Reverse engineering vintage Haz Labs pre

[AgingEngineer]

Since the LHZ was born in this forum, the TalkBass forum gets the scoop when there is news to announce. Three items to announce today:

REVISION 1.8 BETA TESTERS NEEDED
This is a new revision of the LHZ designed to make the installation process easier and more ergonomic. It's the same circuit, same components, same tone... just in a smaller package with connections that make better sense to folks who are not circuit-board geeks like me.

I am looking for TWO prior customers who've purchased the LHZ-02, have a lot of playing time with the LHZ, and who are willing to swap in the LHZ Rev 1.8 test preamp and give me their honest thoughts on the sound, fit, and ability to connect. If you are interested, drop me an email and let me know! (It's in the Install Manual if you forgot it!) I am asking for email-only replies on this as I have a lot of folks that reach me via different platforms and it gets confusing remembering where I had the conversation.

HAZLABS STOMPBOX VERSION
I've been getting regular requests for this. While circuit design and fabrication is my strong suit, making a stompbox that doesn't looked like it was built by an unsupervised 8-year-old using Dad's power tools is apparently a challenge for me. No worries: I can do the engineering and send it to a fabricator to do the pretty work.

Artwork and drill patterns are complete and will be sent for fabrication this week. This will be in tidy commercially painted and drilled 125B box with UV printed graphics. As soon as I have the boxes in I will post and update with photos of the finished product. For now, here is the engineering mockup.

CHIPS CHIPS CHIPS
As we all know, the LF442CN opamp is out of production. All existing stock has been bought up at this point by resellers offering the stock at 10X-20X the original price. I have enough inventory from last year's investment to take me through this Summer.

Currently I am actively testing current FET opamps and circuitry modifications to force these modern opamps to react like the old LF442CN opamps when driven hard. When I get to a workable solution (I am pretty close now) I will be looking for a few beta testers that are willing to do A/B comparisons of this against an original Haz. More to come in the next few weeks!

Brain dump: complete. Thank you to everyone here for being part of this continuing saga.. you rock!

 

[VeryTallBassist]

Since the LHZ was born in this forum, the TalkBass forum gets the scoop when there is news to announce. Three items to announce today:

REVISION 1.8 BETA TESTERS NEEDED
This is a new revision of the LHZ designed to make the installation process easier and more ergonomic. It's the same circuit, same components, same tone... just in a smaller package with connections that make better sense to folks who are not circuit-board geeks like me.

I am looking for TWO prior customers who've purchased the LHZ-02, have a lot of playing time with the LHZ, and who are willing to swap in the LHZ Rev 1.8 test preamp and give me their honest thoughts on the sound, fit, and ability to connect. If you are interested, drop me an email and let me know! (It's in the Install Manual if you forgot it!) I am asking for email-only replies on this as I have a lot of folks that reach me via different platforms and it gets confusing remembering where I had the conversation.
View attachment 5331442

HAZLABS STOMPBOX VERSION
I've been getting regular requests for this. While circuit design and fabrication is my strong suit, making a stompbox that doesn't looked like it was built by an unsupervised 8-year-old using Dad's power tools is apparently a challenge for me. No worries: I can do the engineering and send it to a fabricator to do the pretty work.

Artwork and drill patterns are complete and will be sent for fabrication this week. This will be in tidy commercially painted and drilled 125B box with UV printed graphics. As soon as I have the boxes in I will post and update with photos of the finished product. For now, here is the engineering mockup.
View attachment 5331443

CHIPS CHIPS CHIPS
As we all know, the LF442CN opamp is out of production. All existing stock has been bought up at this point by resellers offering the stock at 10X-20X the original price. I have enough inventory from last year's investment to take me through this Summer.

Currently I am actively testing current FET opamps and circuitry modifications to force these modern opamps to react like the old LF442CN opamps when driven hard. When I get to a workable solution (I am pretty close now) I will be looking for a few beta testers that are willing to do A/B comparisons of this against an original Haz. More to come in the next few weeks!

