Fosi Audio P3 Preamplifier & Headphone Amplifier Discussion

[RCL162]

Same here. And that was even after removing the orange rings. After 3 weeks I decided to re-purchase the P1 which I had previously returned. In side-by-side comparison and with the same 5654W tubes installed, the P1 sounds much better than the P3 IMHO. And provides a bit more volume to boot. P3 will go. PM me if you are in EU and have interest. Rgds... -John

Almost buy the P3. after reading all comments, maybe I'll wait for non-tubes preamp from fosi. Will stick with P1.

 

[Northa40]

I have commented in the thread previously but must insert my thoughts once again. The V3 is a great start drop the volume control. The P3 needs to drop the tubes , keep the volume ditch the tone controls add a balance control and it needs to have 3 RCA inputs and have sub out. Make it the same size as the V3. Now FOSI can make phono preamps, DACS and EQ's to go along with them. Make them all the same size, so you can stack them and now you have a winning package.

 

[Northa40]

As mentioned earlier in this thread something like the NOBSOUND NS-08P. Make it the same size as the v3.

 

[maudio]

I compared the specs of P1 and P3, P3 is higher specd and should sound better.
Also according to some buyers there seem to be an "older" version of P3 where Fosi sent them newer version of the board which sounds better.

I am getting mine today and hope it is the new version!

 

[RCL162]

I compared the specs of P1 and P3, P3 is higher specd and should sound better.
Also according to some buyers there seem to be an "older" version of P3 where Fosi sent them newer version of the board which sounds better.

I am getting mine today and hope it is the new version!

There is a batch number on the PCB board i think

 

[Clmrt]

Changes. Replaced the Crown with BK ST140 at home. P3 in the chain from pre-pro to amp. Noticed when moving it while powered the tubes rang physically and electrically through the speakers. Pulled it. I leave it powered up because the Mrs. likes the glowy tubes.

Where I had used it previously at work I now use a TEC754. It subjectively sounds much better.

I no longer have an application where I need the P3, and if I did, the microphonic tubes would bother me. I'm not interested in spending more money on new tubes for it.

Tubes ring
Volume pot is too hot at the bottom of its travel
Does not integrate well with any current situation I could use it in

 

[timiambeing]

I don’t really think the P3 is viable as a tube headphone amp, didn’t like it in that role at all, totally underwhelming. As a compliment to the V3, in what would seems an unnecessary pre-amp role however, it seems to perform some kind of voodoo magic! After an afternoon comparing V3 on its own, to ICEPower 125asx2 kit I’ve just built on its own, to both with P3 installed between these power amps and DAC has been enlightening.

Obviously I can’t do this blind, and it takes a while to swap cables etc, but with volume matched results were very interesting. The ICEPower (at three times the price!) was overall uninspiring, if nice, comfortable, perfectly ok. The P3 on its own was immediately more dynamic, interesting and impressive - if a little ‘in yer face’. The ICEPower with the P3 as a preamp was bland and boomy, but the V3 with the P3 was altogether more listenable.

There was no loss of detail compared to on its own, lots of dynamics still, just somehow it all hung together better. Perhaps the easiest way to describe it is if instead of a wall of pristine data, individual strands of the mix seemed to be picked out and presented forward, leaving other background detail, well in the background?

I don’t necessarily attribute this to the tubes, it may well be an impedance issue between the DAC and the V3, maybe the P3 is acting as a buffer? Anyway, it stays in and I’m keen to play with other budget Class D amps and maybe build the next one with a variable buffer maybe?

 

[Mojo Warrior]

[Prova d'ascolto] Fosi Audio P3 - vacuum tube line preamp with Bluetooth and headphone output

Fosi Audio P3 - line preamplifier with vacuum tubes, Bluetooth input, subwoofer output and tone controls. An article by Lucio Cadeddu per TNT-Audio, rivista di HiFi in Internet - www.tnt-audio.com

www.tnt-audio.com

Another reviewers opinion FWIW

 

[timiambeing]

[Prova d'ascolto] Fosi Audio P3 - vacuum tube line preamp with Bluetooth and headphone output

Fosi Audio P3 - line preamplifier with vacuum tubes, Bluetooth input, subwoofer output and tone controls. An article by Lucio Cadeddu per TNT-Audio, rivista di HiFi in Internet - www.tnt-audio.com

www.tnt-audio.com

Another reviewers opinion FWIW

I often find it hilarious how one persons mileage can be so far from another’s, till I remember my room isn’t his room, my DAC isn’t his DAC and his speakers are most definitely not my speakers… it’s a wonder there’s any common ground at all!

 

[timiambeing]

I do enjoy reading reviews, and to be honest I would rather read someone’s honest opinion in their system with their ears, than the often white wash given to audio products by endless YouTubers - although this guy is a little extreme, never heard of him, a bit marmite I would suspect and has his followers (a bit like ASR!). I love to be surprised, and like everyone on the planet I am prejudiced and my beliefs massively colour my experience, but the V3 combo really surprised me. I was ready for pretty much what this reviewer discovered but found something very different.

This Fosi kit is standing in for a £2k tube amplifier that is both clear and sweet, and widely enjoyed as such - but it doesn’t have the micro dynamics and sheer sparkle this little combo manages in my system, to my ears. I’m chuffed, and like I say I’m starting all over again after years of very expensive audio equipment - not sure whether to build (the ICEPower was disappointing for £349) or simply try a few other off the shelf Class A designs?

