Hi guys,
Has anybody else had any problems with their hats and cymbal voices? On my unit, both sound more 'ringy' than they should; I can hear a ring-mod-type, metallic sound and not much noise. The envelopes work fine, the voices just sound a bit off.
I did have a problem with the noise section trimmer voltage and completed the build with a slightly higher than recommended voltage after trimming. Could this be causing the problem? I'm going to sub the wrong resistor out tonight.
The noise in other voices sounds fine, just the hats and the cymbals are off.
Cheers,
Dilli
Hats and Cymbal problems?
Hi Dilli,
You should definately get the noise trimmer voltage correct before proceeding. This sets the noise level, so the niose component could be too loud causing distortion.
Next area to look at would be the adjustment of trimmers TM1* & TM2* in the Cymbal section. These control the width of the pulse from the Schmitt Trigger, and will affect the sound of the Cymbal and Cow Bell. Not sure if they affect the Hats however.
You should definately get the noise trimmer voltage correct before proceeding. This sets the noise level, so the niose component could be too loud causing distortion.
Next area to look at would be the adjustment of trimmers TM1* & TM2* in the Cymbal section. These control the width of the pulse from the Schmitt Trigger, and will affect the sound of the Cymbal and Cow Bell. Not sure if they affect the Hats however.
Thanks for your reply lfo2vco,
I replaced the 4k7 resistor in the noise section with a 47k and got the voltage spot on but no change to the sound of the hats and cymbals. I then realised that the noise section shouldn't be affecting the hats and cymbal too much as their tone is generated with square waves. So, I fiddled around with TM1 and TM2 (Cowbell) but still didn't get a change in the sound of the hats and cymbals; they remain 'ringy', a bit like a ring modulator, or, the sound a Korg Volca Beats makes when you dial the hihat 'Grain' control all the way down.
This makes me think that the square waves that make up the hats and cymbal sound are not interacting the way that they should. I'm reading the TR-808 service manual for some insight but just wanted to know if any of you guys have any other thoughts?
Regards,
Dilli
I replaced the 4k7 resistor in the noise section with a 47k and got the voltage spot on but no change to the sound of the hats and cymbals. I then realised that the noise section shouldn't be affecting the hats and cymbal too much as their tone is generated with square waves. So, I fiddled around with TM1 and TM2 (Cowbell) but still didn't get a change in the sound of the hats and cymbals; they remain 'ringy', a bit like a ring modulator, or, the sound a Korg Volca Beats makes when you dial the hihat 'Grain' control all the way down.
This makes me think that the square waves that make up the hats and cymbal sound are not interacting the way that they should. I'm reading the TR-808 service manual for some insight but just wanted to know if any of you guys have any other thoughts?
Regards,
Dilli
tuning cymbals (crash, hi hat and cowbell) is pain in the ass.
here is the method i used :
using an oscilloscope, i set TM1 and TM2 first.
than i followed the 808 service manual and checked the 2 frequencies of the Cowbell (540 and 800 Hz). i then selected a pattern with cowbell only and using the EQ resonance technique (mixing technique consisting to boost a frequency with an Eq +20dB, resonance at the minimum) i verified that the frequencies of the cowbell were right. they were not, so i tuned by hearing, again trimming TM1 and 2. Start with TM2 as it is louder.
then i switched to the closed hihat and compared to the sound cloud sounds made by yocto. once again i had to tune by hearing. and that was finally done ! cowbell was right, hihat too and crash also.
i then checked the periods on TM1 and TM2 and had less than 1,85 ms (1,78ms) and less than 1,25ms (1,19ms). maybe my scope is out of tune. use your ears
IMO precision potentiometers (multiturn) for TM1 and TM2 would be better.
*NB : measuring 50 Hz EDF is ok with my Hameg oscilloscope
here is the method i used :
using an oscilloscope, i set TM1 and TM2 first.
than i followed the 808 service manual and checked the 2 frequencies of the Cowbell (540 and 800 Hz). i then selected a pattern with cowbell only and using the EQ resonance technique (mixing technique consisting to boost a frequency with an Eq +20dB, resonance at the minimum) i verified that the frequencies of the cowbell were right. they were not, so i tuned by hearing, again trimming TM1 and 2. Start with TM2 as it is louder.
then i switched to the closed hihat and compared to the sound cloud sounds made by yocto. once again i had to tune by hearing. and that was finally done ! cowbell was right, hihat too and crash also.
i then checked the periods on TM1 and TM2 and had less than 1,85 ms (1,78ms) and less than 1,25ms (1,19ms). maybe my scope is out of tune. use your ears
IMO precision potentiometers (multiturn) for TM1 and TM2 would be better.
*NB : measuring 50 Hz EDF is ok with my Hameg oscilloscope