lm4730 project

[odysseybmx414]

i am building a chipamp using the lm4730's bridge schematic in the datasheet i was just wondering if anybody else ever attemted it and has any oppinions or anything

[soundNERD]

If you want more power, why not try an lm3875 or lm3886.

They are much easier to use than a bridge circuit. Plus they have higher output levels, and I'm sure higher sound quality.

But if you have the parts you might as well try building out and deciding for yourself

[Peter Daniel]

Originally posted by odysseybmx414
i am building a chipamp using the lm4730's bridge schematic in the datasheet i was just wondering if anybody else ever attemted it and has any oppinions or anything

I assume you mean LM4780 bridged. This guy built it: http://www.diyaudio.com/forums/showt...699#post528699

[soundNERD]

Originally posted by Peter Daniel


I assume you mean LM4780 bridged. This guy built it: http://www.diyaudio.com/forums/showt...699#post528699

I don't know... Look on page 5 of the lm4730 datasheet, theres a bridge circuit.

[Peter Daniel]

I didn't even know if they make LM4730 (as Digi Key show no link). Why use 14W amp bridged, when you can use 60W amp in stereo?

[odysseybmx414]

well i have a 15 volt 5 amp already built power supply all i gotta do is build an amp good for that power and i figured the lm4730 would be a pretty nice matchup unless anybody else has a better idea for me

[soundNERD]

15V single supply, +/-15V supply, or +/-7.5V supply?

If its a +/-15 supply, you should go for a lm3875 or lm3886. For a +/-7.5, go for a Texas Instruments OPA549 or 541.

If it's a 15V single supply, you should be able to use an OPA549, but I don't know how to do it. I tried building one to run off of 12VDC, and it sounded horrible, as in distorting with everything. I thought it may have been caused by low voltage, but I hooked it up to a 40VDC supply, same result. I know it can be done, though. In fact, I'll start a post on that...

[leadbelly]

Originally posted by odysseybmx414
well i have a 15 volt 5 amp already built power supply all i gotta do is build an amp good for that power and i figured the lm4730 would be a pretty nice matchup unless anybody else has a better idea for me

I think the path you are pursuing is hardly worth the time or expense. This picture shows how much power the 4730 can put into 8 ohms, as a single.

http://www.national.com/ds/LM/LM4730.pdf

[Stocker]

SoundNERD don't let them get you down. Some of the most highly regarded amplifiers in the world put out single-digits of Watts, max. If this is what you want to do, listen only to those who will help you actually *do* it.

[soundNERD]

Originally posted by Stocker
SoundNERD don't let them get you down. Some of the most highly regarded amplifiers in the world put out single-digits of Watts, max. If this is what you want to do, listen only to those who will help you actually *do* it.

Yes, I know that. Like the LM3875. Only 56W but the sound is amazing and powerful, as in better than my 100W RMS x 6 Yamaha reciever (which was much more money too!!).

And I know some tube amps only produce 4 or 5 watts of power.

In general, watts means nothing to me (except in certain situations, such as comparing a 250mW 386 amp to a 56W 3875 amp. But when you see a 200W x 2 amp in a store, it can't even come close to my 56W x 2 3875 amp.