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Messages - joecool85

#2491
Preamps and Effects / Re: Preamp thoughts
April 05, 2006, 09:42:34 PM
Naw, I think I am going to find a gutted cab on eBay and use that.  I'm no carpenter either lol.  I've made solid sub boxes for my car, no leaks or anything, but those are made out of advantec and don't need to be pretty since they are covered in carpet.
#2492
Preamps and Effects / Re: Preamp thoughts
April 05, 2006, 09:20:32 PM
I'm thinking about doing a lm1875 combo with 2x8.
#2493
Preamps and Effects / Re: Preamp thoughts
April 05, 2006, 08:56:32 PM
Is that what you needed that lm3886 PCB for?

Good idea to make a test bed btw.
#2494
Yup.  I have prototype boards, but the only difference really is that mine are just a basic PCB and the production boards will be colored and labeled etc.
#2495
Preamps and Effects / Re: Preamp thoughts
April 05, 2006, 07:39:39 PM
So do I  ;D  I spent countless hours reading chipamp threads on diystompboxes a few months ago before I built my amp.
#2496
Amplifier Discussion / Heatsinks for your poweramp
April 05, 2006, 07:37:26 PM
First - Have a good power supply circuit and a big enough/proper voltage transformer
Second - Big heatsink, there is no such thing as too large of a heatsink

Proper heatsink size for two LM1875 chips, or one LM3886:


Overkill(which isn't a bad thing though):
#2497
Preamps and Effects / Re: Preamp thoughts
April 05, 2006, 07:32:56 PM
Ah, RDV got you in here  :P
#2498
Preamps and Effects / Re: Preamp thoughts
April 05, 2006, 07:28:40 PM
First off, welcome to the board RG!  Secondly, those are all great ideas!  I'd like to see our preamp(s) use those features.  How would you protect your inputs from stuff like that?
#2499
Schematics and Layouts / LM1875 Power amp schematic
April 05, 2006, 07:09:19 PM
Now hosted on ssg server.
#2500




#2501
Preamps and Effects / Re: Should we go even simpler?
April 05, 2006, 06:04:53 PM
How much is ample?  Like...47,000uF caps? or are we talking 1500uF caps?  I'm ok with either.
#2502
Preamps and Effects / Re: Should we go even simpler?
April 05, 2006, 05:02:14 PM
Thats what my lm3886 uses, two 10,000uF 50v caps.
#2503
Preamps and Effects / Re: Should we go even simpler?
April 05, 2006, 03:34:07 PM
Huge caps are fine with me!  haha, I love the way they look anyway.  I like the looks of this circuit.  If you build it and like it, I'd like to hear about it.  I think if we just changed the tone stack to a marshall style one I would be all set to use it for my lm3886 amp.  From my research, it seems the lm3886 circuit wants around +/-25v input.
#2504
I'm not sure what chip you'd want to use for a 5w application...I definetly wouldn't use a TDA2003, I've already posted about how I didn't like that too much.  What type of power source are you going to power this thing with?  That should help narrow down possible chips.  Maybe even a lm1875, it goes as low as 16v (+8/-8), you could do +/-9v with a couple 9v batteries.  Doing that would give you about 4watts of power, should be fine.  To get 5w it looks like you'd need around +/-10v. 

As far as heatsinking goes, in an application like that, an 8" piece of this should do it:


Probably less than that would suffice, but its better to have more than less.  You can get that from alltronics.com for about $2
#2505
Preamps and Effects / Re: Should we go even simpler?
April 05, 2006, 02:22:58 PM
This sounds like something that could work with a lm3886.