Reverse engineering vintage Haz Labs pre

[piitxu]

I have bought already 4 LHZs from Loonie. They have worked wonders on all the basses I have tried them: Spector NS Icon, Spector Pulse 5, LTD Surveyor 87... each one with its own personality even if sharing identical electronics at some point. The Icon is the classic NS sound, the Pulse is a more aggresive variant, and the LTD is a very ballsy sounding bass with the LHZ dimed due to it's almost 5kg and classic P arrangement.

Recently I started to experiment further. I have an LHZ 05 in a Harley Benton enhanced, the Sandberg California copy, with EMG P/MM pickups. It has a mix of qualities from the Pulse and LTD: heavy bass with swamp ash body. It's very bold and deep, but doesn't really have the same attack as the alder basses like the Icon or the LTD.

But the biggest surprise is my "rescue" Squier P special standard. It's a parts bass now: Squier P/J body, modified to reverse P, Fender high mass bridge and a Harley Benton P bass neck. And just for science, dropped a set of EMG P/Js and a LHZ 04 on it... and it's the best sounding bass I've ever had! it beats all of the above. It's deeper and bolder than the Spectors, while retaining all of the attack and transients. It has no business sounding this good... specially when playing with the band, it's permanent bass stank face.

There's more science to come, I ordered another Harley Benton Enhanced from Thomann but this time it's the alder body. Going to drop another P/MM with the LHZ05 into it.

Also I want to shoutout LHZpreamps improved shipping to the EU: at least when shipping to Spain, there's no duty/import taxes or paperwork anymore. Taxes are paid directly in the check out and you'll get your preamp in 72h at your doorstep. For comparison, I bought my second LHZ from Bassdirect.uk and it took 11 days and filling 3-4 forms to recieve it. If you guys are in the EU and have doubts about the import, check it again because now i't s a piece of cake.

Aaaand I just burned out the LHZ 05... I Think I've wired the 18v mod wrong...

 

[AgingEngineer]

Aaaand I just burned out the LHZ 05... I Think I've wired the 18v mod wrong...

No worries... you've got a 1 year warranty on it. Just drop me an email and we can arrange a replacement to be sent at no charge.

 

[ThisBass]

I just got my Euro 6LX from my luthier friend, who replaced the Tone Pump pre with an LHZ-04 and said it's a much better-designed pre and sounds cleaner. My first impressions of playing my bass through a Focusrite 2i2 and Beyerdynamic DT 770 Pro X headphones are WHOA!!!!! The sound of my bass is definitely cleaner with a tighter bottom end and clear but not harsh high end! I can't wait to play through my bass rig and gig with it next week!

Your luthier friend might be right when he noticed a cleaner sound with LHZ vers. tonepump.

Petr Michalik once designed the tonepump (which actually is the Michalik bp-4 preamp) as to be more musical sounding when pushed hard to its limits.
This was done with a FET schematic design for the preamp just to push noticeable 2nd order harmonic rather than it was obtainable from (typical) op amp schematic designs.

Here you are with a link to the Michalik bp-4 preamp and, Petr Michalik also did left there a couple of words about the early days of the tonepump at the time of beginning when Stuart Spector an PJ Rubal both together did visit him in his workshop.

Michalík Designs

Musically designed electronic circuits for musicians, preamps, active electronics for bass players, volume and wah-wah pedals for guitar players.

michalik.cz

edit,
it should also be noted that in the very beginning of CZ SSD production area in the Czech Republic, Petr Michalik produced HAZ clones for the SSD bass guitars. These are quite rare birds and are quite hard to found cause only short time later they changed for the tonepump (Michalik bp-4) preamp which then completely replaced the Czech made HAZ clone preamp.

 

[thisSNsucks]

Just popping by to say the LHZ is a great sounding preamp, and super easy to install. It does the aggressive thing but can still be dialed in for some nice fat tones. Works in non Spector basses too. Here’s one I built recently:

 

[AgingEngineer]

Just popping by to say the LHZ is a great sounding preamp, and super easy to install. It does the aggressive thing but can still be dialed in for some nice fat tones. Works in non Spector basses too. Here’s one I built recently:

View attachment 7506259

Beatiful!!! It's great to see the LHZ getting some love from other bass models! In the last year we've got a LOT of folks dropping them into Ibanez, Fender, Schecter, Yamaha, Sire, and various p-bass and jazz bass varieties.

 

[piitxu]

Finally, another happy LHZ equipped bass. Great customer support from @AgingEngineer over my burnt LHZ 05. He contacted me last Friday and the replacement arrived yesterday. Right now it's setup as an LHZ 4 without the mid range control, there's just not enough space in the cavity for the stacked pot, but it's not a big issue, will do modifications in the future.

For now, this thing roars! It's smooth, articulate, big mid presence. It can't get as aggresive as a P/J, but it's a very pleasant tone. Thinking on tuning this BEAD... we'll see.
Also, this is not a Sandberg... it's a 299€ Harley Benton. Superb finish and build quality for the price, and now, killer sound

 

[crazycloud]

Also, this is not a Sandberg... it's a 299€ Harley Benton. Superb finish and build quality for the price, and now, killer sound

That's nice looking for an FSO. Bet it sounds great with the EMGs and LHZ.

 

[AgingEngineer]

Finally, another happy LHZ equipped bass. Great customer support from @AgingEngineer over my burnt LHZ 05. He contacted me last Friday and the replacement arrived yesterday. Right now it's setup as an LHZ 4 without the mid range control, there's just not enough space in the cavity for the stacked pot, but it's not a big issue, will do modifications in the future.

