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Re: r 151 accent resistor burns
Posted: Nov 10th, '14, 09:10
by pato
I see what you are refering to, EchoBoy, the man who was trying to resell counterfeit IC from Shenzen to the US Navy is now in jail.
http://www.adnas.com/company-blog/caugh ... s-channels
For the future of electronic business and DIY and hobby projects,please try to avoid this....
Re: r 151 accent resistor burns
Posted: Nov 30th, '14, 09:12
by EchoBoy
Some said that they replaced the CD4011BE by a CD4011UBE. BAD IDEA !
The length of the trigger pulse (TRIG) will be shortened with a CD4011UBE, which will modify the attack of the bassdrum and some other instruments.
It is recommended to keep a CD4011BE. You may have to adjust R102/C27 to ensure that the TRIG pulse length is 1 ms.
Re: r 151 accent resistor burns
Posted: Dec 2nd, '14, 00:32
by rv0
EchoBoy wrote:Some said that they replaced the CD4011BE by a CD4011UBE. BAD IDEA !
The length of the trigger pulse (TRIG) will be shortened with a CD4011UBE, which will modify the attack of the bassdrum and some other instruments.
It is recommended to keep a CD4011BE. You may have to adjust R102/C27 to ensure that the TRIG pulse length is 1 ms.
Interesting.
What about CD4011BCN ?
Re: r 151 accent resistor burns
Posted: Dec 2nd, '14, 15:09
by peristilius
EchoBoy wrote:Some said that they replaced the CD4011BE by a CD4011UBE. BAD IDEA !
The length of the trigger pulse (TRIG) will be shortened with a CD4011UBE, which will modify the attack of the bassdrum and some other instruments.
It is recommended to keep a CD4011BE. You may have to adjust R102/C27 to ensure that the TRIG pulse length is 1 ms.
I didn't change any components, but I think the attack on my BD is a bit weak, also my rimshot is really short, could this be related to the trigger pulse?
Re: r 151 accent resistor burns
Posted: Dec 2nd, '14, 22:45
by EchoBoy
The Rimshot sound is quite short: ~15 ms. I don't think the TRIG pulse length has much impact its length.
The TRIG pulse length has an impact on the BD since it the oscillator frequency changes while the TRIG is active. When the TRIG pulse ends, the frequency suddenly changes.
The short duration of 1 ms at a higher frequency + the frequency shift at 1 ms creates specific harmonics.
If you shorten the TRIG length to 0.5 ms for instance, the sound will be closer to a Jomox kick (sharper, higher harmonics) than a TR-808 kick.
Regarding the choice of CD4011BCN, you need to take a look at the corresponding datasheet. But since its I/O current range significantly varies between typ and max, I would recommend to measure the actual length of the TRIG pulse and adjust the R102/C27 to get a 1 ms pulse.
For instance, my TRIG pulse was 0.5 ms with a CD4011UBE and 0.8 ms with a CD4011BE. I then increased C27 to 1.2nF to get a 1 ms pulse with the CD4011BE.