 

[Kimbrough Xu]

Almost buy the P3. after reading all comments, maybe I'll wait for non-tubes preamp from fosi. Will stick with P1.

Fosi has non-tubes preamp? Where is it?

 

[RCL162]

Fosi has non-tubes preamp? Where is it?

Fosi guy on Facebook told me there will be...idk when.

There's a lot of interaction there..you should join the group.

 

[Kimbrough Xu]

Fosi guy on Facebook told me there will be...idk when.

There's a lot of interaction there..you should join the group.
View attachment 350681

Thank you for the information.

 

[Joe Smith]

This is the hot item for me that I want from them! Holding off on buying a new integrated amp as if this preamp is good enough, I will just pair with the V3 or an Aiyima amp and be done with it...

 

[codex]

I have got the Fosi Audio P3 and have been listening to it for a week. I use it as a preamp, with my SMSL SU-1 DAC + WiiM Mini as a source.

I love it, didn't feel any perceptible loss in detail retrieval and clarity and there's a noticeable added oompth in bass and harmonics.

The P3 is a cute little device, with a much smaller footprint than I had imagined. I was thinking of stacking my SU-1 and JDS Labs Ol Switcher (which I use as a switcher for my turntable as a source, and switcher/volume control for my headphones), but alas that is not possible, so they stand side by side and it is still quite an elegant array of mighty miniature electronics.

I do prefer to run the headphones directly through the SU-1 + Ol Switcher, though. The sound comes across as slightly more analytical, so I am guessing the P3's RCA and headphone outputs tell slightly different stories, but it may also be my pairing of speakers / headphones.

 

[timiambeing]

I have got the Fosi Audio P3 and have been listening to it for a week. I use it as a preamp, with my SMSL SU-1 DAC + WiiM Mini as a source.

I love it, didn't feel any perceptible loss in detail retrieval and clarity and there's a noticeable added oompth in bass and harmonics.

The P3 is a cute little device, with a much smaller footprint than I had imagined. I was thinking of stacking my SU-1 and JDS Labs Ol Switcher (which I use as a switcher for my turntable as a source, and switcher/volume control for my headphones), but alas that is not possible, so they stand side by side and it is still quite an elegant array of mighty miniature electronics.

I do prefer to run the headphones directly through the SU-1 + Ol Switcher, though. The sound comes across as slightly more analytical, so I am guessing the P3's RCA and headphone outputs tell slightly different stories, but it may also be my pairing of speakers / headphones.

Yes I didn’t find the headphone output to be up to much (completely separate headphone amp chip i understand) but that was comparing to £600 worth of Rebel amp! However as a preamp running into my V3 in another setup it sings just like you describe

 

[Joe Smith]

I'm curious: For those of you using the P3 with the V3 amp, how are you running volume? Max amplitude for the V3 and then do the desired volume control via the P3?

While I've been resisting buying a P3, I'm considering it since cost is low...I had one other Little Bear tube gain stage that did basically, nothing at all, other than decease sound accuracy...

 

[timiambeing]

I'm curious: For those of you using the P3 with the V3 amp, how are you running volume? Max amplitude for the V3 and then do the desired volume control via the P3?

While I've been resisting buying a P3, I'm considering it since cost is low...I had one other Little Bear tube gain stage that did basically, nothing at all, other than decease sound accuracy...

In my setup I have them both set at around 1 o’clock and then I use LeedH digital volume control on my streamer for fine tuning - that setting means if the digital volume went crazy I at least wouldn’t blow my speakers!

 

[codex]

I'm curious: For those of you using the P3 with the V3 amp, how are you running volume? Max amplitude for the V3 and then do the desired volume control via the P3?

While I've been resisting buying a P3, I'm considering it since cost is low...I had one other Little Bear tube gain stage that did basically, nothing at all, other than decease sound accuracy...

An issue seldom addressed here is the (in my experience negligible) impact of pots in general on sound quality. In either scenario described in your question, you start with maximum attenuation in one of the devices and improve (i.e. reduce resistance) from there. I would suspect the V3 to have the better pot between both devices. Does it matter? Perhaps very little.

Pots in both devices have a logarithmic taper. That means that sound increases very fast once it starts to. There is thus little granularity at the bottom. So if you max the V3 out and adjust volume via the P3, you will quickly reach very high volumes. For exactly this reason,@timiambeing's approach above appears sensible to me.

In any event, I wouldn't fear loss of sound accuracy. The P3 is very competent and adds little coloration to the sound. What it does add is a bit more body, if that makes sense. Bass sounds more impactful, harmonics more vibrant, everything a little more fullsome.

To be honest, I too wasn't expecting much from the P3. Planned to continue using my JDS Labs Ol Switcher to passively attenuate sound coming from my SMSL SU-1 and use the P3 merely as a post-phono stage preamp for a new turntable. In the end, though, I liked the P3 so much that I am running everything through it now.

Go for it. You won't regret the purchase.

 

[Cgs0409]

I guess this question is directed to the Fosi member. Will the P3 preamp be upgraded to accept xlr cables to match what will be on the V3 mono amps? Are there any plans to allow for more than one RCA inputs? We need at least two. Thank you