[pekingduck]

Having seen how the Geek Out & Pulse campaigns were handled, I figured it didn't make sense to back the 128 and have LH hold my $1000 for a year (I don't believe they can deliver the Wave early next year

). At the end I only backed a Geek 64 + Standalone DAC (total $257). Might pay for the Dual DAC option later though, once I get my $40 Geek Credit!

 

[miceblue]

  I wonder how the Wave will compare to the iBasso DX90. The DX90 offers dual mono DACs and is only $419 USD.

The diagram you posted isn't the final version, from what I understand. Without knowing how iBasso and LH manage to perform DC decoupling duties and trace lengths on the digital and analog side of things, we won't really know how they'll compare from a performance standpoint. However, I did notice that the DX90 chooses to use bipolar opamps throughout, even in the I/V conversion stage. The final DX90 went for the OPA1602 instead of the LT1678, but it is still a bipolar opamp.

From following the progression of the GO, Pulse, and Wave projects, it seems more and more clear that Larry favors J-FET input opamps, at least for I/V conversion and LPF. He switched to the bipolar OPA1612 at one point for the GO1000, but switched back to the FET OPA1652 in favor of its sound. The two were measurably identical, according to him.

So for someone who is not familiar with these terms, what does that mean? XD

I only know of the basic operations of MOSFETs and JFETs.

 

[germay0653]

  From what I've gathered we should be pretty safe from a U-shaped response on the Wave. It seems Larry loves mids so a V or U shaped signature would be a voicing he'd avoid. Larry has commented on the LHLabs forums about the decision to go with the ES9018K2M over the ES9018 and while I can't remember specifics I do remember that his explanation made perfect sense at the time. I'll see if I can find those posts later and link them here.

I believe the reason was that it requires less power but sounds similar to it's big brethren.  Some specs might be slightly lower but for all intents and purposes it's the same.

 

[m-i-c-k-e-y]

His reason was, with the proper tweaks, ES9018K2M sounds better than the desktop model.

However, the Wave comes on a different model, it's a ES9018K2MV. Asking Larry the difference, he said, he can apply more magic.

Another worthy info is that this "V' model is the same chip used by the Pono.

Sent from my Samsung Note 3 using Tapatalk Pro

 

[AlterSack]

So for someone who is not familiar with these terms, what does that mean? XD

I only know of the basic operations of MOSFETs and JFETs.

Geek Wave has been split up into different options
 
here is a picture showing the different Waves
 

 

[tomscy2000]

  So for someone who is not familiar with these terms, what does that mean? XD

I only know of the basic operations of MOSFETs and JFETs.

 
I don't know the technical details either (not a EE), but the prevailing opinion is that J-FETs sound more "natural" and have "warmth" compared to BJTs. That seems to be what Larry prefers in sound. Whether you believe opamps have a sound or not is not the question here --- if you want to choose an opamp based on spec, for a transimpedance circuit for I/V conversion purposes, the majority of suggestions that I've seen have been for BJT parts, but in many designs, even very high-end designs, I see a lot of people putting in J-FET. I guess the key is that if it doesn't perform any worse, why not go for the part that "sounds better"?
 

  I believe the reason was that it requires less power but sounds similar to it's big brethren.  Some specs might be slightly lower but for all intents and purposes it's the same.

  His reason was, with the proper tweaks, ES9018K2M sounds better than the desktop model.

However, the Wave comes on a different model, it's a ES9018K2MV. Asking Larry the difference, he said, he can apply more magic.

Another worthy info is that this "V' model is the same chip used by the Pono.

 
It's the same IC, it's just that a few features are unlocked and "overt", as in documented in the NDA version of their datasheet. So you can now more easily bypass certain settings, such as the turning off the integrated 8x interpolation filter (and putting your own in, like the DAD perks). You can now also selectively turn different filters on, from the standard linear phase FIR filter, a minimum phase FIR, IIR filter, etc. along with DPLL timing, etc.
 
Basically, ESS want to control how much information gets out into the open, and that's why, historically, DIYers don't like using ESS chips, because they have no idea how to use them as the publicly available datasheets basically said nothing. ESS wants to know who's using their chips and where. However, the K2M chip is a higher-volume chip that was partly made in response to strong demand from smartphone makers in China. The upcoming SABRE9601 is also a part made "for the Chinese". Now that large volume clients are using their chips, they need to make more options more accessible to engineers.
 
