ThorpyFX Fallout Cloud (formerly knows as Muffroom Cloud)

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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Cub
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Post by Cub »

Hello lads, :D

I know it's "merely" a Triangle Big Muff at heart, but the active two band EQ and the exceptionally low amount of hiss has sparked my interest. Has anybody had a peak inside ?

Attached is the only gut shot of I could find, but it's not very helpful. Here's a video the Thorpy pedal compared to other Muff clones and an original Triangle, they get to the Cloud at around 23:35.

cheers :thumbsup

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IMG_7176.jpg
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Post by thorpy6 »

Well I have :) seeing as i build them.

As a small builder, I won't lie, I am worried sick about seeing my schematic out there, I know that won't stop people. But to be honest its not this scene that worries me, hey I've enjoyed building pedals for myself over the years. Its the lurkers that reside in big nameless companies overseas that mine this place for resource that worry me. We've all seen it happen to Paul Cochrane, and many more besides.

It isn't a clone and the "magic" if there is such a thing is in the EQ and build standards I adhere to (particularly the low noise).

Anyway, thats probably not helpful and i guess not really what this place is about so I apologise for that.
Owner and chief Solder wielder at ThorpyFx

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Post by Cub »

Hello Adrian, I had no idea you were a member here!

Certainly, I can respect that you want to keep it under your hat about what's going on in the cloud. But to be honest, I really don't think you need to worry that much. If a company overseas wanted to produce a cloud clone, it's more likely that they'd buy a pedal from you, rather than sit around and wait for a schematic to pop online.

If they didn't want to invest in a pedal from you to duplicate and prefer to just lurk on FSB, our forum brother Chris (mictester) shared a couple of great Muff projects that feature a passive James EQ. The Big Muff Plus and its more tricked out cousin, the 21st Century Big Muff.

Should a trace of the cloud do make its way online, then I say there's still no reason for you to lose any sleep. Marc from Skreddy in California has been very forthcoming with schematics and information about his products on this forum, yet the only clone of his work I can think of is made by a company in Michigan. (Skreddy P19 = Mojo Hand FX Iron Bell)

Thank you for replying and good luck with your business! :thumbsup
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Post by PMowdes »

thorpy6 wrote:Well I have :) seeing as i build them.

As a small builder, I won't lie, I am worried sick about seeing my schematic out there, I know that won't stop people. But to be honest its not this scene that worries me, hey I've enjoyed building pedals for myself over the years. Its the lurkers that reside in big nameless companies overseas that mine this place for resource that worry me. We've all seen it happen to Paul Cochrane, and many more besides.

It isn't a clone and the "magic" if there is such a thing is in the EQ and build standards I adhere to (particularly the low noise).

Anyway, thats probably not helpful and i guess not really what this place is about so I apologise for that.
Do you make them all personally by hand or do you have a team of solderers??

Nice to see some top quality products coming out of the southwest, I've managed to find a small number of fellow builders in and around Bristol and am hoping to have a soldering get together soon.

Good luck, and I hope that no one discovers your magic anytime soon.

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Post by thorpy6 »

PMowdes wrote:
thorpy6 wrote:Well I have :) seeing as i build them.

As a small builder, I won't lie, I am worried sick about seeing my schematic out there, I know that won't stop people. But to be honest its not this scene that worries me, hey I've enjoyed building pedals for myself over the years. Its the lurkers that reside in big nameless companies overseas that mine this place for resource that worry me. We've all seen it happen to Paul Cochrane, and many more besides.

It isn't a clone and the "magic" if there is such a thing is in the EQ and build standards I adhere to (particularly the low noise).

Anyway, thats probably not helpful and i guess not really what this place is about so I apologise for that.
Do you make them all personally by hand or do you have a team of solderers??

Nice to see some top quality products coming out of the southwest, I've managed to find a small number of fellow builders in and around Bristol and am hoping to have a soldering get together soon.

Good luck, and I hope that no one discovers your magic anytime soon.
it was just myself and then my wife got on board and we also have another part time solder jockey too. Its a small team but I love building and love the fact that my products are being used all around the world. its pretty cool tbh and it allows me to have a job that I love.
Owner and chief Solder wielder at ThorpyFx

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Post by PMowdes »

That's so cool that you've managed to make a go of it, I'm massively envious. I've been designing and making my own pcb's for a while but I can never get the enclosures to a good enough standard to sell anything.

If you ever need a spare pair of hands anytime let me know, I'd be happy to help.

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Post by modman »

thorpy6 wrote:Well I have :) seeing as i build them.

