Presentation of the Fosi Audio ZP3 multi-input balanced preamplifier, and my personal experiences

[Sean Heisler]

I’ve had the ZP3 for several days now and agree with the write up here, great sounding unit for the price. One odd thing, and in contrast with most of Fosi’s offerings, they didn’t really make this unit to swap the opamps however it’s not impossible and I did it. This unit is different than some of their other more recent offerings, there is no board that slides out or lid that pops off. To get to the opamps, in which there are two, you need to peel off the black plastic trim (adhesive backed) on the sides of the unit which reveals a metal side panel with four screws that you remove. The 2 opamps are in the middle of the unit and you can see very quickly that any attempt to remove the board, and the numerous number of ribbon cables and wires, is nearly impossible. Matt Coykendall on youtube explains some of this in his video on the ZP3. What I did was use some long tools to grab the opamps (I used a set of long kitchen tweezers), which by the way I can confirm the opamps are LME49720’s (at least in the unit I got), and then wiggle it out of its socket. Pretty much plan on mangling the legs of the opamps. I then installed SX52B discrete opamps and used the tweezers to position them onto the sockets and push them down into place. All in all it took some patience and wasn't too bad.

With the SX52B opamps in place the sound quality took a jump up. Fuller, smoother, larger soundstage, deeper tones, more detailed, deeper/better bass. What you expect from a quality discrete op amp. The stock unit sounds great but it's quite neutral and clear, almost to a fault. The discrete opamps really added some fullness and smoothness. I'm using it with a Denafrips Pontus II and V3 mono's. I'm also using a figure 8 (mickey mouse) to IEC adapter so that I can use one of my quality power cords with it and that elevated the sound as well. I am also using the high pass setting with the sub out to my dual subs (Y splitter) which does sound better than no high pass and using the single ended preouts to my subs.

 

[hunyadi]

I'm wondering how the sq of this preamp compares to the P3. Same goes for the P4 compared to the P3.

I'll probably just buy it and find out for myself. Love the Fosi stuff.

I don't know about the p3. The p4 is a very good sounding preamp. The zp3 is even better.

 

[hunyadi]

I’ve had the ZP3 for several days now and agree with the write up here, great sounding unit for the price. One odd thing, and in contrast with most of Fosi’s offerings, they didn’t really make this unit to swap the opamps however it’s not impossible and I did it. This unit is different than some of their other more recent offerings, there is no board that slides out or lid that pops off. To get to the opamps, in which there are two, you need to peel off the black plastic trim (adhesive backed) on the sides of the unit which reveals a metal side panel with four screws that you remove. The 2 opamps are in the middle of the unit and you can see very quickly that any attempt to remove the board, and the numerous number of ribbon cables and wires, is nearly impossible. Matt Coykendall on youtube explains some of this in his video on the ZP3. What I did was use some long tools to grab the opamps (I used a set of long kitchen tweezers), which by the way I can confirm the opamps are LME49720’s, and then wiggle it out of its socket. Pretty much plan on mangling the legs of the opamps. I then installed SX52B discrete opamps and used the tweezers to position them onto the sockets and push them down into place. All in all it took some patience and wasn't too bad.

With the SX52B opamps in place the sound quality took a jump up. Fuller, smoother, larger soundstage, deeper tones, more detailed, deeper/better bass. What you expect from a quality discrete op amp. The stock unit sounds great but it's quite neutral and clear, almost to a fault. The discrete opamps really added some fullness and smoothness. I'm using it with a Denafrips Pontus II and V3 mono's. I'm also using a figure 8 (mickey mouse) to IEC adapter so that I can use one of my quality power cords with it and that elevated the sound as well. I am also using the high pass setting with the sub out to my dual subs (Y splitter) which does sound better than no high pass and using the single ended preouts to my subs.

I had the zp3 very early. I figured out how it came apart on my own and took the circuit apart. The stock op amps is actually NE5532.. I also put discrete op amps in it. The new version of the akliam lc5 which is flat. Everything is the same, except this one is no longer the standing one. It turned out very good.

 

[Sean Heisler]

I had the zp3 very early. I figured out how it came apart on my own and took the circuit apart. The stock op amps is actually NE5532.. I also put discrete op amps in it. The new version of the akliam lc5 which is flat. Everything is the same, except this one is no longer the standing one. It turned out very good.

Wow, weird they are putting different op amps in. My ZP3 came with LME49720 op amps. There are just so many ribbon cables and boards in there, just looked scary to take all that out. Did you put the film plastic back on the sides?

