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

G-Can

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wow... i bought my 1st pair of subs 30 years ago, when my main speakers - thiel 3.5's - were 2db down at 20hz. the improvement in the low end, and to the thiels as well, as they were actively crossed over at 80hz so they and the amp driving them didn't have to deal with low frequencies, was exceptional. i won't ever listen to my audio playback system without subwoofers. it's because i like every song i choose to listen to, and i want to hear it done right. and, it's also why many major speaker mfr's actually provide subwoofer towers as part of their speaker systems.

sorry, old timer, you've been missing out all these years. ;)

my present set-up, actively quad-amped. it's flat from 20hz-20khz, just from manipulating the volume controls on the active 24db/octave x-overs; no dsp. yes, it's true, if there's no low frequency content in a recording, your subs won't be doing anything. so what?
View attachment 341304

enjoy your less-than full-range listening, old timer.

doug s.
Impressive horns, but do something about that mess of electronics between them.

Get some bigger shelf, or something, it would look soon much better and more comfortable to the eye
 

doug s.

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Impressive horns, but do something about that mess of electronics between them.

Get some bigger shelf, or something, it would look soon much better and more comfortable to the eye
the shelf is perfect, thanks anyway. yes, there are 5 amps and a few other smaller ancillaries in the pic that aren't being used; oh well. i have no problem w/how it looks; i'm more concerned w/how it sounds. ;)

to each his/her own...

doug s.
 

G-Can

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the shelf is perfect, thanks anyway. yes, there are 5 amps and a few other smaller ancillaries in the pic that aren't being used; oh well. i have no problem w/how it looks; i'm more concerned w/how it sounds. ;)

to each his/her own...

doug s.
Whatever. It just looks messy.
 

doug s.

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Whatever. It just looks messy.
if you were looking at the 2nd pic, when i was measuring, i agree, it looked messy. which is why i scarfed on a local equipment stand i found on f/b, offered at a great price shortly thereafter: three shelves instead of two; which for me, was a substantial improvement, (as shown in the 1st pic i posted), and i'm perfectly content. i like my 4" thick lucite block subwoofer/midwoofer amp stands, and don't mind the unused electrocompaniet amps sitting underneath them. and yes, i guess i could put the kelmar/hafler monoblocks somewhere else, but they don't bother me in the slightest. and i could move the misc tubes and diyparadise eva ldr remote off the top of the one x-over, and the other misc remotes, cables, crossover plug-in modules, tools, etc, but i like them close by. and that li'l two-tone gray ge transistor radio isn't going anywhere; it took me over a year to find a duplicate of my 1st ever piece of audio equipment that i received as a b-d present when i was 6 years old.

close-up of the mess:
amps, eq's, power conditioner - gear on rack between speakers.jpg

yah, i'm anal about some things, but i'm far from a neat-freak. which is a good thing, heh - my master is much worse than i am, and i'm picking up after her a lot. ;)

but, i guess everyone has relatives. uh, i mean everything is relative. :D check out the f/b website "the listening chair" - so many "humble systems" fanatically set up; so many of the spaces look unlived-in. :)

doug s.
 

OldTimer

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if you were looking at the 2nd pic, when i was measuring, i agree, it looked messy. which is why i scarfed on a local equipment stand i found on f/b, offered at a great price shortly thereafter: three shelves instead of two; which for me, was a substantial improvement, (as shown in the 1st pic i posted), and i'm perfectly content. i like my 4" thick lucite block subwoofer/midwoofer amp stands, and don't mind the unused electrocompaniet amps sitting underneath them. and yes, i guess i could put the kelmar/hafler monoblocks somewhere else, but they don't bother me in the slightest. and i could move the misc tubes and diyparadise eva ldr remote off the top of the one x-over, and the other misc remotes, cables, crossover plug-in modules, tools, etc, but i like them close by. and that li'l two-tone gray ge transistor radio isn't going anywhere; it took me over a year to find a duplicate of my 1st ever piece of audio equipment that i received as a b-d present when i was 6 years old.

close-up of the mess:
View attachment 341582
yah, i'm anal about some things, but i'm far from a neat-freak. which is a good thing, heh - my master is much worse than i am, and i'm picking up after her a lot. ;)

but, i guess everyone has relatives. uh, i mean everything is relative. :D check out the f/b website "the listening chair" - so many "humble systems" fanatically set up; so many of the spaces look unlived-in. :)

doug s.
How many wattages do all the equipment consume?
 

doug s.

