Wubbaz  Denmark
diyAudio Member
 
Join Date: Feb 2011
@Saturnus

Wouldn't adding a linkwitz transformer mean slightly more output = more power consumption? Or will it just make a better frequency response? I assume that the purpose of the linkwitz transformer in this case is to increase the frequency range

If it means more power consumption, I think I will leave it out for this time

@Darkwithin

Looking forward to following your project!
  Reply With Quote
Old 17th February 2011, 10:57 AM   #832
diyAudio Member
 
Darkwithin's Avatar
 
Join Date: Feb 2011
Location: Kristianstad
It seams like I'm unable to edit my post so I guess I'll be posting pictures in new posts, but that'll work out as well :P

Ordered
-20W Solarpanel(775 SEK) and a regulator(375 SEK). site: 24volt.eu
-Resistance 5W 150 OHM (~7 SEK) site: conrad.se


Not yet ordered
-2x 12v acid-led
-AMP6-BASIC
-4x p.audio HP-10W
-4x Piezo QLM-1005

I don't think i forgot something but if you people notice something out of place, please do not hesitate on putting me on the right track!

thanks // Marcus
  Reply With Quote
Old 17th February 2011, 02:10 PM   #833
diyAudio Member
 
Join Date: Jan 2011
Location: Copenhagen, Denmark
Hi there.
I finally made it through the entire thread...
I'm currently designing our new boombox, with the following components:
-Amp6B (all soldered and working)
-4 Eminence Delta 10A (98.8dB)
-4 Eminence APT 150 (105dB)
I'll won't be able to use the battery from our old boombox, because it died last summer. At 120Ah and weighing ~40kg, it was too big anyway.
So a new one it is, but what to get?
At first I was pretty hooked on a couple of 7-14Ah SLA's. They should supply me with enough power, and they could be wired in series for 24V later on.
They have a few disadvantages, though:
-I've used them as backup for alarm systems at school (I'm an electrician), and they died pretty fast if allowed to run flat (I killed two sets in 8 weeks).
-For the price of two, I can almost get a 75Ah marine battery instead, allowing us to power some LED lights, and charge cellphones and Ipods.

I've been reading a bit about LiFePo batteries. They looked ideal, until I noticed something. In the spec sheet, it says that running them lower than 10V will damage them. In the specs for the TA2020 chip, it says minimum supply voltage is 8,5V. That sounds like a good way to kill an expensive battery pretty fast?
  Reply With Quote
Old 17th February 2011, 04:37 PM   #834
diyAudio Member
 
Saturnus's Avatar
 
Join Date: Jun 2005
Location: Copenhagen, Denmark
Nikolaj, it's highly recommended that you buy a battery protection PCB when you buy your LFC cells. These ensures correct balancing, over- and under-voltage, temperature, and etc protection. It doesn't matter what kind of battery it is. All batteries are irreversably damaged when allowed to run completely flat, it's just a question of how much damage is suffered. LFP cells, especially the newest type with yittrium that has up to 5000 cycles before deteriation (up from 2000 with standard LFP cells), seems to be the most resilient battery type also in this respect.

Wubbaz, yes, it'll mean more power consumption to add a linkwitz transform (a lot more in fact).

Darkwithin, Thanks and good luck on your project. I wouldn't have used chipboard (not even MDF) but plywood which is also what I recommend. Make very sure you seal every single surface also internally, so that the chipboard doesn't pick up too much moisture. Otherwise it'll become very heavy and fall apart very fast. The internal forces put on the wood is quite extreme.

Last edited by Saturnus; 17th February 2011 at 04:45 PM.
  Reply With Quote
Old 17th February 2011, 05:46 PM   #835
ThokN is offline ThokN  Denmark
diyAudio Member
 
Join Date: Jan 2010
Location: Copenhagen
Saturnus, maybe you can help me out here? I've tried to calculate a new boxvolume with different Q's at this site:
Speaker Box Calculations

but no matter what I choose as a Qtc (which I presume is the Q you are talking about?), the calculated boxvolume doesn't change. It is always ~2 cubic feet. What am I missing?

And do you have an estimate of what our Q and target frequency should be in our case?
I haven't been able to find any info on 'outdoor Q' or 'outdoor speaker enclosure volume' etc. anywhere :s
  Reply With Quote
Old 17th February 2011, 05:57 PM   #836
diyAudio Member
 
Saturnus's Avatar
 
Join Date: Jun 2005
Location: Copenhagen, Denmark
Don't know how that calc works. But you can do it in WINISD by putting in different volumes and then read the Qts.

A Q of 1 or slightly above optimum for an outdoor sub meant to be close to the ground. I like my deep bass really tight so I've gone with 0.85 in Q which gives a nice kick.
  Reply With Quote
Old 17th February 2011, 06:52 PM   #837
Wubbaz is offline Wubbaz  Denmark
diyAudio Member
 
Join Date: Feb 2011
I'll leave the transformer out for now then ;-)

I was wondering if this amp:

MKll Version Tripath TA2020 PCB 25w CLass-T amplifier on eBay (end time 11-Mar-11 02:09:19 GMT)

Would play alot different than a Amp6B? I am asking due to limited funds, and since this amp is based on the Tripath 2020 PCB and is cheaper than the Amp6B, I am thinking it would prove for a decent alternative. What are your thoughts on this? :-)
  Reply With Quote
Old 17th February 2011, 07:00 PM   #838
diyAudio Member
 
Saturnus's Avatar
 
Join Date: Jun 2005
Location: Copenhagen, Denmark
Since it uses the same chip If there is any difference at all, you certainly wouldn't be able to notice on a boombox, no matter how good quality it might be.

The main reason I recommend the amp6b is that I know it uses high quality components and have an almost unlimited lifetime. At least my first one is still playing nicely. I've had several of those cheapo e-bay T-amp suddenly die on me and other people. Probably because they're not built to endure the extreme temperature and moisture conditions that a boombox will suffer.

Others again have really good experiences with the e-bay stuff, so it's your call
  Reply With Quote
Old 17th February 2011, 11:38 PM   #839
ThokN is offline ThokN  Denmark
diyAudio Member
 
Join Date: Jan 2010
Location: Copenhagen
ok I am getting the hang of this WINISD thing now, but the weird thing is that there is no Qtc field. I know it should be under the Box-tab, but here is only Volume and Tuning freq., and I've seen screenshots of where it should be, but I don't have it. I've entered all information from the HP-10W datasheet, still no box with Qtc. Well...I might just go with the old 23L 82Hz then.
  Reply With Quote
Old 18th February 2011, 08:29 AM   #840
diyAudio Member
 
Darkwithin's Avatar
 
Join Date: Feb 2011
Location: Kristianstad
Saturnus, Thanks.

You should have seen the surprise on my face when this morning my chipboard had turned into plywood over night. :O

Actually the water resistance of the material had not crossed my mind but I will redo, and do right.

I like this thread, so mush nerd talk haha!
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 02:06 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2