Suhr - Riot

Post by **mxrmxr** » 27 Jul 2010, 19:08

I had a spare few minutes so I went for a degoop

IvIark · Post by **IvIark** » 27 Jul 2010, 19:12

Nice job. culturejam just did it too and I think he needed a couple of values confirming, I'm sure he'll chip in.

sinner · Post by **sinner** » 27 Jul 2010, 19:24

whohoo, clean job! Nice done! Thank you

Steven_M · Post by **Steven_M** » 27 Jul 2010, 21:13

Is this a tube screamer with an op amp buffer and electronic switching?

culturejam · Post by **culturejam** » 27 Jul 2010, 21:19

You did a little bit cleaner job than I did.

Nice work!

I accidentally destroyed C12 when I removed the goop (it got ripped off). Can you measure it in-circuit so we'll have a ballpark idea of its value?

Steven_M wrote:Is this a tube screamer with an op amp buffer and electronic switching?

No. It's more like Guv'nor with a single tone control, three diode clipping options, an op amp buffer, vref biased via op amp, and electronic switching.

I'd love to see someone else trace from these photos and see if you come up with what I did.

chris_d · Post by **chris_d** » 27 Jul 2010, 22:39

Very interesting. Not what i expected from the clips!

Thanks for making the effort!

culturejam · Post by **culturejam** » 28 Jul 2010, 00:17

IvIark wrote:Nice job. culturejam just did it too and I think he needed a couple of values confirming, I'm sure he'll chip in.

Mark, can you figure out from the photo what the SMD package size/code is for C12?

I'd love to get mine put back together for some head-to-head testing.

Grendahl · Post by **Grendahl** » 28 Jul 2010, 04:11

You're my hero!

(Been waiting for a chance to take a stab at this one since it came out)

IvIark · Post by **IvIark** » 28 Jul 2010, 08:27

culturejam wrote:Mark, can you figure out from the photo what the SMD package size/code is for C12?

It looks like a 1210 package to me, assuming the resistor next to it is an 0805. mxrmxr - could you measure and see if C12 measures close to 3.2mm x 2.5mm please?

MoonWatcher · Post by **MoonWatcher** » 28 Jul 2010, 11:58

culturejam wrote:It's more like Guv'nor with a single tone control, three diode clipping options, an op amp buffer, vref biased via op amp,

If it's somewhat Guv'nor based, I like the tonal differences. I never totally liked the LED clippers in the Guv, and it sounds like the Riot has a better combination.

If it's that similar to a Guv'nor with a single tone control, it might be interesting to implement those clipping diodes in a Crunch Box'ish build...

Greg · Post by **Greg** » 28 Jul 2010, 12:22

MoonWatcher wrote:
culturejam wrote:It's more like Guv'nor with a single tone control, three diode clipping options, an op amp buffer, vref biased via op amp,
If it's somewhat Guv'nor based, I like the tonal differences. I never totally liked the LED clippers in the Guv, and it sounds like the Riot has a better combination.

If it's that similar to a Guv'nor with a single tone control, it might be interesting to implement those clipping diodes in a Crunch Box'ish build...

D5,D6 & D7 are smd LED clippers.

Post by **modman** » 28 Jul 2010, 12:26

mxrmxr wrote:I had a spare few minutes so I went for a degoop

Great! For showing true freestompboxes hackers spirit you are rewarded the Degoop Doctor rank. Culturejam already did it, but this is excellent for verification and spotting version changes...

Sweetalk · Post by **Sweetalk** » 28 Jul 2010, 13:24

How do you degoop it?

mictester · Post by **mictester** » 28 Jul 2010, 13:27

Sweetalk wrote:How do you degoop it?

Carefully!!!

culturejam · Post by **culturejam** » 28 Jul 2010, 13:41

mictester wrote:
Sweetalk wrote:How do you degoop it?
Carefully!!!

Yes. Don't do it like I did it.

Sweetalk · Post by **Sweetalk** » 28 Jul 2010, 14:01

mictester wrote:
Sweetalk wrote:How do you degoop it?
Carefully!!!

But HOWWWWWW, the results are very clean.

culturejam · Post by **culturejam** » 28 Jul 2010, 15:59

I'm adding a few photos of mine from the Tracer's Fund degoop process that was started several weeks ago. MxrMxr's photos cover most of what you need, but I also did two shots of the board held up to a strong light source to show all traces at once.

Also included is a PCB layout and schematic drawing from Madbean (called the Uproar). It is verified. Please note that the layout/schematic in the PDF are not *exactly* like the Riot. There are missing cap values, the diode clipper switching scheme isn't exactly the same, and of course there is no relay switching. All in all, it's pretty close, however. I've built it, and it sounds good (and similar to the Riot, as best as I can recall). Also note that the part numbering on the Uproar v1 layout does not correspond to the Riot PCB numbering.

I will finalize my own schematic later on today. It uses the part numbering from the Riot board, and will have the full diode clipping switch options. Honestly, I think what madbean did with the Uproar is more than good enough, but for the purists out there, I'll go the full monty on the switch.

But please, have a look at our schematics and compare to the PCB. We need peer review to verify the preciseness (or not) of our work.

////

culturejam · Post by **culturejam** » 28 Jul 2010, 16:03

Sweetalk wrote:But HOWWWWWW, the results are very clean.

On this particular kind of goop, I was able to slide a very thin knife blade just in between where the goop meets the board. Then I turned the blade slightly and the goop chipped off in large pieces.

The downside is that doing it that way damaged one of the larger SMD caps. The goop was adhered strongly enough to it that removing it ripped off the top part of the cap.

Sweetalk · Post by **Sweetalk** » 28 Jul 2010, 17:01

The schematic is incomplete?, there are some transistors in the PCB that I don't saw in the schematic.

culturejam · Post by **culturejam** » 28 Jul 2010, 17:26

Sweetalk wrote:The schematic is incomplete?, there are some transistors in the PCB that I don't saw in the schematic.

We left out all of the parts related to the relay switching and the other "features". This is just the part of the circuit that makes noise.

But the photos are there so that anyone who wants to draw up the switching and low-battery detection and whatever that slide switch does, go right ahead. They would likely make cool stand-alone project for people to add to their existing pedals.

Suhr - Riot [traced]