LHZ Preamps

Vintage Bass Preamps

LHZ Preamps

Vintage Bass Preamps

LHZ TV

Whether it’s and in-depth technical analysis, preamp comparison, tech tip, review, or just some inspiration that’s worth sharing, here it is!

New for 2025: The LHZ-04 Preamp

The LHZ-04 preamp is a physical re-design of our current LHZ-03 model. It is the same circuit, same components, and same sound. Improvements for 2025 were driven by a significant number of clients using the LHZ in non-Spector basses with very confined control cavities. With smaller board dimensions and extremely low vertical clearance requirements, the LHZ-04 is THE choice for challenging installations.

This video walks you though the differences between the LHZ versions.

LHZ Preamp Installation into American Fender Jazz Deluxe 5 String

This video is a walk-thru of the process of upgrading a American Fender Jazz Deluxe 5 String bass from the EMG BTS to the LHZ-03 preamp. This is NOT a typical installation because it as a custom modification to use a DPDT bypass switch. This allows the LHZ preamp to be bypassed for those times where I want just the un-EQ’d pickup outputs.

HL-1 HAZard LAMPS Pedal by LHZ Preamps

Today we take a look at the HL-1 HAZard LAMPS Pedal, which is designed to give you that classic “Haz” tone on the floor. This pedal was designed for players using Spector® basses (with EQ dimed) who need to use a passive bass for a few songs. The HL-1 allows a passive bass to have the same EQ, dynamic feel, and signature high-frequency overtones as a USA Spector® bass. No, it will not make a Fender® sound like a Spector®!…

LHZ FAQ 02: What’s in the box?

In this we will go through a few of the most common questions regarding the LHZ-03 bass preamp: What’s in the box? Will it fit in my bass? How do I take the liner off the 3M VHB tape? One of the joys of this project is talking to players of every experience level. Truly, there is no such thing as a dumb question! I enjoy sharing what I know and helping others on their tone journey, so if you…

Barrel Jack Pin Identification and Wiring

One of the more common questions we receive are about how to solder the barrel jack. This can feel like a daunting task to players who’ve never soldered before or have limited electronics experience. Thankfully, it is not hard to do! This video walks through a couple concepts to make your barrel jack soldering simple:

Battery Drain Diagnostics

In this video we take a look at two of the most common reasons for rapid battery drain in a bass with an LHZ preamp. A 9 volt battery should last 6-8 months of normal use. However, certain wiring issues can cause an active preamp and pickups to always be powered on and reduced battery life to only a few weeks. While this video specifies the LHZ preamp, the same issues and resolutions apply to almost all active preamps that…

OpAmp Comparison Results

In this video we’ll reveal the opamps that were used in the Blind Opamp Comparison video. This is a longish video, but it goes into a lot of the psychoacoustic challenges that make listening tests difficult (if not impossible) when the difference between the samples is small.

Blind Opamp Comparison

LHZ Preamps have transitioned from the vintage LF442CN opamps to new chips. The LF442CN has been out of production for many years, and Hazlabs have moved to modern surface-mount op-amps a few years ago, so it’s our time to turn the page as well! This video is a blind comparison between 3 opamps: the original LF442CN and two of the new opamps that have been selected as being sonically indistinguishable from the original. Although we are calling this a “blind”…