FOSI

[rollo]

  For the money impossible to beat. The ZV3 mono blocks will also challenge , equal or beat Amps costing thousands. As A dealer of other gear a great compliment. 500 hours of break in or you have not heard them yet. Op amps can be changed as well TI is the way to go.  Still prefer my tubes though however not by much. Truth matters not money spent.

charles

[Nick B]

Have followed the Fosi amps for a while now. Was interested in them as a back up amp, but didn't like the external power supplies. More wires 😳
I have a class d amp coming made with top quality parts and still have the excellent Starkrimson amp. If the new amp beats the Starkrimson, then I still might have the Starkrimson upgraded. Another avenue is a maxxed out Dynaco ST 70 with 6ns7 tubes and solid state rectification. The problem is I am not convinced that amp, even with the best quality parts, will be as noise free as the Starkrimson and hopefully the new amp coming in for evaluation.

[rollo]

  Leo makes a wonderful Amp. The FOSI with the benefit of an outboard power supply leaves room for future upgrades. Nothing like a better power supply. Which I would commission AG Yeung to make with His Cap bank. The Warp-1 is the better of the bunch. IMHO.


charles

[ejk]

Sold my Fosi amps to Topround. He claims they sound like crap. I told him to get new speakers. The Fosi sounded great

[rollo]

Sold my Fosi amps to Topround. He claims they sound like crap. I told him to get new speakers. The Fosi sounded great

  He is a tube Guy. Did they have 500 hours on them. Stock Op Amps ?

charles

[HAL]

Been updating my FOSI ZA3 amps with TI LME49720 opamps.  Great $10 upgrade for the amps.  Pretty easy, only takes about 10 minutes to change the 3 opamps for XLR use or just 2 opamps for the RCA inputs. 

Moded my nephews ZA3's with the TI opamps as well for his Magnepan LRS setup and he heard the improvement very easily.   He has a second ZA3 now for his new OB subs for the LRS setup with the dspNexus 2/8 DSP crossover.

[Nick B]

  Leo makes a wonderful Amp. The FOSI with the benefit of an outboard power supply leaves room for future upgrades. Nothing like a better power supply. Which I would commission AG Yeung to make with His Cap bank. The Warp-1 is the better of the bunch. IMHO.


charles

Yes, that Starkrimson Ultra stereo amp I have is very good. AGY is innovative and I followed his channel for a while. But his price structure is up there as he works with a couple of dealers up in Canada.

I am still interested in the Fosi and probably as a backup. I don't know squat about opamps, but I have the New Class D opamp in my Hattor Big. I really enjoy that preamp not only because of the sound, but also the build quality, functionality and the great remote.

I wonder if the New Class D opamp would fit into the Fosi.

[Nick B]

Been updating my FOSI ZA3 amps with TI LME49720 opamps.  Great $10 upgrade for the amps.  Pretty easy, only takes about 10 minutes to change the 3 opamps for XLR use or just 2 opamps for the RCA inputs. 

Moded my nephews ZA3's with the TI opamps as well for his Magnepan LRS setup and he heard the improvement very easily.   He has a second ZA3 now for his new OB subs for the LRS setup with the dspNexus 2/8 DSP crossover.

Rich, How great that you're nephew can hear these differences. Listening properly for these changes is a skill. It certainly wasn't automatic for me...

[Nick B]

Sold my Fosi amps to Topround. He claims they sound like crap. I told him to get new speakers. The Fosi sounded great

Mike the contrarian  🤷 🤭

[rollo]

Sold my Fosi amps to Topround. He claims they sound like crap. I told him to get new speakers. The Fosi sounded great

  He is a tube Guy. Did they have 500 hours on them. Stock Op Amps ?

charles

Big difference the TI Op amps. Not a fan of the discrete ones.
charles

[rollo]

Been updating my FOSI ZA3 amps with TI LME49720 opamps.  Great $10 upgrade for the amps.  Pretty easy, only takes about 10 minutes to change the 3 opamps for XLR use or just 2 opamps for the RCA inputs. 

Moded my nephews ZA3's with the TI opamps as well for his Magnepan LRS setup and he heard the improvement very easily.   He has a second ZA3 now for his new OB subs for the LRS setup with the dspNexus 2/8 DSP crossover.

Rich, How great that you're nephew can hear these differences. Listening properly for these changes is a skill. It certainly wasn't automatic for me...

   There is a trick to tell. Listen to the cut for 30 seconds several times. Then concentrate on one part say Vocal, cymbal, Bass. Play again and listen for a difference. The beginning of a trained ear. I am known as the blind test crusher. Very easy if you know the trick.

charles

[Nick B]

Been updating my FOSI ZA3 amps with TI LME49720 opamps.  Great $10 upgrade for the amps.  Pretty easy, only takes about 10 minutes to change the 3 opamps for XLR use or just 2 opamps for the RCA inputs. 

Moded my nephews ZA3's with the TI opamps as well for his Magnepan LRS setup and he heard the improvement very easily.   He has a second ZA3 now for his new OB subs for the LRS setup with the dspNexus 2/8 DSP crossover.

Rich, How great that you're nephew can hear these differences. Listening properly for these changes is a skill. It certainly wasn't automatic for me...

   There is a trick to tell. Listen to the cut for 30 seconds several times. Then concentrate on one part say Vocal, cymbal, Bass. Play again and listen for a difference. The beginning of a trained ear. I am known as the blind test crusher. Very easy if you know the trick.

charles

I did that for some time. Nowadays I just prefer to listen to what I have on Roon and often just let Roon pick the music. That allows me to get an overall feel for the sound and how the performance is for all types of music.  If I was limited to a certain number of days, I'd start out doing exactly what you do.
It's also very helpful to have very revealing equipment to then just focus in on those sometime subtle differences.

Nick

[rollo]

Been updating my FOSI ZA3 amps with TI LME49720 opamps.  Great $10 upgrade for the amps.  Pretty easy, only takes about 10 minutes to change the 3 opamps for XLR use or just 2 opamps for the RCA inputs. 

Moded my nephews ZA3's with the TI opamps as well for his Magnepan LRS setup and he heard the improvement very easily.   He has a second ZA3 now for his new OB subs for the LRS setup with the dspNexus 2/8 DSP crossover.

You listened good. Just bought a pair of ZA3 for mono use. Will be getting new Op Amps. TI they will be. Non discrete ones. I believe 1256 ? Going to compare to the Warp-1 Amp. My favorite SS Amp. Benchmark as well. We sell Benchmark and the comparison will be interesting. But but $140 each. We shall see I mean hear.

charles

[Nick B]

Charles,

I've been doing some reading on the Warp 1. What an interesting design and an option to use RCA connections without an external box or an xlr to rca adapter.
Interesting times for Class D amplification.

Nick