simple 2 knob hi gain distortion..collaboration?

[Quackzed]

i still tend to think of this fizz problem as being a consequence of trying to drive too low an impedence, like hooking an amp up to too low an ohm speaker...
i had fizz problems through lower 4 -ohm spkrs where it cleaned up with higher ohm speakers.. a ruby thst is, dedicated to drive a speaker, rather than a stompbox- to drive the input of an amp...
leads me to believe that without a decent load on the output of the whimsical 386 , you get fizz.

[deadastronaut]

It's kind of funny.  I started a thread because I was building a ruby and it has the fizzy decay just like you guys have mentioned.  I have tried everything to get rid of it but it stays.  I am building it on a breadboard and its given me enough promise to build a proper board and put it in an enclosure.  I hope this fixes the decaying fizz since it sounds like not everybody gets this.  I'll probably put a dip socket in so I can switch chips in and out to try to get the fizz to disappear.

hi david. yep it seems like a very common problem...let us all know how you get on with the final project too....

rob.

[deadastronaut]

Rob,

have you considered feeding higher voltage into the FET?

i.e. maybe +18V with a trimmer

I had a variant of the first third of Aron's Shaka express + LED clippers breadboarded, made things LOUD when around 13-15V, with distortion, but nothing fuzzy (unless you starve it). Might also have had a lot to do with the 4558 chip though

Edit: gonna try it this week when my 386's come in

are you going to try the 386 / 1 / 3 ......?

hi phil. i am unable to try that as i only use a 9v psu..and 9v batteries...interesting idea though..i did notice a difference
in the distortion qualities when using a psu compared to the battery though!..like being starved etc...could be onto something there man!..

[deadastronaut]

The fizzle sound on a sustained note is from the 386. I have built many distortion pedals based on Jfets, Cmos, and op amps and the only ones that fizzled at the end of a sustained note was the 386 pedal.

oops, also happened on a Jfet build. but that was because I did not bias the Jfet.

we have got to tame this 386 beast!....
it would be interesting to hear from diyers that have built daniel scwhartz's 'burning crunch' too 386-1 based too.
i think he actually went into production with that.(not sure though).going by the youtube video of it...but alas the demo doesnt
show a decaying note....unless he did get round it ......ive looked at his schematic too...anyone built it?..

[deadastronaut]

i still tend to think of this fizz problem as being a consequence of trying to drive too low an impedence, like hooking an amp up to too low an ohm speaker...
i had fizz problems through lower 4 -ohm spkrs where it cleaned up with higher ohm speakers.. a ruby thst is, dedicated to drive a speaker, rather than a stompbox- to drive the input of an amp...
leads me to believe that without a decent load on the output of the whimsical 386 , you get fizz.

hmmm..you may well be right on that!..it is after all an amp...unlike the normal dual opamps..072.4558 etc...
as for calling it 'whimsical' i can think of a more abusive name for it..


edit:...found an interesting thread...especially the comments by PRR...on the 386/grace/big daddy.

http://www.diystompboxes.com/smfforum/index.php?topic=84410.0

hmmmmmm!.....in the datasheet the applictaions all have a 0.05uf and a 10 ohm on the output to ground!..also a 10k on the input.
hmmmmm again!....... ..i dont have a 50nf...but i do have a 47nf..will have to try this too...

[Quackzed]

i think that may be the culprit... i hope it is anyway...

[davidallancole]

Hi guys,

You could try 0.1uF and 10 ohm in series to ground as well.  PRR mentioned that in the thread you linked to deadastronaut.  The capacitor is double what the data sheet says, but the HI-FI guys use 0.1uF and 10 ohms a lot.

Some other suggestions I found on headphone forums were to add a 2.2k resistor in series with the input as well as change the input from pin 3 to pin 2.  Give those a try.  I have but they didn't help me much.  I still have to try the 0.1uF and 10 ohm.  I have a 0.047uF and 10 ohm right now.

[tubelectron]

Hi all,

Enfer et Damnation - This LM386 is another great FF - not FuzzFace, nor FuzzFactory but... FizzFactory ! Or may be there is something missing again in the design ?

A+!

[davidallancole]

I am starting to thing there is nothing you change but possible the chip to get rid of the fizz.  I changed my output to have the 10 ohm, 0.1 uF cap and that changed nothing.  Changed inputs, that changed nothing.  Added resistor in series with input, that changed nothing.  Added 100uF cap to power supply, that changed nothing.  Added bypass cap on pin 7, that changed nothing.  Swore a ton, that did nothing.  Drew pentagrams, killed chickens and prayed to the powers that be, that did nothing.

