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Author Topic: Noisy Cricket problems!  (Read 16213 times)

joecool85

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Re: Noisy Cricket problems!
« Reply #15 on: October 27, 2011, 10:03:14 AM »
The published circuit and instructions *do* work, the project is popular and has been built by thousands, just build it as-is , play, and then share your experience with us.
After that, you can continue advancing, the Sky is the limit.

This is also what I recommend.  Also, if it turns out the gain knob is "scratchy" then we can advise you on what to do etc, otherwise, enjoy it as is!  Good luck and keep us posted  :tu:
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Dimi Pana

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Re: Noisy Cricket problems!
« Reply #16 on: October 27, 2011, 01:04:07 PM »
Sorry, but all of a sudden I do NOT feel welcome anymore.

When I registered in this forum it did not state anywhere that the minimum requirement should be electronics knowledge higher than 101. How am I supposed to know which of my questions is above or below level 101 if I have never taken the 101 class? I never said or even implied that I am an expert, on the contrary. When I see a schematic like the NC (noisy cricket) I can identify all the components but I am not 100% sure why they are there and what exactly they do.

Yes, I want to learn BUT NOT at the expense of your time or whatever. So, since I am not afraid to use a solder gun, if I am given CLEAR instructions and non-conflicting advice I can build a circuit as simple as this. I guess, my response is, if you find my questions TOO basic, by all means PLEASE do not bother answering them. Perhaps, a few others more experienced than me but definitely less knowledgeable than you, will chose to "waste" some of their time to do so. I personally, never took this forum for granted, sharing is caring, YES, still no one forces any one to do anything, right?

I do fall under the description of a " ... *regular* musician who has developed an interest on how Electronics they use work, etc..." however with all due respect it is not fair to be treated like the village idiot because I have never taken -YET- a 101 electronics class. I am a foreign graduate student at UI of Chicago in Information Technology Management and I tutor younger students on Math, Computers, etc. What do you think will happen, if my students asked me a basic question and I told them to go -first- take the 101 class?   

So, what do you want me to do? Keep posting or basically "get the heck out" until I have a better understanding of 101 electronics? I mean this is basically what your message is Mr. JM Fahey, and I am sorry if you feel I imposed on you and the rest of the members. That was not my intention. However, knowing myself, you will be surprised how fast I learn, with the right teacher, so if you stick with me now, I will be soon asking more challenging questions. If not, we're still friends...

In all fairness if you all go back in this thread, to previously posted messages, you will notice some conflicting advice and comments from various members that contradict each other or -especially- what the datasheet is saying. Yes, I did read the datasheet and understood most of it. I am assuming the datasheet is right, right?

Also, as matter or fact in JMF's last message paragraphs #1 and #2 state two exactly opposite positions. How am I to respond to that? If I say I agree, I am basically excluding myself from this discussion and I should probably un-register. If I say I disagree, I am being ungrateful to ALL this great feedback JMF already gave me. I am sorry, this is getting unnecessarily complicated, I just can't comprehend where this is coming from. Did I say something to offend you? If I did, I apologize.

-

Now to the original point, there is some confusion (at least to me) as to:

1) What exactly C3 is doing attached to pin-7 then going to ground (if pin-7 is a bypass), what is its optimal value and WHY?

2) Pin-7 is also connecting to pin-5 via the "grit" switch and C4. But, what will the effect be trying different C4 values?

3) Finally, is an extra capacitor -indeed- needed across pins 1-8 as the datasheet suggests (and as a matter of fact in series with a resistor) or NOT, and WHY? If you say YES, what are the optimal R, C values and WHY?


--
Thank you very much!

PS: I am attaching the PDF I am following for building the NC.

joecool85

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Re: Noisy Cricket problems!
« Reply #17 on: October 27, 2011, 02:03:16 PM »
Sorry, but all of a sudden I do NOT feel welcome anymore.

...


