Fosi Audio ZP3 Preamplifier Review

[Joe Smith]

People hi

Actually, I think a little differently:

why offer such a device when almost all dacs these days have a volume control (and sometimes even a PEQ...) ?

For: Multiple source switching convenience, some preamp gain may help a system, and a lot of DACs don't have volume control (for instance, the 3 I currently use - Schiit, JDS Labs, Fosi).

 

[JamesC]

For my new setup, the ZP3 fits nicely, I bought it on release day and got the early discount. It’s paired via XLR with two Fosi V3 monoblocks driving Totem Mites, and its sub out feeds my SVS 3000 Micro. Sources include a Topping D90 AKM DAC (XLR) fed by a Roon RPi endpoint, an SMSL PL100 CD player, and a Drop + Audio-Technica Carbon VTA turntable through a Fosi Box X5 phono preamp. The whole setup is compact, works well and sounds excellent. I am happy with the ZP3.

 

[phoenixdogfan]

Having that high pass, is a unique and valuable feature. Any number of subs sold today only have a low pass, leaving the user the option of either running them unaltered or putting the entire system under something like a $600 miniDSP unit. While it's a major inconvenience to not have a volume led, it's one I would rather live without than no high pass. Aside from that it looks very acceptable in performance and it has plenty of gain to drive even the least sensitive amps. For only $189, it's a bargain.

Thanks for the excellent review, Amir.

 

[shuppatsu]

[quoting an Amazon review] ’One minor complaint about its volume control is, it doesn't always remember its last volume setting as indicated by some its reviewers. It immediately outputted its maximum volume when it was powered up on one occasion, which fortunately was caught before any harm was done.

I thought people were overreacting to the lack of volume indicator, but forgetting the volume level and defaulting to max volume is unforgivable, especially with no indicator.

 

[ICIETDIYEUR]

I completely agree with you shuppatsu but what do you want:

when we are (too?) objective there are still many people who want to 'drown the fish' we don't know for what reason...

 

[JeremyFife]

Thanks for the review, always appreciated.

Good performance, and great value, no doubt.

It's ironic though that the main attraction of a preamp for me is to add safe volume control (in case a DAC goes rogue and full volume) ... this actually adds to that worry!!

For me, personally, not safe, not something I'd consider. Shame.

 

[audio_tony]

I'm intrigued by this volume issue.

Continuous rotation suggests that it's a rotary encoder. The digital volume control chip suggests the same thing.

Now, I have several devices with a rotary encoder volume control (including the radio in my car), and when the power is off, one can rotate the volume control as much as one can, and the volume remains at the same level at power on, as it was at power off.

So what makes the ZP3 so different? Is the volume chip powered even when the preamp is powered off?

 

[SoySalsaPicante]

I'm intrigued by this volume issue.

Continuous rotation suggests that it's a rotary encoder. The digital volume control chip suggests the same thing.

Now, I have several devices with a rotary encoder volume control (including the radio in my car), and when the power is off, one can rotate the volume control as much as one can, and the volume remains at the same level at power on, as it was at power off.

So what makes the ZP3 so different? Is the volume chip powered even when the preamp is powered off?

The issue is that the unit can be, "forgetful," so even if you don't touch the volume dial while it's powered off, there is a potential, when it is powered back on, that the volume is no longer where it was prior to shutting down, and now suddenly is at absolute maximum.

 

[redjr]

Beware of volume control when you set up the unit for the first time. I almost blew out my speakers. Its a serious oversight on Fosi's part to have volume control turned up that much out of the box.

You can of course 'teach' your volume control level. The only visual indicator is the dimple on the knob. So, set your volume level to where you normally listen at - regardless of where the dimple is. Turn it off, and then rotate the knob (the dimple) to, say 10:00. Turn the pre back on. It will remember where the level was, but now the volume control dimple is set to a relative/normal area on the dial. I've set up my inputs to be 'normal' at around 10:00. A little trouble, but IMO not unreasonably so.