 

[hunyadi]

Wow, weird they are putting different op amps in. My ZP3 came with LME49720 op amps. There are just so many ribbon cables and boards in there, just looked scary to take all that out. Did you put the film plastic back on the sides?

yes I put it back, I thought about no putting it back. but in the end I put it back.

 

[motorstereo]

My zp3 just got delivered a few minutes ago. I know what I'll be doing this afternoon instead of painting the house in the 90+ degree heat.

 

[motorstereo]

A follow up on my zp3 now that I've had a day with it. Sound quality is outstanding and the little bear balanced passive it replaced has been retired. I had thought I'd need to add 1 click of bass but it's not needed. The zp3 produces more bass at the flat setting than the passive did. The little Fosi also has a bit more drive than the passive did which is nice. The remote is a welcome feature but they need to go back to the drawing board on the volume knob with no stops which really is my only and very minor complaint. For the money spent one would be hard pressed to find anything remotely close to comparable to this little gem from Fosi.

240 wpc monoblocks with usb cooling fans and a balanced preamp on a tiny 2 shelf rack about the size of a small loaf of bread. It didn't break the bank and it sounds far better than any overpriced and problematic vintage gear I've dragged home over the years.

 

[SWL3600]

A follow up on my zp3 now that I've had a day with it. Sound quality is outstanding and the little bear balanced passive it replaced has been retired. I had thought I'd need to add 1 click of bass but it's not needed. The zp3 produces more bass at the flat setting than the passive did. The little Fosi also has a bit more drive than the passive did which is nice. The remote is a welcome feature but they need to go back to the drawing board on the volume knob with no stops which really is my only and very minor complaint. For the money spent one would be hard pressed to find anything remotely close to comparable to this little gem from Fosi.

240 wpc monoblocks with usb cooling fans and a balanced preamp on a tiny 2 shelf rack about the size of a small loaf of bread. It didn't break the bank and it sounds far better than any overpriced and problematic vintage gear I've dragged home over the years.
View attachment 3553494

That's what I'm talkin bout!

 

[Karlaka]

Good afternoon, ladies, gentlemen.

A while back, I inherited some fabulous vintage speakers from the renowned Acoustic Research brand from a friend's father. They're more precisely the AR-92s, direct descendants of the legendary AR-3a.

They're exceptional speakers, but they have the disadvantage of being very demanding when paired with an amplifier, as they require a lot of power, especially to drive those 10-inch bass drivers.

The idea was to put together a setup focused on versatility and performance, without incurring excessive expenses. I decided to try a Crown XLS 2002 PA power amp that I've had for some time, and which has given me varying results depending on the setup I use.

Obviously, the AR-92's power requirements were fully met by the XLS's 650 Wpc, but the trade-off was that the sound was a bit harsh, cold, and had a slight hiss that was perfectly audible from the listening position.

This is why I came up with a solution that required placing a preamplifier between the source and the power amp.

And what better way to fill this role than the new ZP3!

With that introduction out of the way, let me tell you about my experience:

WiiM Ultra + Fosi Audio ZP3 + Crown XLS 2002 + AR-92.

The combination of the Fosi Audio ZP3 preamplifier, the Crown XLS 2002 power amp, and the Acoustic Research AR-92 monitors, driven by the WiiM Ultra as a transport, resulted in a surprisingly dynamic and detailed listening experience.

The ZP3 provides a very subtle (almost neutral) warmth without sacrificing clarity, achieving a perfect balance between musicality and precision. Its gain circuit delivers a robust signal to the Crown XLS 2002, avoiding dynamic loss—ideal for the AR-92, which are cabinets with a neutral character but demanding amplification. With 650W per channel (into 4Ω), the Crown offers tight control over the bass of the AR-92s, speakers known for their low impedance and 10" woofer. The difference compared to traditional integrated amplifiers is huge: the bass is tighter and the soundstage gains depth, yet the sound remains clean and neutral, even at high volumes. Of course, you have to adjust the gain well to avoid residual noise (this is where the ZP3 helps with its very low noise level). The AR-92s, classic from the 80s, are still impressive. With the power of the Crown and the tuning of the ZP3, their crystalline midrange and deep, but not exaggerated, bass stand out.

The combination with the ZP3 slightly softens their original "cold" sound, adding a very enjoyable musicality. The ZP3 allows tone roll-off and bypass mode for a more direct sound, mitigating the "harshness" of the Crown, while the latter gives authority to the AR-92. As an added benefit, this compact and simple preamp almost completely eliminates that annoying hiss, adding musicality, while the Crown and AR-92 deliver an impact faithful to the spirit of "High Fidelity." The WiiM Ultra completes the circle as a modern and flexible source.