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How many wattages do all the equipment consume?
almarro amp - 57w (pretty constant, idle or under load)
pass f2 clone - 200w (pretty constant, idle or under load)
hypex sub amp - idles at ~10w; 1/3 power (never - yikes!) would be ~30w (not shown in the pic; it's in the back of the room)
crown xls2000 - (i have two) each idles at 20w; 1/3 power each (never - yikes!) would be ~70w
the two marchand x-overs consume about 15w each
the klark teknik transmitter/receiver setup (transmitter shown in the pics; receiver is in the back of the room), each draw only a few watts.

the almarro tube amp and the pass f2 clone are certainly the most power hungry, even tho they're only rated at 5wpc.

doug s.
 

G-Can

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if you were looking at the 2nd pic, when i was measuring, i agree, it looked messy. which is why i scarfed on a local equipment stand i found on f/b, offered at a great price shortly thereafter: three shelves instead of two; which for me, was a substantial improvement, (as shown in the 1st pic i posted), and i'm perfectly content. i like my 4" thick lucite block subwoofer/midwoofer amp stands, and don't mind the unused electrocompaniet amps sitting underneath them. and yes, i guess i could put the kelmar/hafler monoblocks somewhere else, but they don't bother me in the slightest. and i could move the misc tubes and diyparadise eva ldr remote off the top of the one x-over, and the other misc remotes, cables, crossover plug-in modules, tools, etc, but i like them close by. and that li'l two-tone gray ge transistor radio isn't going anywhere; it took me over a year to find a duplicate of my 1st ever piece of audio equipment that i received as a b-d present when i was 6 years old.

close-up of the mess:
View attachment 341582
yah, i'm anal about some things, but i'm far from a neat-freak. which is a good thing, heh - my master is much worse than i am, and i'm picking up after her a lot. ;)

but, i guess everyone has relatives. uh, i mean everything is relative. :D check out the f/b website "the listening chair" - so many "humble systems" fanatically set up; so many of the spaces look unlived-in. :)

doug s.

you dont need to convince me it looks good. If its good for you. awesome.

For me in all honesty no chance my "master" would accept random gear laying on the floor like that stacked up on top of each other.

But if you are happy, Im happy.
 

JimBean

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you dont need to convince me it looks good. If its good for you. awesome.

For me in all honesty no chance my "master" would accept random gear laying on the floor like that stacked up on top of each other.

But if you are happy, Im happy.
Master? What sort of relationship are you stuck in? Maybe he lives alone and doesn't mind the "mess". Who cares? Everyone is different. Clean, messy, cluttered, as long as they can enjoy music.
 

doug s.

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Master? What sort of relationship are you stuck in? Maybe he lives alone and doesn't mind the "mess". Who cares? Everyone is different. Clean, messy, cluttered, as long as they can enjoy music.
"slave/master" - it's a longstanding joke with my wife and all our friends. ;)

doug s.
 

G-Can

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Master? What sort of relationship are you stuck in? Maybe he lives alone and doesn't mind the "mess". Who cares? Everyone is different. Clean, messy, cluttered, as long as they can enjoy music.
Hey paratrooper, first start reading then comment so you know what we were chatting about.
It was Doug that called his other half a "master" not me.
 

OldTimer

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almarro amp - 57w (pretty constant, idle or under load)
pass f2 clone - 200w (pretty constant, idle or under load)
hypex sub amp - idles at ~10w; 1/3 power (never - yikes!) would be ~30w (not shown in the pic; it's in the back of the room)
crown xls2000 - (i have two) each idles at 20w; 1/3 power each (never - yikes!) would be ~70w
the two marchand x-overs consume about 15w each
the klark teknik transmitter/receiver setup (transmitter shown in the pics; receiver is in the back of the room), each draw only a few watts.

the almarro tube amp and the pass f2 clone are certainly the most power hungry, even tho they're only rated at 5wpc.

doug s.
So, roughly you spend 1kw per hour. It’s about $1 per hour. Still cheap
 

doug s.

