"Inspired by the Trainwreck Express amplifier (built by the late Ken Fischer), the TWE-1 is solid-state pedal designed to emulate the touch-responsiveness and clean-to-overdriven range you get from a high-grade tube amp. Along with Volume, Hi Cut, and Gain controls, the pedal has 3-position Cab switch (4x12, 2x12, off), a Presence switch that provides three levels of high-frequency boost (post OD), a Voice switch (Traditional and Modern British), and a bypassable Brite switch that provides two levels of high-frequency boost (pre OD).
The TWE-1 with its Gain at noon or higher responded in an amp-like way to changes in guitar volume and picking strength, delivering everything from gritty cleans to richly saturated distortion textures. Thanks to its strong output, the TWE-1 is suitable for clean boosting too. All good stuff, but the standout feature of the TWE-1 is its powerful tone-shaping ability. The Hi-Cut knob attenuates treble when turned clockwise, and the Brite switch makes it easy to get the appropriate sparkle with humbuckers or single-coils. The Cab switch beefs up the low-end significantly in the 4x12 position (I felt the 2x12 setting sounded best with my Deluxe), and the Voice switch lets you choose between a thicker tone in the “M” position or one with more upper-midrange emphasis in the “T” setting. The Presence switch set to Hi restores shimmer when the Hi Cut control is turned up (a cool sound in itself), and between all of these functions, the TWE-1 certainly answers the needs of players who want a compact OD pedal with exceptional sound and flexibility."
The layout should fit in a 125B size box.
You can find Bugg's schematic and easier-to-build pcb on his website here.
This is a buffered effect. Follow the layout to connect the footswitch.
Check out Brett Kingmans video of this also. Killer!!! Im working on Pedalpcb's board now.
ReplyDeleteReally cool indeed, Alex. I was almost about to request this one from you hehe! I just need to find where to get those 1v8 zeners...
ReplyDeleteIt could be the 1N4678 diode: 1.8v zener diode. Pretty rare, indeed. I think someone of us should find some replacement.
Deletewhy not just take 3 1N4148 in serial. They forward around 0,6 V each.
DeleteThree 1N4148 or a LED, a green diffused one, I guess it's ok. In any case we should get about 1.8v forward voltage.
DeleteI just concern about a little detail in case we have to use a LED. I found this note about it on wikipedia:
https://en.wikipedia.org/wiki/LED_circuit
"but voltage drop normally rises as the light frequency increases".
Maybe this is the reason why MAO suggested to reverse the orientation.
Bit late. But in europe you could always send an e-mail to the guys of new-tone
Deleteteam@newtone-online.nl
They don't have the specific zener. But they can usually source a lot of components.
Website is only in Dutch. But they don't shy away from sending international
Looking at the schematic, I think LEDs with a 1.8v forward voltage reading would accomplish the same thing. I'd probably reverse their direction though.
ReplyDeleteWhen you say "reverse" did you mean connect the anode of the LED+diode combo to the cathode of the PCB?
DeleteI would disregard the LED & Diode combo, they had no effect on the sound. In fact, I can't hear and difference with the 1.8v zeners installed or not.
DeleteAlso couldn't "see" any effect when viewing with a scope. Really dont understand their pupose here.
My theory is the 1n4148s clip the signal below the 1.8v reverse voltage of the zeners, so they never "turn on", but they may clip a square wave in the 0.7v direction But again, I couldnt hear or "see" a difference with the zeners installed or nothing installed.
So, try it without anything 1st, then if you have a slightly higher voltage zener, try those, and then try some 1n4148s.
Let us know if you can hear any difference.
Actually I tried swapping their orientation and, I agree, they don't seem to contribute anything to the sound. I wouldn't be surprised to know the same effect even without. Thanks!