 

[Power Pop 23]

You can of course 'teach' your volume control level. The only visual indicator is the dimple on the knob. So, set your volume level to where you normally listen at - regardless of where the dimple is. Turn it off, and then rotate the knob (the dimple) to, say 10:00. Turn the pre back on. It will remember where the level was, but now the volume control dimple is set to a relative/normal area on the dial. I've set up my inputs to be 'normal' at around 10:00. A little trouble, but IMO not unreasonably so.

Yes, a 'workaround' IF one owns a Fosi Audio ZP3. Otherwise, I would consider other preamplifiers.

 

[Anatols_Dad]

Unbalanced in/out shows fair bit of degradation over balanced due to added distortion:

I was extremely surprised about the apparent degradation over balanced in-/output. The manufacturer's specs do suggest otherwise, as far as I can read them - generally (!): "SINAD >115 db".
Thank you, @amirm!

 

[Anatols_Dad]

View attachment 469681
I no longer see this XLR block-diagram posted at their website for the ZP3.

It's still there (or back again)

 

[sergeauckland]

The issue is that the unit can be, "forgetful," so even if you don't touch the volume dial while it's powered off, there is a potential, when it is powered back on, that the volume is no longer where it was prior to shutting down, and now suddenly is at absolute maximum.

My car does that, pretty much at random. Mostly, it stays where it was last set, but occasionally and randomly, it'll set itself to zero. Fortunately not 100%! but nevertheless annoying. Dealer can't find anything wrong, installed new software, but still does it every now and then.

S

 

[SoySalsaPicante]

My car does that, pretty much at random. Mostly, it stays where it was last set, but occasionally and randomly, it'll set itself to zero. Fortunately not 100%! but nevertheless annoying. Dealer can't find anything wrong, installed new software, but still does it every now and then.

S

Resetting to zero is absolutely better than resetting to max.

 

[MCH]

If I remember correctly the default status of the chip is mute. If people is really experiencing max volume after whatever either someone pressed a button unknowingly or there is a firmware issue.

(Not trying to defend the product, that obviously has a huge design flaw)

 

[Fleuch]

From the Fosi web site (viewed at 20:45 on 14th August 2025) nearly all items have the same $USD price regardless of shipping destination. Three of the exceptions are listed here:

		US	UK	AU	EU	Other
ZA3 Balanced Stereo Amplifier (no PS)		$139.99	$129.99			$139.99
ZP3 Preamplifer		$199.99	$249.99	$199.99	$249.99	$199.99
GR70 Tube Headphone Amp		$279.99	$279.99	$269.99	$279.99	$279.99

The price differences for the ZP3 was the killer when considering a purchase; now the issue of the volume control has "put the lid on the coffin". Thank you Amir for highlighting the problem of an infinitely rotating volume control. The ZP3 should use the same volume control as that found on the P4, then this would not be an issue.

As a usually open and transparent company Fosi should explain to ASR why these geographical price variations exist.

Apologies for the poor table layout!!

 

[xanalog]

I love the digital volume control on a little SMSL cheap amp I have in my dining room, the AO100, but that unit has a very clear and bright dB readout and is a real pleasure to use without danger of blowing speakers etc.

Yes, the SMSL AO200MkIII does the same but turns-off the OLED display, after 60 seconds: A fair compromise!
But, even SMSL is no angel, with all their display designs: Their DO100Pro -by default- reverts back to bit-rate display, after 4 seconds.

 

[CJH]

Got one for use as a HP crossover for KEF LS50 metas to a pair of rythmik subs. Set the crossovers of each at 120Hz and it works well. Did the vol level matching by ear and don't use the vol control otherwise.
CJH

 

[SoySalsaPicante]

Got one for use as a HP crossover for KEF LS50 metas to a pair of rythmik subs. Set the crossovers of each at 120Hz and it works well. Did the vol level matching by ear and don't use the vol control otherwise.
CJH

Try HouseCurve; it’s free and reasonably accurate even with the phone mic, at least around 120Hz.

 

[Sir Sanders Zingmore]

coupons available for less).

Silly question sorry, but what does that mean?