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Fosi ZA3 TPA3255 Mono/Stereo Switchable Amplifier, and vs Aiyima A07 Max

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Guddu

Guddu

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Hello and greetings from Germany.

I have a question about my fosi.

I have a little problem with that. When I turn up the volume control from zero to the first tone, I first get sound on the left channel and later also on the right.

Do you have that too?

Can you please try it out? That would be very nice.

Have a nice day

Reply
Hi @Audiophilius
I can confirm that my ZA3 unit has never showed this issue.
Its worth checking with Fosi support.
 
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Guddu

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Considering neither the Za3 nor the AO7 has a remote, if you'd use them with a WiiM Pro Plus, would you be able to control the volume remotely somehow?
Would it be very sub optimal?
Seems like these quite powerful, very capable amps are to be restricted to a desktop use, so mostly for nearfield use, that kind of puzzles me...
Any DAC or pre-amplifier with volume control should work with these units.
you can max out the pre-amp/DAC volume at first and then adjust max volume you want on amplifier. Once adjusted, you can then just leave the amplifier volume knob position stable.
 

Nicolas_

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Any DAC or pre-amplifier with volume control should work with these units.
you can max out the pre-amp/DAC volume at first and then adjust max volume you want on amplifier. Once adjusted, you can then just leave the amplifier volume knob position stable.
Thanks, very helpul.
Is there a perceptible degradation of the sound quality (compared to pre-amp/DAC at max and adjusting the knob on the amplifier), or is it the same at "normal" listening levels?
 

Jeromeof

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Considering neither the Za3 nor the AO7 has a remote, if you'd use them with a WiiM Pro Plus, would you be able to control the volume remotely somehow?
Would it be very sub optimal?
Seems like these quite powerful, very capable amps are to be restricted to a desktop use, so mostly for nearfield use, that kind of puzzles me...
Well if you want either as Monoblocks you would be controlling the volume with a preamp and the WiiM Pro Plus can provide that capability and it is an amazing combination - it would not be sub-optimal as the WiiM Pro Plus has an excellent DAC so the RCA output is very clean.
I didn't use the WiiM remote but controlling the volume via the WiiM app also works very well.
 

Nicolas_

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Well if you want either as Monoblocks you would be controlling the volume with a preamp and the WiiM Pro Plus can provide that capability and it is an amazing combination - it would not be sub-optimal as the WiiM Pro Plus has an excellent DAC so the RCA output is very clean.
I didn't use the WiiM remote but controlling the volume via the WiiM app also works very well.
Thank you.
No interest in the monobloc, just the small(ish) form factor, good amp chip, and sub out.
Looks like an excellent combo, at a low price, with the WiiM Pro Plus.
Compared to the WiiM AMP, I'd have more "boxes" (3, counting the PSU, instead of just one), but I'd gain in quality (very marginally?) and flexibility.
Here I can get the Fosi for 150$ with pre-order discount, or the Aiyiama for 100$ (both with 48V PSU).
I'm going to wait for the WiiM AMP review.
Is there a way to exploit the balanced inputs of the Fosi with a WiiM Pro Plus?
 
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Guddu

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Thanks, very helpul.
Is there a perceptible degradation of the sound quality (compared to pre-amp/DAC at max and adjusting the knob on the amplifier), or is it the same at "normal" listening levels?

Ideally I would like to max out the amplifier volume position in relation to matching the input sensitivity of both power amp and DAC/pre-amplifier.
We know that both A07 max and ZA3 have input sensitivity lower than 1V (ZA3 is probably around 0.7V based in info from Audiophonics, if I remember correctly), if the DAC/pre-amp could be fixed closer to input sensitivity of the amplifier then amplifier volume could be maxed out completely eliminating potentiometer getting in play.

If the DAC/pre-amp is fixed at 2V then I would avoid maxing out amplifier volume position to avoid any potential issues (not saying there must be any issues, but to be on safer side).
 
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In my ZA3 setup, I have the volume of my ZA3 maxed out and I use my Teac UD503 as DAC and preamp. I have a Pi4 acting as a streamer for my NAS music store. I also am running my analog sources through a cheap ADC and using Optical input for that full chain - seems a bit quieter than using the native analog line in for the UD-503. I have used both RCA and XLR - the balanced XLR connection to the ZA3 produces the extra volume as expected and that's my preferred solution. I only touch the ZA3 volume knob when I want to put it in standby mode. In my use, I have seen no channel volume mismatch/imbalance as mentioned a bit in some ZA3 threads. The SUB-Out capability was a real game changer for me and has made some of my legacy equipment now very nervous indeed. My speakers are B&W DM12a which are not very efficient and tend very close to 8 ohms average impedance, so are not terribly easy to drive. The ZA3 has done a better than expected job in that regard and my usually listening level is at -31.5db to -15bd on the Teac volume control. At the max level, it is not loud but authoritative enough in its presentation for my needs.

