Greg, I’m not sure if you got that right about the lone op amp at the back of the board which Fosi has been calling position 1. Directly from Fosi “The op amp in position 1 converts the unbalanced signal from RCA into a balanced signal.” The V3 mono is in fact a balanced circuit due to the PFFB design and the function of the op amp in this position is to convert the single ended signal to balanced and it is audible. When using the single ended inputs there is an easily heard, slightly inferior sound quality compared to the balanced input and it’s widely reported by many that the balanced input sounds best. When I roll the op amp in position 1 and use a single ended input I can hear the differences but when I listen with a balanced input I hear no differences when rolling this op amp.
Hello... I am sorry if my explanation was either unclear or otherwise not what you expected, but, we are saying the same thing... Here is what I said starting at about 3:28 - ua-cam.com/video/jpLtt3hJiCs/v-deo.htmlsi=wFL0-ePNnSIML4Lj&t=208 "Examining the three removable IC OpAmps in the V3s reveals that one of the three, _the one mounted nearest the back of the board, is used to accept and integrate balanced inputs to drive the V3’s_ ." And my further discussion about the common use of ICs to allow for balanced inputs to be used with single-ended designs may have been a bit confusing. Finally, I will have to go back to the tech info on the V3, as, after seeing your comment, I may have mistakenly gotten their intent one hundred eighty degrees reversed. My take on its application was that it was provided ONLY to allow balanced inputs, not that it was crucial to the use of a converted single-ended input. More as I have it. Thanks for writing! 😁
@ Thanks, Greg. You know I’m a fan of your channel and just trying to help out. Yes, I believe that you might have it 180 degrees the other way. Ha ha. The amplifier circuit is a balanced design. The function of that opamp is to convert single ended signals to balanced before the signal moves on to the other two op amps that you have upgraded thus allowing use of a single ended connection with the amp. All that said, Fosi does suggest that there is not as big of a difference changing that opamp and in my case I can attest there is a noticeable, but subtle difference with using various op amps in this position. The balanced connection is better because you avoid that opamp, it’s a bit more quiet, natural and more totally accurate. Bottom line: you need to get another set of Sparkos opamps or move your new ones over and see what you hear. 😀
@@sean_heisler Thanks - again - for the post... I have to tell you, I have found the available info confusing at best. 🤔On one of the Fosi Audio Fourm pages, their "V3 Mono Op-amp rolling" page," following a video on the process posted by kauai82, there is the following statement... "As you can see by the picture, I did not replace socket one on the board. _If you are going to use the balanced inputs, I would also replace this op-amp."_ This statement had influence on, and seems to support my original position and statement...as it suggests that the OpAmp in that particular location has an influence on the balanced input performance, not the single-ended input... I am going to pursue this further, but...I'm still not sure about this... More if/when I have it...
@ I hear you, Greg. It is confusing. I tried once to find out what the input impedance is on these amps it took a while to get that. Have you watched the Fosi V3 mono op amp rolling video on their UA-cam channel? I’m going to attempt to paste the link here but often UA-cam deletes comments with links. You can see at :25 into this video they label the op amp in question as the number 1 position and go on to say it’s responsible for converting the unbalanced RCA input to a balanced signal. ua-cam.com/video/NSZ5T_XhE3U/v-deo.htmlsi=9On6UJWXOs_rHxe0
@@sean_heisler Hey, Sean. Yes, I have... And it was on that same Fosi Forum Page with that posted video (community.fosiaudio.com/threads/v3-mono-op-amp-rolling.108/) where the poster made that comment... I'm still not _necessarily_ doubting that claim, I'm just wondering how it really contributes... There are too many conflicting versions to be sure. I'm going to write to my connection at Fosi and see if they can offer some explanation for the discrepancy... And, seriously, thanks again for engaging here. This is one of the many reasons I do all this stuff! 😉
Inexpensive initial cost plus very reasonable upgrade.... If this all adds up to increased realism to the music from these compact mono designs, causing them to step on the toes of more commonly considered units at comparable price point... It can only be a matter of time and we may see the price increase... If I were looking for this type of solution I would be jumping at this project very quickly. Nice follow up content Greg. 👍🏻
Thanks for your comment, my friend. Keep in mind, this is my Srcond Space system, not a primary music system. As such, these little guys really pull it off beautifully! 😊
I find the biggest challenge doing mods on the V3 mono amp to be the handling of the thermal paste. Unfortunately the board slides into the chassis, so that paste applied to the heat transfer bus on the bottom of the board can smear onto the chassis edge and get on components and potentially short them depending on what type of paste you use. I only use “nonconducting” material meaning it conducts heat but not electricity. But that “nonconducting” is really kinda not true-it’s just *less* conducting than other material… so you have to apply enough paste to get good coverage, but not so much it smears all over…
