You have already been told a few posts back, related to the stereo version, that there is a relay that bypasses the thermistor once the amp is on. In the mono version there is also a relay besides the thermistor that bypasses it and at the same time connects the speaker posts to the output of the amp, so if thermistor is not rated for 10A (what I don't know), it is completely irrelevant.It seems that you are unfortunately not the only one to have a bad experience with this amplifier reference at FOSI AUDIO if we observe the various customer complaints on a large number of internet forums...
AMIR has carried out the review of this device which seems quite decent but it seems to have somehow 'insisted' concerning the power supply to be used since we can see (added in red clearly visible) on the photo of the power supply that it is in 5A and not 10A.
Is it due to 'chance': I don't think so...
I had earlier in this post alerted about the use of a particular component used in the STEREO version of the V3 and it could be very likely that my remark is valid for this model:
this component called 'NTC' (see the picture below) seems to me 'too weak' to be used with a 10A power supply without taking the risk of its 'destruction'.
View attachment 412862
On your device, a simple test (with the volume at minimum) and this 'shunted' device would be enough to bring it back to life, I'm sure, and you could then gently increase the volume to the maximum to ensure that the amplifier works normally again.
Let's hope that it's only about that, otherwise 'it's much more serious, Doctor', and in this case FOSI would have to thoroughly review 'its copy'.
Unfortunately, I cannot be of much help to you in view of the distance that separates us, but it was with great pleasure
If I were you, as it was ordered on AMAZON, I would simply send it back since it is guaranteed and will no longer be so as soon as it has been opened.
Afterwards, I would ask myself several times the question of using an identical model, but that's just my humble opinion
Kind regards.
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Fosi Audio V3 Amplifier Review
- Thread starter amirm
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It isn't. As pointed out further up this thread (or in another - I can't remember) it is only conducing for a few milleseconds while the capacitors charge up. After that a relay closes, and all the current goes through the relay.
ICIETDIYEUR
Active Member
You must be right because everything seems to be going well for the person concerned 
By the way: if the amplifier works as you say then there is a problem with the relay and or its circuit...
... and perhaps other things: it is not really reassuring, but I am convinced that your intervention will have reassured everyone.
Kind regards.
PS: I would like to point out that you wrote '... once the amp is turned on...'
So it would have to turn on first, wouldn't it?
It's the 'DATASHEETS' that 'speak', not me.
PS (2): You know when I see a MONO amp with 3 OPAMPs for a circuit that uses the TPA 3255 chip then I'm already wondering since you can do the same thing with only 1 OPAMP.
Why make it simple when you can make it complicated ?
By the way: if the amplifier works as you say then there is a problem with the relay and or its circuit...
... and perhaps other things: it is not really reassuring, but I am convinced that your intervention will have reassured everyone.
Kind regards.
PS: I would like to point out that you wrote '... once the amp is turned on...'
So it would have to turn on first, wouldn't it?
It's the 'DATASHEETS' that 'speak', not me.
PS (2): You know when I see a MONO amp with 3 OPAMPs for a circuit that uses the TPA 3255 chip then I'm already wondering since you can do the same thing with only 1 OPAMP.
Why make it simple when you can make it complicated ?
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It's a shame you don't understand how to interpret them then.
That chart is allowable switching current, not on state current (to minimize risk from arcing when the contacts open/bounce - why AC currents can be higher). You'll note it switches on when the capacitors are charged and the current is close to zero, And it switches off half a second or so after power has been removed and there is no current at all. When the contacts are closed there is no voltage across them, and the only limit to current is the carry current rating, based on the contact resistance.
I just happily continue on using 5A power bricks with my Fosis and Aiyimas...they don't seem to cause me any trouble...
I think most of these small Damps are being promoted generally as being able to handle more current than they are really suited for, which is a shame. They seem to work perfectly well in the lower power ranges, for the most part...
I think most of these small Damps are being promoted generally as being able to handle more current than they are really suited for, which is a shame. They seem to work perfectly well in the lower power ranges, for the most part...
