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2 x Fosi V3 + 2 x 10A 48V psu - what the hell?

I'm not familiar with any of the speakers you mentioned but with my efficient Klipsch KLF-30's, I have two V3"s, two ZA3's and two more ZA3's arriving in a few days. They all sound great and have solid bass.

They pair great with any preamp I've tried but I gotta admit they shine when combined with a tube preamp. Love these little Fosi amps.
 
Your Fosi V3 monos might be defective or you connected them out of phase?

I am running 86db speakers that have impedance down to 3 ohms.

I bought 4 of the V3 monos. Two arrived as 31/25, the other two 19/25. I hooked up the 31/25 pair and they did not sound very good and one of them failed / lost signal at the RCA output. I put those aside and used the 19/25 set which have been driven to reference levels without any complaint. They control the woofers and dig more musically / detailed everywhere.

Playing Batman sound track "Why so Serious" energized the room with the lowest frequencies. (my speakers are flat to 20hz in-room measured response)
 
dcolak said:
What are 31/25 and 19/25?
Click to expand...
The choices of the gain settings for the RCA input. The choices were reduced from 31 and 25 dB to 25 dB and 19 dB.

B0D31M3DXY.PT07.jpg
 
I just checked, I ordered two, one is 31/25 the other is 25/19... Pffffff.

I don't use RCA inputs but still...

So 25/19 is a good one sq wise?

I ordered them as a part of a bundle, why would they want to ship two different ones :-( ppfffffffff

1756391537885.png
 
This thread is excellent example of people mistaking lack of gain to lack of power and how so many people think that bigger speakers need more powerful amps, when it usually is just the opposite.

@dcolak, the difference in gain between different amps mean that for a given volume setting on your dac or preamp, the ouput level from speakers change. Higher gain amps are louder and get even more louder faster when turning the volume knob. If the sound is not clipping but is not loud enough for you at max volume setting, you are not out of amplifier power, you are out of gain and need higher input level to the amp.
 
Dumu said:
This thread is excellent example of people mistaking lack of gain to lack of power and how so many people think that bigger speakers need more powerful amps, when it usually is just the opposite.

@dcolak, the difference in gain between different amps mean that for a given volume setting on your dac or preamp, the ouput level from speakers change. Higher gain amps are louder and get even more louder faster when turning the volume knob. If the sound is not clipping but is not loud enough for you at max volume setting, you are not out of amplifier power, you are out of gain and need higher input level to the amp.
Click to expand...
Not my situation though, I did make them as loud as I wanted but they didn't sound good.
 
Could you make some measurements to confirm the difference? I bet many in here would be interested in the results.
 
Or just some recordings of the same track with a fixed microphone?

Anything really to give us something tangible.
 
Last edited:
staticV3 said:
Or just some recordings of the same track with a fixed microphone?

Anything really to give us something tangible.
Click to expand...
Soon, I found the microphone :-) Have to install REW on a notebook and I'm good to go.
 
dcolak said:
Not my situation though, I did make them as loud as I wanted but they didn't sound good.
Click to expand...
Given that the channels can’t be matched, due to the differing sensitivity, did you not hear a channel imbalance? Or are both set on 25 by fluke?
 
norman bates said:
Anyone run the v3 monos with a big speaker ?

Using a 12" or a 15" in a 3-way speaker ?

Anyone leave their v3 monos on all the time ?
Click to expand...
I am using v3 monos with a 2-way 96 dB bass reflex - 15" Beyma 15LX60V2 + 1" Beyma Cd10Nd in a Seos15 waveguide (2-nd order xover with passive CD equalization) - and I am happy with. Listening position at about 2.8 meters from speakers. Two other friends use V3 Mono to power up their 15" speakers, both different than mine, with success. The only problem I had was that initially these Fosi V3 Monos sounded thin, which is not the case now (but I do not want to be 'crucified' here for broken-in , as not scientifically proved yet :)) As for leaving the V3 Monos ON all the time: no way. I prefer switching them on/off for each session, especially they get hot just on idle, with no music program (at 22-24 *C room temperature, the outer case temp reaches 43 * C in about 2h). I am using one big heatsink for both monoblocks. Power wise, I never get out of steam with large scale classical orchestra music, electronica, avantgarde jazz or progressive rock/metal . My room is 20 sq meters.
 
good to know.

I worry about buying an amplifier that I cannot leave on for 24 hours a day.....................
 
Nopiano said:
Given that the channels can’t be matched, due to the differing sensitivity, did you not hear a channel imbalance? Or are both set on 25 by fluke?
Click to expand...
Why can't they be matched? I don't use RCA, I use XLR, they are not out of phase :)
 
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