Hello... Thanks for writing. While I take your point, consider some of the facts regarding audio component failure. Having been in and around the consumer electronics industry, at virtually _every_ level, for some five decades, and as the owner/operator of an electronics repair and modification shop, doing repairs and upgrades, you may care to know that if a component doesn't fail right out of the box, or during its first hours of operation - which would reveal a major manufacturing flaw or shipping damage - its likelihood of failure drops drastically. And yes, that likelihood increases over time...but only marginally. And while there is _no question_ that such popular, mass-produced products, so affordable and in high demand, will suffer possible failure due to production and/or shipping damage, I've had these V3s in play on average of ten hours a day for 90 odd days now. When working upstairs, they are always on... AND, I've had each of them opened, jostled, poked, prodded, and done several component swaps, on the order of five or six times. They are - knock on wood - working with no indication of flaw or failure. YES, it could happen...no doubt. And then too, the Fosi Audio V3s, like all other Fosi products, come with a two-year warranty, so...there is that buffer. All things considered, I think you _may_ be looking for a reason to be concerned or skeptical... 😉☺🤔
I’m wondering if these upgraded mono blocks would match the sound quality of a similarity priced Hypex amplifier from the likes of Buckeye amplifiers? If we compared the Fossi mono blocks to the Hypex and we were able to match output somehow I wonder which one would come out on top sonically. I’m curious how much the input stage quality makes because the Hypex should be better but it uses a regular IC op amp as do many class D amplifiers. Anyways I just wanted to compliment this video because I’m not sure any other reviewer is as thorough as you in regards to the op amps and which one does what and it’s important to know which sockets are actually worth paying attention too.
@@michaeldina1103 I'm talking about Chinese clones using high end design patents that have expired so are now available to copy and replicate. Google it dude 😉
Umm- not a mere matter of opening them up-Fosi has videos and marketing specifically discussing op amp upgrades where they tell you how many you need for RCA and for XLR and which positions do what🤣🤣 I went with 2x Muses02 per side on the V3s, thinking the Sparkos might be too much. I used the Sparkos ss3602 x2 for my Fosi ZD3 DAC
While the advantages realized from paralleling multiple IC OpAmps typically result in increased output current and lowered power consumption, making them especially useful across a wide range of operating conditions, these are not necessarily the attributes we look for to realize improved audio performance. When comparing the AUDIO performance achieved with the application of paralleled IC OpAmps to the AUDIO performance possible with the use of discrete OpAmps, the discrete OpAmps typically excel in such specific niche applications, where high output current and very high-quality audio fidelity are required, even though that desired improvement in performance increase comes with increased complexity and cost. While the parallel IC OpAmp approach might deliver slight increases in current capabilities, it does not necessarily offer any significant improvement to its overall bandwidth capability. Further, slight imbalances or differences in the individual OpAmps used for the parallel alignment (slightly different electrical characteristics such as gain, input impedance, and offset voltage…) can significantly amplify noise, especially when dealing with high-impedance sources. To that end, the parallel approach proves an excellent choice for many more general-purpose applications where the goals are high output current, modest cost, and the need for compact size are important. But when it comes to the specific goals, such as high-end audio applications, where sound quality is paramount, discrete OpAmps still win the day…and relatively easily. Their ability to be customized, to utilize top-quality, audio-grade components, (like extremely tightly matched tolerance metal-film resistors or silver mica capacitors), is fundamental to how they accomplish their better audio performance. Such specificity of design affords them notably better performance in terms of distortion, noise, and frequency response than the parallel approach may offer.
I know Gregorz likes speed and slam. In a lower prices system this might be the better choice. However, I'd rather go for the increase of refinement provided by the discrete opamps class A design. That's another way of saying what Greg said in less technical terms. 😊
Audio manufacturers swung too far in favor of ICs instead of discreet components. Home theater with surround sound became the thing over sound quality. Now with more people interested in audiophile systems, there seems to be a shift starting. Maybe the next gen fosi or a competitor will come with discreet components from the factory. FWIW, I have a Carver receiver I bought in the 80s I'm going to recap or I'd be looking at something like this.
Nice follow up. Love to see details about a lot more budget aimed designs that have lots of potential for great sound.
Thank you !