ICIETDIYEUR
Active Member
So everything is fine since you say it:
this amplifier is perfect and I will go back to study
this amplifier is perfect and I will go back to study
somebodyelse
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Why not? Because it won't work properly with at least 2 varieties of balanced output, and probably has a 'Pin 1 Problem.'
In my opinion it is not necessary to find a solution such as repairing the tool, we should say not to put it on the market because it is unreliable.
I have many electronics from 1976 that still work today without problems.
I have many electronics from 1976 that still work today without problems.
ICIETDIYEUR
Active Member
... and which are repairable, even if that is not the primary goal.
@ somebodyelse : Can you 'elaborate' please ?
@ somebodyelse : Can you 'elaborate' please ?
somebodyelse
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Refer to recent discussion about a similar problem with the Topping B100 - although it's mixed up with power output. The Schiit Vidar 2 has the same problem, but at least mentions it in their FAQ. The likely 'Pin 1 Problem' comes from failing to follow AES48.
trevor_bartram
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I'm searching for a backup amp in case my 22+ year old NAD fails. I purchased a Fosi V3 stereo with 32V 5A PSU based on reviews. I chose 32V for long term reliability. I don't need tons of power but I'm used to excellent sound quality. I'll admit I havn't read all 150 pages of this thread, so I'm hoping some experts here will help:
1. Is the V3 great out of the box or does it need to 'run-in' for best sound quality? Does run-in involve just being powered or does it need to get warm delivering power to a load, if so for how long?
2. Is there concensus on the best value substitute opamps for improved sound quality?
Thanks in advance!
1. Is the V3 great out of the box or does it need to 'run-in' for best sound quality? Does run-in involve just being powered or does it need to get warm delivering power to a load, if so for how long?
2. Is there concensus on the best value substitute opamps for improved sound quality?
Thanks in advance!
Run-in for amps is a myth. They work or they don't. Plug in, turn on, and enjoy!
With the V3, you will find that the audio volume pot means you will have the volume knob higher than you are used to, but you have more control over softer volumes. A real plus in my view.
Most of us here feel that the op-amp swapping is equivalent to chasing rainbows. I did try swapping the stock ones (5532) for another chip type (4562s?) - could not really hear a difference. Later, Burson Audio sent me some free V5 and V6 op-amps to test and review - same thing. I didn't get oscillation, but I didn't hear any difference. Others, as you have no doubt read, have a semi-religious experience with changes. It's just a question of your curiosity and your pocketbook, probably more so than your ears. Not sure if Sparkos or others have a return policy, but that would be one way to find out if they do...
trevor_bartram
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Thanks for the reply. The 5532 is a 45 year old design, no doubt TI has upgraded it for modern processes but initial specs remain. I was hoping for proven modern value IC suggestions?
I'll let others chime in here - you're going to get a full range of opinions on it. The question is whether one can truly hear a difference.
I spent a long time running in my V3 stereo, marvelling at the improvements, but when I bought a second, brand new V3, I couldn’t tell them apart. Funny the way perception works.
That probably doesn’t bode well for my op amp recommendations, but at the end of the day, most op amps cost a few pounds only, and it’s fun! I have enjoyed 2134s in the V3, and I have Muses 02 in at the moment which cost £15 each. Are they revelatory- no but I felt there was a slight improvement over the originals, without any evidence to back this up.
Oh my goodness. If you do a web search you will find literally hundreds of threads about this. Here are a few links I got.
www.audiosciencereview.com
www.diyaudio.com
www.stereonet.com
www.blikai.com
www.avaq.com
www.diyaudio.com
www.diyaudio.com
www.head-fi.org
www.stereonet.com
It's endless...
Replace OP amps. Completely pointless, or not?
