EQ / Preamp
This section is quite interesting, it promises a universal adaptation of the musician to the amp. There are several products on the market that are not necessarily designed for harp, as so often.
Boss GE 7
Taken the Boss GE-7 as a model, some firms provide copies, which are usually not bad. An EQ of course has the disadvantage that it is a bottleneck for the level of the bullet, as every pedal is, but with some amplifiers you can thus achieve a significant improvement in sound.
Artec Graphic EQ
What I noticed is, that Artec adds some signal which sounds quite nice "dirty". Some search for that! This device has very little noises.
Lone Wolf Tone +
Also a kind of equalizer, a commonly used active 2-band Bandaxall tone stack - with changed frequency in the bass. As always, constructed well and works quite good. With an EQ you are more flexible, the Tone+ is easier to use.
There is an older version. It is a classic circuit of the Banaxall without the output buffer, which promises more freedom with the level.
Lone Wolf Harp Attack
With tube! Maybe a little muffling. In addition to the Harp Delay, the second Lone Wolf product that makes some sense, good in use with a guitaramp. Direct into a PA there may be issues. I like it for some reason.
Harley Benton American Sound
This pedal, a clone of a Tech21 Blonde, simulates a Fender amp, the tone control is very effective and the "Voice" controller gives us the opportunity to regulate mids and gain. In addition, a speaker emulation is integrated. For a few euros more, this pedal connected to the PA sounds better than any MultiFX super-duper flagship (which I don't like anyway).
Lone Wolf Harp Break
This is a simple distortion in the style of a "Marshal Guv'nor" or "MI Audio Crunch Box", also the "ProCo Rat" is constructed like that - but here with massive bass boost in the first back coupling. The LED distortion is way too hard and the output buffer limits the signal badly .... maybe useful for guitar amps, rather useless for harp amps.
Marble Magic Mike
A Relic, no longer manufactured. The device was designed to provide a high impedance input for high impedance crystal mics, so they are not burdened by the lower impedance of the amplifier and collapse.
In principle a good idea, only the implementation ..... It is particularly funny that they have scratched out the label of the OP in fear of copies .... that's what I call self-consciousness.
Lehle Sunday Driver SW
This is what the Marble MM wanted to be. Very high-impedance input, neutral gain, extremely high level stability even at 9V voltage by voltage doubler .... and a bypass switch, which is listed here because of its reliability. No real need, but can be a problem solver.
With this device, I could not get along very well - works, but rather as a "damper" (which may be useful).
Digital Multi Effect Processors
Sure these devices have their authority, but I can't handle them at all. Not even with the Digitech RPs and the matching harp patches by Hunter. It doesn't sound as I want. However, such devices might be practical and a relief for professional musicians.