The ZP3's analog balance helps compensate for potential imbalances in speaker positioning. The tone controls are practical for adapting to acoustically challenging recordings or rooms.

This combination delivers performance far exceeding its overall cost, with a powerful yet refined sound.







Key Features of the Fosi ZP3 Preamplifier:

1. Pure Analog Design, No Compromises.

No DAC or Digital Processing: The ZP3 keeps the analog signal intact, avoiding unnecessary conversions that can degrade the sound.

The gain stage is based on op-amps widely respected for their neutral and detailed sound, but I gather it allows for interchangeability for customization.

The power supply provides enough headroom to avoid distortion even at high volumes.

2. Precise and Useful Controls

Tone Adjustment (Bass/Treble): Unlike many passive preamps, the ZP3 allows for basic equalization to adapt to acoustically challenging recordings or rooms.

Stereo balance: Ideal for correcting minor asymmetries in speaker positioning. 3-Input Selector (2 x RCA, 1 x XLR): Perfect for connecting multiple sources (e.g., WiiM Ultra, turntable with external phono preamp, CD player, dedicated DAC, etc.).

3. Solid, functional, and high-quality construction.

Metal housing: Minimizes interference and vibrations, very pleasant to the eye and to the touch.

Smooth and precise volume potentiometer: No noise when turning, even at low volumes. I think the implementation of this hybrid technology using an NJR NJU72315 volume IC is groundbreaking, to say the least, and offers an exceptional experience.

Tone Bypass Switch: If you prefer a completely direct signal path.

Gold-plated connectors demonstrate the brand's commitment to maintaining high standards, even in this budget range.



Conclusion:

The Fosi Audio ZP3 is a high-quality analog preamplifier designed for audiophiles looking for control, transparency, and versatility in their audio chain. In my setup with the Crown XLS 2002, the Acoustic Research AR-92 and the WiiM Ultra, the ZP3 proved to be a key component in taking the musical experience to the next level.

The ZP3 can be the heart of any system. An affordable yet well-executed device, it's ideal for setups where simplicity and precise control are paramount. Recommended for those looking for a scalable and nuanced setup.

 

[SWL3600]

Got mine today. So far, so good....sounds great. I plan on replacing the orange knob with a black one like I've done with all my other Fosi gear.
I mostly appreciate the sub output. No splitters needed.

 

[DavidTT]

A follow up on my zp3 now that I've had a day with it. Sound quality is outstanding and the little bear balanced passive it replaced has been retired. I had thought I'd need to add 1 click of bass but it's not needed. The zp3 produces more bass at the flat setting than the passive did. The little Fosi also has a bit more drive than the passive did which is nice. The remote is a welcome feature but they need to go back to the drawing board on the volume knob with no stops which really is my only and very minor complaint. For the money spent one would be hard pressed to find anything remotely close to comparable to this little gem from Fosi.

240 wpc monoblocks with usb cooling fans and a balanced preamp on a tiny 2 shelf rack about the size of a small loaf of bread. It didn't break the bank and it sounds far better than any overpriced and problematic vintage gear I've dragged home over the years.
View attachment 3553494

+1! I'm done with 'big box' gear and have started to wonder when the absolute bottom will fall out of the market for standard-size Class AB amps, especially used ones. I see sellers offering fifty-pound boxes and wonder how on earth they find people to buy them, not to mention the costs to ship them around these days.

 

[motorstereo]

+1! I'm done with 'big box' gear and have started to wonder when the absolute bottom will fall out of the market for standard-size Class AB amps, especially used ones. I see sellers offering fifty-pound boxes and wonder how on earth they find people to buy them, not to mention the costs to ship them around these days.

Just a few short years ago I would've scoffed at the idea of my vintage gear collection being replaced by these Fosi units. The reality is they're much better sounding than any vintage piece I brought home by any manufacturer over the years.

I also don't miss the chore of bringing several pieces to the tech to have back ups for the back ups. It's such a pleasant change to order from Amazon and have it here the next day when I spill coffee down the vent of my V3. The price of the replacement V3 is about the cost of gas and food money for the wasted day spent dragging the gear to the tech's. The anticipation of the diagnosis and hoping the bill doesn't require a home equity loan isn't missed either.

Agreed; leaving the heavy big box gear gear behind and never to return is a no brainer to me now that the chip amps have improved to the point they're at now.