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Old 9th November 2013, 01:55 PM   #21
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at 22k on the input me thinks your loading the guitar's pickups pretty heavily don't decrease the input resistor increase it (it might require redesigning the input stage)
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Old 9th November 2013, 04:43 PM   #22
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Originally Posted by turk 182 View Post
at 22k on the input me thinks your loading the guitar's pickups pretty heavily don't decrease the input resistor increase it (it might require redesigning the input stage)
I would suggest the input impedance is probably nearer 122K than 22K, the base of the first transistor won't be a virtual earth (as with an opamp).
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Old 15th November 2013, 09:27 PM   #23
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Thanks, gents, I got it to work fine now, there was an error in the schematic. On the paired transistors (Q4 & Q5), the resistors going from the bases to rail should both be 100k, and the two to ground both 22k. It showed two of them in the wrong place (the upper left and lower right were switched). Should have been obvious when looking at it. I also saw another alternative that has a .002 uf cap in parallel with the 47k resistor at the collector of Q1, and the resistor going to the base of Q3 as 150k, where mine was 270k (as in the schematic I posted). Do you think changing these would have any effect? I guess maybe I should quit while I'm ahead, I'm sure my musician friend will enjoy this once I get the time to send it out.
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Old 20th November 2013, 06:12 AM   #24
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Voodoo alert - boy haven't some of the fellows above been careful not to offend anyone even when they a convinced that they are talking crap.

What is the difference between a battery and a capacitor AC wise?
Answer NOTHING, the battery is just a bloody big capacitor.

Why did the dud cap in the quoted remote control cause the battery life to go to weeks instead of years? Because the cap did not go O/C (open circuit) but rather went seriously leaky.

Why put a cap across a battery? - well in digital stuff it is to retain user settings while the battery is changed.

frank754 - Glad you got the box working - did you in fact include the totally redundant electrolytic across the battery or leave it out?

Cheers,
Ian
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Old 20th November 2013, 09:07 AM   #25
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Originally Posted by gingertube View Post
Voodoo alert - boy haven't some of the fellows above been careful not to offend anyone even when they a convinced that they are talking crap.

What is the difference between a battery and a capacitor AC wise?
Answer NOTHING, the battery is just a bloody big capacitor.
I suggest you try studying Electronics a bit longer

Quote:

Why did the dud cap in the quoted remote control cause the battery life to go to weeks instead of years? Because the cap did not go O/C (open circuit) but rather went seriously leaky.
Not at all, although it's VERY rare such capacitors going leaky does occur occasionally, but that wasn't what I was describing. I was describing the effect of the capacitor going O/C, or (in a few cases) never being fitted during manufacture.

Quote:

Why put a cap across a battery? - well in digital stuff it is to retain user settings while the battery is changed.
Because it's an absolutely vital component, and that suggestion is ludicrous
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Old 20th November 2013, 11:48 PM   #26
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Originally Posted by Nigel Goodwin View Post
I suggest you try studying Electronics a bit longer
Good advice - I study Electronics every day in my job as an Electronic Design Engineer.

Even after 3 years as an Apprentice, 10 years as a Tech and University Courses, then another 25 yeras as a Design Eng and some Post Grad Study there is always something new we can learn or possibly something old we can un-learn.

Cheers,
Ian
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Old 21st November 2013, 01:19 PM   #27
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frank754
could you please re-post the schematics with transistors numbered
i couldn't figure out the component swap you mentioned in post #23
just trying to learn.
thanks
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Old 21st November 2013, 02:07 PM   #28
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I don't know about the battery life aspect, but certainly as a general design rule having a bulk capacitor off the power supply and other smaller caps on the power rails near current consumers is a good thing. Reducing return path loops is always a good thing (in analog and digital design).
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Old 21st November 2013, 03:50 PM   #29
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Originally Posted by gingertube View Post
Good advice - I study Electronics every day in my job as an Electronic Design Engineer.
And yet you don't consider power supply decoupling capacitors essential? - presumably you've never heard of the internal resistance of a battery then?, or how it increases rapidly as the battery runs down?.

I'm just totally bemused that someone who claims to be an Electronic Design Engineer doesn't understand first principles?.
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