Hello guys.
Two years to build pedals, and now I have some overdrives, distortions and fuzzes, a phase and a tremolo, I have to complete a delay, a reverb and an autowah, adjusting a pair of chorus, and start some other simple pedals.
Is this the time to build something more.
An acoustic simulator.
I don't want to buy one, but I want to build. I chose a Mark Hammer's Woody.
- There are some versions of this, the first version, it needs two 9v batteries, I don't wanna it.
- Sabrotone has a good layout on veroboard, is the same but adjusted to work with one battery. Verified, but someone have problems with it.
- There is Olver Alex version, slightly modded, and it works with one battery. That's ok, but I don't find a veroboard layout of it.
- And then there is a PCB on TH Custom, it is a bit different, but the schematic is the same of Oliver Alex and seems work fine. But I should to buy it.
A stripboard layouts will be perfect to me, but the sabrotone version doesn't convince me fully.
The TH Custom's PCB is used enough by many diyers, but I don't like too much the idea to buy a board instead to build it by myself as usually I did. Anyway the cost is not so high, but it is a further cost. Especially in this case where the board is not so complex.
What layout I could choose?
Thank you!
Hi EB-
Why not modify the Sabrotone vero layout to the Oliver Alex version?
Is that possible? :o Actually seems to me a bit different. I also tried to build it by myself, but... Never mind ::).
I'd need some help even to modify that, and I do not know if it will work or not.
I know, I am complicated. :P
First, get the schematic for each. Compare, and find the differences.
Next, label the components on the vero layout, and mark which ones need to be changed.
Now, for simple resistor or cap value changes, thats just a substitution.
For other types of changes, you will have to look at where they go electrically, and find sections of the vero that will allow you to make these changes. You might have to jumper, or perhaps add a row or column to allow these.
I'll help if you want, or there may be someone on the forum who already has a verified layout?
QuoteMark Hammer's Woody
No matter how hard I try, the inevitable thought that I can now not unthink has been thought.
If the mental image lasts any longer than 4hrs, you should call your doctor.
;D
Quote from: Cozybuilder on April 02, 2016, 02:28:08 PM
First, get the schematic for each. Compare, and find the differences.
Next, label the components on the vero layout, and mark which ones need to be changed.
Now, for simple resistor or cap value changes, thats just a substitution.
For other types of changes, you will have to look at where they go electrically, and find sections of the vero that will allow you to make these changes. You might have to jumper, or perhaps add a row or column to allow these.
I'll help if you want, or there may be someone on the forum who already has a verified layout?
This is based on the original schematic:
(http://blog-imgs-49-origin.fc2.com/z/u/z/zuzuzazuzaza/9vmoddedWoodyMy.gif)
This is the sabrotone's layout:
(http://www.sabrotone.com/wp-content/uploads/2013/02/Woody.gif)
This is based on the modified schematic according Olver Alex:
(http://www.zeta-sound.se/woody/Woody.JPG)
TH Custom's PCB is pretty similar to this with some noise filter caps and some different values.
These three schematics/layouts appear much different between them.
I think there's a lot work here to do. :(
Quote from: karbomusic on April 02, 2016, 03:10:40 PM
QuoteMark Hammer's Woody
No matter how hard I try, the inevitable thought that I can now not unthink has been thought.
Let me fix that for you.
(https://upload.wikimedia.org/wikipedia/en/0/01/Sheriff_Woody.png) (https://upload.wikimedia.org/wikipedia/en/0/01/Sheriff_Woody.png) (https://upload.wikimedia.org/wikipedia/en/0/01/Sheriff_Woody.png) (https://upload.wikimedia.org/wikipedia/en/0/01/Sheriff_Woody.png)
Elijah- There are quite a few differences between the Oliver Alex schematic and Harald Sabro's layout. I'm traveling tomorrow, and will be quite busy for the next few days- it will be next weekend before I have much of a chance to do anything with this.
Thanks a lot for helping, Cozybuilder! ;)
Meanwhile, I'll try to look them.
I have to do place an order in a shop where I found this:
http://www.op-electronics.com/en/other/285-acoustic-simulator-8000285716445.html (http://www.op-electronics.com/en/other/285-acoustic-simulator-8000285716445.html).