3) Finally, is an extra capacitor -indeed- needed across pins 1-8 as the datasheet suggests (and as a matter of fact in series with a resistor) or NOT, and WHY? If you say YES, what are the optimal R, C values and WHY?

Dimi, I'm sure Juan didn't mean to offend and just came off as a little harsh - his first language isn't English either so maybe that is part of it?

I can't help with most of your questions, but as to #3 I can.  Build it as in the NC schematic (w/o a cap), it should be 100% fine.  The cap is there to remove "scratchy" noises that can happen as you adjust the gain with the potentiometer.  If the scratches are there you might want to use a cap in series to remove that noise.  From what I gather the cap size isn't terribly important as long as it's at least 2-3uF in size, bigger wouldn't be an issue.  That said, I've always built mine with an on/off switch that either connects the pins or disconnects them, no resistor, no cap and they work fine.
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Dimi Pana

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Re: Noisy Cricket problems!
« Reply #18 on: October 27, 2011, 04:14:22 PM »
Τhanks for your reply, Joe. I now understand the pin 1-8 configuration and any additions (or not) to it.

I am building this with Volume + Gain + Tone controls, I just wish it did not have the "grit" switch.

From what I have read, "grit" switch augments the distortion. E.g. with this switch OFF the the gain control will still produce distortion, turn it ON and you get more body in the distortion. Perhaps you can put it in better more electronically correct terms.

Anyway, if anyone else cares to answer queston #1 and #2, it would be greatly appreciated.

As far as JMF, I am highly appreciative for all of his advice to date and -hopefully- in the future. I am not offended at all, on the contrary, I am concerned about myself NOT to offend anybody. My first language is not English either.  :tu:

Thank you all!

J M Fahey

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Re: Noisy Cricket problems!
« Reply #19 on: October 27, 2011, 05:45:01 PM »
OK, do you want the full Monty?
Here it is.
*Only* problem is, each answer creates 2 or 3 *new* questions, which in turn, when answered,  create *each* 2 or 3 .... I think you imagine what follows.

Quote
Are you absolutely sure this C3 should be 10μF instead of 100nF ?

Short answer: YES

Longer (although still incomplete) answer:

yes, because its function is to bypass the current source which feeds the (unmarked) transistor which through a current mirror modulates the (unmarked) transistor which has 3 functions I recognize, probably more:
1) inverts again the phase of the signal present in (unmarked) transistor collector
2) receives signal from the non-inverting input, and substracts it from the input signal. making a conventional negative feedback loop possible (like in any Op Amp).
Usually this one is not used, because the network of 15K/1K35/150r does that, but the possibility exists, if a more "conventional" circuit is needed.
3) being symmetrical and built in the same chip, at the same time, allows 2 wonderful things to happen (hail to its designers)
3a) sets the quiescent DC voltage at the output rail to sit quite close to ideal 1/2 +V rail.
3b) being in *real* close contact, compensates thermal drift very well
4) drives the (unmarked) transistor which is the main gain cell in the entire amplifier, as in all Lin architecture amplifiers.

Now to the "mod".
5) using a too small cap (100 nF) makes it behave poorly.
Even 10uF is low, and was chosen because it´s a cheap low power amp which will probably drive a 2" radio speaker; imagine a capacitor 100 times smaller.
6) the "grit" mod, which if you read earlier posts I wrote against, yes, probably adds some distortion to the sound .... in a way similar to slitting the speaker cone with a razor blade, or some other poor way.
In my opinion, just overdriving this little amp with your guitar, full volume, will provide more (and better) distortion.

Well, all of this for just 1 question, imagine the others, plus answering the *new* ones which appear.

I did not mean to disrespect you or any other, never did,here or anywhere else, and in my opinion I gave you a good Friend's advice: go and build it.

PS: the fact that National does not identify parts in their schematic, such as Q1, Q2 , R1, ... etc. , only adds to the confusion.
In fact, since it´s an integrated circuit, you shouldn´t even care as to what´s inside it, just use it as suggested.
Modern ICs do not supply internal circuits any more; at most functional block diagrams.

