Fosi V3 Mono my opinion

L

Lux Man

AK Subscriber
Subscriber
Firstly, Ellymay a fellow AK'er out of the wonderful goodness of his heart sent me a pair just to try out with the 48v supply's.

My JBL 4435's are 96db efficient. I had been using a Crown PS400 and before that a Sunfire Signature 600. In my opinion these Fosi Mono blocks drive these 4435's with no issues power wise, they give up nothing. Sound wise "maybe" just maybe the Fosi is a little brighter but in every other way- this guy can't hear the difference. In the low frequency range - no hear-able difference for me. The bass is just as deep and strong in fact at more than once I thought I had accidentally turned the JBL B460 sub back on because the bass was so good- but it was still off.

At a average vol of 85 db with 95 peaks the bottom case temp was 105F with a ambient of 70. Just for curiosity I put a small fan between them and the bottom case went down to 88. The temps were measured with just a Triplett 9045. For a relatively short period I ran them at 100db but the plaster started cracking....and the spiders starting moving out of the man cave.

When the day comes that I need to replace or repair one of these other amps I will have zero hesitation to buy these. The brightness, if it is in fact real can be easily dealt with. I kept the parametric equalizer settings the same as I had them.

Fosi could sell these for a whole lot more if they put them in bigger boxes and put a 48v supply inside that weighs 50lbs.

I just picked up one of our dogs from a teeth cleaning today. That cost 2x what 2 of these mono blocks cost. Or 15- 12packs of beer and we all know where THAT eventually goes!
 
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Your experience is like most people that have tried these newer Fosi high value amps and some other brand amps. I will never go back to using vintage components again because there are no reasons to do so. I have a hard time wrapping my mind around why these newer class D TPA3255 based amps are so good. They don't seem to use any new technology that I can see. The quality of system one can put together these days, sans speakers, for as low as $200-$400 has not been seen before, IMO.
 
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I have had the same experience with the Fosi V3 mono amps and a pair of 3e A7 mono amps. I've used these amps to drive Quad ESL-63, JBL 4430, and Klipsch RF-83 speakers. I currently have the Fosi amps setup with Quad speakers and the 3e A7 amps with the Klipsch speakers. I have miniDSP DDRC22 unit in both systems to correct for room effects. I honestly don't believe my systems have ever sounded better. They have far surpassed what I expected to hear from them.
 
I'm running 6 Fost ZA3 in mono mode to drive my 20:20 3-way horns. They are not the weak link in my system by a long shot- that weak link is an order of magnitude higher in price than one of those amps. I also picked up Fosi's newest headphone amp and yet again, I'm blown away by its performance, both as an amp and as a dac as well. We're really living in a golden age for affordable audio.
 
I just recently sold mine off. Had them for a couple of years. I really wanted to like them. Whatever speaker and pre-amp I paired them with, I just found the performance just so so. They were clean and powerful, but always sounded somewhat congested. For me, the satisfaction they provided roughly matched the cost. I feel they a good value, but not a replacement for a lot of amps priced at $1000 or more.
 
lissenup said:
I just recently sold mine off. Had them for a couple of years. I really wanted to like them. Whatever speaker and pre-amp I paired them with, I just found the performance just so so. They were clean and powerful, but always sounded somewhat congested. For me, the satisfaction they provided roughly matched the cost. I feel they a good value, but not a replacement for a lot of amps priced at $1000 or more.
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I don't think anyone here is saying these amps are replacements ones costing thousands of dollars, in general. I am sure that there are some $1,000 plus amps that they do better than because price doesn't necessarily reflect performance. IMO, where they really compete well is with vintage amps, integrated amps and receivers. You are the first person I have seen hear that describe them as congested.

Also, there is a dynamic at play when building a system with these high value components. Take a $2,500 budget. You can spend $500, or less, on the electronics and then spend $2,000, or more, on speakers. Or you could spend $1,250 on each and have a less capable system overall, IMO. The number one determiner of sound quality in a system is the speakers. Better speakers could very well override whatever the small SQ difference might be between the budget electronics and the $1,250 ones. This comparison likely scales with even higher budgets up to $4k, or more.

I don't expect these high value components to please everyone. I do know from personal experience that their sound quality can be substantially improved by using inexpensive upgrades like op-amps, linear regulated power supplies for non amp components, XLR connections, etc.
 
OldJBL said:
I don't think anyone here is saying these amps are replacements ones costing thousands of dollars, in general. I am sure that there are some $1,000 plus amps that they do better than because price doesn't necessarily reflect performance. IMO, where they really compete well is with vintage amps, integrated amps and receivers. You are the first person I have seen hear that describe them as congested.

Also, there is a dynamic at play when building a system with these high value components. Take a $2,500 budget. You can spend $500, or less, on the electronics and then spend $2,000, or more, on speakers. Or you could spend $1,250 on each and have a less capable system overall, IMO. The number one determiner of sound quality in a system is the speakers. Better speakers could very well override whatever the small SQ difference might be between the budget electronics and the $1,250 ones. This comparison likely scales with even higher budgets up to $4k, or more.

I don't expect these high value components to please everyone. I do know from personal experience that their sound quality can be substantially improved by using inexpensive upgrades like op-amps, linear regulated power supplies for non amp components, XLR connections, etc.
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Yes I agree with what you say on competing with vintage equipment. However, I am from the other camp and would spend $2000 on the amp and $500 for speakers. But that is an old discussion and better left alone. I’m not trying dump on or trying to start a pissing match about the Fosi equipment. I just wanted to share my experience with them. As I said, I feel they are a good value.

Maybe my word “congested” was not the right word. I just felt the sound was not as open, light, and airy as some other amps, albeit costing more. I think what it come down to is these amps, although great value, were just not for me. I know many enjoy and will continue to enjoy these and the latest versions of these amps as they develop.
 