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So, roughly you spend 1kw per hour. It’s about $1 per hour. Still cheap
in fact, it's at least half of that, if not less. 5wpc on the subs would equate to about 100db; 1/3 power would be about 60wpc on the hypex amp and >200wpc on one channel of each crown amp, and 125wpc on the other (one channel drives a 4 ohm load, the other 8 ohms.) so the actual power draw is closer to the idle draw.

in any event; i'm glad it gets the oldtimer seal of approval. ;)

i must say that, if i could find inexpensive class d amps that sound as good running the drivers >175hz, i'd certainly consider it, in the interest of energy conservation, more than the cost/hr. and yes, i'm all about cheap: my entire system, as presently configured - including sources, power conditioners, cables, etc. - cost me a bit under $12k...

doug s.
 

marpe

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in fact, it's at least half of that, if not less. 5wpc on the subs would equate to about 100db; 1/3 power would be about 60wpc on the hypex amp and >200wpc on one channel of each crown amp, and 125wpc on the other (one channel drives a 4 ohm load, the other 8 ohms.) so the actual power draw is closer to the idle draw.

in any event; i'm glad it gets the oldtimer seal of approval. ;)

i must say that, if i could find inexpensive class d amps that sound as good running the drivers >175hz, i'd certainly consider it, in the interest of energy conservation, more than the cost/hr. and yes, i'm all about cheap: my entire system, as presently configured - including sources, power conditioners, cables, etc. - cost me a bit under $12k...

doug s.
Now that I know you have a resolving system. Can you tell me if you hear the awful grain, hash and congestion of these 3255 amps? I'm curious why there is so little discussion about inherent sound quality and so much talk about construction, measurements and op amp rolling.

I bought a 7498 amp years ago because I didnt like the heat thrown off my Cary Audio EL34 amp in the summer. I just recently changed out the 7498 for a 07 Max (48V) and find it a disappointment.

I only run them above 200 Hz to power my 4 ohm, 60" Carver planar magnetics. I'm crossing them over at about 96 db/octave with a DEQX 4. The 07 Max and the 7498 both feel very warm / hot at idle.

Thanks
 

doug s.

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Now that I know you have a resolving system. Can you tell me if you hear the awful grain, hash and congestion of these 3255 amps? I'm curious why there is so little discussion about inherent sound quality and so much talk about construction, measurements and op amp rolling.

I bought a 7498 amp years ago because I didnt like the heat thrown off my Cary Audio EL34 amp in the summer. I just recently changed out the 7498 for a 07 Max (48V) and find it a disappointment.

I only run them above 200 Hz to power my 4 ohm, 60" Carver planar magnetics. I'm crossing them over at about 96 db/octave with a DEQX 4. The 07 Max and the 7498 both feel very warm / hot at idle.

Thanks
sorry, you lost me there. what 3255 amps are you talking about? none in my system. maybe in the future, if i find something that can play nice over 175hz? will the fosi v3 w/48v gan p/s and upgrade opamp do it? or maybe something like the class a schiit gjallarhorn? class a/ab, inexpensive, doesn't use much juice...

meanwhile my class-d crown amps, w/their "drivecore" tech, whatever that is, don't drive anything except my bass subs below 50hz, and my bass bins from 50-175hz... and the hypex amp, driving the subs behind the listening area, is crossed at 80hz...

doug s.
 

marpe

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sorry, you lost me there. what 3255 amps are you talking about? none in my system. maybe in the future, if i find something that can play nice over 175hz? will the fosi v3 w/48v gan p/s and upgrade opamp do it? or maybe something like the class a schiit gjallarhorn? class a/ab, inexpensive, doesn't use much juice...

meanwhile my class-d crown amps, w/their "drivecore" tech, whatever that is, don't drive anything except my bass subs below 50hz, and my bass bins from 50-175hz... and the hypex amp, driving the subs behind the listening area, is crossed at 80hz...

doug s.
My apologies. I thought you had listened to the TPA3255 amps like the Fosi ZA3 or A07 Max in your current system.
 
OP
Guddu

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**Power ON/OFF issues with my beta ZA3 unit**
I have already reported this to Fosi and sent a video as well, but I think I should mention in this thread as well.
After almost 2 months of testing (loads of testing sessions for comparison with friends), my beta/test unit ran into on/off issues with power knob.