For the ES9018S, a lot of functions weren't switchable by default, you had to "trick" it into certain modes, which was more work for the DAC designer. That's likely the big reason why people are favoring the ES9018K2M --- it's just easier to design around because the option for "on or off" is right there for almost all features.
 
LH should also be an "official" client, as Larry mentioned somewhere that the design heads of ESS (Dustin Forman and Martin Mallinson) were involved in technical support for the GW. R&D for ESSTech is located in Kelowna, BC, which is a stone's throw from Sacramento (okay, more like a skip and a hop), but the point is that they're in the same time zone, so Larry can confer with the ESS guys in real time.

 

[germay0653]

His reason was, with the proper tweaks, ES9018K2M sounds better than the desktop model.

However, the Wave comes on a different model, it's a ES9018K2MV. Asking Larry the difference, he said, he can apply more magic.

Another worthy info is that this "V' model is the same chip used by the Pono.

Sent from my Samsung Note 3 using Tapatalk Pro

There's no "public" info available for the "V" designation.  What's up with that?

 

[tomscy2000]

  There's no "public" info available for the "V" designation.  What's up with that?

 
You need to sign an NDA with ESSTech. See my previous post.

 

[germay0653]

   
You need to sign an NDA with ESSTech. See my previous post.

Saw that - thanks.  You hast posted while I was typing mine.

 

[miceblue]

So for someone who is not familiar with these terms, what does that mean? XD


I only know of the basic operations of MOSFETs and JFETs.

Geek Wave has been split up into different options

here is a picture showing the different Waves

Yeah I know that chart well, but that doesn't explain why JFETs were chosen in the circuit over BJTs as explained below.

I don't know the technical details either (not a EE), but the prevailing opinion is that J-FETs sound more "natural" and have "warmth" compared to BJTs. That seems to be what Larry prefers in sound. Whether you believe opamps have a sound or not is not the question here --- if you want to choose an opamp based on spec, for a transimpedance circuit for I/V conversion purposes, the majority of suggestions that I've seen have been for BJT parts, but in many designs, even very high-end designs, I see a lot of people putting in J-FET. I guess the key is that if it doesn't perform any worse, why not go for the part that "sounds better"?

  I believe the reason was that it requires less power but sounds similar to it's big brethren.  Some specs might be slightly lower but for all intents and purposes it's the same.

  His reason was, with the proper tweaks, ES9018K2M sounds better than the desktop model.


However, the Wave comes on a different model, it's a ES9018K2MV. Asking Larry the difference, he said, he can apply more magic.


Another worthy info is that this "V' model is the same chip used by the Pono.

It's the same IC, it's just that a few features are unlocked and "overt", as in documented in the NDA version of their datasheet. So you can now more easily bypass certain settings, such as the turning off the integrated 8x interpolation filter (and putting your own in, like the DAD perks). You can now also selectively turn different filters on, from the standard linear phase FIR filter, a minimum phase FIR, IIR filter, etc. along with DPLL timing, etc.

Basically, ESS want to control how much information gets out into the open, and that's why, historically, DIYers don't like using ESS chips, because they have no idea how to use them as the publicly available datasheets basically said nothing. ESS wants to know who's using their chips and where. However, the K2M chip is a higher-volume chip that was partly made in response to strong demand from smartphone makers in China. The upcoming SABRE9601 is also a part made "for the Chinese". Now that large volume clients are using their chips, they need to make more options more accessible to engineers.

For the ES9018S, a lot of functions weren't switchable by default, you had to "trick" it into certain modes, which was more work for the DAC designer. That's likely the big reason why people are favoring the ES9018K2M --- it's just easier to design around because the option for "on or off" is right there for almost all features.

LH should also be an "official" client, as Larry mentioned somewhere that the design heads of ESS (Dustin Forman and Martin Mallinson) were involved in technical support for the GW. R&D for ESSTech is located in Kelowna, BC, which is a stone's throw from Sacramento (okay, more like a skip and a hop), but the point is that they're in the same time zone, so Larry can confer with the ESS guys in real time.

Interesting to read. I've only used BJTs for the EE-related labs I've done, so I don't know too much about JFETs. I wonder how the two can vary in sound quality if they're both implemented in their optimal configurations.

This is why I'm not too fond of subjective opinions sometimes because "sounding better" to person A might "sound worse" for person B, or vice versa. "Better" is a really vague term and although terms such as "better separation" and things of the sort have also been used throughout these campaigns, they really don't mean anything since they're subjective and they've only been stated by one person, the chief engineer himself, which doesn't carry too much weight in terms of subject size and what "common folks" can hear.