Not trying to turn this into a Fosi commercial but I just now ordered the MC351 for the family room tv. My bride was not a fan of the previous equipment stacked in the corner. This should all be out of sight behind the TV. If it really does recognize a optical input to bring it out of hibernation and if my SVS1000 really does allow for vol adj. with a high level input we will be golden.
 
lissenup said:
I just recently sold mine off. Had them for a couple of years. I really wanted to like them. Whatever speaker and pre-amp I paired them with, I just found the performance just so so. They were clean and powerful, but always sounded somewhat congested. For me, the satisfaction they provided roughly matched the cost. I feel they a good value, but not a replacement for a lot of amps priced at $1000 or more.
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I had a similar impression when I got my first pair of ZA3 to use in mono. I thought they were a remarkable value, dead silent without a hint of hiss, but I struggled to explain the sound- I'd never heard a darker dark in quiet passages of my favorite test tracks, however, in stock form, they lacked sparkle. Changing the op amps, first with MUSES02, followed by Sparkos 3602 and ultimately, Burson V7 Classic and Vivid, (which don't fit in the V3 mono, unfortunately) each one became increasingly more revealing, with improvements in soundstage and imaging. I now have 6 of them powering my 20:20 3-way horns via a DSP Processor and they're magnificent. Granted, they're now approximately $275 per amp, or $1650 for the whole lot and I'd rate them nearly as good as, if not better, than individual amps at that combined price point. Would individual amps of comparable power be better? At $1000 a piece, the Schiit Aegir comes close in power, 100W of class A vs roughly 130W of class D output and for $6000, they'd better sound better, but I'm not convinced that they're $4300 better, especially in the summer, with 600 watts of class A heat radiating off of them.

Yes, stock, they're pretty much as you'd described, but Fosi cleverly designed these amps and others in their lineup with the express intent of the end user opening them up and modifying them to shape the sound to their preference, by swapping op amps. They even gave instructions on how to do it. If you didn't do that, it's not a failure of the product, that's entirely on you.
 
Gigantic said:
I had a similar impression when I got my first pair of ZA3 to use in mono. I thought they were a remarkable value, dead silent without a hint of hiss, but I struggled to explain the sound- I'd never heard a darker dark in quiet passages of my favorite test tracks, however, in stock form, they lacked sparkle. Changing the op amps, first with MUSES02, followed by Sparkos 3602 and ultimately, Burson V7 Classic and Vivid, (which don't fit in the V3 mono, unfortunately) each one became increasingly more revealing, with improvements in soundstage and imaging. I now have 6 of them powering my 20:20 3-way horns via a DSP Processor and they're magnificent. Granted, they're now approximately $275 per amp, or $1650 for the whole lot and I'd rate them nearly as good as, if not better, than individual amps at that combined price point. Would individual amps of comparable power be better? At $1000 a piece, the Schiit Aegir comes close in power, 100W of class A vs roughly 130W of class D output and for $6000, they'd better sound better, but I'm not convinced that they're $4300 better, especially in the summer, with 600 watts of class A heat radiating off of them.

Yes, stock, they're pretty much as you'd described, but Fosi cleverly designed these amps and others in their lineup with the express intent of the end user opening them up and modifying them to shape the sound to their preference, by swapping op amps. They even gave instructions on how to do it. If you didn't do that, it's not a failure of the product, that's entirely on you.
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This brings up another point that reinforced my decision but was not going bring up, the diminishing return on spending more on these amps. Apart from custom power supplies, I basically went whole hog on these with two 48V, 10A power supplies (one for each unit), along with a variety of op-amp switching. In my arsenal I have Sparkos, Burson, Muses02, and TI as I have other DACs, pre-amps, and a power amp where I have upgraded op-amps. I am a believer in sound differences in these various devices. But whatever combination I tried, for me, they sounded good, but just not what I was after.

But I think you are misunderstanding my post. There was never a failure of the product, in fact I said they were a good value. I bought them to delve into the Class D world. I liked what I heard but wanted a bit more. And unfortunately that “a bit more” ends up costing ALOT more! So yes, I’ll say it again, I do think they are a good value.
 
lissenup said:
This brings up another point that reinforced my decision but was not going bring up, the diminishing return on spending more on these amps. Apart from custom power supplies, I basically went whole hog on these with two 48V, 10A power supplies (one for each unit), along with a variety of op-amp switching. In my arsenal I have Sparkos, Burson, Muses02, and TI as I have other DACs, pre-amps, and a power amp where I have upgraded op-amps. I am a believer in sound differences in these various devices. But whatever combination I tried, for me, they sounded good, but just not what I was after.

But I think you are misunderstanding my post. There was never a failure of the product, in fact I said they were a good value. I bought them to delve into the Class D world. I liked what I heard but wanted a bit more. And unfortunately that “a bit more” ends up costing ALOT more! So yes, I’ll say it again, I do think they are a good value.
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Everyone's ears are different along with their systems. Sounds like you gave the V3 Monos a good effort to work for you. From what I have seen, I don't think there is a whole lot more to be gained from using a 10A PS over a 5A one. It might give a little more headroom but it makes very little difference with power output. I know that these newer class D amps will not be everyone's cup of tea. Instead of going the op-amp route, I added a Fosi ZD3 DAC and upgraded its power supply to a linear regulated one. I think this got me more SQ improvement than another op-amp swap.
 
The Fosi MC351 showed up today for my AV TV family room. After a short disappointment that optic out does not allow vol adjustment with the TV remote. Forgot about that. I then connected via bluetooth- problem solved. Nice- with Zilch modded Minimus 7's and a SVS1000- all good. It sits behind the TV- wouldn't know it is there-very WAF friendly.
 
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