**** please note that mine is a beta testing unit, and I cannot confirm anything related into production units.
 

doug s.

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My apologies. I thought you had listened to the TPA3255 amps like the Fosi ZA3 or A07 Max in your current system.
no worries; the fosi v3 amps are (were?) under consideration, as well as lower powered a/ab amps; strictly for less electricity use. it sounds like you're not too fond of the sonic signature of the 3255-based amps, heh! i'm wondering of opamp upgrades would improve things. if you have suggestions for inexpensive low power amps that don't suck juice like class-a or tubed amps, yet still sound good, i'd love to hear about it. the schiit gjallarhorn could possibly fit the bill...

doug s.
 

daniboun

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no worries; the fosi v3 amps are (were?) under consideration, as well as lower powered a/ab amps; strictly for less electricity use. it sounds like you're not too fond of the sonic signature of the 3255-based amps, heh! i'm wondering of opamp upgrades would improve things. if you have suggestions for inexpensive low power amps that don't suck juice like class-a or tubed amps, yet still sound good, i'd love to hear about it. the schiit gjallarhorn could possibly fit the bill...

doug s.

Take a look at the latest Sylph Audio FB100 . Will be reviewed soon by Amir. Lester claims for a nice 108db Sinad under ASR conditions with its advanced PFFB implementation.
I also know that FOSI purchased a module from Sylph Audio probably to study its implementation

 

doug s.

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Take a look at the latest Sylph Audio FB100 . Will be reviewed soon by Amir. Lester claims for a nice 108db Sinad under ASR conditions with its advanced PFFB implementation.
I also know that FOSI purchased a module from Sylph Audio probably to study its implementation

well, since i last posted, i ended up buying two aiyima a07 max amps w/the 48v/5a power supplies. cost was <$170 shipped. i also bought four akliam lc2 discrete class-a op amps; cost was $60 shipped. i received everything on 5 feb; ran them for a few days, and i was delighted w/what i heard. so, i opened them up to install the op amps. it turns out they won't fit inside the case, so i decided to install them only in the amp driving my full range drivers in my oris 150 horns (operating from 175hz to 7khz). they were definitely worthwhile. not sure that installing them in the amp driving the ribbon tweeters >7khz would do much, so i didn't bother installing the 2nd pair in that amp. i did fab a makeshift cover for the amp w/the akliam op amps.

considering the price of the sylph audio components, and the performance i'm now getting, i don't think they would offer much improvement, if any. a pffb implementation wouldn't be audible in my system; neither would a 108db sinad, vs asr's measured 86db sinad of the a07 max's.

pic of my aiyima amps; one w/my makeshift cover:
1707678547084.png


pic of my present system; active quad-amped (2nd pair of vmps larger subs are ~20' behind the listening area):
1707678651173.png


doug s.
 

daniboun

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well, since i last posted, i ended up buying two aiyima a07 max amps w/the 48v/5a power supplies. cost was <$170 shipped. i also bought four akliam lc2 discrete class-a op amps; cost was $60 shipped. i received everything on 5 feb; ran them for a few days, and i was delighted w/what i heard. so, i opened them up to install the op amps. it turns out they won't fit inside the case, so i decided to install them only in the amp driving my full range drivers in my oris 150 horns (operating from 175hz to 7khz). they were definitely worthwhile. not sure that installing them in the amp driving the ribbon tweeters >7khz would do much, so i didn't bother installing the 2nd pair in that amp. i did fab a makeshift cover for the amp w/the akliam op amps.

considering the price of the sylph audio components, and the performance i'm now getting, i don't think they would offer much improvement, if any. a pffb implementation wouldn't be audible in my system; neither would a 108db sinad, vs asr's measured 86db sinad of the a07 max's.

pic of my aiyima amps; one w/my makeshift cover:


pic of my present system; active quad-amped (2nd pair of vmps larger subs are ~20' behind the listening area):


doug s.

The Aiyima A07 Max is poor performer....huge channels dismatch..... To put it mildly, a big design error.
If ASR tests exist it is precisely to avoid this type of error that you have just made))) :facepalm:



1707683415468.png


108db VS 88db is a huge difference for me.....
As such, if you don't see the difference or the problem with this Aiyima A07 Max, you might as well not read the tests offered by Amir....
 
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