Greg, I’m not sure if you got that right about the lone op amp at the back of the board which Fosi has been calling position 1. Directly from Fosi “The op amp in position 1 converts the unbalanced signal from RCA into a balanced signal.” The V3 mono is in fact a balanced circuit due to the PFFB design and the function of the op amp in this position is to convert the single ended signal to balanced and it is audible. When using the single ended inputs there is an easily heard, slightly inferior sound quality compared to the balanced input and it’s widely reported by many that the balanced input sounds best. When I roll the op amp in position 1 and use a single ended input I can hear the differences but when I listen with a balanced input I hear no differences when rolling this op amp.
Hello... I am sorry if my explanation was either unclear or otherwise not what you expected, but, we are saying the same thing... Here is what I said starting at about 3:28 - ua-cam.com/video/jpLtt3hJiCs/v-deo.htmlsi=wFL0-ePNnSIML4Lj&t=208
"Examining the three removable IC OpAmps in the V3s reveals that one of the three, _the one mounted nearest the back of the board, is used to accept and integrate balanced inputs to drive the V3’s_ ."
And my further discussion about the common use of ICs to allow for balanced inputs to be used with single-ended designs may have been a bit confusing.
Finally, I will have to go back to the tech info on the V3, as, after seeing your comment, I may have mistakenly gotten their intent one hundred eighty degrees reversed. My take on its application was that it was provided ONLY to allow balanced inputs, not that it was crucial to the use of a converted single-ended input. More as I have it. Thanks for writing! 😁
@ Thanks, Greg. You know I’m a fan of your channel and just trying to help out. Yes, I believe that you might have it 180 degrees the other way. Ha ha. The amplifier circuit is a balanced design. The function of that opamp is to convert single ended signals to balanced before the signal moves on to the other two op amps that you have upgraded thus allowing use of a single ended connection with the amp. All that said, Fosi does suggest that there is not as big of a difference changing that opamp and in my case I can attest there is a noticeable, but subtle difference with using various op amps in this position. The balanced connection is better because you avoid that opamp, it’s a bit more quiet, natural and more totally accurate. Bottom line: you need to get another set of Sparkos opamps or move your new ones over and see what you hear. 😀
@@sean_heisler Thanks - again - for the post... I have to tell you, I have found the available info confusing at best. 🤔On one of the Fosi Audio Fourm pages, their "V3 Mono Op-amp rolling" page," following a video on the process posted by kauai82, there is the following statement...
"As you can see by the picture, I did not replace socket one on the board. _If you are going to use the balanced inputs, I would also replace this op-amp."_
This statement had influence on, and seems to support my original position and statement...as it suggests that the OpAmp in that particular location has an influence on the balanced input performance, not the single-ended input... I am going to pursue this further, but...I'm still not sure about this... More if/when I have it...
@ I hear you, Greg. It is confusing. I tried once to find out what the input impedance is on these amps it took a while to get that. Have you watched the Fosi V3 mono op amp rolling video on their UA-cam channel? I’m going to attempt to paste the link here but often UA-cam deletes comments with links. You can see at :25 into this video they label the op amp in question as the number 1 position and go on to say it’s responsible for converting the unbalanced RCA input to a balanced signal. ua-cam.com/video/NSZ5T_XhE3U/v-deo.htmlsi=9On6UJWXOs_rHxe0
@@sean_heisler Hey, Sean. Yes, I have... And it was on that same Fosi Forum Page with that posted video (community.fosiaudio.com/threads/v3-mono-op-amp-rolling.108/) where the poster made that comment... I'm still not _necessarily_ doubting that claim, I'm just wondering how it really contributes... There are too many conflicting versions to be sure. I'm going to write to my connection at Fosi and see if they can offer some explanation for the discrepancy... And, seriously, thanks again for engaging here. This is one of the many reasons I do all this stuff! 😉
Interesting, you’ve got me curious!
I would like to know what you think about fosi za3 with sparkos op amps
Inexpensive initial cost plus very reasonable upgrade....
If this all adds up to increased realism to the music from these compact mono designs, causing them to step on the toes of more commonly considered units at comparable price point...
It can only be a matter of time and we may see the price increase... If I were looking for this type of solution I would be jumping at this project very quickly.
Nice follow up content Greg. 👍🏻
Thanks for your comment, my friend. Keep in mind, this is my Srcond Space system, not a primary music system. As such, these little guys really pull it off beautifully! 😊
I find the biggest challenge doing mods on the V3 mono amp to be the handling of the thermal paste. Unfortunately the board slides into the chassis, so that paste applied to the heat transfer bus on the bottom of the board can smear onto the chassis edge and get on components and potentially short them depending on what type of paste you use.
