Hamlet + Tap Tempo and LED

[PhiloB]

Loving this delay but having an issue.  I ordered extra digital pots because I had read there was a 40% tolerance on those jokers.  Auditioned a few and found one that was pretty close: I tap in 120bmp with a metronome and I get 124-126 consistently on the repeats.  The other chips ranges from 138-148 on the repeats with 120bpm tapped.  I can live with that small discrepancy. 
But, the LEDs flash at a different rate than the tap and repeats (slower).  It is very notice able.  Is there a way to fix this?  It is certainly not a deal breaker as it doesn't affect the sound but visually is a little distracting (I'm not usually looking at the pedal when I play so it really isn't a big deal).
Any ideas?

Thanks,
Phillip

[jkokura]

What are the LED CLR's rated at? Also, the type of LED makes a difference. What LEDs did you use?

Jacob

[PhiloB]

I'll have to check the CLR values but I'm sure I used whatever was in the BOM.  I used the diffused red LEDs from Tayda.

[PhiloB]

CLRs were 4.7K

[jkokura]

Try 1K resistors and see if that fixes things. If it's the same, I'm not sure but you might need to try different LEDs, like a diffused or something along those lines. I think the forward voltage matters in this case.

Jacob

[PhiloB]

Thanks Jacob.  I have diffused in there but might try and order from a different vendor.  I'll try the 1k first.

[muddyfox]

Is this the first you've heard of this issue, J.?

I won't be building mine for another month or so but would be curious to know if this led thing can be prevented....

[jkokura]

I'm not sure it's the first I've heard about it. I encountered it myself, and found that playing with the values of the CLR and LED makes a difference. The LED feedback is not quite perfect, largely because there's too much variance between the various LEDs and resistors we used.

I should make a note of this in the Hamlet+ doc. I've been super slammed at work the past several weeks, so that's really put a limit on how much work on JMK PCBs I've been able to accomplish.

Jacob