I am still considering giving the Ayima A07 MAX a try just for fun. I have the non max A07 and the only issue for me was the lack of sub out. That said, creating Y cable connections form the Teac UD-503 to the sub was something I first did as a test and it was also good, so the specific need to have a dedicated SUB-out is nearly not life and death for me. But why not take advantage of a cheap option which does all that I need :)
 

surroundman

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In my ZA3 setup, I have the volume of my ZA3 maxed out and I use my Teac UD503 as DAC and preamp. I have a Pi4 acting as a streamer for my NAS music store. I also am running my analog sources through a cheap ADC and using Optical input for that full chain - seems a bit quieter than using the native analog line in for the UD-503. I have used both RCA and XLR - the balanced XLR connection to the ZA3 produces the extra volume as expected and that's my preferred solution. I only touch the ZA3 volume knob when I want to put it in standby mode. In my use, I have seen no channel volume mismatch/imbalance as mentioned a bit in some ZA3 threads. The SUB-Out capability was a real game changer for me and has made some of my legacy equipment now very nervous indeed. My speakers are B&W DM12a which are not very efficient and tend very close to 8 ohms average impedance, so are not terribly easy to drive. The ZA3 has done a better than expected job in that regard and my usually listening level is at -31.5db to -15bd on the Teac volume control. At the max level, it is not loud but authoritative enough in its presentation for my needs.

I am still considering giving the Ayima A07 MAX a try just for fun. I have the non max A07 and the only issue for me was the lack of sub out. That said, creating Y cable connections form the Teac UD-503 to the sub was something I first did as a test and it was also good, so the specific need to have a dedicated SUB-out is nearly not life and death for me. But why not take advantage of a cheap option which does all that I need :)
But the A07 MAX's AUX OUT is not controlled by the volume knob, correct? I need to replace my V3 ASAP with one that controls the sub-out volume.
 
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Guddu

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Thank you.
No interest in the monobloc, just the small(ish) form factor, good amp chip, and sub out.
Looks like an excellent combo, at a low price, with the WiiM Pro Plus.
Compared to the WiiM AMP, I'd have more "boxes" (3, counting the PSU, instead of just one), but I'd gain in quality (very marginally?) and flexibility.
Here I can get the Fosi for 150$ with pre-order discount, or the Aiyiama for 100$ (both with 48V PSU).
I'm going to wait for the WiiM AMP review.
Is there a way to exploit the balanced inputs of the Fosi with a WiiM Pro Plus?

I think some clarification is required related to xlr/trs inputs, the amplifier eventually converts it to unbalanced.
It’s probably just another input at best (I wouldn’t be surprised if I am mistaken), it’s surely useful but not same as other amps like 3e or topping PAx series.
Nevertheless, it’s a good amplifier.
 

gordinho

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Hello and greetings from Germany.

I have a question about my fosi.

I have a little problem with that. When I turn up the volume control from zero to the first tone, I first get sound on the left channel and later also on the right.

Do you have that too?

Can you please try it out? That would be very nice.

Have a nice day

Reply
This is normal in pots. What you want to do is go less hot into the amp so that you're not listening very close to the lowest position of the pot controlling the volume on the ZA3. You can do this in the DAC ( potentially digitally) or in a preamp if you have it.

I need to dial down my USB pre 2 or I easily overdrive ZA3 input and I can barely go higher than the lowest volume on ZA3.
 

Audiophilius

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This is normal in pots. What you want to do is go less hot into the amp so that you're not listening very close to the lowest position of the pot controlling the volume on the ZA3. You can do this in the DAC ( potentially digitally) or in a preamp if you have it.

I need to dial down my USB pre 2 or I easily overdrive ZA3 input and I can barely go higher than the lowest volume on ZA3.
hi, thank you very much for your answer.

So I tried it too and it worked. I'm surprised that some people don't have it, but that also has something to do with the sensitivity of the speakers.

