[silverfishla]

Totally get your point about ”can't really recommend the Acmee MF0 right now!”

People are really high on Bursons V5is but I saw this review on YouTube in regards to Sparkos Labs SS3602 and literally my jaw dropped from what it's described to be. I wish I had a portable unit to put it and man it's a drag Acmee MF0 skips beginning of sounds, etc. Basically it's an dual op-amp that gets out of the way without processing the audio sound into a shape. It's just pure audio playback.

I trying find a portable device to put them in. I'm thinking a portable headphone amp to power iems!!!

They make it in colorado. I have seen these type of discrete op amps with breadboards on Aliexpress for far less with ridiculous spec descriptions that I may go with at first!

The zishans need to be modded with love to get them play smoothly. My main gripe about the Dsd is the tremble is a bit higher than I would like at times!

I was one of the first ones to bring the Sparkos to the attention to the community (pats self on back) at least one of the first to buy one and try it out. They are good, but even harder to fit in these cases (none of them actually do), so I use it in my Little Bear tube amp (Zishan + tube amp = a little magic).
My T1 still works, even though the screen is incapacitated. It’s on permanent shuffle, but I can still ffwd and reverse with the buttons.

 

[fabien32]

Totally get your point about ”can't really recommend the Acmee MF0 right now!”

People are really high on Bursons V5is but I saw this review on YouTube in regards to Sparkos Labs SS3602 and literally my jaw dropped from what it's described to be. I wish I had a portable unit to put it and man it's a drag Acmee MF0 skips beginning of sounds, etc. Basically it's an dual op-amp that gets out of the way without processing the audio sound into a shape. It's just pure audio playback.

I trying find a portable device to put them in. I'm thinking a portable headphone amp to power iems!!!

They make it in colorado. I have seen these type of discrete op amps with breadboards on Aliexpress for far less with ridiculous spec descriptions that I may go with at first!

The zishans need to be modded with love to get them play smoothly. My main gripe about the Dsd is the tremble is a bit higher than I would like at times!

You should check this out, it's a SA200 Full Discrete Dual OP AMP

https://www.aliexpress.com/item/330...&terminal_id=7ee30b5adebb4456b2fbd42cc24b1028

https://www.aliexpress.com/item/400...&terminal_id=7ee30b5adebb4456b2fbd42cc24b1028

 

[cqtek]

Totally get your point about ”can't really recommend the Acmee MF0 right now!”

People are really high on Bursons V5is but I saw this review on YouTube in regards to Sparkos Labs SS3602 and literally my jaw dropped from what it's described to be. I wish I had a portable unit to put it and man it's a drag Acmee MF0 skips beginning of sounds, etc. Basically it's an dual op-amp that gets out of the way without processing the audio sound into a shape. It's just pure audio playback.

I trying find a portable device to put them in. I'm thinking a portable headphone amp to power iems!!!

They make it in colorado. I have seen these type of discrete op amps with breadboards on Aliexpress for far less with ridiculous spec descriptions that I may go with at first!

The zishans need to be modded with love to get them play smoothly. My main gripe about the Dsd is the tremble is a bit higher than I would like at times!

I got the ACMEE MF-01 yesterday and after a day with it, I have seen that the firmware is in a very initial phase and can improve a lot. But I think it's a rough diamond. In terms of sound it has a unique signature and bass is tremendously full. The mids have a special virtue and the highs may not be as present as in T1, but their sound is very detailed and distinctive. At sound level I prefer it over the Zishan T1 AK4493EQ*2.

I still have to change the electrolytic capacitors in the T1 to try to correct the filtering in the low-end.

 

[HeyManslowdown97]

I still have to change the electrolytic capacitors in the T1 to try to correct the filtering in the low-end.

You should also replace the stock op amps as well that will improve the sound greatly.

It looks like the ACMEE MF-01 AK4490EQ has a 9V battery which would explain a ton about the better audio quality as power supply plays a HUGE role in Audio Signal.

I wish the Zishan makers would take note and put in a 9V or even 12v battery powered portable unit! 9V+ is ideal to power iems regardless of high current (BAs??) or not in my opinion!