For now, this thing roars! It's smooth, articulate, big mid presence. It can't get as aggresive as a P/J, but it's a very pleasant tone. Thinking on tuning this BEAD... we'll see.
Also, this is not a Sandberg... it's a 299€ Harley Benton. Superb finish and build quality for the price, and now, killer sound

Awesome, and I'm glad we got you back to good and everything is sounding great!

Can you give me an idea of what the space constraint was with the concentric pot? Was it the height or width of the pot, or something else?
The reason I am asking is that we're working with out potentiometer factory to spec out a smaller concentric pot in a 9mm body. It'll use the same 8mm/6mm shafts, but they body portion in the cavity is a lot smaller.

Cheers!

 

[piitxu]

Awesome, and I'm glad we got you back to good and everything is sounding great!

Can you give me an idea of what the space constraint was with the concentric pot? Was it the height or width of the pot, or something else?
The reason I am asking is that we're working with out potentiometer factory to spec out a smaller concentric pot in a 9mm body. It'll use the same 8mm/6mm shafts, but they body portion in the cavity is a lot smaller.

Cheers!

Hope this helps:

These are the positions of the two tone pots in this bass. In the lowest position, the stacked pot's PCB hits all walls around it, just barely. You can make it fit but it can get unconfortably tight. If you turn the pot so the PCB faces north, towards the second pot then it clashes with the output jack cables, and you have to do a 180º bend of the cables under the pot so it gets even more crowded. The issue compounds when you add the active balance which also has a big PCB.
You can make it work in this bass with a little patience, but on a Fender/Squie P/J there's even less space. I had to get rid of the balance pot and run a two knob setup with one volume and the stacked pot for the LHZ4 in a Squier P/J.

 

[AgingEngineer]

I finally finished testing the Legacy preamp to see how it performs when the batteries start to die and... learned some new things!

I went into this video assuming I'd find the Legacy preamp (using the power-hungry 5532 opamp) would stop working at a higher voltage. The reality is that the Legacy works all the way down to 4 volts, just like most other preamps. The real story is how internal battery resistance changes when a battery is depleted. That, coupled with preamp that requires more current, creates a steep voltage-drop cliff that can go from sounding fine to nothing at all within minutes.

To be clear, this is NOT a condemnation of the Legacy preamp! It is a fantastic preamp. It just requires more current. Which means we need to be aware of that difference so we don't get caught short.

 

[Hillie]

What's your take on the NE5532 redesign I've read about that removed some protective components and reduced the supply voltage range?

 

[AgingEngineer]

What's your take on the NE5532 redesign I've read about that removed some protective components and reduced the supply voltage range?

I’d think that’d qualify to be a completely different part number. I assume there’s probably an IP or branding reason for not retiring the original design and making this a new derivative PN.

 

[Hillie]

I’d think that’d qualify to be a completely different part number. I assume there’s probably an IP or branding reason for not retiring the original design and making this a new derivative PN.

I had (and still have) trouble believing it's true, because it indeed would seem like a completely different part. I'll have to try and find out more now.

 

[AgingEngineer]

TALKBASS EXLCUSIVE!

I'm looking for a couple beta testers for a UNIVERSAL BLEND module that we are planning on releasing in a few weeks. The Universal Blend looks and feels like our normal Active Blend control, but with a couple important differences:
1. It works with both passive and active pickups. No more selecting the correct pot value: one blend does it all.
2. It lets you mix an active and passive pickup together.
3. Extremely high 1M input impedance. This is intended to let your passive pickups have the same brilliance as if they were wired directly to the output jack.

What I'm looking for in beta testers:

• Domestic address in the US preferred. (If you're a prior client outside the US, that works too.)
• You've got passive pickups and are currently using an LHZ or EMG modular blend control.
• You have a bass with an active EMG and passive pickup a want to type your hand at blending these.
• Willing to give honest feedback on sound and operation.

If you are interested, please message me directly here on TB and let me know. I'm only looking for 5 testers maximum, so once those units go out that is all there is until this round of testing is complete.

 

[therocket290]

I installed a set of EMG PJHZs and an LHZ-05 preamp in my $85 Glarry short scale bass. It sounds fantastic and plays great after a bit of fret work and a setup. I was too excited to try it out and forgot to snap a photo of the cavity with everything in it. I put the battery in the back. Note that I use a dremel for my routing projects and just hack away until things fit, but it got the pickups and battery box in there.
I can wait to take it to practice tomorrow.

 

[piitxu]

I installed a set of EMG PJHZs and an LHZ-05 preamp in my $85 Glarry short scale bass. It sounds fantastic and plays great after a bit of fret work and a setup. I was too excited to try it out and forgot to snap a photo of the cavity with everything in it. I put the battery in the back. Note that I use a dremel for my routing projects and just hack away until things fit, but it got the pickups and battery box in there.
I can wait to take it to practice tomorrow.

View attachment 7562260
View attachment 7562261View attachment 7562262
View attachment 7562284

These kind of projects are fun! And with the modularity of the LHZ and EMGs you can always transplant them in a few minutes so It's never wasted money. The LHZ on my SquireBenton has been on 3 basses before finding a more permanent host

 

[AgingEngineer]

I love seeing posts like these from @therocket290 and @piitxu!! It makes me miss the "mad max" days in my teens and early 20's where I'd try anything just to see how things would sound!