Fosi Audio ZA3 - Initial Review

[OldJBL]

I recently picked up a second ZA3 due to Fosi having a screaming deal on them recently. I paid $102 shipped to my door with the 48v PS. I ran it in two channel configuration for a couple of days to burn it in before setting up the dual mono configuration. Also, this is the first dual mono setup I have run. Well, I am more than impressed with the sound output. The improvements with channel separation, soundstage and detail were immediately noticed. It sounds like the music has a more three dimensional airy quality to it.

Additionally, there is a very noticeable improvement in bass output. It's not boomy or obnoxious, it is fuller in a very good way. There just seems to be more dynamics to the sound across the board. I know the ZA3 doesn't produce a lot more power in mono mode but it sure sounds like it does. I have always been somewhat skeptical of whether a mono setup was more hype than substance. Well, I now know there is a lot more substance than hype and it took the lowly ZA3 to let me figure this out. Anyone that is thinking about buying a second ZA3 to have a dual mono setup, I highly recommend doing so. For those who will be buying two amps I recommend going with the V3 Mono as this amp has a better feature set than the ZA3 since it is a newer model.

Lastly, we are living in a great time to be able to buy such high quality, great sounding amps at such low prices. I purchased both amps for around $240 shipped. My JBL L100t3 speakers, I bought new in 1989, that I use in this 2.0 system have never sounded better. Now I am wondering how good a home theater setup would sound using a V3 Mono to power the full range speakers instead of an AVR.

 

[OldJBL]

I am getting ready to replace the right channel op amp in the new ZA3. I know some here have removed all the other op amps that are not being used because it supposedly improves SQ. Is this something that is it worth doing?

 

[Gigantic]

I did it, but I can’t claim that it made a significant difference, as I didn’t a/b them.

 

[OldJBL]

I did it, but I can’t claim that it made a significant difference, as I didn’t a/b them.

I decided to leave them in. It sounds even better using the MUSES02 on each channel. I will upgrade to Sparcos at some point based on what I have heard from people here who have done this. For now I am just going to enjoy them as they are.

 

[Retro_Pete]

Opamp swapping is not something that should be needed doing. It is matched for the amplifier design and, if any change is made at all, can make it oscillate which can be the explanation for the increased perception of "airyness" to the sound via. lower harmonics. In other words distortion of the signal. Why one would do that to an amplifier with flat frequency response I wouldn't know. If one want a change to the sound I'd suggest using EQ to taste or swapping what matters e.g. speakers.

Burn-in of solid state electronics is a moot point. It has never really been proven to exist. There are no components in a solid state device that change their characteristics enough to amount to anything audible at all.
"Burn-in" of ears and sighted bias and expectations are with certainty things that do exist though and are with all likelihood the explanations for the perceived difference. These traits of the human biology is worth to take into consideration when reviewing audio equipment. Sadly they are often neglected by both hobbyists and professional reviewers.

 

[OldJBL]

Thanks for your opinion but many people disagree with it, including the manufacturers of audio gear.

 

[seikosha]

Opamp swapping is not something that should be needed doing. It is matched for the amplifier design and, if any change is made at all, can make it oscillate which can be the explanation for the increased perception of "airyness" to the sound via. lower harmonics. In other words distortion of the signal. Why one would do that to an amplifier with flat frequency response I wouldn't know. If one want a change to the sound I'd suggest using EQ to taste or swapping what matters e.g. speakers.

Burn-in of solid state electronics is a moot point. It has never really been proven to exist. There are no components in a solid state device that change their characteristics enough to amount to anything audible at all.
"Burn-in" of ears and sighted bias and expectations are with certainty things that do exist though and are with all likelihood the explanations for the perceived difference. These traits of the human biology is worth to take into consideration when reviewing audio equipment. Sadly they are often neglected by both hobbyists and professional reviewers.

On burn in…isn’t capacitor “forming“ a real phenomenon. Could that contribute to a slight change in sound attributed to “burn in”

 

[Retro_Pete]

On burn in…isn’t capacitor “forming“ a real phenomenon. Could that contribute to a slight change in sound attributed to “burn in”

No. Not likely with new capacitors. Maybe on rare occasions for old capacitors that has been unused for many years reforming is necessary to obtain its correct values. I have yet to hear about new capacitors that needed this kind of treatment. A lot of equipment would then have a disclaimer to first use it in application when been switched on for xxx hours. Like, say, critical measurement tools, frequency converters etc.

It seems this phenomena is only present and shared IR to audio equipment, which is kind of odd if you think about it.

 

[seikosha]

No. Not likely with new capacitors. Maybe on rare occasions for old capacitors that has been unused for many years reforming is necessary to obtain its correct values. I have yet to hear about new capacitors that needed this kind of treatment. A lot of equipment would then have a disclaimer to first use it in application when been switched on for xxx hours. Like, say, critical measurement tools, frequency converters etc.

It seems this phenomena is only present and shared IR to audio equipment, which is kind of odd if you think about it.