Deletehttps://www.mouser.com/ProductDetail/Central-Semiconductor/1N4678-BK?qs=sGAEpiMZZMtQ8nqTKtFS%2fNTW9pm8IdF6NwWdEkMc7Gx7JO0zV3Ng4Q%3d%3d
ReplyDeleteI did a search and I think it's not possible to get those 1N4678 zener here in europe. Mouser has a website even in german and a contact in munich, but there are about 20 Euros for shipping ...
ReplyDeleteNice blog about the guitar FX. If you need custom picks please let me know. www.custompicks.com
ReplyDeleteReally verified?
ReplyDeleteThat was a mistake. Changed this instead of the GTC Bloody Finger.
DeleteGot it. Thanks!
DeleteHey Alex, what is your idea about this zener diode?
ReplyDeleteThe reverse voltage drop of the zener is 1.8V but the forward drop is 0.7V like a normal diode. Therefore the drop across the back-to-back zeners is around 2.5V in both directions. However, low-voltage zeners such as these have a soft knee, i.e. they don't turn on abruptly. This should have a soft clipping effect, probably why they were chosen.
ReplyDeleteI have built this pedal using this layout and it works very well.
ReplyDeleteI tested 3.3V zener instead of 1.8V and there is not much different of how the pedal sounds.
Thanks Alex for a good work!
Cool! Thank you for verifying it!
DeleteThanks!
DeleteIn case I'll build this pedal the lowest zener I could find is 2.7v from Musikding.
These look ok for the 2.2 uf MLCCs?
ReplyDeletehttps://www.mouser.com/ProductDetail/810-FG18X5R1E225KRT6
Thanks
Yes those capacitors will work fine.
ReplyDeleteFor anyone having trouble to find the 1.8 zener diodes an alternative is to buy the smd version.It's not difficult to solder each one across two rows of a small vero board in the space between two holes.Then use two pieces of wire to create a homemade through hole diode.
Thanks Dimitris. Appreciate the confirmation. There were several versions of the same thing - I read the data sheets but just wanted to make sure I was in the ballpark.
DeleteI also got my 1.8 zeners from Mouser.
https://www.mouser.com/ProductDetail/Central-Semiconductor/1N4678-BK?qs=sGAEpiMZZMtQ8nqTKtFS%2fNTW9pm8IdF6NwWdEkMc7Gx7JO0zV3Ng4Q%3d%3d
Thanks again!
This comment has been removed by the author.
DeleteAnd of course, thank you Alex for the excellent layout!
DeleteHi Alex! Sorry for disturbing here, but I haven't found any contacts on the site. I would like to thank you for sharing the awesome 4ms Swash layout, that was my first ever DIY project, and I was succesful. I would like to ask You something, is there a way to talk privately?
ReplyDeleteHi Zorius. No problems. The emails are available in the Forum section. Mine is alexcannonball@hotmail.com
DeleteFinished mine up last week, after a quick listen was surprised at how good it sounded with all the controls flat.
ReplyDeleteIMO, most of the professional youtube videos make just about any pedal sound great...this one really does sound great!
After a couple nights of play, this is one versatile high-gain pedal, with multiple settings sounding awesome, rather than just one or two settings.
Had thought before actually building this, I would probably eliminate a switch or 2 and hard wire my favorite settings, but after listening to it live, I'm going to keep all four. Don't even think I'm going to tweak anything.
No doubt this one will be replacing my Sovereign Distortion.
Highly recommended!
Note regarding zeners:
For now, I subbed a yellow LED in series with a 1n4148 for each of the zeners. I hope the money I spent on the 1.8v zeners will be worth it, 'cause it sounds pretty great right now.
Thanks for the tip on the zener subs, MAO.
DeleteI would like some explanation about this replacement.
DeleteHow a yellow LED and a 1N4148 have to do with this famous 1.8v?
Thanks!
See EddieB's note regarding from July 20th.
ReplyDeleteReplacing each zener with a diffused yellow LED and 1n4148 wired in series would give about 2.4v drop in each direction, very close to the 2.5v mentioned by EddieB.
However, EddieB also mentioned the turn on time of these zeners is slower, whether or not this difference will be audible remains to be heard.
