building a amp box for home use.
Today I pulled an old Linear Power 5002 amplifier out of my closet and powered it with a power supply from a computer server rack. I ran the amp to my home stereo speakers (A pair of Klipsch RF5's), and the sound quality was just superb. Much better than the Onkyo amp im running now.
I was just pulling the amp out of storage to offer it up for trade because im looking for some home audio gear but having heard it outplay my home theater amp im thinking about just running the Linear...
I think it would be neat to build a box for testing/using car amplifiers at home. I'm thinking something like an old server rack box or something like that with on-board power and everything you need inside it to hook up a car amp. I have a server power supply capable of outputting 75A at 12V.
Obstacles i want to overcome: It took the power supply a second to really get the juice flowing when i would plug it in. During this period the (right when i turn the supply on) my speakers would pop a little bit. I think a large capacitor in line with the amp might be the answer.
I know the easy way is to buy a capacitor made for car audio but I was hoping someone could recommend a basic capacitor that would do the same thing, minus all the shinny marketing surrounding car audio caps... After all, it is going to be concealed in a box..
Most computer power supplies require a small but minimum current draw to provide stable output. This may be the cause of the turn on transient your talking about. A good stable bench supply does not need this. So your thoughts about this setup needing a large capacitor may be incorrect. You might need a load resistor to create a constant current draw situation so the power supply is stable. If this is so the load resistor will likely get very warm and need to be vented to free air in some fashion for cooling reasons.
But if you wish to pursue the cap idea try Maxwell capacitors. They are a manufacturer of high quality storage caps used for many industrial applications. Just Google search them or even look on Ebay they are their also. Here is a link to a typical 16.6 volt rated cap they make:
Maxwell Technologies Boostcap BMOD0430 Ultracapacitor Module 16 Volt | eBay
At 430 farad it might seem overboard for your need but they do make smaller units that can be custom assembled to any desired value.
Again I think the turn on issue is the power supply reaching a minimum stable operating current draw level, which could cause bounce around quite a bit at low listening levels.
Also if I recall correctly LP amps did not have any turn on muting control inside the amplifier channels. SO here again the turn on thump might just be inherent in the amps design, and require some form of RCA muting control to eliminate your turn on noise issue.
And you might not want to hide the amp inside of a box as it needs free air to cool itself down. Perhaps your computer power supply cooling fan can be used to draft air across the amp in some fashion. The amp is only about 50% efficient so half of all the power going into the amp will likely leave it as heat.
Either way I hope I have given you some food for thought... Happy holidays...;)
The 5002 has speaker relays, i believe its for speaker protection but maybe for turn on/off thumps. I had a 5002 that would turn on but the relays wouldn't engage. Found out a capacitor was bad (no sign of damage).
You should have the supply powered up and then switch the amp on/off with the remote lead. If it still pops, there is likely excessive DC offset. If that's so, the amp would likely have to be repaired to eliminate the popping.
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