I have used this pre-amp for three years. Adds nice warm sound to Class D amps (they can be a bit too sharp). My favorite use is after my ifi Zen phono preamp and then to my amp. For me, the ifi Zen is too crisp and lacks "warmth" and lacks some "punch" which this Fosi adds. Lots of affordable fun here. Thank you for sharing.
Totally agree. I've been using the P1 with the V3 Fosi amp and it brings a musical involvement that the stand alone amp isn't capable of. No need to change op amps on the V3 or tube changes on the P1. They compliment one another on the cheap. BTW, The speakers I've been using are the wonderful Mirage M290's. An absolute killer combo.
The 2 internal OP Amps can be upgraded to High Performance HiFi LM4562NA OP amps that will improve sound & reliability. They just plug into the existing sockets on the board. The 6K4 tubes are Chinese Military spec tubes that are reliable & used as buffers.
@@Pe721 Absolutely plug & play with the Muse01 op amp just be sure to install both in the correct direction matching the half moon notch to the pin sockets.
@@poyogamesbrcan this be done to the fosi X2? It has a jrc2028d opamp I think. I would wanna swap them out for a better one, I already rolled the tubes to 5654, I have ordered a pair of voskhod tubes.
I have a simular Aiyima tube A3, they come under many brand names. No hum at all, i use a larger PS and exchanged the op amps for opa 2604AP and it sounds great and "warms up" the sound of the 07, this is close to high end. it drives a Aiyima 07 with opa 2134 op amps. I had several tube amps and good vintage AB amps and this combination easy holds up. Unbeatable price - quality. Tried the GE 5654 tubes but did not improve the sound. The original tubes work best for me.
Fosi Audio's dirty little secret. Loaded with cheap and fake components. I have brought one previously. Not really very impressive sounding, and after I looked inside I found out why. The NE5532 Op Amp chips are fake. Most likely a $.10 chip that is marked as a NE5532. Along with counterfeit Elna audio caps. The other electrolytic caps are a known bad Chinese brand (no good) but are dirt cheap. The hum is likely from these terrible caps in the power supply section. If you ever test the Chinese fake Op Amp chips, you find they have a poor slew rate and a not so good response. Fortunately, they put sockets in for these, and it is super easy to replace the fake chips with real ones. Replacing the caps is not so easy or cheap but can be done. That is why it is so cheap. You have to remember that Amazon gets about 35%-45% of the cost of the item they sell, so it is really a $25 preamp. You can't build a quality unit, ship to America or wherever, and sell it on Amazon for $40. It is basically a nice aluminum shell with crap inside, made to have a look of quality.
Bravo, congratulations to you, I have 2 fosi audio a3 amplifiers, bender, I replaced the 5532s on them with the original american ne5532s I bought from digikey, which I have, there was a lot of sound, I think it is necessary to replace the fakes with the original parts for all devices from China to give good performance.
@JohnZornAscended 5532's have reverse protection diodes across the inverting and non-inverting inputs pins 2 and 3. With a multimeter in diode check mode, check between pins 3 and 2, and you should get approximately .8 volts. Reverse lead, and it should read about the same, indicating a diode in both directions. If you measure and there is nothing they are fakes. The Fossi came with fakes.
I have used this pre-amp for three years. Adds nice warm sound to Class D amps (they can be a bit too sharp). My favorite use is after my ifi Zen phono preamp and then to my amp. For me, the ifi Zen is too crisp and lacks "warmth" and lacks some "punch" which this Fosi adds. Lots of affordable fun here. Thank you for sharing.
Totally agree. I've been using the P1 with the V3 Fosi amp and it brings a musical involvement that the stand alone amp isn't capable of. No need to change op amps on the V3 or tube changes on the P1. They compliment one another on the cheap. BTW, The speakers I've been using are the wonderful Mirage M290's. An absolute killer combo.