As a small builder, I won't lie, I am worried sick about seeing my schematic out there, I know that won't stop people. But to be honest its not this scene that worries me, hey I've enjoyed building pedals for myself over the years. Its the lurkers that reside in big nameless companies overseas that mine this place for resource that worry me. We've all seen it happen to Paul Cochrane, and many more besides.

It isn't a clone and the "magic" if there is such a thing is in the EQ and build standards I adhere to (particularly the low noise).

Anyway, thats probably not helpful and i guess not really what this place is about so I apologise for that.
Hi Thorpy6!

Really surprised to see this because you profile makes it clear you have been a member of freestompboxes.org since 2008. If your are scared sick about seeing your schematic out there, you could have known better. You even contributed a few bucks toward our tracer's fund set up to bust open the Klon, some Peter Cornish and the like. I always thought that freestompboxes would defer people from starting a pedal business, but quite the opposite is true. However those who did come out of the DIY scene to become big brands didn't do so with the 90s idea of the magic schematic.

Seeing as you state this yourself, I do encourage to share the schematic, pressure is building hard. The price of fame...
Anyway, take care...
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Post by SpencerPedals »

modman wrote: You even contributed a few bucks toward our tracer's fund set up to bust open the Klon, some Peter Cornish and the like.
:shock:

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Post by k.kobain »

I suppose it's triangle muff with modded eq. Any ideas? Sound is nice. From muff to dist territory.

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Post by modman »

Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

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Post by highlifefin »

Take it for what it is, I'd say 95% certainty of correctness(with the caveat that the pcb from Bugg is a correct layout).
Parts count match anyway.
Have had the Pcb for awhile, just been busy and today was my only chance to do some tracing, which I'm at best moderatly good at...ADD and all
Hope it'll do some good.
Fallout Cloud.jpg
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Fallout Cloud.pdf
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NOT an original.

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Post by Cub »

Thank you for taking the time to do this! Apart from the tone control and output stage, it appears to be a mixture of the both the regular Dice Works Muff Diver and the Finale version. Those were based on the V1 72#2 Triangle Big Muff.
No switches on Adrian's pedal, obviously, just imagine they're all in the stock positions. Other differences are BC549C instead of BC327 transistors and a Log pot for the volume.

I attached a couple of schematics from Kit Rae that further illustrate the above, but I should mention that in my own notes about the Dice Works Muff Diver pedals, four resistors are different from what's in Kit's schematic.
I have no reason to doubt Kit's work, so it could be that the schematics I've used to come up with these notes were incorrect? Please do chime in if you can shed some light on this.

R10: 835r reg - 825r Fin
R11: 22k reg - 10k Fin
R13: 22k reg - 12k Fin
R22: 835r reg - 825r Fin
Attachments
Dice Works Muff Diver schematic from Kit Rae
Dice Works Muff Diver schematic from Kit Rae
Electro Harmonix Big Muff Triangle V1 72#2 schematic from Kit Rae
Electro Harmonix Big Muff Triangle V1 72#2 schematic from Kit Rae
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Post by andy-h-h »

Can anyone explain what's happening with the tone control section? I have limited technical knowledge, and I'm confused as to why one side of the treble control connects to the collector of T4.

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Post by Nocentelli »

andy-h-h wrote: 08 Aug 2020, 21:03 Can anyone explain what's happening with the tone control section? I have limited technical knowledge, and I'm confused as to why one side of the treble control connects to the collector of T4.
BOTH pots connect to the collector.
It's a baxandall bass + treble control: Both tone pots have their "cold"/lug1 connected to the output/collector of Q4, their wipers/lug2 connected to the input/base of Q4, and their "hot"/lug3 connected to the output of the previous stage.

A baxandall can cut or boost a range of frequencies determined by the cap values - You can choose appropriate cap values and use a third pot to allow cut or boost of bass, treble AND middle if you so desire, e.g. EQD Talons.

The lug1 connections to the collector will direct feedback from Q4 back into the base: The collector is out of phase/inverted WRT the base of the same transistor, so this is NEGATIVE feedback. You can more easily understand how it works if you analyse one pot at a time: Look at the bass pot - At maximum rotation (full bass boost), the output from Q3 goes through a 10k resistor (slight attenuation of all frequencies, but full audio spectrum allowed through) then directly through lug3->lug2 (zero resistance because the pot is max'ed) and through a 33k to the base. At the same time, the bass pot is also applying 100k (plus the 10k on lug1 and the 33k) of resistance to the negative feedback via lug1->lug2->Q4 base. Increasing resistance here reduces the amount of negative feedback, therefore increases the gain of Q4 (this is how opamps work).

