[Elecraft] Re: Mod for more AF gain on K2

[wayne burdick]

I think we're on the same page, Mike. I just want to make sure builders 
know there are other alternatives before they jump into a different AF 
amp IC. Lord knows I've designed LM386's into a lot of rigs (the NorCal 
40A, Sierra, SST, K1, and KX1, to name just those which made it out of 
the lab). I tame the noise by putting a resistor/capacitor network in 
series between pins 5 and 8. But ideally the gain and NF ahead of the 
amp would be adequate so that no heroics are required here.

Regarding "how loud is loud," the place where you need the audio levels 
that the '380 is capable of is in mobile or high-noise outdoor 
situations--such as Field Day with a generator nearby. Or in my rickety 
VW van at 60 MPH  ;)

73,
Wayne


On Oct 22, 2004, at 5:06 PM, Mike S wrote:

> At 06:42 PM 10/22/2004, wayne burdick wrote...
>
>> However, because of the problem with clipping at high signal levels, 
>> I definitely don't recommend that anyone do this unless they're 
>> desperate for more audio. The LM386 is a lower-power part and is also 
>> noisier than the LM380, partly because of all that extra gain.
>
> I was able to make both clip, but in both cases it was when the volume 
> exceeded a comfortable level. The LM386 was putting out over 1/2 W 
> when it did.

---

http://www.elecraft.com