Noise section trimmer voltage?

Acid303 wrote: 1st: Print the "Detail Yocto Kit v1.0" from Downloads
2st: Count all parts (resistors etc.) and seperate them (Mark them on the "Detail Yocto Kit v1.0" that they are complete. Put each value in an extra bag (4.7k in a bag, 47k, 470 and so on)
3rd: One part after the other: I/O board: check if you get all necessary voltages (-15v, +15v, 5v and ground). If that is correct go to noise section.

I don't wanna say that the other ones who have problems have made mistakes but i just can tell my experience. Be very careful. At the beginning I checked every resistor with my voltmeter.

+1 for all of this.

In the excitement of getting it all done, it's easy to look at capacitors/resistors in a bag, see a value and assume that they are all the same value, especially with how easy it is to confuse red and orange rings on a resistor..

I'm now checking values as they are taken out of the bag, then checking them again with an online value calculator *and* a meter before they are soldered in.

Better to do it once slowly than do it once fast and then again even slower

That said, I'm still not getting a correct voltage at the noise trimmer pot, after going through and checking all resistor values with a meter, and double checking all the capacitors are correct. +15/+5/-5 voltages have been fine all the way through, bassdrum finished last night.

That said, I'm still not getting a correct voltage at the noise trimmer pot, after going through and checking all resistor values with a meter, and double checking all the capacitors are correct. +15/+5/-5 voltages have been fine all the way through, bassdrum finished last night.

Sorry, but you wrote +15/+5/-5 ? Correct is +15/-15/+5V

and just to be sure...the 130mV in AC on your meter

This is how I organized my build:

I labeled one page per section ("HiHats" in the photo) and taped the number of each component to each page in the order shown in the build instructions. When I work on a section, there are no little baggies to search through; it's all on the page. Static-sensitive ICs and transistors I keep separate until needed.

The measurement of the AC voltage isn't exactly by me.
My cheap 4 digit shows 130mV,
A expensiv and calibrated 6 digits DMM Shows 250mV but in AC mode it changes every second to a other value near 250mV.
A new digital Oscilloscope shows arround 150mV.
Have inserted a 68k resistor to have enough space for the trimpot.

effegee wrote:This is how I organized my build:

I labeled one page per section ("HiHats" in the photo) and taped the number of each component to each page in the order shown in the build instructions. When I work on a section, there are no little baggies to search through; it's all on the page. Static-sensitive ICs and transistors I keep separate until needed.

Good idea - saves buying a load of little bags

Acid303 wrote:
That said, I'm still not getting a correct voltage at the noise trimmer pot, after going through and checking all resistor values with a meter, and double checking all the capacitors are correct. +15/+5/-5 voltages have been fine all the way through, bassdrum finished last night.
Sorry, but you wrote +15/+5/-5 ? Correct is +15/-15/+5V

and just to be sure...the 130mV in AC on your meter

Ah yes 15, -15 and 5v...

Measurement Info for 130mV

from the Roland Servicemanual is the 130mV RMS (with measurement technology in 1981)

its a noise waveform, the peaks are different.
its a difference in measurement between TRUE-RMS, RMS and cheap DMM without RMS..
RMS is only exact on SINUS signals
TRUE RMS are better as RMS and handle all signal forms - but its a mathematical function and you have to respect this tolerances.
from my POV: the best choice is a oscilloscope and for doublecheck a TRUE RMS multimeter

here you find a graphic from AC RMS measurements with different DMM:
http://www.radiomuseum.org/forum/die_me ... e_rms.html

Patrick wrote:Measurement Info for 130mV
from my POV: the best choice is a oscilloscope and for doublecheck a TRUE RMS multimeter

I have a question and please excuse my ignorance in these matters if it proves to be a bit dumb.

My Multimeter cannot show AC Millivolts, so can I safely use a software Oscilloscope on my computer? The input would be via the soundcard.

lfo2vco wrote:
Patrick wrote:Measurement Info for 130mV
from my POV: the best choice is a oscilloscope and for doublecheck a TRUE RMS multimeter
I have a question and please excuse my ignorance in these matters if it proves to be a bit dumb.

My Multimeter cannot show AC Millivolts, so can I safely use a software Oscilloscope on my computer? The input would be via the soundcard.

Your soundcard oscilloscope must have a calibration /specially voltage regulation.
Or you must feed a 1v signal to get a voltagebaseline on your pc.
A analog oscilloscope cost arround 50€ on ebay and its a must have for troubleshooting

Just another question for clarification, as I am also measuring approximately 260mV at least (and I am absolutely sure that I did not pick the wrong parts (R127 is 4.7k for now):

Is it really correct to change R127 already now to 47k, at this point, even if the Noise part is the only part finished so far (besides the Power Supply of course)? Wouldn't the value measured change under load (i.e. if the rest of circuits are finished)? In that case I would continue building the rest first and check again at the end. But if I am getting this wrong and the value does not change under load, it would make sense to change the value now.

When did you guys change your R127? Right at the point you measured for the first time or after everything was built?

How should I proceed?

Cheers,

jmx.