Dumbloid  [traced]

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Coma
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Post by Coma »

Instead of going through 23 pages....is the Dumbloid pedal Close to the CJOD? I've built a few of those already.

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thesmokingman
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Post by thesmokingman »

pretty much ... :roll:

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MoonWatcher
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Post by MoonWatcher »

Coma wrote:Instead of going through 23 pages....is the Dumbloid pedal Close to the CJOD? I've built a few of those already.
I'd have to say actually no, because it doesn't really use clipping diodes like the CJOD does, even if there are other YATS similarities.

You'd need a YATS with a no clipping diode setting to have a better idea if it really is that close to CJOD.

It's also been mentioned that the Dumbloid has a really low input impedance. I wouldn't discount the effect of that so much. How often do you see a YATS like that? This is the first instance I'm aware of even if it was probably a mistake.

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Post by AlienSexGod »

mirosol wrote:Yup. The crappy decay is a feature. Which rather funnily makes not only a slight TS derivative, but a bad TS derivative.
Ok but have we 100% this....the original Dumbloid has crappy decay also not sure I heard that on various tube clips?

Is there anyone with some clone boards made up or does there need to be another run for mid 2015? I'd put in for a few. 8)

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Post by AlienSexGod »

OK I found where to order the boards (so many pages ... so little sleep OMG!)
In case someone else is looking order boards here!

https://oshpark.com/shared_projects/HOGyoUdG

If someone could link where the schematic is and provide any recommendations on the build, in one place, that would be great ! :P

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Post by casey73 »

My first post here. I stumbled on the Dumbloid/Big Bloom phenom late last year. The samples I saw on youtube sounded pretty okay. I built mine on a tonepad ts-808 board since I've built quite a few TS varients and have several unused boards. I used the tonepad schematic that had the new Dumbloid values in it. I fired it up this morning, and gotta say I"m pretty disappointed. The tone control has very little effect at all and the voicing control seems only to work from about 2 - 5 o'clock. And, it has lots of gain and distortion, but it really doesn't sound good and has what appears to be a common issue, and nasty farty decay.

So did I do something wrong or is that just the nature of the breast?

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Post by 1oldsidewinder »

casey73 wrote:My first post here. I stumbled on the Dumbloid/Big Bloom phenom late last year. The samples I saw on youtube sounded pretty okay. I built mine on a tonepad ts-808 board since I've built quite a few TS varients and have several unused boards. I used the tonepad schematic that had the new Dumbloid values in it. I fired it up this morning, and gotta say I"m pretty disappointed. The tone control has very little effect at all and the voicing control seems only to work from about 2 - 5 o'clock. And, it has lots of gain and distortion, but it really doesn't sound good and has what appears to be a common issue, and nasty farty decay.

So did I do something wrong or is that just the nature of the breast?
If the taper of your pots is correct, I'd probably say nature of the beast. If you're interested in some lower gain "D" pedal tones, you might try cutting the gain of the first stage using something like .1uf/3k9 ohms at the HP filter. The op-amp won't be pushed as hard and it will help with the nasty decay. The second stage can then be tuned by replacing the 3mm LED with a lower vF diode like a 1N4148 or something since it will be getting hit with a lot less gain from the first stage. I've had pretty good success using this approach in my SD-1 mods but there may be a little more involved with an actual Dumbloid. It's a starting place, anyway...

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indyguitarist
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Post by indyguitarist »

Coma wrote:Instead of going through 23 pages....is the Dumbloid pedal Close to the CJOD? I've built a few of those already.
sorta. looks like it's here: download/file.php?id=23613&mode=view

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Post by peterc »

Hi all

I got a pair of the Oshpark pcbs and am really looking forward to trying this pedal out.

The component overlay on p14 of this thread does not seem to match the circuit numbering. Does anyone have a build doc for it?

Many thanks
Peter

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Post by peterc »

Managed to get it done......
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Dumbloid-Purple-BW-Web.jpg

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mutante
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Post by mutante »

BB OPA2134 is correct op amp chip. Original Dumloid pedal using tantal capacitor for 22uF output coupling capacitor - it's a secret of Dumloid sound. I changed the capacitor to tantal and It works perfectly with OPA2134 chip.

When 22uF capacitor is eletrolytic capacitor, OPA2134 chip is meaningless but LM833N is awesome. I tried so many op amp chips - 2262, 5532, 1458, 275G, 627, 637,,,,,,,but LM833N is best with eletrolytic capacitor.

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Post by plush »

mutante wrote:BB OPA2134 is correct op amp chip. Original Dumloid pedal using tantal capacitor for 22uF output coupling capacitor - it's a secret of Dumloid sound. I changed the capacitor to tantal and It works perfectly with OPA2134 chip.