I suppose it could be possible if the shelf life of the capacitors that the manufacturers are using is excessive. Who knows how long they keep parts in inventory?

 

[Retro_Pete]

I suppose it could be possible if the shelf life of the capacitors that the manufacturers are using is excessive. Who knows how long they keep parts in inventory?

I suppose it could happen in theory. We are talking decades of shelf life. The chances of that as the reason is slim to none. I'd call it a red herring.

The odds of acclimatisation of ears and expectation bias being the reasons is by far the best, if not only, explanation.

When it comes to speakers I am more lenient IR to break-in / burn-in but with solid state electronics it's not just me telling that it doesn't exist in the form it is being presented here. It's the industry. I'd guess you'd be hard pressed to find an electrical engineer believing in burn-in this way.

In general the hobby is much more well-informed than it used to. Snake oil salesmen have a harder time than before, which is good. Unfortunately some old tales still linger. My personal take on it is because of the echo-chamber effect, reinforcing some of this stuff all from the sales-brochure with the nice story to expectation bias from the buyers, sharing their experience with others, telling the same story as the sales-brochure said with their own words. And they had that experience, no doubt. But they had it because they failed to identify how powerful the mind is with these sorts of things and did comparisons sighted, not volume matched etc. etc.

Someday we might get there. But there are some great story tellers in the business..

 

[Retro_Pete]

Thanks for your opinion but many people disagree with it, including the manufacturers of audio gear.

Many wrongs don't make a right.

I don't particular trust manufacturers and you shouldn't either. They'll sell more if they tell a nice story behind their unique product and are particularly focused to how they are convincingly enough with their advertisement.

 

[OldJBL]

Many wrongs don't make a right.

I don't particular trust manufacturers and you shouldn't either. They'll sell more if they tell a nice story behind their unique product and are particularly focused to how they are convincingly enough with their advertisement.

You still must drone on to me about this? At this point I feel like I am being stalked. Just accept that you are never going to change my mine on this and move along.

 

[Retro_Pete]

You still must drone on to me about this? At this point I feel like I am being stalked. Just accept that you are never going to change my mine on this and move along.

Huh? -What an odd response and allegation..

 

[OldJBL]

Huh? -What an odd response and allegation..

You seem to be on a crusade to to convince me that my ears are lying to me regarding and the ZA3s I own never having a burn in period. I will never convince you that this happened and you will never convince me that I didn't hear it happening. I guess you will be the first person I have set to ignore in my fifteen years of being a member here.

 

[prisoners]

JFC this thread has gotten ridiculous. Congratulations on representing the worst of this hobby; I’m out.

 

[seikosha]

I suppose it could happen in theory. We are talking decades of shelf life. The chances of that as the reason is slim to none. I'd call it a red herring.

The odds of acclimatisation of ears and expectation bias being the reasons is by far the best, if not only, explanation.

When it comes to speakers I am more lenient IR to break-in / burn-in but with solid state electronics it's not just me telling that it doesn't exist in the form it is being presented here. It's the industry. I'd guess you'd be hard pressed to find an electrical engineer believing in burn-in this way.

In general the hobby is much more well-informed than it used to. Snake oil salesmen have a harder time than before, which is good. Unfortunately some old tales still linger. My personal take on it is because of the echo-chamber effect, reinforcing some of this stuff all from the sales-brochure with the nice story to expectation bias from the buyers, sharing their experience with others, telling the same story as the sales-brochure said with their own words. And they had that experience, no doubt. But they had it because they failed to identify how powerful the mind is with these sorts of things and did comparisons sighted, not volume matched etc. etc.

Someday we might get there. But there are some great story tellers in the business..

Retro, I‘ve seen posts on non audio electronic forums from both manufacturers and hobbyists, that reforming is sometimes necessary with only 1-2 years of shelf life and recommendations that it mostly is an issue after two years of shelf life. I could easily see a capacitor with a two year old production date in a product. After all, it sits on the shelf after it’s produced by the capacitor company, then again after it’s bought by the audio manufacturer, then put into the product, where it is then sold to a middleman who finally sells it to the consumer.

I first learned of capacitor reforming years ago as a photography enthusiast. It was common practice that if you hadn’t used your flash units for a number of months, you needed to charge and discharge them a few times to reform the capacitors. If you didn’t do this, you could actually see sometimes that your pictures would be underexposed for a few frames until the capacitors reformed and the flash units discharged correctly.

Anyway, my personal experience after doing a lot of listening and experimenting is that I do believe a tiny bit of burn in does occur with many products for a very brief time, but the human brain needs to be “burned in“ as well And that takes longer.

 

[ejman]

You seem to be on a crusade to to convince me that my ears are lying to me regarding and the ZA3s I own never having a burn in period. I will never convince you that this happened and you will never convince me that I didn't hear it happening. I guess you will be the first person I have set to ignore in my fifteen years of being a member here.

Join the club. It just so happens that this same individual is the only one I have on ignore since I joined audiokarma 18 years ago.