Ohms law:

The resistor's current I in amps (A) is equal to the resistor's voltage V in volts (V) divided by the resistance R in ohms (Ω): V is the voltage drop of the resistor, measured in Volts (V)

Resistance:

The resistance R in ohms (Ω) is equal to the voltage V in volts (V) divided by the current I in amps (A): Since the current is set by the values of the voltage and resistance, the Ohm's law formula can show that: If we increase the voltage, the current will increase.

 

[IcedFrosty]

Finally, I wrote my first review here on Head-Fi, and pof course, it's the T1 review
Here you go: https://www.head-fi.org/showcase/zishan-t1-hifi-player.23935/reviews#review-22612

Thank you,
God bless

 

[silverfishla]

I got the ACMEE MF-01 yesterday and after a day with it, I have seen that the firmware is in a very initial phase and can improve a lot. But I think it's a rough diamond. In terms of sound it has a unique signature and bass is tremendously full. The mids have a special virtue and the highs may not be as present as in T1, but their sound is very detailed and distinctive. At sound level I prefer it over the Zishan T1 AK4493EQ*2.

I still have to change the electrolytic capacitors in the T1 to try to correct the filtering in the low-end.

I would agree with your assessment. Changing the caps on the T1 does bring up the bass presence a bit, making the overall sound more pleasing to me. The T1 is similar to the DSD unmodded version where I think everything from the mids on up sound a bit “pushed” (like it’s just at the edge of having too much gain). The MF01 sounds more controlled and like you said, the bass presence is there from the get go. I’m a fan of it, just a couple more firmware updates and we may see a new competitor to the throne of DIY boxes. One thing that they could have had a better solution for...the back plate. Double sided tape holds it on....really? Like carpet tape and hard to pry off without damaging the paint.

 

[vyrux]

Zishan T1 amp modules on Ebay
https://www.ebay.com/itm/AK4490-AK4...hash=item3fca49e244:m:mGHtcdJ4mj3aAzrt3mg8ERg

What's new in FW 0.2c?
http://zishan.ru/files/ZiShan-T1/

 

[HeyManslowdown97]

The T1 is similar to the DSD unmodded version where I think everything from the mids on up sound a bit “pushed” (like it’s just at the edge of having too much gain).

Updated:Replacing the LDOs does help a great deal and makes it sound way better but it’s still runs a bit aggressive in the Tremble. It is this reason that making mods that improves the digital filters to “offset” the unpleasant frequencies is pertinent!

Correction: ACMEE MF-01 has a 3.7v battery like the T1 so there goes my theory. (Apologies to the thread for the misinformation disregard the below information)

(I don’t thing it’s too much gain (I thought that same thing at one point). I actually believe it’s significantly underpowered which explains the harshness on the top end in some tracks playback on the dsd and probably the T1.)

Here’s the ACMEE MF-01 description I found by a seller and this really stuck out to me:

“Full material, double V9 output, 300 ohms without pressure.”

 

[Ivan TT]

3.7v battery like the T1 so there goes my theory. (Apologies to the thread for the misinformation disregard the below information)

DC-to-DC boost converter is used to bring the voltage from 3.7V (or below, depending on battery charge %) to 9V.
So while this process is not without an issue (e.g. noise that is filtered using inductors), all the conclusions re: gain and power could be based on a false premise or somewhat misinformed?

 

[HeyManslowdown97]

So while this process is not without an issue (e.g. noise that is filtered using inductors), all the conclusions re: gain and power could be based on a false premise or somewhat misinformed?

LDO Powered vs true voltage VDC effects the input/output of the audio signal with isolated independent paths to the correct voltage input/output is best!

So say you are starting with 9v by the time it goes through the series circuit it maybe down to 4.5 volts of true voltage without conversion of LDOs.

There’s more involved in the conversion. Starting with more voltage is way better in my opinion even with performance of op amps in many cases. However, there are some very clever ways circuitry can made more efficient and probable that many engineers have found successful work arounds.

“Could be based” conditional phrase based on a conclusion? This lawyerly stuff is so exhausting to read. “false premise or somewhat misinformed” two independent phrases that are similes to mean the same thing about no conclusively or disclosing argument. Ie The chicken or the egg what came first?