It is the same PCB of TH Custom, included some noise filter, and same price: 6 €. The schematic is the same, just two resistor's values, but I need just the PCB so I don't care.
Should I buy it? It is a further cost, I never bought a PCB, but I admit, I am a bit curious. :P
A quick look at this PCB indicates it follows Mark Hammer's schematic. I don't have the time to do a full tracing right now (double sided takes a bit of time), and this site didn't show the component values so can't say for sure, but the connections I checked are the same. For 6 euros, this is something I'd buy.
Indeed, the PCB seems to me pretty similar, or maybe identical to TH Custom PCB.
You can find the schematic and the bill of material in the datasheet PDF document in the page I linked. Just for take a look.
I checked every single components, the name R1, R2, C1, C2, etc. are the same. The only exceptions in the two PCBs are two resistors: R1 and R2, TH shows 10k, Op-Electronics shows 12k. And TH has one of the two noise filter cap of 330pf instead 470pF like Op-Electronics, but that is ok.
6 € is a further cost, but I'd like to buy a PCB for once, it is verified (well, TH custom it is, but Op-Electronics should be a real copy of it). Considering I have no many choices... It should be good, in the end.
Thanks!
There's nothing wrong with spoiling yourself by purchasing a PCB now and then!
Exactly. I was expecting I'd buy a PCB in case like a flanger effect, or complex delay or something. Ok, this acoustic simulator, it's pretty simple, but I didn't found nothing could satisfied me on veroboard layout, so it is kind of similar thing: I didn't find the right layout for me and I buy a PCB. :P And I can build my effect how I wanted.
I'm also lucky, because I found, coincidently, what I want in a shop I was planning to make my order. I have just to wait a bit to place my next orders.
I spent the winter woodworking and haven't made any pedals for a while. This thread reminded me that I always intended to build a Woody so I finally got around to it. I used the vero layout posted by Elijah-Baley above and it reminded me that I really don't care for vero. 32 cuts and 15 jumpers for such a small project! At any rate, that is not the reason for the post. I thought the Woody should have a wood themed enclosure so I tried something new for me. I put the pedal in an old aluminum enclosure I had from a prior project for now and then laminated on a piece of birdseye maple veneer (from the woodworking hobby). I made some quick labels using the reverse printing on transparency stock method and then glued that down with spray adhesive. The results are shown below. I will have to put the pedal in a nicer powder coated enclosure and do a bit more work on the labels, but I think the prototype was a success.
(http://i66.tinypic.com/15e8lcn.jpg)
WOW! :icon_eek: Really nice!
So, you used the sabrotone layout? (Where's gain pot?)
I put the gain trim pot on the board where it shows on traces K and L. It connects one end of C10 and the associated diodes to the 150K resistor. Note that the numbering for these parts is a bit different on the vero layout and the schematic.
Here's the big disclaimer. I haven't even fired up the pedal yet. I cut my left little finger on Easter Sunday (seven stitches worth, right on the end of the finger) and haven't picked up a guitar since.
I will go try out the pedal with a "one finger" playing method that will be somewhat akin to my typing style. I won't be playing any chords for another week or two.
Note added a bit later: OK, I tried the pedal. It works. No surprise since ALL of my builds work first try ;D
However, I will have some tweaking to do. I have read Mark Hammer's original description of the pedal and I have confirmed that the trim pot is in the correct location based on his schematic. However, there is WAY too much top end "sizzle" (as Mark calls it). Sounds more like a distortion pedal than an acoustic guitar. I would like to get more of the bass mixed in and calm down the sizzle. I actually used a twenty turn Bourns trim pot because that was what I had on hand. I tested it with a meter before I used it to set it at the midpoint, so I know that it is functioning properly. I can crank it from end to end with little or no change in impact on the high end.
K-man- Look at it as a golden opportunity to work on your slide technique.
Well, I'm honoured that such a fine piece of handiwork bears my name. On the other hand, if my name is on it, it better sound damn good if you play it for anyone! :icon_mrgreen:
Yeh, I will have to try a few open chord tunings. I think that the "real" slide guitar guys always used a cut off whiskey bottle neck as a slide. Time to head to the store for a good bottle of Kentucky bourbon.
