The Lusithand Devices 800JP is a solderless onboard preamp for bass, loaded into a Jazzplate: a control plate made for Jazz-style basses with the jack switch mounted on the body. Lusithand describes it as inspired by the EQ section of the GK800RB amplifier, served on a Jazzplate with active/passive switching and a new Contour switch feature. The manual says the preamp borrows that amplifier's EQ section and squeezes it into an onboard unit, with what the maker calls serious high frequency power and a very deep bottom end, just like the amplifier it is based on1.
Controls
The 800JP's controls depend on which of the two layouts you choose. The Jazzplate comes in two options: Neck Volume and Bridge Volume, or Master Volume and Blend1.
| Control | What it does |
|---|---|
| Active/Passive switch | On/off for the preamp2 |
| Stacked Bass/Treble | Active bass and treble controls on one stack2 |
| Hi-Mid | Boost and cut at around 1kHz2 |
| Contour switch | Pre-shape EQ that scoops the mids, changing the overall tone spectrum; on in the down position1 |
| 3-way Passive Tone Switch | No Tone, Tone 1, Tone 22 |
The manual notes that the Hi-Mid and Treble controls are highly interactive, and the same goes for the Lo-Mid and Bass controls, so the EQ sections shape each other as you adjust them1.
The passive tone switch
The three-position passive tone switch works even with the preamp off. The top and middle positions apply two different filter cuts, the same as a standard tone control completely rolled off, while the down position has no filtering. On the filtering positions, the tone capacitors interact with the volume control when it is rolled back1.
The manual adds a note for players chasing a particular sound: this combination is a trick that Reggae players use to get that deep bass Reggae sound1.
Pickups, wiring and installation
The 800JP is compatible with passive and active pickups, but there is one restriction: if using active pickups, the three-way tone switch will not work2.
Installation is solderless throughout. Lusithand states that all its preamps are solderless, and the manual warns that any tampering with the preamp, such as soldering or unsoldering directly on the preamp or any of its components, can void the warranty21. The wiring follows a color code: B is hot from the bridge pickup, N is hot from the neck pickup, red is the battery positive wire, black is the battery negative wire, with grounds for each pickup, and the jack's tip, sleeve and ring connections follow the colors plus an extra ground1.
Soldering on the preamp or its components can void the warranty. The 800JP is designed to be installed without soldering at all1.
Versions and support
The two control layouts suit different playing styles: separate neck and bridge volumes for players who adjust pickup balance by hand, or a master volume with a blend control for mixing two pickups against each other1. Lusithand's manual lists nuno@lusithanddevices.com as the support contact, and the maker's warranty covers defective products being replaced or fixed with all expenses covered, provided the problem is not from bad handling or negligence; shipping costs are not covered in negligence cases1.
Lusithand also builds other onboard preamps in the same family, including the Double NFP MKII, the Double NFP Jazzplate and the 800BMF, for players comparing circuits before choosing.
Videos
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the wetter bass
Questions
What amplifier is the Lusithand 800JP based on?
The 800JP borrows the EQ section of the Gallien-Krueger GK800RB amplifier and puts it into an onboard preamp. Lusithand describes the tone stack as having serious high frequency power and a very deep bottom end, just like the amplifier it is based on.
Does the Lusithand 800JP work with active pickups?
Yes. Lusithand states the preamp is compatible with both passive and active pickups, but with active pickups the three-way passive tone switch will not work. The active EQ and the rest of the preamp are unaffected.
What voltage does the Lusithand 800JP run on?
The 800JP runs on 9 to 27VDC and draws around 2mA at 9V, according to Lusithand's product page. That low draw makes a standard 9V battery a practical power source.
Does the Lusithand 800JP need soldering?
No. All Lusithand preamps are solderless, and the manual warns that soldering or unsoldering directly on the preamp or its components counts as tampering and can void the warranty.
Which basses is the Lusithand 800JP made for?
The 800JP is a Jazzplate, made for Jazz-style basses with the jack switch mounted on the body. It comes in two control layouts: Neck Volume and Bridge Volume, or Master Volume and Blend.
What was the Lusithand 800JP called before?
The 800JP was previously called the 800TS. Lusithand renamed it when the current Jazzplate version was introduced, which also added the Contour switch feature.
Sources (2)
- 800JP-Jazzplate-Manual.pdf, Lusithand Devices, 2025-08
- 800JP (Jazzplate), Lusithand Devices, 2026-08-25
