Another Philosophic question - Dumbloid results

[dbat69]

Damn my sticky "n" key, I eed to get a ew keyboard

Thanks Frank, I haven't come across this seller, and a recommendation is better than anything

[rocket88]

I was just thinking, reading over all the discussion again and I thought about something. Sometimes the manufacturer doesn't always select the parts, the parts select themselves to create amazing tones. For instance anything made by this guy up until more recently.



Btw, dbat if you need a new keyboard I can send you one when I send you the special package.

[dbat69]

Thanks Zach, I have another one, but just need to get motivated to find it and change it.

Err - this is where I show my total ignorance - who is the picture of?  It looks like a jolly sailor

[IvIark]

It's either Mike Matthews or Uncle Albert out of Only Fools and Horses

[dbat69]

Yeah - Uncle Albert

[dexxyy]

Yep that`s Uncle Albert, must be a pic from the jolly boy`s outing cos that looks like Margate in the background

Anyhoo, PCB, vero, perf, whatever, all are just conductors to allow components to be connected. Each of these have their merits and drawbacks, vero is cheap as chips and there are hundreds of layouts readily available, on the down side vero can be restrictive for bigger layouts as you may end up with a huge board. Perf is similar to vero but rows are not connected so can make it easier to layout using only a schematic, perf is as cheap as vero, downside is generally the back (solder side) of your board may not look as neat (in my case, a feckin mess). PCB`s fall into 2 categories, home etched boards can be a lot of work, involve nasty foul smelling chemicals and tedious drilling, they do allow for bigger circuits on smaller boards but only if you can source layouts or can design your own. Commercially available PCB`s take all the work out of the process, are ready just to populate, generally well designed and can be multi-layered to cater for just about any size of layout, in relative terms they are not as cheap as the others and there are certainly not as many layouts available.

So the truth is they all do their jobs and they all do them well, so I guess it`s down to personal preference.

BTW I`ve seen a couple of old 60`s fuzz pedals that were completely point to point, no board no nothing, just components linked together hanging inside the enclosure and still going strong.

[rocket88]

And here I thought I found a picture of good old Saint Nick.

But in all seriousness. The more I think about it the more I think the parts that make the most difference are the transistors or IC's since they can vary so much between each part. Think about why we sort transitors based on gain, and the big muff is a good example, since using a transistors with too low gain will result in a farty sounding fuzz.

And for those that don't know that is in fact mike mathews, I think he had been locked away somewhere to design effects and finally been released.

[motterpaul]

Once again - thanks to you all. I actually went to FSB to read their entire thread before I came back here to see what I missed.

1) for the record, I had NO idea this pedal was so controversial when I started this thread. I only brought it up because like others I never noticed the farty fadeout in the demos I'd heard of it. Also - if anyone still cares I can do the demos of the pedal with and without LED, and different LEDs and ICs.

IVIark - according to my eyeballs it seems that you are the person who originally got the circuit to FSB and here - I only say that because someone shows pictures of the build, and then suddenly your VERO layout appears with no mention of how it was derived - not that I saw anyway, although I might have missed it.

This has taught me a lot. That this is a quest for making any given circuit better, partly to dissect it, and partly just for the fun of figuring out a puzzle. I find all of the experiments made in the comments to be interesting. Some I still want to try on this - raising the input impedance, changing the pots.

I saw someone post this over there about sone cap value: "It makes no difference really. With the 22uf the corner frequency is .723hz and with a 10uf it would be about 1.6hz. Both are well below guitar frequencies."

That person does not have a very solid understanding of overtones and how the ear interprets sonic differences between instruments. If fundamental frequencies were the only ones that mattered then a soprano sax would sound the same as a kazoo - or a Martin with Piezo would sound like an Ibanez with EMG pickups. The ear hears differences all the way up to 20 kHz very very clearly (I am sure all of you know that, but only thinking about fundamental frequencies is a common error made by people who do not have much experience listening to EQ.)

Anyway - I think I understand the quest here now - and frankly if I happened to find the combination for a great new pedal and wanted to go into manufacturing I would also put a hidden dual-layer somewhere in the PCB. There really is no reason to give it away, not so much for fear of the DIY community, but for fear of the smarter competitors who have to get their ideas from someplace.