Also, what is the purpose of the current/voltage converter in the block diagram? For other DACs and/or amplifiers, I haven't seen such a diagram for those.

 

[tomscy2000]

  Interesting to read. I've only used BJTs for the EE-related labs I've done, so I don't know too much about JFETs. I wonder how the two can vary in sound quality if they're both implemented in their optimal configurations.

This is why I'm not too fond of subjective opinions sometimes because "sounding better" to person A might "sound worse" for person B, or vice versa. "Better" is a really vague term and although terms such as "better separation" and things of the sort have also been used throughout these campaigns, they really don't mean anything since they're subjective and they've only been stated by one person, the chief engineer himself, which doesn't carry too much weight in terms of subject size and what "common folks" can hear.

 
All audio products are made with the vision of the designer in mind, though. Of course Larry is going to design it in a way he thinks sounds better. Contrary to what hardcore objectivists say, I don't think everything about digital audio can be bottled down into DNR, THD+N, IMD, RMS voltage, jitter, DC offset, and residual noise as absolute metrics --- there are likely small factors that we really don't know how to quantify and qualify yet. At the same time, these numbers can tell a designer whether they're doing something wrong (poor measurements) or whether they're on the right track (improved measurements from tweak to tweak), but what if two devices measure extremely close to each other, so close, that it's difficult for even the best instrumentation to detect its differences? Or the difference in numerical values really doesn't make an impact because they measure 0.0000XX% apart? Then it's up to the designer to make a subjective choice --- whether it's through sighted tests, blind tests, a central design philosophy, etc.
 

  Also, what is the purpose of the current/voltage converter in the block diagram? For other DACs and/or amplifiers, I haven't seen such a diagram for those.

 

I/V conversion is required for current output DACs, so it converts the current output to a voltage value, a process known as transimpedance. Voltage output DACs like the ES9023, PCM5102A, and WM8740/8741/8742 have this I/V conversion step integrated into the chip, simplifying design. The ES9023 and PCM5102 even have an integrated charge pump that "pumps up" the voltage output to a line-ready 2 Vrms for even less design complexity (which is why all the thumb-drive sized DACs use the ES9023 or PCM5102, or even lower end models that have the same features). With a standalone current output DAC chip, however, I/V conversion and how it's implemented has substantial impact on how the DAC ends up sounding and is thus a crucial element of the analog design aspect of a DAC that is important to audio design. Some will integrate I/V conversion, low-pass filtering, and gain all in one stage, while others will separate it out into different steps. When it comes to charge-pump devices like the ES9023 and PCM5102, the designer is essentially putting the trust in the hands of ESSTech and TI Burr-Brown, respectively, to do a good job of doing the I/V conversion, low-pass filtering, and gain all integrated into a chip the size of your thumbnail. They're then free to obsess over the analog gain and buffer stage like a typical headphone amplifier. Others feel like doing it themselves. Of course, integration of that scale comes at a price. Charge pumps have substantial switching capacitor noise and will modulate the noise floor of the DAC, and that's why these line-out DAC chips have a performance ceiling quite a bit lower (usually ~112 dB DNR) than their counterparts without a charge pump.
 
That's the thing about DAC design --- it's digital-to-analog --- so DAC designers have to understand both digital and analog signal processing. I think Gordon Rankin has mentioned before that most DAC designers are always better at one aspect than the other, so some people are amazing at DSP and can suppress jitter like nothing else, but will end up with an average analog output, while others obsess over power supply and analog output, but forget about things like PLL timing, oversampling settings, etc. Of course, that's an oversimplification; with DACs you can't just have one or the other --- it's always both designed in conjunction with one another.

 

[goodvibes]

 

[Hawaiiancerveza]

Did anyone get their hands on the geek wave 32?  I didn't read through all of the comments as theres a lot but I was wondering if anyone could comment on it?  Or post a link to someone who has commented on it?  
 
Thanks

 

[Buddhahacker]

  Did anyone get their hands on the geek wave 32?  I didn't read through all of the comments as theres a lot but I was wondering if anyone could comment on it?  Or post a link to someone who has commented on it?  
 
Thanks

I am not aware that any have been built.  They are still working out the components.  Maybe there is a prototype somewhere.

 

[miceblue]

I believe the only prototype they've let people listen to is the XD variant, in which LFF seemed to really enjoy and called it one of the best portable media players he's had the chance to listen to.
http://geek.lhlabs.com/force/geekwave/1458-headphones-for-wavexd-is-their-enuff-power.html#24478