[HeyManslowdown97]

You still have to check datasheets. LT makes some chips based on similar designs of TI and onsemi. For example, LT1085/LM317/LM340 (these have on-semi counterparts) are actually "the same" chip. Most LDOs don't like ultra low esr in the output and they typically will specify what to use.

Bro, they are CMOS. None of the ones you mentioned are!

Speaking from experience, I put 2.2 uf ceramic low ESR (It’s all I had) in the output and have NO issues! I do get what you’re saying though about DC issue. It depends how low they are.

https://www.analog.com/en/products/adp7142.html

 

[HiFan]

Bro, they are CMOS. None of the ones you mentioned are!

https://www.analog.com/en/products/adp7142.html

According to datasheet, it doesn't help with noise but transient response, as I previosly mentioned. It seems the chip uses it only to save space, not because of its cmos input stage. On the other hand, DO NOT USE X5R as LT recommended, as they are subject to piezoelectric effects. Use NP0/C0G instead or organic polymers.

BTW, voltage of this is too low for me, I was looking for things that can output 16-32V. Dual rail supplu with +-15V sounds better to my ears than low voltage monorail 5V supply.

Output Capacitor
The ADP7142 is designed for operation with small, space-saving
ceramic capacitors, but functions with general-purpose capacitors
as long as care is taken with regard to the effective series resistance
(ESR) value. The ESR of the output capacitor affects the stability
of the LDO control loop. A minimum of 2.2 μF capacitance with
an ESR of 0.3 Ω or less is recommended to ensure the stability of
the ADP7142. Transient response to changes in load current is
also affected by output capacitance. Using a larger value of output
capacitance improves the transient response of the ADP7142 to
large changes in load current. Figure 44 shows the transient
responses for an output capacitance value of 2.2 μF.

 

[HiFan]

Bro, they are CMOS. None of the ones you mentioned are!

Speaking from experience, I put 2.2 uf ceramic low ESR (It’s all I had) in the output and have NO issues! I do get what you’re saying though about DC issue. It depends how low they are.

https://www.analog.com/en/products/adp7142.html

Side note, even with LDOs that don't like low ESR caps, you can still use them after a small resistor (e.g. .0.33R) in series with LDO output pin. The only draw back is that this causes voltage to drop with current throughput, i.e 1A casues 0.33V drop. This is not good application for high current devices.

 

[HeyManslowdown97]

I wish I had space for organic polymers.

I could also tell that you were talking about larger voltage (just by the way you were talking). Then, you really, really have to pay attention!
It’s a portable music player and not my design and when your modding another persons design it’s hard to everything exactly like the Datasheets says.

You are correct in correcting me with ultra low esr in the output but what about the next caps it’s faces. That’s a joke.

The cap was already at 2.2 uf on the existing design (I measured it) so it was already stable. Was just messing with you.

My main point was that CMOS is being used more often and It’s interesting to me. I do believe the materials affect the sound

 

[HiFan]

I wish I had space for organic polymers.

I could also tell that you were talking about larger voltage (just by the way you were talking). Then, you really, really have to pay attention!
It’s a portable music player and not my design and when your modding another persons design it’s hard to everything exactly like the Datasheets says.

You are correct in correcting me with ultra low esr in the output but what about the next caps it’s faces. That’s a joke.

The cap was already at 2.2 uf on the existing design (I measured it) so it was already stable. Was just messing with you.

My main point was that CMOS is being used more often and It’s interesting to me. I do believe the materials affect the sound

Modding exsiting design is difficult. True, hard on me to get my UD503 right.

When you have multiple caps in parallel, it is best to avoid paralleling low ESR caps. PCB has inductance, thus you are looking at possibility of C-L-C oscillation if you parallel low-esr caps. This is why film caps are typically avoided in power supply, as film has even lower ESR. In my amps, I typically use a 10uf tantalum as output cap, then will use a 47uf alu-cap for each power input of opamp.

Take Whammy amp for a better example, you can see it uses a resistor between all its input flter caps (3 on each rail) to create a voltage differential, damping the caps and avoiding ripple "bouncing" back-and-forth between them.This is good practice when low esr caps are in parallel.

