lil green watter project 12au7 1 watt

[maiko]

Ive built a lil green Watter 1 watt 12 au7 hybrid off NZCdogs design :

http://www.madbeanpedals.com/forum/index.php?topic=6869.0

And have been enjoying it for quite sometime now.  However i was using the lm386-N1 OPamp for the power section.   

Recently lm386-N4 came available and since its what the guys in the thread were using so i ordered it.   it was an easy swap since i used a socket.

However it was quite disappointing as it gave a harsh/farty/distorted tone.   and as the sustain died out it also cleared up.   I dunno maybe i need to swap out a cap to make it work with the N4 but i followed the build notes and i tried the suggested values but no avail.







MAybe you guys can help me determine what could be/where i went wrong.   I thought i could just swap out the IC's but it wont work

[alanp]

How was the volume with the N1, compared to the N4 ?

[maiko]

It had significantly higher output but was unusable as is.     I hope i can solve this to continiue using the n4

[Scruffie]

What brand IC was it? I think the 386 is actually a case where they're not all created equally.

[nzCdog]

awesome to see another one in the wild, great build maiko!
whats the deal with all the extra wiring?! looks serious 

What brand IC was it? I think the 386 is actually a case where they're not all created equally.

Thats interesting to know!

[maiko]

Ive built a Zen drive into the amp.    thats why there alot more hook up wiring in there .  It actually gives it a clean boost for more volume and dirt if i so please.

havent solved the n4 problem though.    i same chromesphere in youtube built a distortion circuit and initially it had the same farting problem i had.   he solved it with a 2.2uf cap very close to the + and - on the chip.  I think i might try this.

[chromesphere]

Cant remember specifically maiko, I think that cap possibly helped, worth a try.  I ended up canning the 386 for the tda7052a which was much easier to work with.  My 386 came from tayda and was a nightmare to work with. I think it was an n4....I honestly felt like it was possessed, one minute it worked next minute it would oscillate, farty distortion, back to working, etc.  Life was too short to mess around with it any longer.

Anyway, hope you work out the problem!

[maiko]

Hey Chromeshpere thanks for that reply  i didnt even knew you were in the forums here.

Its just frustrating cause i ordered a bunch of these and I had to wait about a month to get em only not to be able to use them.   

BTW i also tried the twin 386 bridged with the circuit.   I couldnt get that to work either.  Anyways its still an excellent amp and i use it everyday.     

[chromesphere]

Hey, this is like...MY HOME lol

Im sure when I was working on the smokey amp / dead easy dirt reading about versions that don't play nice and tracking back to my tayda 386 being that particular version / model.  I guess it must have been N4...Others using different versions / models / revisions / or whatever had absolutely no issues whatsoever.  The chip I was using was totally unstable.

[maiko]

Ill check which n4 i got.    https://ph.rs-online.com/web/p/audio-amplifier-ics/5342911/   It says texas instruments

[chromesphere]

Found my original trouble shooting thread on diystompboxes.  Might help you.  I don't remember the conclusion it was some time ago but I seem to be happy with the solution, a cap to ground in close proximity to the chip (toward the end of the thread)

http://www.diystompboxes.com/smfforum/index.php?action=printpage;topic=101528.0

[nzCdog]

Thanks for the suggestions Paul...
Maiko, I'm using the n4 chip without any issues here, let us know how you get on

[maiko]

Tried the 2.2uf from pin 6 (+) to 4 (-)   What that did was apparantly made some sort of a highpass filter and chopped of the highs. This was with the 386n 

When i tried the n4 it farted "Less"  but never the less still farts.   like braaaattttt braaaatttt like when you try the low strings.

I think the amp is perfect as it is and i really like the stock tone.   So this is me officially giving up on the N4.