Fosi Audio ZP3 Preamplifier Review

[somebodyelse]

Welcome @OC6Huki - since you seem to be using balanced interconnects all round, one or more of the components is probably not following AES48 and has a 'Pin 1 Problem'. There's a good chance it's the ZP3 but it could be one or more of the others in a way that doesn't cause a problem in that combination. You can find out for sure which component(s) aren't following standard using the method in Jensen Transformers' Application Note AN007 sections 3.3 and 3.4 if you can do a bit of DIY. If the Outlaw has a ground lift switch then you could try that - the ZP3 doesn't. Another option would be to try a cable with the shield disconnected from pin 1 at the receiving end - see AN007 section 3.6 for why it's the receiving end not the source end. Failing that, see the transformer isolation proposed in AN007 section 3.5.

 

[gino1961]

Hi to All ! sorry to jump in but i am very interested in this little unit I have already a P4 that i like a lot
But the idea of getting a unit also with balanced connection is inviting
First i really do not understand the need of tone control given that the best measurements are with them bypassed
I guess that the circuit should be similar to that of the P4 but the THD using rcas is surprising me
The main attraction for me is the use of a chip for the volume control I strongly believe in these chips Many cheap pots have unbalance issues
Is there anyone using a ZP3 through XLRs with satisfaction ?
thank you very much

 

[Schlippwhip68]

If Fosi revise the ZP3 to iron out the obvious flaws then it will be in my crosshairs when they do. I like the balanced option as well as the sub out which the current P4 negates. I use the P4 from time to time and have to say the tone controls are better than expected, certainly a big step up in actual tonal shift over many of the integrated amps I have tried, quite a clean sound to be fair. The opa828 has excellent bass control and sits well in the P4.

If a MK2 version were to arrive then I would hope Fosi would revise the side panels. For those whom don't believe in rolling op amps then not touching the amp is not a concern but to negate the option altogether for opinion strikes me as a little unfair all round. In my meagre experience rolling op amps makes enough of a difference to either make or break a deal. To leave the option available does not impede on any performance of the product. Those side panels, imo, are awful and an hinderance at best for the 'Rollers' among us like myself. The also look a little cheap. I would stick to the matt metal panel and allow easy access to the internal board.
In regard to the tone controls, either clean up the sound with better implementation and better parts or just drop the tone control altogether from the unit.

If this unit is as clean, when bypassing the tone control, as this review claims then the opa828 should theoretically at least, shine in the ZP3! The opa828 is a super clean, neutral op amp with excellent frequency control especially in the bass. I haven't found an op amp that comes close to the control that chip has over the bass yet. I use them in both my Fosi P4 and Douk Audio P7 pre amps. If the unit is revised to house better access into the PCB (dropping the glossy side panels) better volume implementation and maybe revised tone control purity then I would probably zero in like a Pit Bull on a Rabbit sandwich but for now its a just a quick snack that I can avoid quite easily.
My Douk Audio P7 with the opa828 and replacement Psvane Horizon 12ax7-AT valves is already do a suprerb job of feeding my Audiolab M-PWR power amp via balanced connection. The advantage of the ZP3 is balanced input and sub out in this case, but even without balanced in on the P7 (it converts the single line signal internally) the P7 provides a balanced out. No option of a sub out on the P7.

The volume dial is obvious, I am not sure why they didn't use the same analogue control as the P4 but apparently there is a reason somewhere...?

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