cowbell sound problem, not the right 808 sound

Check Mate wrote:Hi Guys,
I only have a minor issue with my Cowbell. The Tuning-Range of TM1 is not enough although I already changed the Resistor to a 100k.
I get a C with max Trimmer Setting but I cannot get a good Cis (as it is supposed to be).
Is there anything I can do to extend the tuning range (maybe change the resitor to an even lower value)?

I had to change the 2 x resistors as below to get the correct pitch -

Adjust TM1* up to a period of 1.85ms. If TM1* adjustment range is not large enough for this period change the value of R44 * per a resistor of 100Kohm. (supplied in kit)

Adjust TM2 * up to a period of 1.25ms. If TM2* adjustment range does not allow you to get this period change the value of R45 * per 68kohm. (Supplied with the kit).

@seven
Thanks for your reply but as I wrote above I already cheanged the resitors R44 to 100k and R45 to 68k and I still cannot get a clean Cis out of TR1.
So I'd like to know what I can do to to extend the range of TM 1 even more?!

...is there anybody who can help to resolve the issue? E-Lictronic? It is much appreciated!!

Check Mate wrote:...is there anybody who can help to resolve the issue? E-Lictronic? It is much appreciated!!

Could you post a sound card oscilloscope screen shoot of your measurement?

Best regards,
e-licktronic

Hello, seems to have the same problem, i already changed R44 and R45, i tried after osc mesurement to make it by ear, and it seems that TM1 range, isn t large enough to reach the 808 cowbell sound...Do you have an idea?, is it possible to replace R44 with a lower resistor than 100k ?Or the problem could be something else?
thanks!

Hi Guys,

Patrick was so kind and exchanged Resistor R44 with a Trimmer set to 50k.
I was able to tune my Cowbell to the exact tune of an original 808 (Db / Ab).
With changing Resistor R44 to 50k you should get the same result.
Best,
CM

Here's the link to the sound:

Check Mate wrote:Hi Guys,

Patrick was so kind and exchanged Resistor R44 with a Trimmer set to 50k.
I was able to tune my Cowbell to the exact tune of an original 808 (Db / Ab).
With changing Resistor R44 to 50k you should get the same result.
Best,
CM

I have the same issue with the Cowbell in my Yocto. I would like to know:

1) Was the Resistor on R44 faulty? Do you have a replacement (or new) part number?
2) Can I still use the existing Trimmer or is it required to buy a new one as well? Part number?
3) Did you revert R45 back to the original Resistor or does that need to be 68k for this to work?

Thanks,
Mark

I just tried with a 47 kohm resistors att R44.... (Earlier 68 kohm)..

Still sounds noooothing like my real tr-808. First the Yocto then the 808.

https://soundcloud.com/lostyears/cowbel ... to/s-M757m

So what do I do now?

Changed the Q1 +Q5 transistors to new ones, still the same. (Have no clue what I'm doing)
What next?