The LEDs never light up, so it will be interesting to hear the difference, if there is one.
I plan to report back my findings after my zeners arrive. (end August)
Thank you MAO, and I thank EddieB, I have underestimated his note.
DeleteMao, I'm waiting your next report about the zener.
Ok, the 1.8v zeners came in.
ReplyDeleteAs EddieB stated, they measure 1.88V in one direction, and 0.7v in the other.
Results:
I cannot hear a difference at any gain setting between the zeners and the led+diode combo I had subbed in (described above).
In fact, I hear no difference with them completely removed from the circuit!
I measured the voltage where the zeners connect to the circuit (Vref and 220R,D3,D6)
Vref = 4.5v
220R,D3,D6 junction = 4.4V
So about equal DC voltage on either side of the zeners.
I don't have a scope to check out the AC waveform.
But I'm thinking given an AC waveform greater than +/- 2.5vs, the zeners would create a square wave with +/- 2.5v peaks prior to passing through the 1n4148s.
And if that is true, then either the AC waveform isn't greater than 2.5v and the zeners are doing nothing, or my ears aren't sensitive enough to detect their influence.
I just can't hear any audible difference with them in or out of the circuit. (Pedal still sounds awesome to me regardless)
Hoping someone in the know can better explain the zeners purpose here.
Until then, I would say save your money and hold off on purchasing the zeners.
Request: Maybe someone else who has built this can lift one side of the zeners to see if they can hear a difference?
Thanks
Mike
Built this last night without zeners, worked just fine. I´m gonna try to tame the gain a bit to see if it fits my sound better. It´s to higain for me.
DeleteHey Leif,
DeleteI'd start by swapping out the 1M and 220p that are in parallel with a 470k and 470p.
And change the gain pot to a 10k audio taper.
There should still be plenty of gain on tap, but this should tame the lower gain settings a bit.
Mike - to check the audio signal I use soundcard and Visual Analyser software, plus very simple "probe" (https://www.build-electronic-circuits.com/wp-content/uploads/2014/08/sound-card-oscilloscope-probe-schematics.png). With VA you can have two channel oscilloscope.
ReplyDeleteT.
Thanks molu!
DeleteTook about 15 mins to put the LM7805 probe together (found in comments section of the site you referenced)
https://www.facebook.com/SoundCardOscilloscopeProbes
I'll post some details in the forums, but at this point I'm unable to detect an audible or visual change with the zeners connected per the schematic.
Scope pics:
http://guitar-fx-layouts.42897.x6.nabble.com/Ethos-TWE-1-1-8v-Zeners-tp43628.html
Can I run 2x 1uF MLCC's in parallel in replacement of the 2u2 MLCC's?
ReplyDeleteI think you can.
DeleteFor the lower 2.2uF in the board the upper legs of the caps have two free holes, for the bottom legs you could junction those together, or create a free hole moving to right the upper leg of that 1M resistor, so you can solder the two 1uF caps slightly oblique.
For the 2.2uF in the first stripe you have a free space for a second caps, just be careful to how much space take those two caps.
The 2.2uF close to the D1 is a bit complicated. I guess you just joint the legs and to use the only two holes.
With two 1uF, of course, you will get 2uF and not 2.2uF. I don't know how much difference it will do in the sound. I advice to looking for the 2.2uF.
Thanks. How about running this on 1n914 instead of 4148?
DeleteI think those diodes are interchangeable, but I'm sure you can find the 1N4148s without problem.
DeleteI try always to follow the original layout. Maybe you could socket the diodes, and later solder the 1N4148s. Or the 1N914s if you like them.
I just finished building it and plugged it in my test box
ReplyDeleteI built it without the zener diodes and with TL072 instead of 2134
Everything is working fine but I have a few remarks I'd like to share:
- I have a huge volume boost between the 3 positions of the cab switch
- Same with the Hi position of the presence switch
- Bright switch is pretty subtle
Are you guys experiencing the same ?
