Dumbloid  [traced]

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

Ripdivot wrote: A friend of mine owns the AN Big Bloom and it has the same crackling decay
Well, that has made my day.
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 1oldsidewinder »

Ripdivot wrote:The dumbloid does have a nice voicing though.
400hz HP filter and an Eternity-like 7k tone control. It would be easy to take the things you like about the D'loid and add them to the Tube Screamer of your choice.

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Post by Manfred »

1oldsidewinder wrote:
Ripdivot wrote:The dumbloid does have a nice voicing though.
400hz HP filter and an Eternity-like 7k tone control. It would be easy to take the things you like about the D'loid and add them to the Tube Screamer of your choice.
I would appreciate very much, if you could mark the mods on the Tube Screamer schematic.

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Post by ipm »

Nocentelli wrote:
I think you have zero chance of a reply because AN has:
a) Too much respect for the designer
b) $300 clones for sale on his website

If Mr Amplifiednation is following this thread anymore I think he WILL answer. At least with a hint. It would be polite.
Maybe he learned something from this forum and will give something back.
I'm sure that he will not lose buyers for his built because people who are ready to spend 300 USD on pedal will not bother to build one themselves.

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Post by amplifiednation »

Nocentelli wrote:
ipm wrote:Hi Mr Amplifiednation,

What seems to cause fizzy decay? What is wrong in ivlark's layout?
Thanx.
I think you have zero chance of a reply because AN has:
a) Too much respect for the designer
b) $300 clones for sale on his website
Sorry I haven't been watching the thread. The schematic looks right. I think you guys got it. I'm not sure exactly what the crackling is. I don't hear that in my Blooms. I'll have to pay closer attention. I have had a two customers where the pedal just DID NOT work with their rigs - both times it was fizzy crackly decay and/or very little sustain. I don't know why because the pedals got returned and sounded great. It has been less than 2% though... I sent one guy a replacement and it still did it...both came back, sounded great with my rig. I sold those pedals, and the new users loved them too, no issues.

So it might not be your build, try a different amp or guitar. I've built quite a few of these now, they are great sounding pedals.

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Post by Ripdivot »

amplifiednation wrote:
Nocentelli wrote:
ipm wrote:Hi Mr Amplifiednation,

What seems to cause fizzy decay? What is wrong in ivlark's layout?
Thanx.
I think you have zero chance of a reply because AN has:
a) Too much respect for the designer
b) $300 clones for sale on his website
Sorry I haven't been watching the thread. The schematic looks right. I think you guys got it. I'm not sure exactly what the crackling is. I don't hear that in my Blooms. I'll have to pay closer attention. I have had a two customers where the pedal just DID NOT work with their rigs - both times it was fizzy crackly decay and/or very little sustain. I don't know why because the pedals got returned and sounded great. It has been less than 2% though... I sent one guy a replacement and it still did it...both came back, sounded great with my rig. I sold those pedals, and the new users loved them too, no issues.

So it might not be your build, try a different amp or guitar. I've built quite a few of these now, they are great sounding pedals.
I have a Deluxe Reverb, Egnator Tweaker, Vox AC15, Marshall JTM30 and several smaller amps and the Big Bloom and my bread boarded Dumbloid do the fizzy crackling decay through all of them. I have 7 guitars and that's doesn't change anything either. It's very obvious once you hear what's happening. Play a chord and let it decay. As it transitions from dirty to clean you will hear the staticky, crackling decay.

ipm
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Post by ipm »

Thanx, Mr Amplifiednation.

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Post by amplifiednation »

Ripdivot wrote:
amplifiednation wrote:
Nocentelli wrote:
ipm wrote:Hi Mr Amplifiednation,

What seems to cause fizzy decay? What is wrong in ivlark's layout?
Thanx.
I think you have zero chance of a reply because AN has:
a) Too much respect for the designer
b) $300 clones for sale on his website
Sorry I haven't been watching the thread. The schematic looks right. I think you guys got it. I'm not sure exactly what the crackling is. I don't hear that in my Blooms. I'll have to pay closer attention. I have had a two customers where the pedal just DID NOT work with their rigs - both times it was fizzy crackly decay and/or very little sustain. I don't know why because the pedals got returned and sounded great. It has been less than 2% though... I sent one guy a replacement and it still did it...both came back, sounded great with my rig. I sold those pedals, and the new users loved them too, no issues.