Brain dump: complete. Thank you to everyone here for being part of this continuing saga.. you rock!

Sending email now.

 

[AgingEngineer]

I just finished this week's builds and had an epiphany while I was testing: One of the tests is a 20Hz to 20kHz sine sweep where I look both a matching EQ response and audio artifacts as compared to a reference output sample taken from an authentic HazLabs board.

You know what I can make with a sweep file and the resulting post-Hazlabs sample?
An Impulse Response file that can be loaded into an amp modeler. That's right, I can create a HazLabs preamp IR that I can run in my Helix!

Hello, next project..

 

[fibz]

An IR would be awesome. It’s great what is possible nowadays with technology.

 

[ThisYouCanTrust]

I just finished this week's builds and had an epiphany while I was testing: One of the tests is a 20Hz to 20kHz sine sweep where I look both a matching EQ response and audio artifacts as compared to a reference output sample taken from an authentic HazLabs board.

You know what I can make with a sweep file and the resulting post-Hazlabs sample?
An Impulse Response file that can be loaded into an amp modeler. That's right, I can create a HazLabs preamp IR that I can run in my Helix!

Hello, next project..

So the haz magic is really just EQ then .. ? No saturation or any kind of harmonics enhancement (for lack of a better word) ?

 

[VeryTallBassist]

So the haz magic is really just EQ then .. ? No saturation or any kind of harmonics enhancement (for lack of a better word) ?

I may be mistaken but I believe the audio artifacts Lonnie is referring to are the saturation/overdrive in the higher frequencies.

 

[JKos]

I may be mistaken but I believe the audio artifacts Lonnie is referring to are the saturation/overdrive in the higher frequencies.

Which are not captured by an IR.

 

[AgingEngineer]

So the haz magic is really just EQ then .. ? No saturation or any kind of harmonics enhancement (for lack of a better word) ?

No, there IS more than just EQ going on in a Haz. It goes non-linear when you press it hard, and it kicks up unusual harmonics that are a result of that non-linearity and the peculiarities of the opamp.

I'll admit, my understanding of how IR's work is pretty incomplete! I am still not entirely sure how an IR can capture not just a frequency response curve, but also the non-linear reverberation in a room. I assumed that if an IR can capture that, it might be able to capture the unique non-linear action of an preamp. But, perhaps not.

This is how I start most projects: with a black box I don't understand. I ask all kinds of kindergarten questions and test things until I finally understand it.

 

[ThisYouCanTrust]

Ah ok, no worries

Well, basically an IR can only capture linear things - it's just a short sample of audio, and "applying" it is just a multiplication, to put it shortly.
And a reverb IR is also totally linear, contrary to an algorithm-based reverb where you could whatever funky things you may want to.

So, anything saturation-related won't be captured (or at least not correctly) by an IR unfortunately.

 

[wintremute]

Subbing

 

[eadbass]

Maybe plugins like Neural Amp Modeler (open source freeware) would be more suited to capture the whole thing than an IR.

 

[Low Commotion]

I’d like to share my experience with the LHZ. I have a Spector NS Pulse 2 with the EMG pickups and it came with the Tonepump Jr preamp. It sounded great and I got a lot of compliments on it when I played it.

I read about this LHZ preamp and how great it sounds, and how the Tonepump Jr is good, but not as great. I held off getting the LHZ for the longest time because I’ve made mods to several of my basses, but I wasn’t totally satisfied with the result. In fact I’ve reversed several mods (remove a preamp in one bass, put the original pickups back in two other basses to name a few).

After going through the Spector Owners thread and this thread, I contacted Lonnie and asked a couple questions. He was quick to respond and offered a return policy if I wasn’t 100% satisfied. I caved in and ordered the LHZ-01 preamp.

It arrived immediately and I installed it right away. I can say without hesitation that he’s not getting this back. I liked the Tonepump Jr, but I felt it had a limited range. What I mean is that I would never solo one pickup because it didn’t sound great with either one soloed. It was good, but I would use both on full, or dial back one of the pickups just a little. And I would never dime the treble or bass controls or even go as high as 80%. I feel that the LHZ has a wide range that sounds great.

