2000gtl

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redlght
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2000gtl

Post by redlght »

When i do this part of the mod C102 Change to a 910pf ceramic disc the audio gets choppy on sideband if i take out that cap it sounds the same if i put the oem back in it sounds fine. does this cap make a big diff in the outcome if so why would it make my radio's audio trashy? Thanks
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Goldfinger
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Re: 2000gtl

Post by Goldfinger »

C102 is for positive feedback in the first amp stage. The stock cap gives the circuit a rising response from 800hz and up. Making it lower in value takes away the midrange boost and raises it to 3000hz and up. In other words there is gain at treble frequencies only and no longer at midrange. Lowering gain in the midrange shouldn't make it "choppy". I've never heard of anyone having any problems with this mod. If you don't like it, feel free to experiment.
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redlght
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Re: 2000gtl

Post by redlght »

rest of the mod seems fine just that one cap change the 910 if i make a steady sound into the mic it get choppy the original cap corrects it dont know why
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Re: 2000gtl

Post by Goldfinger »

I originally changed this cap to suppress the mid-bass and low midrange. On AM, the radio is muddy/boomy with a stock mic and needed more highs to compensate. lowering the value of C102 helped.

The values I post here are not set in stone, so always feel free to try different values and experiment on any of the caps.
I have actually started using 4.7uF caps on all of the series caps for even more bass. Then I change C182 to a .01 to even out the highs.
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redlght
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Re: 2000gtl

Post by redlght »

Which ones do you swap out to 4.7?

C46 2.2uf
C101 1.5uf
C102 910pf
C104 2.2uf
C108 2.2 uf
C71 1uf
C75 .001 to .0001uf
C76 2.2uf
C182 .001 to .0001
C183 2.2uf
C187 2.2uf
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Goldfinger
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Re: 2000gtl

Post by Goldfinger »

C101, C104 and C108
I use two 10uF in series with the negatives tied together to make a 5uF non-polarized on C46.

426 put the wrong value range on C182.
426 wrote:C182 Change to .001 to .0001 for more highs on rx and tx
optional
It should be: C182 Change to .01 to .001 for more highs on rx and tx
optional.

I'll edit his post.
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Re: 2000gtl

Post by redlght »

Could of got choppy because i had a .0001 in for C182?
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