Marc bareilles MOTM 440 extrapole DG filter mod problem

[lexvortex]

Hi,

Has anyone here built the Extrapole DG mod by Marc B? I have finished it and put onto my filter but with no luck. All 16 positions are lowpass although there are a few variations of lowpass (some of them pretty cool). I'm not sure why it's not working, has anyone run into problems building this addition and can shed some light onto my problem? Also there is no F (I used the texas instruments TIL311) to make 16 different filter types, the LED only goes to E to make 15 types. I've tried replacing all the chips except, the ADC804 and the TL071.

Thanks,
Dave

[djthomaswhite]

I built the Extrapole DG. I have also noticed there is no "true" highpass only type of filter, but you will find many useful variations of lopass and bandpass and highpass together in combination. However, you should have O-9 and A-F. I would start by looking for the error I had on my board.

The PCB, without a solder mask has some really close together traces and they are prone to solder bits bridging them together. Double check each trace. I always hold my PCB up to a halogen light for nice bright trace checking from both sides of the pcb, and in some cases with the light behind the PCB top side helping me to see the outlines and pathways of the traces from the bottom. Once I fixed my tiny solder blob I have normal operations and am glad to have built this mod to get more (as if it was possible) out of my MOTM-440.

Hope this helps,

Thomas

[lexvortex]

Hi Thomas,

Thanks for the info I went and double checked all my solder points and what do ya know, I found a solder bridge. I fixed it and replaced the ADC0804 and now I can get to F (still sounds the same though). I talked to Marc about the filter types and he said that this is normal. All in all I think this is a good mod to do, there are some really cool sounding filter types there!

Thanks,
Dave

[djthomaswhite]

Good news!

Yeah, it is a great mod to do and really adds some interesting character to my favorite LPF of all time.

Thomas

[aerogramma]

hey thomas first of all thanks for the alogen light > pcb trick... it's great advice

i stumbled into this thread because i'm still scratching my head trying to fix my Marc Bareill's Warp633

I knew i had some bridges but since there's a pcb trace between the accidental bridges anyway (bridging the coponents already) i though it'd wouldn't matter... but now your post makes me think.

i'm posting a couple of pictures.. what do you think?



aero

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[e-grad]

If I get you right: You wonder about solder bridges which link parts of cicuit that are connected via a trace anyway. Never mind those bridges.

Probably it's the best to start a dedicated thread to your problem where you describe the problem.

[aerogramma]

hello e-grad
yep that's exactly what i meant

actually i did start a thread about the problem i'm having

http://electro-music.com/forum/topic-29677.html

you're right probably i should've posted my bridge question there


thanks !


aero

[oldenjon]

I'm getting ready to start this project and want to ask anyone who's built it if they would mind posting or sharing pictures of your build for reference? Thanks

[Vo1t]