 
Quote
What is the reasoning behind that? I am not questioning your input -on the contrary- I am just curious why, just want to learn.
Well, you had a small sample of the reasoning involved.
Congratulations on your wish to learn, please keep doing so.

You never stop, I'm still learning a lot 43 years after having started with this ..... and even worse, giving up on a LOT of things which I know I won't learn in a reasonable time.
Does it mean I won´t be able to do anything at all in those areas ?
No, but I´ll be happy in "following the book/standard rules/datasheet examples"

If I haven´t said so before, good luck. :tu: :tu:

PS2: just as a personal curiosity, what would your first language be?
I speak quite a few, yet my last addition, Chinese, is driving me crazy.

Dimi Pana

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Re: Noisy Cricket problems!
« Reply #20 on: October 27, 2011, 09:11:07 PM »
Hello JMF -

Thank you for the long explanations, most of that is obviously way above me, but I was able to follow your reasoning.

I tend to be fast when I get infatuated with something, that is my shortcoming, I need to learn to curb my over-enthusiasm. I realize I have agitated you, and I apologize for that.

Regarding the NC, I have collected all the parts and I will build it as is. I want to hear how it will sound into a bigger cabinet. Eventually though I think I will try a non "grit" version, exactly per your advice. It sounds like for such a simple design a Volume and Gain control should yield a sufficient range of clean and "dirty" sound.

So, if I decide to NOT use the "grit" switch do I just remove SW2, jumper the gap, and leave everything else as is, or do I remove C4 and C3 as well?

--

I would have never attempted to learn Chinese, so -really- I admire your courage. I speak decent English, average French, basic Spanish and Italian. I can "fake it" in German as long as I keep my responses to an absolute minimum ;D.  Finally, I am fluent in Hellenic since I was born and bred in Athens, Greece.

Best regards!
« Last Edit: November 02, 2011, 02:09:54 PM by Dimi Pana »

J M Fahey

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Re: Noisy Cricket problems!
« Reply #21 on: October 28, 2011, 06:25:19 AM »
Hi Dimi.
I would skip the Grit Mod and just use the 10uF capacitor as suggested in the Datasheet.
As a simpler explanation, it works like some kind of Tremolo (volume modulation), but instead of using an external oscillator to drive it (causing the typical up-down-up-down volume) it uses the speaker output itself to do such modulation.
It does not sound as a tremolo but as a funky, synthesizer type waveform, very "plastic" or "cheesy", not nice at all to my ears.
Since it can´t go "more up" than its limited power, it won´t, so it can only go down, losing power, which in a 1/2W amp isn´t the best option.
If , on the contrary, you overdrive it with a strong signal, it will clip like any overdriven amplifier and provide almost 1 W (squarewave).
As a couple free samples of what an LM386 can do, just as the datasheet application (pins 1-8 shorted) and *nothing* else, not even a humble transistor buffer (not even a volume pot .... which you already have in your guitar)
This one is even simpler than the NC.
Hear for yourself:
Note: here you will clearly hear the base of a myth, that Tube Amps are fat and sweet, and SS amps are thin and buzzy.
Truth is, cheaper SS amps usually come in small cabinets and with small/cheap/poor speakers, which don't exactly help them, while expensive Tube amps "justify" big expensive speakers.
Hear for yourself what happens when the cheapest simplest SS amp gets plugged into a 4x12" Marshall !!!!
http://www.youtube.com/watch?v=og_RiEB-74U&feature=player_embedded

http://www.youtube.com/watch?v=j9VqN0Kna0U

Here again plugged into a "real" speaker
http://www.youtube.com/watch?NR=1&v=7VaxzLjWcRU