Why do so many OPs change amps in, for example, the amplifier AIYIMA A07 TPA3255? What's the point of that? Does not modern OPs amps amplify the signal completely linear straight(if the construction they sit in is well constructed, and made to fit OP amp X)? Do not modern OP amps have a...
www.audiosciencereview.com
NE5532 or OPA2134
Hi! I have a cd player SONY XA2-ES, It has four opamp NE5532, I'm thinking to change them with OPA2134. Is it really a good sound improvement? Can you give me some advices? Best Regards. Enzo
NE5532 OP chip - worth changing out ?
I have a 'Little Bear B4' portable tube amp and i love its characteristics. Its based around the NE5532 OP chip ..... and do you think its worth while changing it out some something so called 'better' ? I have been reading this interesting article and im now reluctant to do so > https://www.ee...
www.stereonet.com
OPA2134 vs NE5532: A Comparison of Performance, Features, and Applications
OPA2134 and NE5532 are popular functional amplifiers(op-amps) famed for their audio fidelity and versatility.
5532 swapping
...hmmm well this is interesting. i had been wanting to upgrade the op amps in my ancient Yamaha DA2X dac...this dac was a pro studio piece circa early 90's,so while it is older digital,it's also fully balanced input to output[two dacs in one box really] it has a very high quality build,it's...
audiokarma.org
LM4562 vs NE5532: What are Differences and How to Choose - Avaq
The comparison between the LM4562 and NE5532 operational amplifiers (op-amps) is an essential journey into the world of audio electronics, where the intricacies of sound quality and performance are paramount. In this article, we will delve into the distinctions between the LM4562 and NE5532 op-amps.
LM4562 vs TL072 and NE5532 ..impossible ?
I got curious today and decided to try and see how our old friends compared against the latest and greatest (?) chip. The chips were put into the active filter at the output of a DAC ( Zhaolu V2.5 ). Results . 1. LM4562 -- not by a very large margin ! 2. TL072 was VERY good !! Equal or better...
Choosing of best sounding OP AMPs for the lowest possible THD+N -really the best Way?
Choosing of best sounding OP AMPs for the lowest possible THD+N - really the best Approach ?? First some extracts from the rubric "Integrated Opamps and their Properties" (From page 109-165 in the book "Small Signal Audio Design" - go to Facebook from Mr. DOUGLAS SELF) Introduction: Audio...
LM4562 vs OPA2134 vs [ ? ]
Im interested in op amp rolling for my amp since its not expensive to try out and I was surprised to find a lot of variation between them, the amp has a very simple circuit so my results could be more siginificant than with other amps. Using hd600s and 400is to test them Ive compared the...
www.head-fi.org
The best sounding op amps for audio work.
G'day all, I guess that this sounds suspiciously like the subject of 'op amp rolling, but actually it isn't. As much as I think that op amps do have a 'sound', in recent days I've been revisiting the LM4562 and sonically wise, to my ears it doesn't really have that 'typical' op amp signature, it ...
www.stereonet.com
It's endless...
trevor_bartram
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I hoping for expert CONCENSUS for the V3 5532s?Oh my goodness. If you do a web search you will find literally hundreds of threads about this. Here are a few links I got.
Replace OP amps. Completely pointless, or not?
Why do so many OPs change amps in, for example, the amplifier AIYIMA A07 TPA3255? What's the point of that? Does not modern OPs amps amplify the signal completely linear straight(if the construction they sit in is well constructed, and made to fit OP amp X)? Do not modern OP amps have a...NE5532 or OPA2134
Hi! I have a cd player SONY XA2-ES, It has four opamp NE5532, I'm thinking to change them with OPA2134. Is it really a good sound improvement? Can you give me some advices? Best Regards. EnzoNE5532 OP chip - worth changing out ?