I only use “nonconducting” material meaning it conducts heat but not electricity. But that “nonconducting” is really kinda not true-it’s just *less* conducting than other material… so you have to apply enough paste to get good coverage, but not so much it smears all over…
I own these. They still need to prove longevity to be valued as you are presenting them
Hello... Thanks for writing. While I take your point, consider some of the facts regarding audio component failure.
Having been in and around the consumer electronics industry, at virtually _every_ level, for some five decades, and as the owner/operator of an electronics repair and modification shop, doing repairs and upgrades, you may care to know that if a component doesn't fail right out of the box, or during its first hours of operation - which would reveal a major manufacturing flaw or shipping damage - its likelihood of failure drops drastically. And yes, that likelihood increases over time...but only marginally.
And while there is _no question_ that such popular, mass-produced products, so affordable and in high demand, will suffer possible failure due to production and/or shipping damage, I've had these V3s in play on average of ten hours a day for 90 odd days now. When working upstairs, they are always on... AND, I've had each of them opened, jostled, poked, prodded, and done several component swaps, on the order of five or six times. They are - knock on wood - working with no indication of flaw or failure. YES, it could happen...no doubt. And then too, the Fosi Audio V3s, like all other Fosi products, come with a two-year warranty, so...there is that buffer.
All things considered, I think you _may_ be looking for a reason to be concerned or skeptical... 😉☺🤔
I’m wondering if these upgraded mono blocks would match the sound quality of a similarity priced Hypex amplifier from the likes of Buckeye amplifiers? If we compared the Fossi mono blocks to the Hypex and we were able to match output somehow I wonder which one would come out on top sonically. I’m curious how much the input stage quality makes because the Hypex should be better but it uses a regular IC op amp as do many class D amplifiers. Anyways I just wanted to compliment this video because I’m not sure any other reviewer is as thorough as you in regards to the op amps and which one does what and it’s important to know which sockets are actually worth paying attention too.
I'd rather just get one of the many integrated clones that are everywhere at the moment. Based on 15k + designs for $500 odd
@ I’m sorry, integrated clones? What are you referring too?
@@michaeldina1103
I'm talking about Chinese clones using high end design patents that have expired so are now available to copy and replicate.
Google it dude 😉
Umm- not a mere matter of opening them up-Fosi has videos and marketing specifically discussing op amp upgrades where they tell you how many you need for RCA and for XLR and which positions do what🤣🤣
I went with 2x Muses02 per side on the V3s, thinking the Sparkos might be too much. I used the Sparkos ss3602 x2 for my Fosi ZD3 DAC
thank god for 1.5X speed
VirtualHifi Supersonic V2 are still a lot better than Sparkos with my Fosi ZA3. Worth checking out.
While the advantages realized from paralleling multiple IC OpAmps typically result in increased output current and lowered power consumption, making them especially useful across a wide range of operating conditions, these are not necessarily the attributes we look for to realize improved audio performance.
When comparing the AUDIO performance achieved with the application of paralleled IC OpAmps to the AUDIO performance possible with the use of discrete OpAmps, the discrete OpAmps typically excel in such specific niche applications, where high output current and very high-quality audio fidelity are required, even though that desired improvement in performance increase comes with increased complexity and cost.
While the parallel IC OpAmp approach might deliver slight increases in current capabilities, it does not necessarily offer any significant improvement to its overall bandwidth capability. Further, slight imbalances or differences in the individual OpAmps used for the parallel alignment (slightly different electrical characteristics such as gain, input impedance, and offset voltage…) can significantly amplify noise, especially when dealing with high-impedance sources.
To that end, the parallel approach proves an excellent choice for many more general-purpose applications where the goals are high output current, modest cost, and the need for compact size are important.
But when it comes to the specific goals, such as high-end audio applications, where sound quality is paramount, discrete OpAmps still win the day…and relatively easily. Their ability to be customized, to utilize top-quality, audio-grade components, (like extremely tightly matched tolerance metal-film resistors or silver mica capacitors), is fundamental to how they accomplish their better audio performance. Such specificity of design affords them notably better performance in terms of distortion, noise, and frequency response than the parallel approach may offer.
I know Gregorz likes speed and slam. In a lower prices system this might be the better choice. However, I'd rather go for the increase of refinement provided by the discrete opamps class A design.
That's another way of saying what Greg said in less technical terms. 😊
@@theaudioanalystjust shut up and try them
Audio manufacturers swung too far in favor of ICs instead of discreet components.
Home theater with surround sound became the thing over sound quality.
Now with more people interested in audiophile systems, there seems to be a shift starting.
Maybe the next gen fosi or a competitor will come with discreet components from the factory.
FWIW, I have a Carver receiver I bought in the 80s I'm going to recap or I'd be looking at something like this.