 

[HeyManslowdown97]

When you have multiple caps in parallel, it is best to avoid paralleling low ESR caps. PCB has inductance, thus you are looking at possibility of C-L-C oscillation if you parallel low-esr caps. This is why film caps are typically avoided in power supply, as film has even lower ESR. In my amps, I typically use a 10uf tantalum as output cap, then will use a 47uf alu-cap for each power input of opamp.

Yes, I learn this the hard way. When I first discovered the “power” of ultra low esr and went crazy putting everywhere until my player wouldn’t turn on. It took a month to figure that one out once I took some out it worked again!

Used wisely, Ultra low ESR caps do wonders! Film caps are better but when space isnt issue.

I have an unrelated question but is about op amp outputs.

I have this Zishan DSDs and the output transitors are bjt can they swapped for jfets??

The reason is because I have some jfet op amps and since jfet is better with current noise, I figure (if it’s possible) to swipe them if it improves the output sound?
The red circled area is what I’d like to swap the sod-123.

 

[HiFan]

I have this Zishan DSDs and the output transitors are bjt can they swapped for jfets??

The reason is because I have some jfet op amps and since jfet is better with current noise, I figure (if it’s possible) to swipe them if it improves the output sound?
The red circled area is what I’d like to swap the sod-123.

I won't touch that. Transistors need to be manually matched for current. And, if you swapped to jfet, there is a high chance you also need to add gate stopper resistor to ensure stability. It's hard to do so with smd parts.

 

[HeyManslowdown97]

I won't touch that. Transistors need to be manually matched for current. And, if you swapped to jfet, there is a high chance you also need to add gate stopper resistor to ensure stability. It's hard to do so with smd parts.

Agreed on two parts one it is soooo frickin’ hard to match transistors and Jfets need a gate. This is what I read too but you know... wishful thinking is a helluva drug!

I am beginning to believe that larger Audio systems it’s all about Voltage and portable is all about current!

When I first started op amp Rolling I never looked at datasheets and you know you listen and read about boutique amps than you get them and you don’t know why your battery life is half what was before.

Because portable is more about current than voltage op amp’s like the opa1692 are at times your best option in saving some. Of course when you have a larger power supply the world is your Oyster.

Often what’s around an op amp is more important than the op amp itself, it’s true but op amp Rolling is much fun.

 

[HiFan]

Agreed on two parts one it is soooo frickin’ hard to match transistors and Jfets need a gate. This is what I read too but you know... wishful thinking is a helluva drug!

I am beginning to believe that larger Audio systems it’s all about Voltage and portable is all about current!

When I first started op amp Rolling I never looked at datasheets and you know you listen and read about boutique amps than you get them and you don’t know why your battery life is half what was before.

Because portable is more about current than voltage op amp’s like the opa1692 are at times your best option in saving some. Of course when you have a larger power supply the world is your Oyster.

Often what’s around an op amp is more important than the op amp itself, it’s true but op amp Rolling is much fun.

I think it all depends on the designer. ESS chips output can be set to current mode and voltage mode, while AKM are voltage mode only (newer chips removed internal I/V converter for greater flexibility). So if the designer choose to build around a voltage signal circuit, he will be using fet a lot. Another thing about BJT devices is that they are expensive.

Portables are limited by their batteries so constant high current drain is unfavored, so you don't want to use current signal (since you need a certain amplitutde to raise SNR). I probably would just use a fet opamp and build a current source after it, and it is the same with your device's original design.

BTW, you have a fun device. I just don't like muses02 that much (hype IMO and it is very expensive). And, oh, opa1656 has a FET-input stage but uses a cmos process.

 

[HeyManslowdown97]

BTW, you have a fun device. I just don't like muses02 that much (hype IMO and it is very expensive). And, oh, opa1656 has a FET-input stage but uses a cmos process.

Haha. I am well aware of this and so do some bipolar like opa1612. That’s why it’s a good choice for this application. I’m aware of the opa1656 fet input. It’s sounds pretty good in the Zishan. Muse02 is in the stock of the ak4499 version, it’s not really a choice. I’ll be getting that toy this week in the mail after a long delivery delays b/c of Covid-19. (Something else to play with...already have some ideas to implement on it)

I would never buy MUSE02 willy nelly because of the exact same reasons: hyped up and expensive.