PS: when I arrived in Greece, I said, watching the street signs, "wow ! , at least now I feel I'm travelling" ... which I had not felt in Spain (obviously) Italy, France or England.
The sensation quickly faded when I realized I understood most of what was written, and quite a lot of what was said, just by getting the root of any word, which is often the root of one (or more) of our Spanish ones.
Oh well.
For example: I went to a book shop to buy a Greek copy of Antoine de Saint Exupery's "The little Prince".
The shop owner didn't understand what I needed, until I spotted on a shelf the "Mikrós Prinkipós" (or something like that).
Of course!!, The Micro Prince !!! Clear as water !!
The language institute in front of my Hotel offered to teach languages from "Gallia", "Germanía" and so on.
At the market I pointed to some flat bread, the salesman asked if I wanted "pitzá". Well, pizza, of course!
So I found I already understood *a lot* of Greek, without even trying.
Now you understand why I´m getting into Chinese ! :lmao:
« Last Edit: October 28, 2011, 06:44:47 AM by J M Fahey »

Dimi Pana

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Re: Noisy Cricket problems!
« Reply #22 on: October 29, 2011, 01:41:54 PM »
Hola Juan, muy encantado de conocerte! Cómo está el tiempo hoy en Argentina?

Well, I won't attempt any more of my broken Spanish, all I know is from the guys I play fútbol with.

I am pleasantly surprised that you have visited my country, especially because after landing in Athens, most people "hit" the beaches and the bars/night-life in the islands. But you -instead- went into a bookstore and then a bakery shop. And as much as I can understand the bakery (cuando viajas te da hambre y tengo que comer, no?) shopping for a copy of Antoine de Saint Exupery's "The little Prince" is definitely remarkable!

Modern Greek (or Hellenic as is the proper term) is the direct descendant of Ancient Greek, simplified and adapted to people's ever-changing needs over the last 2,500 years. Still it is a language that is -according to my favorite saying- unnecessarily complicated, definitely not for the fainted at heart. However your approach makes a lot of sense and speaking a latin based language yourself clearly gives you an advantage. The only simple thing about Greek is that we say what we read and we write exactly as we say it. Sounds and letters do not change between words, i.e. like in English. One other thing is that Greek and Spanish have pretty much the same sounds that -say- Americans are not used to. My soccer buddies make fun of me when we play because when I get mad I start yelling at them in Spanish and actually my accent changes depending who I am yelling at. :grr  I play goalie, (y porteros suelen ser locos) so I get to yell at them a lot, you get the picture :duh  

OK, I am grossly abusing the terms of this forum. So back to business, I read your post, here's my take:

1. I am skipping the "grit" switch but keeping the variable R and C between pins 1-8 to adjust my gain and keep it scratch free. I am posting a modified schematic. Please comment if you see any mistakes.

2. I would have never thought using the speaker output itself to do such modulation can a Tremolo effect. WOW!

3. I heard the YT samples and I was blown away! If appears that a great amp will sound bad through a small/cheap speaker, while a basic amp will sound OK via, if not good enough, via a nice 4x12" cabinet.

4. In Greek the book you were looking for is "Ο Μικρός Πρίγκηπας" (o Mikrós Prínkipas) and the bread you asked for was not pizza but probably some kind of "πίττα" meaning some kind of variation of the famous "pitta" bread widely found in in the USA in those fast-food places selling gyros. BTW, "γύρος",  means when something goes around completing full 360 degree revolutions. You've seen how they cook "gyros", right?

5. I still have not made the connection why you are "torturing" yourself with learning Chinese but since I cannot help you with that I can only wish you "good luck", I admire you! If you ever want to brush-up on your Greek, you know who's your tutor gonna be! :tu:

Ηasta la próxima vez!

--
Δημήτριος Παναγιωτίδης του Γεωργίου
PS: Τhat's my full name, so now you know why the abbreviated Dimi Pana
« Last Edit: October 30, 2011, 02:15:36 PM by Dimi Pana »

J M Fahey

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Re: Noisy Cricket problems!
« Reply #23 on: October 29, 2011, 02:25:13 PM »
Well, let´see by heart, not cheating by looking it up anywhere (and forgive the mistakes)

Δημήτριος would be Dimitrios

Παναγιωτίδης would be Panationis

του ??? this one beats me

Γεωργίου would be Georgiou

..........
close enough?