Here is a true story. I bought an early Keeley compressor, which inside was handwritten "#97, this one sounds great! Robert Keeley." When I went to sell this I put that info in the ad, and the person who bought from me admitted (after a pretty long conversation) that he worked for a major musical equipment manufacturing company. I later learned from someone else at the same company that the buyer was in R&D.

I guess all that really says is that if you really want to reverse engineer something - its probably best to have it in your actual hands. But I don't think the Dumbloid was worth $600 even for the sake of cloning it. It has nice voicing, but the fizz out fade away makes it largely second tier when there are so many other good pedal alternatives out there.

And after reading the FSB thread I (1) I find it amusing TGP has such a funny reputation with builders, when you guys could make a fortune just doing mods for them. (2) You will only find a handful of my 5000 posts at TGP in the "Effect Pedals and other things"  section.  The places I frequent are "recording" and "playing and technique" And yes, I have built a KlonE. I hear the Silver Centaur mods make it sound most like the original - yeah, with German Germaniums.

By the way - I thought I saw a mention of tantalum in the Dumbloid - is that a recommended cap?, because I didn't notice it in the listing.

[Frank_NH]

"The ear hears differences all the way up to 20 kHz very very clearly (I am sure all of you know that, but only thinking about fundamental frequencies is a common error made by people who do not have much experience listening to EQ.)"

Well, the general rule is that indeed the human ear (at least ones that haven't been affected by age and abuse) can hear from about 20 Hz to 20 Khz, but that guitar frequencies start at about 50 - 60 Hz and that guitar amps roll off everything above 6 - 7 Khz.   Most guitar pedal designs work in that range (50 Hz to ~ 10 Khz).  So there's usually no need for circuit filters which operate below 10 Hz range or above 10 kHz.  Cleverly crafting the signal filtering in overdrives, distortions and fuzzes is, I believe, one of the keys to a successful design and where you do a lot of experimentation.  

Just today I got an idea for a amp sim I recently built, specifically the original ROG Supreaux.  It's a simple circuit and I wanted to experiment with it (different JFETs etc.).  It sounds fine at certain settings and guitars, but with a hot signal from a humbucker is was sounding a bit "farty".  This is think is due to the low frequencies being boosted in the first JFET stage.  To avoid this, I'm going to try eliminating the 33 uF cap at the source of the first stage.  Alternatively, if you instead substitute a lower value film cap (~100 nF) it should act as a treble boost.  I could even wire this up with a switch.

So, this is just an example of how I go about modding circuits to my liking.  And if it doesn't work out, I'll set it aside and perhaps come back to it later.

Really bad circuits, however, don't even make it to the "Island of Lost Circuits" but instead get their organs ..er I mean components.. harvested for future builds!    (My first Thor build met this fate...).

[motterpaul]

I had to look up Mike Mathews.

The LPB1 - for those who were not around - was a true breakthrough (and so simple). The original was a box with a guitar plug permanently mounted on it that you stuck in your amp. Then you plugged your guitar into that. Everybody bought one in a short amount of time. Still being sold - has to be one of the the most popular guitar effects ever. That and the wah-wah.

[motterpaul]

"So there's usually no need for circuit filters which operate below 10 Hz range or above 10 kHz."

Just to be clear for those who might have missed it, the guy said 1.6 kHz which is well below the top of even your range, Frank, and I doubt the roll-off at 10k is a steep cliff, even if you start to roll off at 10k, you are still going to hear higher frequencies. It is just the point that some people forget that the "magic" of EQ and tone actually happens above the fundamentals - more in the "haunting mids" category (that's a joke.)

I do remember teaching younger recording engineers that you could roll off most freqs above about 12 khz on most electric guitars (especially with overdrive) because there was not much up there but noise. I got some crazy looks, but it is true.

[motterpaul]

Supreaux --

The guy who first built those - Zinky, lives in Flagstaff AZ, and so I often see hand-built Zinky amps around town. He has done some amazing amps over time.

I saw one where every single dial on the amp had a ring of LEDs, as part of a netwrok to record the settings of each dial. He then integrated that with midi so you could take any amp setting and record it to a midi preset controllable by a midi footswitch. When you recalled one, the LEDs would light up to show you where the dials would go for that setting (in case you wanted to tweak it).

The amp was a two channel with great tone, too. I was thinking of buying, and then I thought - "yeah, but what if it needs repair" - too complicated to think about.

