Circuitbenders Forum

Circuitbenders Forum => Drum machines => Circuitbending discussion => circuitbenders.co.uk CB55 - DIY Boss DR55. => Topic started by: DavidKatz on November 17, 2020, 02:50:49 PM

Title: Verifying sounds.
Post by: DavidKatz on November 17, 2020, 02:50:49 PM

Hi,

I hate for my very first post to be one for help.

After a few hours of checking my CB55 only to find out the transistors installed had the wrong pinout, they were 2SC945 ordered from Tayda but base and collector were wrong, lesson learned, always check the datasheet.

Can somebody confirm whether my board sound right? the hat doesn't to me but I have uploaded a short video testing each, yes I did adjust UR1 and UR2 but not much improvement.
I'm not sure about the Accent pin on Trig_IN1 pin 5 either but it works when I adjust the pot.

https://youtu.be/85fFq262R2g

I appreciate any feedback/comments.

Cheers
Dave.

Title: Re: Verifying sounds.
Post by: Circuitbenders on November 18, 2020, 11:57:14 PM

For a start you have the bass and snare the wrong way round in that video!  ;)

Have you got the correct value in VR2? If i recall correctly adjusting VR2 should stop that squeal happening on the hats.
As it says in the build guide:
"The noise level for the hat and snare sounds is adjusted using VR2. We'd recommend using a decent quality trimmer for this as theres sometimes a fairly thin range of adjustment between the noise level being too quiet, and it starting to resonate strangely."

Title: Re: Verifying sounds.
Post by: DavidKatz on November 19, 2020, 08:02:58 AM

I appreciate your feedback.

Oh yeah, I have the green and yellow cables crossed over  :-[

That was the best sound I got from adjusting VR2, it only got worse, I’m sure it’s the correct value but I will double check later and order a new one regardless from a more reputable supplier.

Cheers
Dave