Donner Vowel Mini Active Wah Volume Effect Guitar Pedal 2 in 1

The Donner Viper Volume & Expression pedal is a great lttle piece of kit.It is made of sturdy plastic and should withstand being gigged. Its size, measured at 140 L x 65 W x 55 H mm when the Viper is down, is not dissimilar to my Boss fx pedals, measured at 128 L x 70 W x 55 H mm, which makes it ideal for fitting into a single row pedal board.The input jack is on the right and the output jack on the left. I was only able to test it as a volume pedal because I have no kit that accepts an expression pedal.The operation of the pedal is smooth and quiet. You can feel a very slight resistance when you operate it by hand, however, this should reduce over time as the moving parts polish their surfaces against each other.The Viper is fitted with a 100KΩ linear potentiometer; if you are going to plug a guitar with a high impedance pickup directly into this then you will experience tone-sucking because you will have an impedance mismatch. The simple answer is to plug your guitar directly into a pedal with a high impedance (1MΩ) input first and then plug that into the Viper's input.I compared the Viper mechanically with a good old Schaller Fusschweller F121 (which also has a 100KΩ linear potentiometer) and, to my surprise, found that the Viper has a slightly greater angle of travel than the Schaller. The Schaller is less smooth to operate and certainly much noisier. I do believe, however, that the smaller size of the Viper does not encourage the user to place their foot to best advantage, but this is easily achieved with a bit of practise.I was certainly able to produce some very credible swells with the Viper after playing with it for only half an hour.If you want a compact volume pedal to fit on a single row pedal board then this will fit the bill very nicely.

great sound

I bought this pedal to do volume swells, rather than to set and leave a guitar volume or as an expression controller (I have yet to try it in that mode). As such, it does this very well.The unit is compact, the same width and just very slightly longer than a Jim Dunlop Cry Baby Mini Wah, so is ideal for small pedalboards. It's made of a robust ABS-like plastic, with a pressed steel base plate. The baseplate comes with 5 small square rubber feet attached, which you'd probably want to remove if attaching it to a pedalboard.Being passive, it's a very simple device, consisting internally of one large PCB with the input and output jacks mounted on it, linked via a ribbon cable to a much smaller PCB with the control potentiometer mounted on it. The potentiometer is turned by a standard arrangement of a toothed rod connected to the treadle, turning a gear attached to the pot shaft. The treadle movement is smooth, and its stiffness can be adjusted if necessary by tightening or loosening the treadle's mounting bolt/pivot. The treadle has (according to my trusty protractor) 15° of movement, but the active range of the pot is slightly less than that.Like almost all passive volume control pedals, the potentiometer provides a much lower input impedance than an active pedal does. I measured a constant 90k ohms throughout the pedal's travel. This means that if you plug a passive guitar straight into the pedal, you will load the pickups and you will get some loss of treble. So this is a pedal that is best placed after a buffered (not true bypass) pedal or after an always-on pedal such as a nice sounding booster, which will preserve the guitar's sound.I am constantly amazed by the quality of cheap pedals are these days, and this is certainly a good pedal IMO. The only real drawbacks as far as I can tell at the moment, are that you'll need to fully dismantle the pedal to get enough access to the pot to squirt some contact cleaner in if it goes a bit crackly, and that the mini 6-pin pot is going to be very hard, if not impossible, to replace once contact cleaner can't cure any crackles. On a full sized pedal using a standard pot, pot replacement would be far less of an issue.

I'm using a small pedalboard (pedaltrain nano+) and wanted to experiment with a small expression pedal. The wah effect seems to be a clone of the crybaby. The volume pedal lets you do swells or control gain depending on placement. I've been using the following setup:Tuner > Octave > boost > Gain > Donner Vowel (Wah/Volume) > Delay > AmpThis lets me do both volume swells and a passable Maggot Brain impression. I'd move it back after the octave if I wanted to use it to back off the gain and have a more subtle wah effect. Power input is on the right hand side above the input jack which is useful to offset the pedal takes up about as much space as a powered Boss unit (see photo).Like all mini-expression pedals, the pedal is small enough that it disappears completely underfoot when in use. This takes some getting used to, but isn't hard to control after you've worked out where to place your foot. The pivot is quite far back making it easy to rock back and forth quickly. Could be difficult in giant boots! So far just bedroom practice but I've not had problems with plastic pedals breaking. The LEDs are always on (one colour for each mode) - I imagine this would be helpful for knowing where you are in a dark or noisy environment.The switch between modes requires an intentional effort to turn on (I haven't managed to do it by accident) and switching from wah to volume is nice, in that you're going from full volume with wah to 100% volume.It's half the price of the Mooer (which I've not used but has the extensible rings I hope more pedals copy), and about a third of the price of the crybaby mini. Neither work as volume pedals, so it wasn't much of a decision.