As far as the original Supro sound, Led Zeppelin 1 territory. It's got is place but not for me. I just don't care for small, bright tube amps (usually based on EL-84s or 6V6s) - too compressed and brittle in the upper end - when on overdrive. Of course, the cleaner tones on an AC30 is unbeatable, the blue alnicos help.

I remember reading you wanted to do that Cornish SS-2 pedal, too. I like that one, too. I also like "gearmanndude" "white curly cable" guy. he does the demo on that that. Sounds great cranked up.

[Beaker]

Thank you Frank for this great link - I've never come across it before, but I can see that I will be a regular customer soon!

http://diy.thcustom.com/

And he has ROG Supreaux boards!


dbat you won't be sorry with PCBs from http://www.pedalparts.co.uk

I have used several of them - I'm building a Superfuzz using one of his boards at the moment. They are great boards at a great price.

[Frank_NH]

Re: Supreaux
"And he has ROG Supreaux boards!"

Just wanted to point out this is the Supreaux Deux, which runs at 18V and has lots of additional mods, versus the original Supreaux which I linked to.  Note the difference in the JFET stage (no source bypass cap and different JFET).  

Re: Supro Amps
Yes the Supro is supposedly the amp of Led Zeppelin 1 but remember that Jimmy Page was using a Telecaster at the time, so a lot of the brightness in his sound is due to the single coils.  Led Zeppelin 2 is the Les Paul + Marshalls.

BTW Supro Amps is now alive and kicking once again...
Supro USA

"I remember reading you wanted to do that Cornish SS-2 pedal, too"

Yes my build list is long...I need something to occupy my time during the long New Hampshire winters...

[Beaker]

Thanks Frank. I've been meaning to build a ROG Supreaux Deux for ages now, but not got around to it. Having a nice PCB to work with will swing it for me.

I just love those old Supro, Valco, Magnatone type amps, so it's good to see that Supro are back in production.

If I remember right, Neil Young swore by Supro amps for recording for many years.

[Frank_NH]

Hey all - just a quick note.

If you are interested in projects using PCBs made by DIY-TH custom effects or 1776 Effects, if you join the Madbean Forum at Madbean Pedals, both have subforums there where they answer questions and users provide build reports.  It's a great way to check out builds that others have done as well as problems and solutions with specific projects.

[dbat69]

THanks again Frank, I'll have to spend a bit more time over at Madbean.  I've been intending to get a couple of his PCBs too

[induction]

motterpaul wrote

I saw someone post this over there about sone cap value: "It makes no difference really. With the 22uf the corner frequency is .723hz and with a 10uf it would be about 1.6hz. Both are well below guitar frequencies."

That person does not have a very solid understanding of overtones and how the ear interprets sonic differences between instruments. If fundamental frequencies were the only ones that mattered then a soprano sax would sound the same as a kazoo - or a Martin with Piezo would sound like an Ibanez with EMG pickups. The ear hears differences all the way up to 20 kHz very very clearly (I am sure all of you know that, but only thinking about fundamental frequencies is a common error made by people who do not have much experience listening to EQ.)

I'm gonna have to disagree with your analysis, here. The cap in question is an output cap, which functions as a high-pass filter. This means (over-simplification alert) that it attenuates frequencies below the corner frequency and passes frequencies above the corner frequency unmolested. Guitars are not capable of producing frequencies as low as either of the corner frequencies mentioned (BTW it was 1.6 Hz, not 1.6 kHz), thus the two output cap values will have roughly the same sonic result. Overtones are not relevant here because overtones are always higher in frequency than the fundamental (hence the name), so both caps will treat both the fundamentals and the harmonics in the same way. The only difference would be if the two caps have significantly differences in capacitance as a function of frequency, but I doubt this is likely to be a problem. It's true that the fundamentals are not the only frequencies that matter, but there are many cases, including this one, where the frequency range of the instrument and signal chain implies that a wide variation in cap values will be sonically undetectable.

[motterpaul]

"I'm gonna have to disagree with your analysis, here."

You are right, then. I didn't know they were talking high pass. I should not post too early in the morning. I am too used to "audio-speak" when it comes to frequencies and it didn't even occur to me they would be talking about frequencies far outside even the range of human hearing let alone what guitars can produce. When I saw "what guitars can produce" I read it as 723 Hz and 1.6 kHz.