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Fosi Audio V3 Amplifier Review
- Thread starter amirm
- Start date
hello,
just received my v3.
excited (trying to replace my "broken" yamie ax590) - still needs some acclimatisation time.
while waiting i reviewed the connectors:
and, the speaker connectors are really small.
the diameter of a bare speaker cable connected to such connectors can not exceed ~2mm (3.14mm2/12AWG).
the diameter of the connector itself is 10mm (0.39inch) and the screwable cap is tiny, and can not hold a bare speaker cable of decent diameter.
the only way to use bare speaker cable is while fiddling it through the little hole (2mm) or use some kind of plug or spade.
even if one insists to use bare cables the connector holes are positioned to input the cable from the top or bottom (12/6 o'clock) only for each connector the same.
there was no thought designing this. they should be placed so, that cables can be inserted from the side (and also, not to disturb the power cable or input cables on the way).
as i am at it - speaker's plus/minus is 15mm/0.59inch apart and speaker left/right are 20mm/0.79inch apart.
input plus/minus are 14mm/0.55inch apart.
inputs and right speaker are 27mm/1.06inch apart.
speaker connectors are 15mm/0.59inch higher than surface (where v3 stands on).
another thing i noticed, the little resistance to power/un-power the amp using the volume knob reaches far up 8:45 (starting 7:30).
so, volume starts at short to 9:00 position and switches off at around 8:00 (starting 8:45).
not so much audiophile input (yet) but the outside dimensions are important too, imho.
still wonder why there is such a form factor as with the v3, when a normal amp has a defined size (~17inch).
-----EDIT-----
some facts:
using the 48V/5A power supply.
the V3 volume knob and its volume adjustment is not nice.
1: there is no 100% silence at pos 0 (right after turning on and before turning off volume knob position) - sound leaks very quietly
2: a slight hiss is audible throughout the volume range (no source, just speakers; increases a bit after 5 o'clock position until end) - not audible on listening position (3-4m/10-13feet)
3: turning the knob produces scratchy noise (not constantly, more random, not volume knob position related, slight audible "crackling") - not using the v3 as volume adjusting device, so does not matter for me
4: there is no real V3 adjustable silent volume mode - dont feel the advertised non-linear volume knob level adjustment - it goes from silent to louder in short turn of the volume knob (with source at full volume) - once out of silent mode it is at listening level and goes fast into loud (9 o'clock to 11 o'clock volume knob position). my source (CXN in pre-amp mode has a more logic volume adjustment, v3 in full volume then)
subjective audio update:
compared to my aged yamaha ax590 (20+years; left right imbalance on pre-amp; used only as main-in power amp)
V3 driving 2 Quadral Platinium mk2, 89.5db sensitive, 100W RMS (180W max)
CXN V2 providing RCA input - roon+qobuz
V3 on max volume with CXN's volume to adjust volume (CXN pre-amp on; same as used on yamaha main-in power amp mode)
CXN V2 offering a great pre-amp experience (silent volume up to louder in fine adjustable "steps") - great sounding.
i have a measured frequency response of the ax590 (starts loosing at 3k already with -1.5db at 16k+ terrible cross-talk in 30-200Hz range) and can compare it with the V3's one (-0.5db at 20k starting at 9k). and one can hear it. nice improvement.
V3 to adjust volume (CXN pre-amp off; max volume)
CXN V2 giving full range into the V3
not feeling the quality of sound as when using the CXN as pre-amp.
waiting for the P3 - but sounds great now already
ciao
If and when comparing the volume control between the V3 and the AX590, keep in mind that the Yamaha is a real integrated amp that has active volume control, whereas the V3 really is a power amp, fitted with a taper volume control that is passive. It would be a better comparison using both as power amp and drive them with an active preamp.
MAXIminiME
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sorry i did not explain myself correctly
the ax590 runs as power amp (using main-in with by-passing the pre-amp) the ax590' volume knob is not working in that mode.
i needed to turn (bypass preamp) the ax590's into power amp mode due to the stereo imbalance the preamp mode adds
with that i see the v3 and ax590 comparable (v3 full volume, same as ax590 has full volume in power amp mode). only a preamp connected to either device is able to adjust volume (as i do with the CXN in preamp mode, atm)
You were clear, so I know you were using the AX590 as power amp. My comments was more about your issue with the V3 seemed to be concentrated on the Volume control so it you leave it at max., and use a preamp or even a dac to drive it, all the issues you have with the V3 will go away. That's really what I wanted to say but obviously I was the one who didn't express my points correctly.sorry i did not explain myself correctly
the ax590 runs as power amp (using main-in with by-passing the pre-amp) the ax590' volume knob is not working in that mode.
i needed to turn (bypass preamp) the ax590's into power amp mode due to the stereo imbalance the preamp mode adds
with that i see the v3 and ax590 comparable (v3 full volume, same as ax590 has full volume in power amp mode). only a preamp connected to either device is able to adjust volume (as i do with the CXN in preamp mode, atm)
Welcome!
