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postive DC in place of negative DC?

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  • #16
    The 7660 drawing is kind of ridiculous, why not show the pin out from the top like normal? The circle that normally denotes pin1 is shown at pin8. Look at a data sheet to confirm your connections.
    Like JM mentioned, the 1044 drawing is normal top view, circle denoting pin1.
    Originally posted by Enzo
    I have a sign in my shop that says, "Never think up reasons not to check something."


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    • #17
      yeah...i know it's been over 6 months, BUT....
      i'm about to tackle this particular idea again and i wanted to clarify some things.
      (as a reminder i'm taking a 4558 distortion circuit that operates w/ +9v on pin 8, and -9v on pin 4 and wanting to change things around so that there is NO negative voltage in the circuit. instead, i will achieve the 18v differential by using a voltage doubler on a standard 9vdc supply.)

      A) my pin 4 (-9v) connections get moved to ground.
      B) my pin 8 (+9v) connections are now +18 and stay
      C) "all points which had a DC path to ground (through a resistor) now will go to the 4.5V bias point", do i have to create this bias point w/ a voltage divider after my doubler circuit, or can i use the +9v rail coming off of my power supply before the doubler? (9v being the bias point in an 18v circuit)
      OR... do i have to use a bias point IN the circuit, like off of one of the chip pins or something?

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      • #18
        It's a personal choice, but *in this particular case*, 9V straight from the battery is a valid "bias point".
        Anyway I´d separate it by going, say, through 10K or 22K and decoupling with 22uF to 100uF to ground.
        Although getting -9V from that battery is about as complex as getting +18V and symmetric rails *do* simplify design.
        Juan Manuel Fahey

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        • #19
          4558可以单电源供电,也可以双电源供电。这些是在芯片的手册中说明的。单电源供电的情况下,只要是给运放的了偏置, 就会正常工作了。

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          • #20
            means:
            4558 single power supply can also be a dual power supply. These are described in the manual of the chip. The case of single power supply, as long as it is put to the transport of the bias, it will work properly.
            Juan Manuel Fahey

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            • #21
              1) It's not immediately clear to me that employing a higher supply voltage in a distortion pedal accomplishes much of use. Indeed, I would think that, while we believe IC-based distortion circuits derive their tone and clipping from diodes and such, at least some of their characteristic tone comes from running up against the voltage-swing limitations of the chip. I'm not even sure we would know what a circuit where everything is clean, except for what the diodes do, would even sound like.

              2) Note that the charge pump will not deliver 18v, but rather double the 9v input, minus what two diodes take away (= roughly 17v).

              3) The risk of audible whine, even with a 1044, is real if layout is not adequately attended to. Is it wise to employ a HF clock of any kind within a circuit that applies substantial gain and risks amplifying clock signal that might bleed through by several hundred times? I'm not so sure. Certainly, the risk is diminished by using a 1044 instead of a 7660 or 7662, but you're still going to want to make sure you have some lowpass filtering on that output.

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              • #22
                Originally posted by liangty View Post
                4558可以单电源供电,也可以双电源供电。这些是在芯片的手册中说明的。单电源供电的情况下,只要是给运放的了偏置, 就会正常工作了。
                Top notch advice.

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                • #23
                  Originally posted by soundguruman View Post
                  Top notch advice.
                  I don't know if I'd agree with that. Why just the other day, someone on TGP noted ",       , ". Of course, they also said "          ", but I'll disregard that for the moment, and give credit where it's due.

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                  • #24
                    您说的意思,基本上就是我想说的。在这谢谢您。不过很高兴,您能看懂中文。我刚刚注册论坛号码不长,而且自己的英语不是 太好。很多朋友们的留言理解的不是特别清楚。但是很想积极的参与进来,和大家成为好朋友。但是我在中国河北,和当地时间 有12小时的时差,很多地方都不方便,很多说的不合适的地方请大家多谅解,在此谢谢大家!这是我自己做的失真效果器,传 个图片给大家看看,希望多指教。Click image for larger version

Name:	SNC00204 (2).jpg
Views:	1
Size:	554.2 KB
ID:	824439(Mean you said, basically, I want to say. Thank you for this. However, very pleased, you can understand Chinese. I just registered number of the Forum is not long, but their English is not very good. Understand the message of a lot of friends is not particularly clear. But would like to actively participate, and we became good friends. But I'm in China, Hebei, and local time, 12-hour time difference, many places are not convenient, many of the wrong place to say more than understanding.This is my own distortion effect, transfer a picture for everyone to see, more advice,Thank you!

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                    • #25
                      Not that much, just cheated and used Google translator.
                      I *am* starting to study Chinese, but still beginning with 你好 , 你是那国人?and very basic stuff like that.
                      I suggest you use Google translate too, posting in Chinese here may be found confusing.
                      Nice pedal.
                      I suggest you label the LED "On" or "Power" and spell the pedal name as "Broken" or "Breaking" Crunch.
                      if possible, post a tutorial on how you printed and attached that front panel graphic.
                      Is it a glued label or you printed straight on the box?
                      I find the edges very smooth.
                      Thanks.
                      Juan Manuel Fahey

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                      • #26
                        My apologies, liangty. We have received many spam posts over the years. By mistake, I thought your original post was one, and made fun of it. I now know you are sincere. Welcome.

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                        • #27
                          ,I used google translator,too。I learn English When I studied in the middle school,until in the university ,about 10 years。but English is not very good…… I am Chinese,( 中国 河北省 唐山市 ) You can find me by the GOOGLE EARTH . I work in Tangshan KaiYuan Panasonic and live in Tangshan City .( 39°41'20.81"N;118°10'8.77"E.) Have you been to China? Where are you?U.S.A?
                          Thanks for you advices! I will change"Breaking".
                          First make the pictures by the Photoshop, Illustrator,and CAD; The second print the pictures by the printer of color , but the paper is a special paper,you can transfer pictures to the metal box. Finally Spray transparent paint and baked dry.
                          Do you have the number QQ or MSN? that you can add me as friend. (My qq number 1397912080 )And we can video call or voice!!

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                          • #28
                            It does not matter. thank you, I would like to become good friend with everyone. We all like the guitar, like electronics, prefer to do the effects pedal. We have expressed in the language difference, but the heart and the music is the same.I am honored to join you.Thank you very much!

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                            • #29
                              没关系,一个说汉语的人在全是英文的论坛留言,是会让大家意外,这不怪你。但是特别感谢你和我说了这些。希望有一天您能 来北京玩,这里离我这很近。还有我想问一下,这个论坛是那个国家的,大伙都是美国人吗?(it does not matter, a Chinese-speaking people in the whole English Forum message, will make all accidents, which do not blame you. But special thanks to you and me to say these. I hope one day you could come to Beijing to play here this close away from me. And I would like to ask that this forum is that country, and everyone are all Americans?)

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                              • #30
                                I had already Googled Tangshan , saw you are South West of Beijing, quite close.
                                As a curiosity, post a couple pictures of your Factory, and yout City ,we always want to know where the stuff we use comes from.
                                What does that Panasonic factory do?
                                If you can give us a personal view of your work there, even better.
                                Personally never been to China ... yet.
                                One of my dreams is to take the full Trans Siberian train trip, end to end: Moscow/Beijing.
                                Now *that* will be an Adventure !!!
                                Juan Manuel Fahey

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