But why is it BASS control? The 22n cap across the pot will short/bypass the 100k pot resistance for all but the lowest frequencies (i.e. higher frequencies in the feedback signal are NOT attenuated) so higher frequency feedback is large (and so not boosted) but lower frequencies in the feedback cannot bypass the pot, feel the full 143k resistance and are therefore significantly boosted as they pass through Q4.

You can see the same thing going on for the treble control, but with the caps arranged to select the highest frequencies. The 2n2 cap from the Q3 output cap (4u7) means that only very high frequencies can pass into lug3 of the treble pot, through lug2/wiper and on into the base via that 10k fixed resistor. If the treble pot is max'd, there is also a large resistance between the collector and base through lug1+2 of the treble pot, but this time the (2n2) cap in the feedback path is in SERIES with the pot resistance (not in parallel like the bass pot): This means that only the highest frequencies in the feedback signal make it through this pot back to the base and therefore only higher freqs are boosted when the pot is rotated clockwise.

When the pots are turned counterclockwise, the reverse effect occurs: The input signal from Q3 is attenuated by larger resistances between lug2 and 3 of each pot, AND the amount of frequency-specific negative feedback allowed through is increased by the reduced resistance between lug1+2: There is therefore a major cut in those frequencies.

You can get a similar effect without using a gain stage (by connecting each lug1 to ground instead of the output) and this is called the James tonestack: It is effectively a "passive Baxandall" tonestack. This retains some of the benefits (e.g. there is not much interaction between the two controls like you get with the standard Fender/Marshall/Vox amp tonestack) but it cannot actually boost any frequency above the level that existed at the input to the tonestack.

TLDR: This is a baxandall tonestack: Frequency-specific pots can both cut and boost selected frequencies using negative feedback
Steven_M wrote: 21 Jan 2011, 17:52
biffa wrote: Sorry,but u r not the only member here

I'm not? Well fuck this site then. I only want meaningful conversations with myself.

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Post by andy-h-h »

Awesome :thumbsup Thank you for taking the time to post a detailed explanation. I noticed some similarities to the Colorsound Power Booster, which also has bass and treble controls in a similar configuration.

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Post by Ichabod_Crane »

There's just a missing value one it: R15. Maybe 82R.
I emulated that schematic. It doesn't have the mid scoop because it was in the classic Big Muff tone control.
Is there some easy trick to get a scooped mode option?

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Post by andy-h-h »

Ichabod_Crane wrote: 10 Aug 2020, 08:04 There's just a missing value one it: R15. Maybe 82R.
I emulated that schematic. It doesn't have the mid scoop because it was in the classic Big Muff tone control.
Is there some easy trick to get a scooped mode option?
Based on the parts lists / count on the pedal pcb build doc, looks like 820 ohms.

PS, I did a vero layout tonight. Checked it a few times, looks OK. UPDATED: missed a cut

Image

And for some reason I though P2P would be a good idea too... :scratch:

Image
Last edited by andy-h-h on 12 Aug 2020, 08:14, edited 1 time in total.

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Post by Nocentelli »

Ichabod_Crane wrote: 10 Aug 2020, 08:04 Is there some easy trick to get a scooped mode option?
With a baxandall, with both treble and bass controls at maximum (and the volume reduced a little) you will get a mid "scoop"; both controls at minimum (and a little more volume) should sound like a mid "boost". In both scenarios, the mids level is actually unchanged but the relative levels of bass and treble give the perception of boost/cut if the volume control is also used the compensate for the overall level change.
baxandale-response.jpg
Steven_M wrote: 21 Jan 2011, 17:52
biffa wrote: Sorry,but u r not the only member here

I'm not? Well fuck this site then. I only want meaningful conversations with myself.

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Post by EmmG »

The Catalinbread Manx Loaghtan was another Muff with Baxandall EQ.

The manual gave some suggested settings to get close to triangle and rams head mid scoops. https://catalinbread.com/pages/manuals

Thanks for the good explanation on the tone control too. I've really liked it on other builds like the Colorsound and Xotic drives.

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Post by Ichabod_Crane »

Nocentelli wrote: 11 Aug 2020, 12:43
Ichabod_Crane wrote: 10 Aug 2020, 08:04 Is there some easy trick to get a scooped mode option?
With a baxandall, with both treble and bass controls at maximum (and the volume reduced a little) you will get a mid "scoop"; both controls at minimum (and a little more volume) should sound like a mid "boost". In both scenarios, the mids level is actually unchanged but the relative levels of bass and treble give the perception of boost/cut if the volume control is also used the compensate for the overall level change.

baxandale-response.jpg
Thank you, I knew it. I just I wonder if with the Baxandall transistors based there was an easy mod to create a mid bump or a mid cut without adding another band. Maybe is not possible. That's ok, I was just a bit curious. :wink:

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