When 22uF capacitor is eletrolytic capacitor, OPA2134 chip is meaningless but LM833N is awesome. I tried so many op amp chips - 2262, 5532, 1458, 275G, 627, 637,,,,,,,but LM833N is best with eletrolytic capacitor.
Any explanation? Or this is purely subjective?

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Post by mictester »

I think that you all might have missed the "trick" in this pedal! The 3mm red LED could actually be a pair of LEDs back-to-back in one package - an "AC" LED - Like the Kingbright L57D range. I used the green 2.2V bidirectional L57D in an audio limiter as an overshoot protection device - it would clip the audio symmetrically at exactly +6dBm. It was a crude fix, but allowed the limiter to be used for broadcast purposes (where no over-level can ever be tolerated).

Op-amp clipping generally sounds pretty unpleasant, and certainly nothing like a "Dumble"!
"Why is it humming?" "Because it doesn't know the words!"

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Post by mictester »

I think that you all might have missed the "trick" in this pedal! The red LED could actually be a pair of LEDs back-to-back in one package - an "AC" LED - Like the Kingbright L57D range. I used the green 2.2V bidirectional L57D in an audio limiter as a simple overshoot protection device - it would clip the audio symmetrically at exactly +6dBm. It was a crude fix, but allowed the limiter to be used for broadcast purposes (where no over-level can ever be tolerated).

Op-amp clipping generally sounds pretty unpleasant, and certainly nothing like a "Dumble"!
"Why is it humming?" "Because it doesn't know the words!"

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Post by Intripped »

i tried a little mod, in order to get rid of that annoying fizzy decay:
i just put a 100n ceramic (multilayer) capacitor across pin 8 and 4 of the IC.
I don't know if i'm going nuts or what, but seems to me that the decay of the notes is much better now. there's still a little fizz, but ...now i kinda like it, it's not the farty fizz from distorted to clean anymore.

note1: This little mod has to be confirmed by someone else, because I really don't want to touch the PCB anymore
Last edited by Intripped on 13 Aug 2021, 12:54, edited 1 time in total.

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Post by mutante »

all resistors : carbon film resistor
all film capacitors : MLCC
22uF output capacitor : Tantal
OP amp TI 2134

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Post by Intripped »

mutante wrote: 09 Aug 2021, 23:15 all resistors : carbon film resistor
all film capacitors : MLCC
22uF output capacitor : Tantal
OP amp TI 2134
I used carbon film res (well almost all), the output tantalum cap and BB2134 IC.
The main diff are the film caps; I used a mix of wima, panasonic SMF, greenies and one HV ceramic (the 82pF).

Anyway, are you just saying that using those components you don't get any fizzy decay? :hmmm:

Edit: I doubt it, if it's not clear

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Post by 56335130 »

mictester wrote: 03 Jun 2021, 00:27 I think that you all might have missed the "trick" in this pedal! The red LED could actually be a pair of LEDs back-to-back in one package - an "AC" LED - Like the Kingbright L57D range. I used the green 2.2V bidirectional L57D in an audio limiter as a simple overshoot protection device - it would clip the audio symmetrically at exactly +6dBm. It was a crude fix, but allowed the limiter to be used for broadcast purposes (where no over-level can ever be tolerated).

Op-amp clipping generally sounds pretty unpleasant, and certainly nothing like a "Dumble"!
Dear friend,I was listening at anderton's music demo on youtube today and grow a huge interest on this pedal.I do broadcast audio job and I know your 'ac led ' thing about analog limiting gate for audio mixer. it's more like a double way led,+voltage at long leg display one color,and +voltage on short leg displays another.but this still doesn't solve the distortion decay hiss thing logically

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Post by 56335130 »

mictester wrote: 03 Jun 2021, 00:25 I think that you all might have missed the "trick" in this pedal! The 3mm red LED could actually be a pair of LEDs back-to-back in one package - an "AC" LED - Like the Kingbright L57D range. I used the green 2.2V bidirectional L57D in an audio limiter as an overshoot protection device - it would clip the audio symmetrically at exactly +6dBm. It was a crude fix, but allowed the limiter to be used for broadcast purposes (where no over-level can ever be tolerated).

Op-amp clipping generally sounds pretty unpleasant, and certainly nothing like a "Dumble"!
[media]<iframe width="2481" height="808" src="https://www.youtube.com/embed/DjcUQ331jRE" title="Made In Japan: The Dumbloid Special BTM by Shin&#39;s Music | Reverb Demo Video" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>[/media]
here the video,seek to about 1:30,the original pedal with a big chord also has this decay fizz.

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