For now my Woody simulator sounds like one of those resonator guitars with a handful of marbles thrown in through the f holes. Just gotta figure out how to tame the high end a bit.
I got the PCB. My first. Looks very nice! :D
(http://i.imgur.com/e3uX58Y.jpg)
I have some parts, but I have to wait my next order for all components.
Hey guys, I just populated the PCB, with pots and wires, too. Tested it, and it works fine! ;)
Nice sound, not really and realistic acoustic sound, but I knew it and that's ok.
About the trimpot the TH Custom says: «The trimpot is there to adjust the highpass filter. You will need a certain level of signal to generate the right harmonic content. Depending on your pickup this varies. Just dial in the nicest sounding tone.»
Someone knows how I should adjust it? By my ear? I would that it sounds ok with all kinds of guitars, with single coils or humbuckers.
Thank you.
If I haven't noted it already, faking an acoustic convincingly will usually need an extended frequency response from the amplifier speakers. Many speakers tend to roll off sharply above 5-6khz, which can take the edge off distortion and overdrive nicely, but takes a lot of the "air" out of even real acoustics. Indeed, many people who try out "exciter"-type pedals will end up asking "Is this thing even on?" when they try it with an HB-equipped guitar into a regular guitar amp. Both the pickups and speakers have to be able to provide audible top end for exciters and acoustic simulators to yield anything obvious.
I've built one on Mark's schematic (thank you for making this) and it sounds surprisingly well. :)
I've a strange question: because of personal needs I would like to know if there is a way to turn this circuit into a simple presence boost through a switch that bypasses the tone circuit. If yes I need a help to understand how to place this switch. Thank you anyway. ;)
My pedal Woody is complete! ;)
I tried better, now. It isn't a real acoustic guitar simulator how I expected, and as I can hear in the demo of Boss AC-2 or AC3, or as the Behringer (Boss clone), or as some pedal else.
It is a sort of EQ, mid scooped seems to me. It cannot cut treble and can cut just a bit of the bass. It enhances much treble, instead the bass control is more versatile. The internal trimpot is set to half.
It gets the clean sound, more... clean? bright? maybe get a nicer clean.
I never tried an acoustic simulator, but I think the Woody isn't a real alternative to an acoustic simulator (too bad), but an alternative to the clean sound of the amp in certain case.
Picture later.
In my defense, when I whipped it up in 2003, the state of acoustic simulation was not what it is now. I would imagine that any design from that period has been eclipsed many times over.
Thanks for reply, Mark. It's ok! :D
2003? Wow!
I have to say I knew how the woody could to be, before to build it, but I expected too much anyway. My fault.
Nevertheless, it is an interesting pedal. ;)
Is it possible that what the Woody needs is an Expander to get closer to that dreadnought feel?
As much as I would defend the circuit, adding expansion strikes me as putting lipstick on a pig.
Hah. What about compression before the clipping?
I got this wild idea to swap the LPF and HPF opamps with a Compander chip for respectively boomier lows and more consistent harmonics on the highs.
I've built Woody and it sounds nice, I really like it. But I have a problem - it is rather noisy - noise gets louder when playing and once I stop, it fades. It is high frequency noise and is lowered when I turn down treble pot. Could it be connected to trim pot setting, or there is something else going on? Any hints?
Did you build the original schematic version? Which layout?
I excluded the Sabrotone version, a bit different, because somebody got some bad noise.
I used this schematic:
(http://i414.photobucket.com/albums/pp228/Mark_Hammer/Woody.png)
Found here: https://www.diystompboxes.com/smfforum/index.php?topic=77747.msg648685#msg648685
After I noticed noise issue, I found another schematic, marked v1.1 http://diy.thcustom.com/download/acoustic-simulator-v1-1-build-instructions/. It is almost the same as the one I used, except it uses smaller biasing resistors (2M2 instead of 5M1) and has two additional high cut capacitors (C17 and C18).
I have used four NE5532AP, and added 100n multilayer caps to filter power supply noise for every one of them. This is my layout:
(http://i66.tinypic.com/2gwfbe0.jpg)
So I have added those capacitors (330p and 470p) but it didn't change the noise problem.
