HiHat section issue ?

I recently finished my build and noticed something weird about the Hihat section, but actually don't know if it's normal or not.
At first, both closed and open Hihats outputs worked perfectly then after testing and playing with the sequencer I noticed that Open Hihats had a problem with its decay. It sounded like the decay was muted and didn't evolve anymore from noon to full CW.

Then I figured out that it was because closed HIhat has the same step buttons selected than Open Hihat (1 and 9) and it was influencing its decay. It took me a while to figured this out because closed Hihat output level was at 0% (Full CCW). This why I think it is an issue.

Here is a sample of the open Hihat with step button 1 and 9 selected and decay button turned Full CW + closed Hihat with step button 9 selected but with output level at 0% (Full CCW) : https://soundcloud.com/roots_vibes/openhihat-issue01

Another sample but this time with closed Hihat with step button 12 selected (Output level is first at O% then at 100%) : https://soundcloud.com/roots_vibes/openhihat-issue02 ... Open Hihat decay is a bit longer but still muted by the closed Hihat.

So, can anybody confirm if it Is normal or not ?
And if it is not, any idea about where the issue could come from ?
Hope this is clear.

Regarding your second sample, the closed hi-hat always mutes the decay of the open hi-hat. This is normal behavior, even for real hi-hats.

As for the first sample, I do know that the Boss DR-110, also a Roland analog drum machine, produces a "third" hi-hat sound when both open and closes hats are programmed on the same position. It sounds very similar to the sound in your audio sample, so I'm assuming this is normal behavior as well. As far as I know this is done to mimic the sound of a real hi-hat when closing it with the pedal without striking it with the stick.

Thanks ElSchtroumpf for your reply !
I actually didn't know that the Yocto / Tr-808 could emulate the real Hihats by combining Open and Closed Hihat in the sequencer, this sounds logical, but I thought all the instruments, Hihats included, were independent from each other. so, sorry for my ignorance !

Could you or anybody else, try with their own Yocto to reproduce my samples, just to compare and confirm that everything is ok with my build. I'd really appreciate !

A last thing is that the output volume of the Hihat section (Closed + Open) sounds a bit quieter than all the other instruments. Which resistor or component should I change to fixed that ?

You can try to lower the values of R169 and R172, they're both 1kOhm.

Thanks Ikke
So, I was thinking about replacing R169 and R172 with trimmers, this way I can adjust the volume more easily. Any infos about doing this, as trimmer has 3 leads and resistor 2 leads ?
Also which value of trimmer should I take ?

That's also possible.
I would take a trimmer with a value of 1 or 2kOhm.
The wiper is the middle pin and the outer pins are CW and CCW (clockwise and counter clockwise).
So to use a trimpot as a variable resistor you make one connection to one end of the pot (CW or CCW) and the other connection to the wiper.
You only have to use these two pins.
Try to see what happens with your multimeter and you'll figure it out, i'm sure.

Good luck!

Sounds good to me, I'm going to give this a try.
Thanks for the tip !

Just be careful that you don't open the trimmer too much.
It's not a beautiful solution, but maybe it's wise to use a resistor in serie with the trimmer to be sure
that the resistance can't go too low and therefore might damage the Master volume circuit.

Good point !
Thanks

I don't know why i didn't think of this in the beginning....
But if you have all IC's in sockets you could also swap U7 from the Hat section with U4 in the Master section
to see if the problem still exists.
Might be the easiest way to check if it's not the op-amp that's less hot before you start desoldering.

edit*

This seems not the way to make the Hats louder. Please refer to this thread:

viewtopic.php?f=16&t=376