So it might not be your build, try a different amp or guitar. I've built quite a few of these now, they are great sounding pedals.
I have a Deluxe Reverb, Egnator Tweaker, Vox AC15, Marshall JTM30 and several smaller amps and the Big Bloom and my bread boarded Dumbloid do the fizzy crackling decay through all of them. I have 7 guitars and that's doesn't change anything either. It's very obvious once you hear what's happening. Play a chord and let it decay. As it transitions from dirty to clean you will hear the staticky, crackling decay.
Maybe it's your cable. I don't hear it...

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Post by bloomz »

I've (of course) been following this as well and have no idea what crackling and fizzing you guys are talking about. I don't hear it either, or if I do it's just a part of the total sound I love about this pedal.

I don't play many chords with it tho, just leads - I'll try chords tomorrow when the wife ain't sleeping - tho I can't really grok why I would want distorted/overdriven chords

I have a DRRI

Manfred
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Post by Manfred »

The fizzy makes me dizzy! :D
I watched the Dumbloid demo guitar playing by Pete Thorn, the pedal sounds great.

Have a look at the "Accent" setting it is at most at the one-o'clock position or less.
Maybe is the decay fizz due to blocking distortion of an overdriven tube stage when the output level of the pedal is too much.

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Post by amplifiednation »

The accent control when turned up too high makes the pedal too tinny, combine it with extreme settings of the tone control, and it oscillates.

I had a customer who was getting the crackly fizzy thing I think you are referring to. It happened with TWO different Blooms. It was so strange he thought customs had tampered with the pedals. I heard clips, the notes were just dying out, in a weird fizz after a few seconds. I though there was a bad solder joint or the op amp was bad.

Both pedals came back, I refunded his money, but they were perfect! I took clips right out of the box and he was speechless. It was something in that guys rig, I've played more of these than anyone, and sold a shitload of them (and still am). If they were fizzy and crackly, I would have fixed it by now. Neither was the Dumbloid. I would look at some other variables before you go crazy with the design. I can't speak for the tag board layout, I build mine on a 2-layer PCB I designed.

It's a great sounding OD. I had some of the lower gain settings on last night, it was nice and smooth.

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Post by IvIark »

It's the guitar that makes the difference. A strat won't be driving it as hard as a Les Paul so you'd expect it to be more problematic for some people than others.
"If anyone is a 'genius' for putting jacks in such a pedal in the only spot where they could physically fit, then I assume I too am a genius for correctly inserting my legs into my pants this morning." - candletears7 - TGP

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Post by bloomz »

K I just tried mine with my DRRI and 4 different guitars. The SG with active EMG's the hottest, down to my old Rickenbacker and 2 strats.

I can make a G chord sound like a bloody ugly mess with the bloom dimed - but I hear no fuzzy/fizzy decay. And I don't play overdriven chords anyway.

You guys must have way better discerning (read as fussy - lol) ears than I do. FSB is the only place I've heard this complaint about fizziness, so my conclusion is.......

sumting wong

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Post by mmolteratx »

I haven't had the time to test the newest revision boards that came in, and won't be able to for a few weeks at minimum. So in the mean time, for those of you who have been waiting, I've put the first verified revision up on OSH Park if you don't want to wait any longer.

https://oshpark.com/shared_projects/HOGyoUdG

EDIT: On the topic of crackle, that's just how op amps distort...

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Post by The G »

If you're using the op amps in their linear (and recommended by the manufacturer) part of their operating area, they're more or less the same.
But as clipping goes, each one is quite unique, especially in the decay part of the signal envelope.
What I'm trying to say is that fizzy decay is common (some would say inherent) with op amp clipping and it highly depends on the particular op amp used. Most of the time you don't need fussy ears to hear it. It depends, among others, on the op amp specimen, on how long is the signal bordering the clipping level and on how bright is your setup. It doesn't really matter if you play a chord or a note - for me it's easier to make it noticeable by playing a note on the thinner strings and letting it die. To make things better, you can swap the op amp and you can alter the gain (at high gain is harder to notice the fizzy decay). Of course, having a subsequent clipping stage that has a nice decay obfuscates a great deal of the problem. I don't know if one LED clipping stage qualifies, though, or if the second stage makes enough clipping to mask what happens before it.