I built the TH Custom version using the TL074s specified for that build. No noise that I've detected (in fact, it sounds very good indeed.) Is it worth trying to swap out your opamps for 072s?
Quote from: bluebunny on May 16, 2018, 03:04:25 AM
I built the TH Custom version using the TL074s specified for that build. No noise that I've detected (in fact, it sounds very good indeed.) Is it worth trying to swap out your opamps for 072s?
Damn, I knew I should put sockets :) I'll try that as the last option.
compare the input oppie in this dia:
(http://blog-imgs-49-origin.fc2.com/z/u/z/zuzuzazuzaza/9vmoddedWoodyMy.gif)
with the input in the above "Hammer's Woody". something screwy about the second schem inverting input ......
Quote from: duck_arse on May 16, 2018, 11:48:31 AM
compare the input oppie in this dia:
with the input in the above "Hammer's Woody". something screwy about the second schem inverting input ......
Have you build it using this schematic?
Biyang produced a pedal called the "Woody", using the same font for legending as I used in the schematic posted just above. I originally used the circuit in which the input stage was inverting, and then re-inverted with the output stage to be in phase with the input signal. Oliver Alex approached me about adapting the basic circuit for use with a single-ended supply, and what you see is what came out of that exchange. It may well be what Biyang released. Oliver suggested that using a non-inverting buffer at the input would improve input impedance and noise specs. I couldn't argue with that.
In some respects, the circuit needs a simple noise gate applied to the "exciter" signal, coming off P1b, That's the primary source of any noise, given that it boosts only high end.
Quote from: rankot on May 16, 2018, 01:28:29 PM
Quote from: duck_arse on May 16, 2018, 11:48:31 AM
compare the input oppie in this dia:
with the input in the above "Hammer's Woody". something screwy about the second schem inverting input ......
Have you build it using this schematic?
built? no. I'm only scoping the schems provided.
I have replaced 100p ceramic cap which is parallel with diodes with 220p mylar and most of the noise is gone. Probably some of "acoustic" sparkle too, but not much. I have also found out that it is much better to use B10k potentiometers instead of A10k for top/bottom control.
And I used multiturn trim pot 500k for top gain control, but turning it doesn't seem to change things much.
I've tried to add 100p capacitors in parallel with all feedback resistors hoping it will reduce HF noise, but not much have changed. However, I like this pedal with my bass, it really gives it A PUNCH, so I can live with some noise, for now :)
I even tried this with a switch for different excited diodes. 1N34A's make a sound with less highs, while no diodes at all sound the same as default 1N4148's.
Try this: stick a back-to-back pair of Schottky diodes between the output of the fixed allpass stage and the input of the "Top" level pot, in series with the signal. , and reduce the value of the 12k resistor to maybe 6k8.
The Schottkys will "steal" some of the high end level, though not much. Reducing the 12k resistor on the Top control output to maybe 6k8 will bring the high-end level back up to compensate.
The Schottky pair will serve as a VERY crude gate, blocking passage of anything below their forward voltage. While we would not tolerate what they do if serving as a gate for an overall audio signal, since they would be blocking passage of what is an already distorted signal, it's not like they'd be doing anything "wrong" in this application.
I used this trick to gate out annoying whine in a ring modulator, and it worked nicely, if maybe not quite as well as a more sophisticated noise gate would have. There's a pretty good chance it will work as well here.
I'll try this, but I still can't figure out why 1N4148 diodes sound the same as without them?
I'll check again in the morning, when I get some rest.
Many op-amps will distort when the gain is too high. I recall well many years back when forum members would remark that their Distortion+ build sounded the same whether they used a pair of clipping diodes to ground or not. Some companies (e.g., Tech 21, and Black Cat) have made a point of using the "natural" clipping tendencies of op-amps aiming for too much gain.
Of course, whether the clipping you hear with and without the diodes is exactly the same, or simply distorting when you didn't expect it to, is another matter.
I have finally added a simple tone control with pot and capacitor right after volume pot. It makes adjustable low pass filter and does just what I wanted - a possibility to reduce hiss a little, while keeping overall effect.
(https://i.postimg.cc/XrnpwH7T/woody-filter.jpg) (https://postimg.cc/XrnpwH7T)