DIY Audio Projects Forum

Chip Amp Power supply
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Author:  Failure [ 24 Jun 2008, 13:32 ]
Post subject:  Chip Amp Power supply

Why does the kit for the LM3668TF on require MUR860 rectifiers as opposed to a regular full-wave rectifier ex: ... R-KBU8A-E4 or can I use a well regulated DC powersupply rather than getting an xfmr and rectifiers?

Author:  gofar99 [ 24 Jun 2008, 17:19 ]
Post subject:  Re: Chip Amp Power supply

Hi, I'm not sure why someone hasn't jumped in on this one. So even though I seem to be the tube guy around here, I'll answer. I do have one chip amp in my system (it works very well). Not everything in the system glows in the dark.

You can use any kind of rectifiers and supply that suits your desires. What it must do is provide lots of clean current at the right voltages. Typically the MURs are used because they do the job well and are inexpensive. There are many others that will work. Same on the transformers. Toroids are usually used as they are cost effective and available in the sizes needed. If parts are hard for you to get, be creative and substitute what you can get. Don't skimp on the large electrolytics though. They flavor the sound. Use good Low ESR caps. IMHO they are critical and will make or break the sound quality of the amp. OK you other guys jump in if I err anywhere.

Good listening

Author:  Gio [ 24 Jun 2008, 17:45 ]
Post subject:  Re: Chip Amp Power supply

Failure wrote:
Why does the kit for the LM3668TF on require MUR860 rectifiers as opposed to a regular full-wave rectifier

The MUR860 (or discrete diodes) are not a requirement. There are several examples of gainclones that are built using bridge rectifiers. Mark's baking pan gainclone amplifier is one example.

Here is a picture of another example:
Image ... hp?pos=-26


Author:  RiGuy [ 29 Jun 2008, 16:10 ]
Post subject:  Re: Chip Amp Power supply

I am always plugging for this guy but here goes again. Buy some regular rectifiers from ApexJr at then get your caps there as well. Interconnects are cheap to here and good quality. Does not really matter which rectifier. You need some amp overhead so maybe 10amps or more and the voltage needs to be a few hundred since you will be feeding it 120V already. The caps are 12,000uf at either 50V or 63V, forget but they are 1.99 each by Nichicon from Steve at ApexJr. He has transformers but I think your best be for the proper voltage is ebay and Get about 18V out since it will end up multiplied by 1.4 when rectified. I have a supply built with these parts running a LM3886T and I am very impressed. Sounds great. Limitless power. No bogging down on bass. No noise.
I used this build:

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