I agree, using bare speaker wires on the V3, and almost every other tiny class D amp, is a pain. It is probably electronically dangerous; you must be very precise and avoid moving the amp around.
Banana Plugs (not spade lugs) are the best safe/easy/reliable way to hook up speaker wire to these amps. Fosi and others should include a set in each box.
Hmm - I'm using 16 guage (1.3mmsq) wire. This is fine for desktop use - I have less than 1m to each speker. In fact according to the well known speaker wire selector it should be good up to 24 feet, even with 4 ohm speakers.
It fits through the hole in the binding post. Carfully stripping the correct amount of insulation ensures there is no risk of shorts.
Not a problem in this application.
It fits through the hole in the binding post. Carfully stripping the correct amount of insulation ensures there is no risk of shorts.
Not a problem in this application.
I don't think wire gauge or fitting it through the hole is the primary issue. The terminals are so closely spaced that shorts are far more likely if they are not stripped just right, and twisted. Errors, loose strands, are also harder to see. Because the plastic binding posts themselves are 1/2 the size of standard ones, they also jiggle loose far more frequently as there is less friction.
If you are extremely careful every time they can work fine. I am not that precise, for example, sometimes I spell speker or carful incorrectly. It's easier for me to turn on spell check and get the bananas and not worry about it
That's awesome. Great value speaks again.
- Joined
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We'll see what happens when it shows up on Saturday. The only thing I can say for sure is it will use less power at idle than my Crown XLS 1502.
yes about 7watts .. I measured my 48v v3 with smart socket.
MAXIminiME
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once more
you mention active volume control of the AX590
with that you mean it's preamp logic offers volume control in the signal processing chain ?
the V3 has volume control directly at the analogue out of its amp chain - therefore passive ?
what is the fosi P3 preamp - having active or passive volume control ?
tx
MAXIminiME
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- Joined
- Nov 2, 2023
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- 4
reporting back on this one:hello,
just received my v3.
excited (trying to replace my "broken" yamie ax590) - still needs some acclimatisation time.
while waiting i reviewed the connectors:
and, the speaker connectors are really small.
the diameter of a bare speaker cable connected to such connectors can not exceed ~2mm (3.14mm2/12AWG).
the diameter of the connector itself is 10mm (0.39inch) and the screwable cap is tiny, and can not hold a bare speaker cable of decent diameter.
the only way to use bare speaker cable is while fiddling it through the little hole (2mm) or use some kind of plug or spade.
even if one insists to use bare cables the connector holes are positioned to input the cable from the top or bottom (12/6 o'clock) only for each connector the same.
there was no thought designing this. they should be placed so, that cables can be inserted from the side (and also, not to disturb the power cable or input cables on the way).
as i am at it - speaker's plus/minus is 15mm/0.59inch apart and speaker left/right are 20mm/0.79inch apart.
input plus/minus are 14mm/0.55inch apart.
inputs and right speaker are 27mm/1.06inch apart.
speaker connectors are 15mm/0.59inch higher than surface (where v3 stands on).
another thing i noticed, the little resistance to power/un-power the amp using the volume knob reaches far up 8:45 (starting 7:30).
so, volume starts at short to 9:00 position and switches off at around 8:00 (starting 8:45).
not so much audiophile input (yet) but the outside dimensions are important too, imho.
still wonder why there is such a form factor as with the v3, when a normal amp has a defined size (~17inch).
-----EDIT-----
some facts:
using the 48V/5A power supply.
the V3 volume knob and its volume adjustment is not nice.
1: there is no 100% silence at pos 0 (right after turning on and before turning off volume knob position) - sound leaks very quietly
2: a slight hiss is audible throughout the volume range (no source, just speakers; increases a bit after 5 o'clock position until end) - not audible on listening position (3-4m/10-13feet)
3: turning the knob produces scratchy noise (not constantly, more random, not volume knob position related, slight audible "crackling") - not using the v3 as volume adjusting device, so does not matter for me
4: there is no real V3 adjustable silent volume mode - dont feel the advertised non-linear volume knob level adjustment - it goes from silent to louder in short turn of the volume knob (with source at full volume) - once out of silent mode it is at listening level and goes fast into loud (9 o'clock to 11 o'clock volume knob position). my source (CXN in pre-amp mode has a more logic volume adjustment, v3 in full volume then)
subjective audio update:
compared to my aged yamaha ax590 (20+years; left right imbalance on pre-amp; used only as main-in power amp)
V3 driving 2 Quadral Platinium mk2, 89.5db sensitive, 100W RMS (180W max)
CXN V2 providing RCA input - roon+qobuz
V3 on max volume with CXN's volume to adjust volume (CXN pre-amp on; same as used on yamaha main-in power amp mode)
CXN V2 offering a great pre-amp experience (silent volume up to louder in fine adjustable "steps") - great sounding.
i have a measured frequency response of the ax590 (starts loosing at 3k already with -1.5db at 16k
V3 to adjust volume (CXN pre-amp off; max volume)
CXN V2 giving full range into the V3
not feeling the quality of sound as when using the CXN as pre-amp.
waiting for the P3 - but sounds great now already
ciao
P3 has arrived:
bass lever is a bit off-centre - cosmetic - but no functional loss.
volume is not fine controllable as with V3.
not sure if bass/treble are +- or just + as one could read at the phonograph's review - imho its +-.
it would be good +- db values would be marked on device front.
