Tonepad TS808 working...sort of.

Started by bubba_b, August 26, 2009, 02:05:33 PM

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bubba_b

Got it all hooked up, played through it and all controls work as they should, but the overall volume with effect ON is very low, about half of what it is when OFF. It may just be the volume thing, but it also sounds a bit muffled, even with all controls maxed out. Here's some voltages I measured:

Battery: 8.36V

JRC4558:
1 - 4.15v
2 - 4.25v
3 - 4.16v
4 - 0.00v
5 - 4.15v
6 - 4.15v
7 - 4.15v
8 - 8.36v

3904's:

Q1:
C - 8.36v
B - 3.125v
E - 2.615v

Q2:
C - 8.36v
B - 3.130v
E - 2.620v

Positive side of 47uF elec. cap = 4.16v
Positive side of 10uF elec. cap = 2.62v

Using 2 zener diodes for symmetrical clipping.

Also, I ordered 1uF/Non-polarized caps, but the ones that came clearly have a negative pole stripe down the side and a longer positive side leg. If inserted correctly, should they work anyway? Like I said, I get sound and effect, just very low output.

Anything else I need to check?

kurtlives

Your voltages are fine.

You sure you are using the right values for all the pots? Didn't know Zeners work as clippers....
My DIY site:
www.pdfelectronics.com

bubba_b

Sorry, double checked, they're not zeners, they're 1N4148's. The pots are as shown on the layout:

Drive - 500K LOG
Level - 100K LIN
Tone - 20K REV LOG "W" (from Small Bear)

Still wondering about those NP caps...

kurtlives

Non polarized caps will work fine.

If they do happen to be polar they nee to have the right polarity.
My DIY site:
www.pdfelectronics.com