Is it worth purchasing 2 2134 to replace the TL072 ?
Thanks
Mine responds exactly as you described, and I believe that is by design so you are good there.
DeleteThe 2134s may have an effect on the touch sensitivity and possibly on the edge of breakup, but that's just a guess.
If you can hold off for a week or so, I am planning to build another one and will try it with TL072s. I can then AB the two and see if there is a difference between the 2134s and TLs. (was planning on doing this regardless)
Those zeners are still a mystery to me. And the diodes look like some kind of crossover distortion arrangement, again kind of unique as I haven't spotted that setup in another pedal.
Whatever the case, I love the sound and responsiveness of this pedal. We will have to see how much influence the 2134s have, the zeners appear to have none.
Thanks for your answer !
DeleteI will try playing with caps values for the brite switch
Also, I think the gain pot tap is a bit off, it's kinda on/off thing. I'll try the mod suggested before in the comments, maybe with a log taper pot.
The bass response is a bit flubby, not very tight, but also may be from playing at low volume on a 10" speaker.
I'll be interested in your feedback with opamps, thanks !
Finished mine this past weekend. My switches are exactly as you describe. I'm glad you indicated that as I would possibly have thought that I had a build error. Especially that bright switch - can barely hear the difference between the settings. May tweak those cap values on the next build ( sockets...).
DeleteThanks
Did anyone try plugging this straight to PA?
ReplyDeleteI have not but I did replace the preamp of a little practice amp with it.
DeleteThe power amp and speaker are very dark in this amp, but the TWE was able to adjust for it with the cab, presense and hi cut controls.
It was a bit loud, so I had to lower the gain of the power amp, but sounds great.
I'm thinking it will work well direct. Most likely with completely different settings than feeding an amp.
R4 is 1K / not 10K.
ReplyDelete10K is volume up a bypass signal.
and cause pop noise when truebypass
Why aren't the schematic shared along with the tagboard layout, so that the source of the build can be identified?
ReplyDeleteThis has been explained numerous times. The schematics are not our work and as such we can not share them. In most of the layouts there is a link to the source of the schematic, if not you can find them by using google.
DeleteThanks for the reply Zach, and I understand the explanation. I just feel that there always ought to be a link to the schematic that was the basis for the tagboard build. Some constructions have a lot of different schematics out there, and to be able to debug a build, the correct schematic is essential.
DeleteJust built this with a few subs, op275 op amps and 3.3v zeners. It sounds great but it seems too dark compared to all of the demos. If I turn the hi cut up past a quarter turn anyway. Also, I can't detect any noticeable difference between the bright switch settings. Maybe an error somewhere on my side. Anyone else have this issue?
ReplyDeleteTry a log taper for both the high cut and gain controls, IMO that puts more of the pot rotation within the sweet spots for this pedal.
DeleteThe bright switch is only noticeable with lower gain control settings. Again, a log taper will stretch out the lower zone.
On another note, the switches have a very wide range, some settings are not usable depending on your gear. Best to tweak some values based on your needs.
But even without tweaking values, still my favorite amp in a box pedal...FWIW.
Nice, that sounds like a good fix. Don't get me wrong, I'm loving this thing. So much so that I wanna make sure I squeeze every drop of functionality out of it. Did you ever compare tlo72s to the 2134s? I'm out of 2134s and should probably order some. Thanks!
ReplyDeleteI did try TL072s, they were fine.
DeleteBut I was so impressed with this pedal I ordered more of the 2134s and went with them in every build.
I never could tell the difference with or without the 1.8v zeners though. I'm still wondering what their purpose is...or if there is a schematic error. Never seen that type of arrangement before, or since.
I've tweaked just about every switch setting to get them just right for my setup.
Let me know if you decide to modify any settings, I might be able to save you some time.
Awesome, thanks!