Everyone knows power supply effects sound. LDOs are tricky ways to get around this engineering dilemma so I’m sure what’s the point that it’s a variable option. Ok, fair enough.

Disregarding the circuitry design even found on page 38 of the Ak4497eq to hi jack the DSD Pro could be misinformed or on a false premise, no?

“Indeed.

AK4497 DSD is based on AK4497EQ evaluation board schematics, page 38, adding extra current buffer:

https://www.akm.com/akm/en/file/ev-board-manual/AK4497EQ.pdf

Sourcing differential amp input from input bypass caps is conceptually not unlike I/V and LPF design from AK4490 datasheet (similar to Z2 and Z3), where LPF opamp is configured as a differential amplifier, as opposed to Sallen-Key active filter topology in DSD AK4497. Actually I could probably source input straight from DAC's outputs come to think about it...”

 

[citral23]

Thanks for the reviews, so far it looks like a complete waste of money to be honest. Enjoy it until the screen or USB port breaks tho. Out of thread, cheers.

 

[silverfishla]

DC-to-DC boost converter is used to bring the voltage from 3.7V (or below, depending on battery charge %) to 9V.
So while this process is not without an issue (e.g. noise that is filtered using inductors), all the conclusions re: gain and power could be based on a false premise or somewhat misinformed?

Just to clarify, I wasn’t actually saying that there IS too much gain. Just making an observation on the sound quality with my ears and describing it. I don’t actually know what the cause of it is(and some may not even see it as a problem). Just comparing the sound of the two units.

 

[DBaldock9]

DC-to-DC boost converter is used to bring the voltage from 3.7V (or below, depending on battery charge %) to 9V.
So while this process is not without an issue (e.g. noise that is filtered using inductors), all the conclusions re: gain and power could be based on a false premise or somewhat misinformed?

Have you determined which DAP/DAC/Amp devices have the best quality of DC boost converters?
I've been looking at off the shelf 3VDC to ±12VDC or ±15VDC boost converters, and it looks like most them are only able to supply about 150mA on the negative rail.
The ones that have higher output current, need at least 5VDC on their input - so they won't run from a 3.7V Li-Ion battery.

I guess I need to do some sort of power analysis, to see how much power the op-amps actually need, to work best in my DAP/DAC/Amps.

 

[HeyManslowdown97]

I've been looking at off the shelf 3VDC to ±12VDC or ±15VDC boost converters, and it looks like most them are only able to supply about 150mA on the negative rail.
The ones that have higher output current, need at least 5VDC on their input - so they won't run from a 3.7V Li-Ion battery.

So have I looked into it and it’s very limited some LDOs also require low esr output ceramics caps or minimum of 2.2 uf to be stable. The conversion also needs to PWM DC-to-DC Switching Converter in the filters. I changed them on my DSD Pro and sounds and plays cooler.

But some op amp do actually do perform better above a certain voltage even if the datasheets say it has a wide range of voltage.

You are actually limited by low power. The opa1692 is really great for this but it sound isn't for everyone.

And you spot on about the higher output current op amps needing more voltage. I don't think it's wise to remove filters and resistance to achieve that result!

 

[cqtek]

I would agree with your assessment. Changing the caps on the T1 does bring up the bass presence a bit, making the overall sound more pleasing to me. The T1 is similar to the DSD unmodded version where I think everything from the mids on up sound a bit “pushed” (like it’s just at the edge of having too much gain). The MF01 sounds more controlled and like you said, the bass presence is there from the get go. I’m a fan of it, just a couple more firmware updates and we may see a new competitor to the throne of DIY boxes. One thing that they could have had a better solution for...the back plate. Double sided tape holds it on....really? Like carpet tape and hard to pry off without damaging the paint.

LOL.
I can't really think how the back cover is joined only by double-sided tape...I don't dare remove it...could they have put a screw or two?

On the other hand, I have measured the maximum RMS voltage at 75Hz of the Acmee and it is... 3.97V in vacuum and 3.54V at 32 Ohms...a lot. I don't have the oscilloscope yet...it's in Madrid...