 

[Retro_Pete]

Retro, I‘ve seen posts on non audio electronic forums from both manufacturers and hobbyists, that reforming is sometimes necessary with only 1-2 years of shelf life and recommendations that it mostly is an issue after two years of shelf life. I could easily see a capacitor with a two year old production date in a product. After all, it sits on the shelf after it’s produced by the capacitor company, then again after it’s bought by the audio manufacturer, then put into the product, where it is then sold to a middleman who finally sells it to the consumer.

I first learned of capacitor reforming years ago as a photography enthusiast. It was common practice that if you hadn’t used your flash units for a number of months, you needed to charge and discharge them a few times to reform the capacitors. If you didn’t do this, you could actually see sometimes that your pictures would be underexposed for a few frames until the capacitors reformed and the flash units discharged correctly.

Anyway, my personal experience after doing a lot of listening and experimenting is that I do believe a tiny bit of burn in does occur with many products for a very brief time, but the human brain needs to be “burned in“ as well And that takes longer.

Looking at Elna and Nichicon tech docs. seem to confirm that this is a non-issue. The reforming is done with nom. voltage in a matter of minutes to reach specified leakage current. A caution is issued IR to a protective circuit if the capacitor has been stored for more than 2 years. This would surely be to slowly increase voltage and control the current to not cause damage to the circuit, equipment or capacitor itself. This is me guessing, as the procedure is not described in more detail. In the DIY section there are probably many that have re-formed old caps.

Manufacturing:
Source: https://www.elna.co.jp/en/product/manufacture_aluminum/


Changes when stored > 2 years:
Source: https://www.elna.co.jp/wp-content/uploads/2023/04/0-caution_AL_e.pdf


A spec. sheet for electrolytic cap. Nichicon brand:
Source: https://www.nichicon.co.jp/english/series_items/catalog_pdf/e-lgu.pdf

 

[EddNog]

With regards to op-amp rolling, I categorize it similarly to rolling tubes on a tube amp. You’re not taking something and necessarily improving it from a measured standpoint, you’re adding or changing the coloring of the sound offered by the component.

I purchased a pair of V3 Monos to upgrade from the pair of ZA3s I was using originally, but I discovered that the Burson V7 Vivid op-amps I preferred the color of the sound from (I compared against Sparkos S3602 in my ZA3s previously before receiving the V3 Monos) did not fit inside the tiny cases of the V3 Monos. As it so happens my dad prefers the color of the sound from the Sparkos op-amps, and I had gifted him the ZA3s when the V3 Monos came in, I just ended up swapping him the V3 Monos with dual Sparkos op-amps (yes, more money in op-amps than the amps themselves cost—snicker all you want) for the ZA3s back so I can run my Burson V7 Vivids in the ZA3s. I also swapped from XLR connection to RCA to bypass one signal conversion in the ZA3s when we did this swap, which had the added benefit of allowing me to utilize all three modes on my Schiit Freya+ preamp without losing gain coherence between my subwoofer (hooked up via RCA to my preamp) and my speakers (the difference in gain level between XLR and RCA changes when switching between passive, solid state buffer, and tube buffer modes).

Not all of us are after absolute dead accuracy of sound. Some of us just want to hear the music the way we like it to sound. It’s like accepting some grated cheese at the table when the waiter offers it while serving you your order of pasta.

-Ed

 

[OldJBL]

With regards to op-amp rolling, I categorize it similarly to rolling tubes on a tube amp. You’re not taking something and necessarily improving it from a measured standpoint, you’re adding or changing the coloring of the sound offered by the component.

I purchased a pair of V3 Monos to upgrade from the pair of ZA3s I was using originally, but I discovered that the Burson V7 Vivid op-amps I preferred the color of the sound from (I compared against Sparkos S3602 in my ZA3s previously before receiving the V3 Monos) did not fit inside the tiny cases of the V3 Monos. As it so happens my dad prefers the color of the sound from the Sparkos op-amps, and I had gifted him the ZA3s when the V3 Monos came in, I just ended up swapping him the V3 Monos with dual Sparkos op-amps (yes, more money in op-amps than the amps themselves cost—snicker all you want) for the ZA3s back so I can run my Burson V7 Vivids in the ZA3s. I also swapped from XLR connection to RCA to bypass one signal conversion in the ZA3s when we did this swap, which had the added benefit of allowing me to utilize all three modes on my Schiit Freya+ preamp without losing gain coherence between my subwoofer (hooked up via RCA to my preamp) and my speakers (the difference in gain level between XLR and RCA changes when switching between passive, solid state buffer, and tube buffer modes).

Not all of us are after absolute dead accuracy of sound. Some of us just want to hear the music the way we like it to sound. It’s like accepting some grated cheese at the table when the waiter offers it while serving you your order of pasta.

I learned a long time ago that pursuing audio perfection was, for me, a fool's errand. A graph of cost versus percent of perfection achieved is not linear but logarithmic, as it is with most quests for perfection. Getting to 85%-90% perfection is relatively attainable from a time and money perspective. Getting the last 10%-15% where the graph line approaches vertical and becomes a situation, for me, where the juice isn't worth the squeeze.