(1) CXN (volume control) -> P3 (max vol + bass/treble according my liking) -> V3 (max vol) -> speaker
- great - my AX590 has been replaced with much better subjective audio/sound experience
(2) CXN (max vol) -> P3 (volume control + bass/treble according my liking) -> V3 (max vol) -> speaker
- P3 volume control does not deliver proper silent sound level as previously mentioned with V3
- P3 volume builds up slowly to a full sound level with some left/right imbalance on the way but, once up (9 o'clock) the sound is great
(3) CXN (max vol) -> P3 (volume control with V3 + bass/treble according my liking) -> V3 (volume control with P3) -> speaker
- fiddling around with P3+V3 to find a sweat volume spot and use V3 to fine adjust up or down (or even P3's)
- sound is great
(4) there would be a 4th option with volume control at each device
playing around with (1) or (3) - probably go with (1) or (4)? which gives me a remote - even though loosing full dynamic bit range from CXN (when on max vol / power-amp off).
so, my journey (in finding a proper set to replace the AX590) comes to an end and i am happy as it is.
tx to the forum for the vast amount of information.
reporting back on this one:
P3 has arrived:
bass lever is a bit off-centre - cosmetic - but no functional loss.
volume is not fine controllable as with V3.
not sure if bass/treble are +- or just + as one could read at the phonograph's review - imho its +-.
it would be good +- db values would be marked on device front.
(1) CXN (volume control) -> P3 (max vol + bass/treble according my liking) -> V3 (max vol) -> speaker
- great - my AX590 has been replaced with much better subjective audio/sound experience
(2) CXN (max vol) -> P3 (volume control + bass/treble according my liking) -> V3 (max vol) -> speaker
- P3 volume control does not deliver proper silent sound level as previously mentioned with V3
- P3 volume builds up slowly to a full sound level with some left/right imbalance on the way but, once up (9 o'clock) the sound is great
(3) CXN (max vol) -> P3 (volume control with V3 + bass/treble according my liking) -> V3 (volume control with P3) -> speaker
- fiddling around with P3+V3 to find a sweat volume spot and use V3 to fine adjust up or down (or even P3's)
- sound is great
(4) there would be a 4th option with volume control at each device
playing around with (1) or (3) - probably go with (1) or (4)? which gives me a remote - even though loosing full dynamic bit range from CXN (when on max vol / power-amp off).
so, my journey (in finding a proper set to replace the AX590) comes to an end and i am happy as it is.
tx to the forum for the vast amount of information.
So, you need the cxn, the V3 and an equalizer (not a preamp). Maybe you need something like the schiit eq and not the P3.
If you want to know more about the difference, you can read up Tom's (@tomchr if I 'am right):
The Ultimate Guide to Preamp Design | Neurochrome
What is a preamp or line amp and why would I use one? This guide answers this question and also explains the difference between active and passive preamps.
MAXIminiME
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- Nov 2, 2023
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yeah, with the V3 and P3 on full volume i see the P3 tone controls as such (EQ)
i have checked some options: schiit and behringer - wanted to go with the P3 as it was meant to fit the V3
the good thing - one can always change parts of the audio processing chain - opposed to an integrated amp
You are missing a core benefit, the P3 is also a tube buffer. According to Fosi, the P3 allows V3 owners to embark on a warm rich musical journey. The essence of tube amplification, experiencing the perfect harmony of technology and nature."
A side benefit is the tube rolling option; there are a lot of inexpensive compatible tubes to try. To further the analogy, its like rolling around on the forest floor near a clear mountain stream. You do not get that from a schiit EQ.
You are missing a core benefit, the P3 is also a tube buffer. According to Fosi, the P3 allows V3 owners to embark on a warm rich musical journey. The essence of tube amplification, experiencing the perfect harmony of technology and nature."
A side benefit is the tube rolling option; there are a lot of inexpensive compatible tubes to try. To further the analogy, its like rolling around on the forest floor near a clear mountain stream. You do not get that from a schiit EQ.
For me, is only other way to do deep eq in the sound and to add "fancy" harmonics.
For the first point i prefer DSP processing and for the second I use vinyl format and my cartridge takes care of that.
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