I have a 'Little Bear B4' portable tube amp and i love its characteristics. Its based around the NE5532 OP chip ..... and do you think its worth while changing it out some something so called 'better' ? I have been reading this interesting article and im now reluctant to do so > https://www.ee...OPA2134 vs NE5532: A Comparison of Performance, Features, and Applications
OPA2134 and NE5532 are popular functional amplifiers(op-amps) famed for their audio fidelity and versatility.5532 swapping
...hmmm well this is interesting. i had been wanting to upgrade the op amps in my ancient Yamaha DA2X dac...this dac was a pro studio piece circa early 90's,so while it is older digital,it's also fully balanced input to output[two dacs in one box really] it has a very high quality build,it's...audiokarma.orgLM4562 vs NE5532: What are Differences and How to Choose - Avaq
The comparison between the LM4562 and NE5532 operational amplifiers (op-amps) is an essential journey into the world of audio electronics, where the intricacies of sound quality and performance are paramount. In this article, we will delve into the distinctions between the LM4562 and NE5532 op-amps.LM4562 vs TL072 and NE5532 ..impossible ?
I got curious today and decided to try and see how our old friends compared against the latest and greatest (?) chip. The chips were put into the active filter at the output of a DAC ( Zhaolu V2.5 ). Results . 1. LM4562 -- not by a very large margin ! 2. TL072 was VERY good !! Equal or better...Choosing of best sounding OP AMPs for the lowest possible THD+N -really the best Way?
Choosing of best sounding OP AMPs for the lowest possible THD+N - really the best Approach ?? First some extracts from the rubric "Integrated Opamps and their Properties" (From page 109-165 in the book "Small Signal Audio Design" - go to Facebook from Mr. DOUGLAS SELF) Introduction: Audio...LM4562 vs OPA2134 vs [ ? ]
Im interested in op amp rolling for my amp since its not expensive to try out and I was surprised to find a lot of variation between them, the amp has a very simple circuit so my results could be more siginificant than with other amps. Using hd600s and 400is to test them Ive compared the...The best sounding op amps for audio work.
G'day all, I guess that this sounds suspiciously like the subject of 'op amp rolling, but actually it isn't. As much as I think that op amps do have a 'sound', in recent days I've been revisiting the LM4562 and sonically wise, to my ears it doesn't really have that 'typical' op amp signature, it ...
It's endless...
I just don't think you are going to get to any consensus on this. There are many who feel that Fosi and Aiyima should not even have made the products with sockets, that it's a bit of a marketing gimmick, just like the overstated power figures. They can upsell customers though for the more expensive power supplies and the different op-amps. They do better in the end by playing to the never-ending "tweaking" and "refinement" that most of us are prone to.
I read a lot of threads on this after my first Aiyima A07 arrived...the 4562's were inexpensive to try, and so I did. The Burson ones were free to me, so I tried those.
There a lot of folks who feel the Muse and Sparkos op-amps sound different, those seem to get the most ink. The newest Burson 7 op-amps are sized to fit these smaller cases, where the 6 series was too high.
I think this is mostly a matter of your ears and your pocketbook. Try one and see if you feel there's a positive effect? And if you can return them, all the better, or you can of course sell them off as well.
trevor_bartram
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Thanks for your further thoughts. There's a YT vid on this with music samples. The comments are illuminating, the general concensus is 5532 is good (rare Philips preferred), the OPA2604 is better, with a few outliers preferring (expensive) discretes. I believe Fosi bought the entire stock of OPA2604AP (DIP) & charges an arm & leg.
There's a discussion of fake 5532s but I believe I saw a post where Fosi showed a TI invoice for 5532s, that dispelled the myth. There are OPA2604AQ ceramic DIPs available on Ali but they could be fakes too.
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Yeah, Fosi did jump in and show that was a bogus claim. Their internals are good. The main gripe is some early units had 50V power caps inside, pretty close/too close if one was using a 48v power brick. Since I use 32v and 36v bricks, that doesn't concern me. I think all the current ones have 63v power caps.
When I bought my 4562's, I got from Mouser or Digikey, even though they are inexpensive, there do seem to be eBay and Amazon fakes out there. I think there are fake Muse op-amps out there too.
With Sparkos or Burson, you just order direct, of course.
I just remembered, I did get one early chip-type amp set that caused oscillation, but I shut down in time. Don't remember what the code was. The 4562s seem to work fine. Fosi is good about answering direct questions about ones that are OK to use, beyond what's on their web site.
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