I made quite some Sansamp GT-2's (which are based solely on op amp cliping plus they were not designed to go into a tube amp) that had the decay problem. Some of the originals had it, too. For me, the op amp that was the best at mitigating this problem was OPA2132 (not 2134), so try it if you can. Or you can try (resulting a different flavour) a low-speed/low bandwidth op amp, as the ProCo Rat does.

All being said, I'd rather believe that a rig can obfuscate the fizzy decay coming from a pedal than that a rig can introduce it at the same time the said pedal was inserted into the rig. Please, don't try to pretend that op amp clipping has a pretty decay and the ugly one came from somewhere else.

LATER EDIT: Haha, mmolteratx just said everything I said in 11 words.

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Post by Manfred »

Is the single clipping LED of the Dumbloid a common red LED.
I wonder because there are special 5V red LEDs availabel which conducting already at lower voltages.
The latch-up happens at first at the negative voltage output swing, so a 5V LED could make sense to avoid the latch-up.
Who knows about the applied LED-Type at the Dumbloid?
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182427-da-01-en-LED_5MM_L_53ID_5V_ROT(1).pdf
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Post by mmolteratx »

ggedamed wrote:If you're using the op amps in their linear (and recommended by the manufacturer) part of their operating area, they're more or less the same.
But as clipping goes, each one is quite unique, especially in the decay part of the signal envelope.
What I'm trying to say is that fizzy decay is common (some would say inherent) with op amp clipping and it highly depends on the particular op amp used. Most of the time you don't need fussy ears to hear it. It depends, among others, on the op amp specimen, on how long is the signal bordering the clipping level and on how bright is your setup. It doesn't really matter if you play a chord or a note - for me it's easier to make it noticeable by playing a note on the thinner strings and letting it die. To make things better, you can swap the op amp and you can alter the gain (at high gain is harder to notice the fizzy decay). Of course, having a subsequent clipping stage that has a nice decay obfuscates a great deal of the problem. I don't know if one LED clipping stage qualifies, though, or if the second stage makes enough clipping to mask what happens before it.

I made quite some Sansamp GT-2's (which are based solely on op amp cliping plus they were not designed to go into a tube amp) that had the decay problem. Some of the originals had it, too. For me, the op amp that was the best at mitigating this problem was OPA2132 (not 2134), so try it if you can. Or you can try (resulting a different flavour) a low-speed/low bandwidth op amp, as the ProCo Rat does.

All being said, I'd rather believe that a rig can obfuscate the fizzy decay coming from a pedal than that a rig can introduce it at the same time the said pedal was inserted into the rig. Please, don't try to pretend that op amp clipping has a pretty decay and the ugly one came from somewhere else.

LATER EDIT: Haha, mmolteratx just said everything I said in 11 words.
:lol:

But yea, I'd agree with all of that. Filtering out a lot of the high end can help, as can a clipping stage after the clipping op amp, but that's about it. Once you push the op amp out of its linear range, it gets a bit unpredictable, and as it returns to the linear range with signal decay, you straddle that line and get the crackle between clean/clipping. Diodes do this as well, to a lesser extent.

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Post by IvIark »

bloomz wrote:FSB is the only place I've heard this complaint about fizziness
So you haven't heard the fizzy decay mentioned on TGP?
"If anyone is a 'genius' for putting jacks in such a pedal in the only spot where they could physically fit, then I assume I too am a genius for correctly inserting my legs into my pants this morning." - candletears7 - TGP

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Post by 1oldsidewinder »

I don't understand the purpose behind the lower values of the biasing resistors for Q1 and Q2 (150k and 100k) on the D'loid and BB. Has anyone tried the Tube Screamer value of 510k for these? It seems possible some weirdness might be occurring there.

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Post by Intripped »

1oldsidewinder wrote:I don't understand the purpose behind the lower values of the biasing resistors for Q1 and Q2 (150k and 100k) on the D'loid and BB. Has anyone tried the Tube Screamer value of 510k for these? It seems possible some weirdness might be occurring there.
this

and also: what about reversing the polarity of the LED? it should then clip the other half of the signal, and the rail distortion on the op-amp would then occour at the other side too (on the +9V side if it was on the ground side).
perhaps it won't change anything ...but who knows, since the rail distortion decay is kind of unpredictable... it's an easy and quick try

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