0

x0xb0x jumps a few in between G# & A keys
Moderators: altitude, adafruit_support_bill, adafruit, phono, hamburgers

Please be positive and constructive with your questions and comments.

x0xb0x jumps a few in between G# & A keys

by will.moindrot on Wed Feb 01, 2017 3:22 pm

Hi,

I have sent an email to sound-imperium from where I bought my kit from but wondered if any folks on here would have any ideas or seen similar.

I put together my x0xb0x last year from kit. Unfortunately I have found there to be an occasional problem seen here: https://youtu.be/FhqGajcDi14

What I see is that in the middle octave, there is a jump between the G# and A key on the keyboard. If I control the b0x through midi the problem is also present. I have been able to fix things in the past by opening it up and using a tool to prod/touch the components, so I think it is probably a bad solder joint, but I have not been able to locate it. Any ideas?


Many thanks, Will
will.moindrot
 
Posts: 7
Joined: Mon Oct 22, 2012 6:18 am

Re: x0xb0x jumps a few in between G# & A keys

by MMM on Sat Feb 04, 2017 11:41 am

Hello,
this means that your resistors for the DAC (R74 to R90) are not precise enough. The 1% resistors included with most kits are not sufficient; you need 0.1% precision. If you've accidentally used 5% precision resistors it would be even worse.
Or perhaps one different resistor slipped in there; just check all of them.

Starting with the "A" the highest bit becomes active; if that resistor is a bit out of spec it naturally will affect everything above this.
MMM
 
Posts: 486
Joined: Tue Apr 24, 2012 1:51 am

Re: x0xb0x jumps a few in between G# & A keys

by will.moindrot on Sun Feb 05, 2017 2:52 pm

Hi, thanks MMM.

I saw some of the after posts that others had reported and to which you had replied to so was going to build up a bit of info around this problem to work out which bit and which resistor might be the issue. Had hoped to get a chance to look at it this weekend but the monitor on my PC broke so it's put me back a bit. Hopefully will have a few evenings this week to check all the resistors. It seems to me that all keys lower than A might be too low, and then from A upwards they are correct. I need to check them with a tuner. It

Thanks very much for posting back and I will post on how I get on. Will
will.moindrot
 
Posts: 7
Joined: Mon Oct 22, 2012 6:18 am

Re: x0xb0x jumps a few in between G# & A keys

by will.moindrot on Sun Feb 12, 2017 3:23 pm

Hi MMM, Thanks again for replying. I opened my x0xb0x today, eyeballed the resistors and looked good (1% tolerance),m took the front panel off and resoldered the resistors and it seems to have solved the issue. Best wishes, Will
will.moindrot
 
Posts: 7
Joined: Mon Oct 22, 2012 6:18 am

Please be positive and constructive with your questions and comments.