[blooze_man]

100uf on the power elmiminated all fizz from my smash drive (which I gotta say sounds pretty dang good)

[arma61]

I also have 100uF on +9 to gnd, longest decay but still "short", not like Rob's last video but good enough, could it be the position of the cap on the board ? (mine is still on breadboard)



Shall we all also start to state which LM386 we are using, makers,N ? I will tonight.

you can not compare Spaghetti cooked in Italy with the ones cooked in ... (put any land in the world you want!), they both are named spaghetti but the taste is completely different! (you know what I mean!)

[blooze_man]

my 100uf cap is directly soldered to the power jack in the pedal. The 386 is an LM386 N-3. I have an N-1 that I will swap and see what happens.

Edit: Just tried and did not hear a significant difference ( both did not fizz ). The N-1 might have been slightly noisier but that's it.

[deadastronaut]

I also have 100uF on +9 to gnd, longest decay but still "short", not like Rob's last video but good enough, could it be the position of the cap on the board ? (mine is still on breadboard)



Shall we all also start to state which LM386 we are using, makers,N ? I will tonight.

you can not compare Spaghetti cooked in Italy with the ones cooked in ... (put any land in the world you want!), they both are named spaghetti but the taste is completely different! (you know what I mean!)

what is on your breadboard...the big daddies b*****d sister!...(the big daddy/smash drive hybrid).

i wouldnt have thought the placing of the cap would matter...by the way i used a 50v 100uf..not that i think that would matter
either..but just to let you know ok.....oh and yes.the spaghetti analogy..yep state which chip number too..and bolognese sauce

rob.

[deadastronaut]

my 100uf cap is directly soldered to the power jack in the pedal. The 386 is an LM386 N-3. I have an N-1 that I will swap and see what happens.

Edit: Just tried and did not hear a significant difference ( both did not fizz ). The N-1 might have been slightly noisier but that's it.

hi adrien. so it did fizz without the 100uf then?...good to hear you got a good result...

[deadastronaut]

I am starting to thing there is nothing you change but possible the chip to get rid of the fizz.  I changed my output to have the 10 ohm, 0.1 uF cap and that changed nothing.  Changed inputs, that changed nothing.  Added resistor in series with input, that changed nothing.  Added 100uF cap to power supply, that changed nothing.  Added bypass cap on pin 7, that changed nothing.  Swore a ton, that did nothing.  Drew pentagrams, killed chickens and prayed to the powers that be, that did nothing.

so swearing a lot didnt help then?..

but seriously, so it didnt change anything....shame... some projects seem to have got round it though!..
or maybe they havent, because we havent heard the proper decay on them.......!!!!!!!

[blooze_man]

hi adrien. so it did fizz without the 100uf then?...good to hear you got a good result...

Correct. I wish I had the parts to breadboard this pedal so I could be working with the same circuit as you, but sadly that's not possible at the moment.

[deadastronaut]

right im going to go with the original circuit (page 1)..even with its design flaws just out of curiosity..and try the 100uf cap with it tonight..its 10:30pm here...

so i'll be having a late one..and maybe a beer or 2..will post the results later or tomorrow ok guys....

[arma61]

what is on your breadboard...the big daddies b*****d sister!...(the big daddy/smash drive hybrid).

yes it's the big daddies b.... on the breadboard with a JC8RA LM386N-1 I still have to test an UTC WMAD LM386L and a JR56RQ LM38N-1
will report later on about these last 2 ICs

i wouldnt have thought the placing of the cap would matter...by the way i used a 50v 100uf..not that i think that would matter
either..but just to let you know ok.....oh and yes.the spaghetti analogy..yep state which chip number too..and bolognese sauce

rob.

           BEWARE NOOB THINKING AHEAD     




 


I was thinking about this   

when the guitar signal decays the IC is still trying to amplify it so it try to "suck "  more power and that power may come from the volts stored in the cap ?! (really I don't know what I'm talking about  !)

[deadastronaut]

(really I don't know what I'm talking about  !)



ha ha that makes 2 of us then! ....nor do i ha ha ....i tried different value caps on the power...but the 100uf seemed the best
behaved....

cant wait to hear your results with the different ic's...

[arma61]

cant wait to hear your results with the different ic's...

sorry m8 you'll have to wait, I 'm going to bed now, it 00:02 here