I´m just using the "Spanish built in" Greek I used to read road and shop signs, menus, and deciphering newspaper headlines.

A special mention apart for Greek women: for a Classic tastes (in the literal way) guy like me, I was blown away by having classic beauty statues ... *alive* , moving around, clad in jeans and t-shirts.
Only problem? ... they tried to be "too American" ...... fine but didn´t fit them as well as Classic clothes would.
Oh well.
And when they speak .... oh my God .......

Dimi Pana

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Re: Noisy Cricket problems!
« Reply #24 on: October 29, 2011, 02:58:37 PM »

Δημήτριος would be Dimitrios

Παναγιωτίδης would be Panationis

του ??? this one beats me

Γεωργίου would be Georgiou

..........
close enough?

You got 3 our of 4, that's impressive!

The "του" word is a declension of the singular form of the masculine article, in the genitive case (i.e. possesive). It basically means "of the". Thus my name is: 1st name Dimitrios (meaning, I was named after the Christian orthodox Saint Dimitrios), 2nd name Panagiotidis (that's my family name which -simplified- means the decendants of Panagioti who was my great-great grand father) and 3rd name (of the) Georgios (meaning that my father's 1st name is Georgios). According to Greek culture we name our children after their grand father/mother's names, which -you guessed- creates ever more complicated combinations.

I agree about the external quality or the greek women, and I am with you 100% on their pointless and futile desire to look less "Hellenic" and more American. But what can you do? Nothing... Can't live with can't live without them. Luckily, for the time being I am taking a hiatus from Greek women. Living in the US -definitely- gives one the advantage to be ethnically more ...selective.

--

BTW, any comments on the modified schematic? Let's not forget what we're here for eh!  8|

'Till later!   

J M Fahey

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Re: Noisy Cricket problems!
« Reply #25 on: October 29, 2011, 04:19:01 PM »
Thanks.
Do not join pin 7 to 5 *at all* and use 10uF instead of 100nF.
You´ll be able to get or surpass the You Tube sounds.
The tone control will have little if any effect, because it has a 100K pot working against a 10K volume pot.
It will do nothing most of the way, and suddenly work in one end, more like a switch than a potentiometer.
The tone pot in your guitar will work much smoother and better.
Good luck.

Dimi Pana

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Re: Noisy Cricket problems!
« Reply #26 on: October 29, 2011, 04:38:10 PM »
C3=10μF and no pin7-5 circuit at all.

Shall we say this is FINAL?

(at least for today?) :D

J M Fahey

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Re: Noisy Cricket problems!
« Reply #27 on: October 29, 2011, 07:37:07 PM »
Yes, it´s fine, it will work as intended.
Now you build it and post MP3s and pictures to help others in the future.
Good luck.

Dimi Pana

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Re: Noisy Cricket problems!
« Reply #28 on: October 30, 2011, 02:47:27 PM »
Hello all!

Ι was building the NC today and I think I got a little impatient (i.e. careless) towards the end, I believe I "fried" the MPF102 with too much soldering heat. I wish I'd bought a socket for it, just like I did for the LM386 IC. I mean there is a socket for this part, right?

I bought my parts from RS (radio shack) and that particular store did not have a socket for the transistor. I mean the attendant in the store I went (Rt. 83 in Des Plaines) probably knew less about electronics than -even- me... I don't know, from the first time I stepped into a RS, it did not feel right somehow.

So, anyone from the Chicagoland area? Do you know a decent and novice-friendly (yes, that's me!) retail electronic parts store?

Thank you!     

J M Fahey

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Re: Noisy Cricket problems!
« Reply #29 on: October 30, 2011, 05:53:46 PM »
Unfortunately most shops (not only Electronics) are like that, they hire the cheapest help available.
Don´t worry about the socket, solder a new Fet there.
Or do what Phatt suggests, buy a protoboard and experiment there; commit the project to PCB (or perfboard) only after you are happy with it.

 

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