ReplyDeleteI'm sure there is a simple explanation but its eluding me right now - but why not use a 3PDT instead of the DPDT switch for bypass? Sw4-1 seems to be the effect output so this would go to the out of the 3PDT and the 'in' of the board would go to the In of the 3PDT. Not sure what the purpose of Sw4-3 is?
ReplyDeleteThis layout was based on Bugg's original schematic which had a buffered bypass rather than a true bypass.
DeleteSw4-3 is the bufferred output, basically it taps into the signal coming off pin 1 of the 1st IC.
You can go with the true bypass as you described, if so you don't need the 1k, 10k or 22u that trace back from the Switch 4-3 connection. And you wouldn't make the Sw4-3 connection either.
Ah thank you very much! That makes sense now.
DeleteCan anyone please tell me Instead of 1.8v zener diode,may i use 1.8V 5mm Red LED ?
ReplyDeleteHi. I've just built this and like it a lot, so thank you very much! I've already built a couple of pedals but I'm a beginner as to understanding and modifying the circuits, so pardon me as these are probably trivial questions. There are two things I'd like to modify, maybe you can help me out. First the B10k pots. In my build, the input level is already matched at about 1/3 of the volume pot and my personal gain sweet spot is also well below 1/2 of the pot and I find it fiddly to hit the sound I'm looking for. I've already replaced the B10k with A10k, which has improved the situation a little. Still I'd prefer to have about half the volume and half the gain - what would I have to change? The second thing is the cabinet switch. Both non-off positions produce a significant volume boost that I'd like to even out. How would I go about this?
ReplyDeleteHey Luc,
DeleteRegarding the Gain, see my post on 11 September 2018. If those values are still too much, try the combo 270k and 820pf.
To lower the output, if you already have a 5k Audio pot, try that for the Volume control. If you don't have one, put a 10k resistor across lugs 1 and 3 and see if that helps. You can also try and increase the value of the 1k output resistor.
But probably the most effective would be to add a resistor between the output's 22u cap and lug 3 of the Volume pot. Try this: Add a temporary pot between the 22u cap and volume control by disconnecting the wire running to lug 3 of the volume pot, hookup another pot's lug 1 to that wire, then run a wire from lug 2 of the temporary pot to lug 3 of the volume pot. Then with the volume pot set at noon and the temp pot turned all the way down, adjust the temporary pot clockwise until you get the output volume you are looking for while the volume control is still at noon. Then disconnect the temporary pot and measure the resistance between lugs 1 and 2. That's the approximate value of the resistor you'll want to add between vol control lug 3 and the 22u output cap.
As for the Cabinet switch, that switch boosts the low frequencies which in turn increases the volume. If you really-really-really wanted to try and lower the volume on one those outer switch settings, you could use a DPDT On/Off/On and wire up the 2nd pole to alter the output volume. Couple of ways this can be done, but I would suggest just turning down the volume control as originally intended. But if you want to give it a go, start a thread in the forum's troubleshooting section and I'll give you a hand.
Hey MAO,
ReplyDeletethanks for your detailed help. VOL: I went down the easy road first and soldered a 10k resistor between lugs 1 and 3 of the pot. There's still a lot of volume so I'll try your second suggestion later on.
GAIN: I swapped the 1M and 220p with sockets and put in a 470k and 470p, according to your earlier suggestion, which was already a lot better. As I didn't have a 270k resistor I eventually went for middle ground and put in 330k/680p, which seems perfect. There's one issue though, I now have a slight pop every time I turn down the gain pot to zero. It happens with 470k/470p as well as with 330k/680p. Do you have any idea how that could be fixed?
As for the cabinet switch, it's not really much of an issue so I'm going to stay away.
Update: removing the 10k resistor from the vol pot got rid of the gain pot pop. Mysteries of electricity.
DeleteDon't know what to make of that, but anyway disconnect the wire from lug 3 of the Vol pot and put a 10k resistor between lug 3 and the board. See what that does for the volume, then adjust the 10k from there. Higher value will equal a lower output.
Delete