I have the wharfedale linton with a specified 90 db efficiency
 
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But the A07 MAX's AUX OUT is not controlled by the volume knob, correct? I need to replace my V3 ASAP with one that controls the sub-out volume.
Yes I think that is correct - my assumption is that would be nice for a headphone amp feed. Since the A07MAX uses only RCA connections, for me using an RCA y cable from my preamp to feed A07 MAX and Sub can be easily accomplished, But really the question for me is why bother, since it also brings the Fosi V3 also into play for the same reason. So maybe for me, like you, the A07MAX really doesn't fit a gap that we are trying to fill since the ZA3 does seem to fill my gap, if not also yours @surroundman.
 

G-Can

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you guys tend to overcomplicate everything here

just run you Fosi V3/ZA3 at 50-70% on the volume knob, and then use your dac to control the volume.

At least that how I use my V3 with SMSL C100 DAC that comes with remote. I have it on desktop, so I can either actually move the volume knob on V3, or grab a remote for C100.

Both works fine, and no change in sound quality.
 
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Related, but general question. A typical power amplifier does not have a "volume control". And form this I assume that there is little to no attenuation aside from such designed into the amplifier. So if the ZA3 has a "volume control", which it does, if fully clockwise (Spinal Tap 11 or FULL ON), is that the equivalent of the typical power amplifier I mentioned?

And from that, it seems as though the only logical variable volume management capability, would be via something acting as a volume control, either a preamp as a device, or a specific attenuation circuit, such as a passive preamp.

So from this, why does it not make sense to have something like a ZA3 volume control on "fully clockwise, Spinal Tap" mode? I don't recall form any measurements that volume control at full would in and of itself, cause distortion. My general belief is that gain stage distortion is due to how much input signal is then amplified. So maybe to pre-answer my now question, less than full ZA3 "volume" may be required when the input signal os so very hot that it violates base input sensitivity (nominally 0.775v RMS I think).

Thoughts?
 
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Guddu

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Related, but general question. A typical power amplifier does not have a "volume control". And form this I assume that there is little to no attenuation aside from such designed into the amplifier. So if the ZA3 has a "volume control", which it does, if fully clockwise (Spinal Tap 11 or FULL ON), is that the equivalent of the typical power amplifier I mentioned?

And from that, it seems as though the only logical variable volume management capability, would be via something acting as a volume control, either a preamp as a device, or a specific attenuation circuit, such as a passive preamp.

So from this, why does it not make sense to have something like a ZA3 volume control on "fully clockwise, Spinal Tap" mode? I don't recall form any measurements that volume control at full would in and of itself, cause distortion. My general belief is that gain stage distortion is due to how much input signal is then amplified. So maybe to pre-answer my now question, less than full ZA3 "volume" may be required when the input signal os so very hot that it violates base input sensitivity (nominally 0.775v RMS I think).

Thoughts?

I largely agree, and probably a go to option is to have amplifier's volume set up max to get potentiometer resistance out of play on amplifier.
Problem is when input sensitivity of the amplifier is noticeably lower than the input signal from pre-amp/DAC/source. Although I have tried this by putting in 2v DAC out to amplifier with max volume and it has worked in general but it kept me worried of any accidental high volume from source, specially when different inputs on DAC has different volume level variations.
For me, the better option is to max out the source volume level and then adjust the volume knob on amplifier to the max you might want. Once you get your satisfied max level, you then may just leave the amplifier volume as it is and control on your source/DAC/pre-amp.

Having volume control on lower priced amplifiers is not a bad option, as long as parts used are of decent quality and can survive for decent period of time.

I must add, such problems aren't just applicable to Aiyima, Fosi, Sabaj, etc. Topping PA7 isn't cheap in comparison and its volume pot doesn't seem high quality to me, similar is the case with toggle switches.

Good thing here is that the channel imbalance issues are observed with such amplifiers at very low volume knob position, and keeping it around 50% or more keeps it out of equation most of the times.
 

cyclo

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I am just wondering why Fosi nor anyone has yet to send Amir a ZA3 to test. When the v3 came out or even before it was for sale on Amazon, Amir already had one tested here on ASR.
 

G-Can

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I am just wondering why Fosi nor anyone has yet to send Amir a ZA3 to test. When the v3 came out or even before it was for sale on Amazon, Amir already had one tested here on ASR.

id assume its same sxit as V3 in measurements. For me personally I only like it for its 12V input trigger. I dont see any other benefit to this ZA3 over V3.
 
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