To be fair never heard it but I doubt ill be blown away when I do...

The AKM newest Chip is current output and voltage input I believe.

“I probably would just use a fet opamp and build a current source after it, and it is the same with your device's original design.”

Yep, hands down the best approach I have found!

 

[HiFan]

The AKM newest Chip is current output and voltage input I believe.

“I probably would just use a fet opamp and build a current source after it, and it is the same with your device's original design.”

Yep, hands down the best approach I have found!

I am aware that many think that way, especially that's on akm4499's datasheet (the only one from akm that has a current output). But it depends on output impedance, real current output stage will use higher output impedance to raise SNR, which 4499 doesn't have (akm does 64ohm as oppsoed to 774 ohm on ess9038q2m, and pcm1794 even has 2k ohms. ). AKM only puts that I/V conversion on the outside so you can choose what to use.

However, it is exciting to see new designs that push the limit.

 

[HeyManslowdown97]

But it depends on output impedance, real current output stage will use higher output impedance to raise SNR, which 4499 doesn't have (akm does 64ohm as oppsoed to 774 ohm on ess9038q2m, and pcm1794 even has 2k ohms. ). But it is not difficult to convert that signal back to voltage with a resistor in series.

However, it is exciting to see new designs that push the limit.

Thanks for the feedback. I'm definitely gonna look into it. The output impedance is 10 ohms that can be easily changed. You can put a jumper to output stage however, if you take it to the floor or ”floor it” you MUST lower the RMS on your digital music files and make sure there aren't any quantization errors.

Delta Sigma Modulators aren’t really efficient it’s important to oversample correctly. These chips can do multi bit but it’s not the same as R2R bit perfect DACs. Also in the Zishan you don’t have the mediator chips AK4118 that’s in the datasheets. A well thought out modular chain when you have space and have mapped out all the kinks is the way to do it. The pre amps have that kind of space!

Actually these Delta Sigma Modulators are quite pedestrian circuitry designed compared to the art form of R2R DACs. In those DAC resistance isn’t futile!

But it is not difficult to convert that signal back to voltage with a resistor in series.

How?? What’s the procedure to do this???

 

[HiFan]

Thanks for the feedback. I'm definitely gonna look into it. The output impedance is 10 ohms that can be easily changed. You can put a jumper to output stage however, if you take it to the floor or ”floor it” you MUST lower the RMS on your digital music files and make sure there aren't any quantization errors.

Delta Sigma Modulators aren’t really efficient it’s important to oversample correctly. These chips can do multi bit but it’s not the same as R2R bit perfect DACs. Also in the Zishan you don’t have the mediator chips AK4118 that’s in the datasheets. A well thought out modular chain when you have space and have mapped out all the kinks is the way to do it. The pre amps have that kind of space!

Actually these Delta Sigma Modulators are quite pedestrian circuitry designed compared to the art form of R2R DACs. In those DAC resistance isn’t futile!





How?? What’s the procedure to do this???

The easy way will be using a resistor, as current flows through, voltage drops accordingly. But it’s possible to use chips like opa1612 to do it. The new 4499 is very flexible.

Remember i mentioned a gate stopper ifyou want to change BJT transistor to FET one?

 

[HeyManslowdown97]

Remember i mentioned a gate stopper ifyou want to change BJT transistor to FET one?

One minute...(mind blowing) Eureka Moment

Next minute....(mind still blowing) and that explains the choice for MUSE02 since it’s a input fet dual bipolar like the opa1612.

oh, look at the way things come out full circle! Ha!

This opens up my entire universe! That’s some Zen stuff right there!

 

[HiFan]

One minute...(mind blowing) Eureka Moment

Next minute....(mind still blowing) and that explains the choice for MUSE02 since it’s a input fet dual bipolar like the opa1612.

oh, look at the way things come out full circle! Ha!

This opens up my entire universe! That’s some Zen stuff right there!

I hope this makes your life easier.
https://www.electrical4u.com/source-of-electrical-energy/