The 2 internal OP Amps can be upgraded to High Performance HiFi LM4562NA OP amps that will improve sound & reliability. They just plug into the existing sockets on the board. The 6K4 tubes are Chinese Military spec tubes that are reliable & used as buffers.
I swapped mine with opa2134 and they sound better, also I swapped tubes for ge 5654
Does it hold Muse01? would be a crazy build.
@@Pe721 Absolutely plug & play with the Muse01 op amp just be sure to install both in the correct direction matching the half moon notch to the pin sockets.
@@poyogamesbrcan this be done to the fosi X2? It has a jrc2028d opamp I think. I would wanna swap them out for a better one, I already rolled the tubes to 5654, I have ordered a pair of voskhod tubes.
Where do you get them?
The most interesting thing is that the lamp legs are not connected by paths to the rest of the circuit))
It added warmth and dimension to my V3. For $40, you can't go wrong.
I agree.
I have a simular Aiyima tube A3, they come under many brand names. No hum at all, i use a larger PS and exchanged the op amps for opa 2604AP and it sounds great and "warms up" the sound of the 07, this is close to high end. it drives a Aiyima 07 with opa 2134 op amps. I had several tube amps and good vintage AB amps and this combination easy holds up. Unbeatable price - quality. Tried the GE 5654 tubes but did not improve the sound. The original tubes work best for me.
Thanks for the info, I need to check out the Aiyima stuff!
What opamps come with the P1 ?
@@elidrissihafid Ne5532ap op amp you find in most pre amps and class D amps
@birdyflying4240 thanks for your reply. These are the same opamps we find in the V3?
@@elidrissihafid yes, and you can replace it with Sparkos SS3602, MUSES02, OPA2604, OPA2134PA, OP249, AD827, RM4559, LM4562, LME49720HA.
What are the pair of op'-amps doing? You'd think.theybperformed the function that the tube/valves are supposed to be doing.
I have replaced it with the Fosi P3. Basically I think they are head to head even though they are different tubes 6k4 vs GE.
using mine for like 2 years now, starting to get popping sounds, going to try to replace the amps now.
Popping; replace the tubes not the amp.
Basically an aiyima tube A3
All the real gain comes from the ICs, the valve just adds distortion, colour and hum. Like all valve amplifiers.
Thanks for the info!
Can something like this add tube warmth to my Marantz 1030 vintage amp?
It colors the sound with the tube curve.
Hello, sir.
I've sent you an email because the Fosi guy confused me.
Fosi Audio's dirty little secret. Loaded with cheap and fake components. I have brought one previously. Not really very impressive sounding, and after I looked inside I found out why. The NE5532 Op Amp chips are fake. Most likely a $.10 chip that is marked as a NE5532. Along with counterfeit Elna audio caps. The other electrolytic caps are a known bad Chinese brand (no good) but are dirt cheap. The hum is likely from these terrible caps in the power supply section. If you ever test the Chinese fake Op Amp chips, you find they have a poor slew rate and a not so good response. Fortunately, they put sockets in for these, and it is super easy to replace the fake chips with real ones. Replacing the caps is not so easy or cheap but can be done. That is why it is so cheap. You have to remember that Amazon gets about 35%-45% of the cost of the item they sell, so it is really a $25 preamp. You can't build a quality unit, ship to America or wherever, and sell it on Amazon for $40. It is basically a nice aluminum shell with crap inside, made to have a look of quality.
Bravo, congratulations to you, I have 2 fosi audio a3 amplifiers, bender, I replaced the 5532s on them with the original american ne5532s I bought from digikey, which I have, there was a lot of sound, I think it is necessary to replace the fakes with the original parts for all devices from China to give good performance.
How did you find out the op amp is fake?
@JohnZornAscended 5532's have reverse protection diodes across the inverting and non-inverting inputs pins 2 and 3. With a multimeter in diode check mode, check between pins 3 and 2, and you should get approximately .8 volts. Reverse lead, and it should read about the same, indicating a diode in both directions. If you measure and there is nothing they are fakes. The Fossi came with fakes.