I took the bass to band practice and it was good, but I gigged with it on Saturday night and I must say that it was glorious. So if you’re on the fence, I would say go for it. If you have questions about this preamp, Lonnie will respond immediately. He’s great to deal with.

 

[AgingEngineer]

I caved in and ordered the LHZ-01 preamp. It arrived immediately and I installed it right away. I can say without hesitation that he’s not getting this back.

Dude... this made my night! True story, my wife just said the other day that she's going to make my an LHZ t-shirt, and on the back it'll say "Hold on, I just gotta answer this guy..." lol

One of the things I really love about this project is talking with this amazing community of musicians. I don't get a lot of messages (and I protect my personal time), but when I do I am genuinely interested in learning what a client is trying to achieve and helping them find the right answer.

Your comment on the difference gigging is spot on: the LHZ (and any Haz clone) really hits the sweet spot when played harder. Practice is one thing, but at a gig is where we tend to get into zone and dig in. I'm glad the LHZ is giving you the tone you wanted!

 

[AgingEngineer]

Well, the first test unit has been built! Going to put it through some tests this week (I have an American Fender Jazz hanging on the wall that I've been itching to run through the LHZ) before it ships off to my beta tester to beat up in the field.

Assuming all goes well, we should have this in the store within a month!

 

[VeryTallBassist]

Well, the first test unit has been built! Going to put it through some tests this week (I have an American Fender Jazz hanging on the wall that I've been itching to run through the LHZ) before it ships off to my beta tester to beat up in the field.

Assuming all goes well, we should have this in the store within a month!
View attachment 5353779 View attachment 5353780

Man, now I'm gonna have to buy a passive bass just to rock this stomp box. Damn you, Lonnie!

 

[bigsnack]

Looks amazing man!

 

[AgingEngineer]

I'd gotten a lot of questions about the impact of battery voltage on the preamp over the last few months:

• Can my battery suddenly die during a gig?
• What's the sound difference between 9volts and 18volts?
• How will I know when the battery start to go bad?

Being the electronics nerd I am, I decided to run some audio tests on the preamp running from 18volts all the way down to 3 volts to see what happens. I learned some interesting things along the way and made a video to share.

 

[BKsGarageBand]

I'd gotten a lot of questions about the impact of battery voltage on the preamp over the last few months:

• What happens if the battery dies during a gig?
• What's the sound difference between 9volts and 18volts?
• How will I know when the battery start to go bad?

Being the electronics nerd I am, I decided to run some audio tests on the preamp running from 18volts all the way down to 3 volts to see what happens. I learned some interesting things along the way and made a video to share.

Well done!

It’s nice to see the results of audio in quantifiable format. Combining the two samples in a subtractive form is a great way to show that sometimes we don’t hear what we think we hear.

 

[direktor]

I'd gotten a lot of questions about the impact of battery voltage on the preamp over the last few months:

• Can my battery suddenly die during a gig?
• What's the sound difference between 9volts and 18volts?
• How will I know when the battery start to go bad?

Being the electronics nerd I am, I decided to run some audio tests on the preamp running from 18volts all the way down to 3 volts to see what happens. I learned some interesting things along the way and made a video to share.

Fantastic video. Was able to follow all of it. And it confirmed everything I’d guess about power supply vs sound. Although I figured “moar haz” at 3V would sound better, but it really doesn’t.

Just an idea while I’ve got you on the phone. I’d kill for a LHZ install that can be switched passive and still had tone roll off via cap on the treble. I suspect can be done with a stacked treble pot?

Just sayin.

 

[BKsGarageBand]

Well, the first test unit has been built! Going to put it through some tests this week (I have an American Fender Jazz hanging on the wall that I've been itching to run through the LHZ) before it ships off to my beta tester to beat up in the field.

Assuming all goes well, we should have this in the store within a month!
View attachment 5353779 View attachment 5353780

I see one of these units paired with an acoustic bass in my future…