Audiosciencereview.com/. legit?

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PENG

Audioholic Overlord
How about this?

Unfortunately the server doesn’t allow me to post links yet. But I believe you will be able to find the datasheet (google for it). You do not need to believe me or not, just look at the datasheet, and if you can read them, you will see. It’s on the page 4 in the section “AC characteristics”.
If you can not, google “how to read the data sheets of components”.
This is strange indeed, didn't you read my earlier post#57 in which I included a link to the data sheet of that chip? Of course I read it, every page of it, including all the graphs.:D There is no need for you to re-link it, but it never hurts..
 
P

PENG

Audioholic Overlord
Just FYI, PENG is an EE and knows how to read a data sheet. He is also, IMO, one of the most knowledgeable and helpful posters on this site, I've never seen him assert anything without knowing what he's talking about. He's also more of a gentleman than I am. So I think you should stow your sarcasm; he deserves better.
Thanks, through out my whole professional career, reading and understand, or at least try to understand data sheets, have always been part of the job requirements lol..
 
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PENG

Audioholic Overlord
@Irvrobinson, to save you time downloading and searching, I just PM you two pages. Please let me know if you can open the files, and that they legible, or not.
 
P

ProFan

Enthusiast
https://electronics.stackexchange.com/questions/290825/what-is-typ-in-a-datasheet
typ stands for typical. Min and max are guarranteed specifications.
Because semiconductors often have a spread of performance
, always designing to the guaranteed specifications could result in having a too conservative design. The typical performance is what you can expect for 'most' parts. The guaranteed performance will not be exceeded for all parts.
Are we done with the data sheet, gentlemen?
I highly doubt the 3.6 Vrm - 4.2 Vrms are tolerance values
3.6 Vrms is the minimal guaranteed maximum output voltage of NJU72343, while 4.2Vrms is the typical maximum output voltage of the same chip.
Thus, they are the known tolerance values for this parameter of the chip per it’s data sheet.
 
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Irvrobinson

Irvrobinson

Audioholic Spartan
@Irvrobinson, to save you time downloading and searching, I just PM you two pages. Please let me know if you can open the files, and that they legible, or not.
I was able to look at them, but they're not true schematics; too high level. They don't show buffers, but at this 10,000 foot level that doesn't mean they don't exist. I'm not sure what to think, and since I don't know anything about VC ICs, I'm not sure what to think.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
3.6 Vrms is the minimal guaranteed maximum output voltage of NJU72343, while 4.2Vrms is the typical maximum output voltage of the same chip. Thus, they are the known tolerance values for this parameter of the chip per it’s data sheet.
As PENG said, no IC I've ever seen has variances like that.

Just out of curiosity, do you have analog circuit design experience?
 
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PENG

Audioholic Overlord
As PENG said, no IC I've ever seen has variances like that.

Just out of curiosity, do you have analog circuit design experience?
Yep, for a volume IC, I certainly don't want to be the lucky one to end up getting one with the "guaranteed" 3.6 Vrms, knowing "typical" is 4.2 Vrms and maximum would likely be higher, though not specified in the data sheet.

It is not that I disagree with the min. being, as he said, a guaranteed minimum. Just that for it to be16.67% lower than "typical", I think they might have (could well be wrong as I am just guessing/surmising..) allowed for unspecified factors such as the load resistance. Below is the graph of Max output voltage rms vs load resistance (ohms):

1564873815418.png


Note that the only specified test conditions for table on page 3 under electrical characteristics.

1564873874016.png


That is, again, load resistance (just an example) is not specified. Specs, and data sheets, don't always provide enough details. I am sure I am not the only one who, quite often, have to contact the manufacturers for more details in order to explain the otherwise seemingly inexplicable numbers. I would be tempted to contact NJU for clarification in this case, but I won't because I measured mine and I know the limit already.:D
 
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PENG

Audioholic Overlord
https://electronics.stackexchange.com/questions/290825/what-is-typ-in-a-datasheet

Are we done with the data sheet, gentlemen?

3.6 Vrms is the minimal guaranteed maximum output voltage of NJU72343, while 4.2Vrms is the typical maximum output voltage of the same chip.
Thus, they are the known tolerance values for this parameter of the chip per it’s data sheet.
So the 3.6 Vrms is the minimum guaranteed maximum output voltage of the vol IC, are you still insisting the pre out level is 1.2V/2.4V unbalanced/balanced? Or you are now coming around and accept that the specified 1.2/2.4V are not the"maximum output". Just curious, that's all. By the way, I have measured the pre out of a few units including my Denon AVR and Marantz AV8801. I don't have the AP, but I used a very accurate Fluke meter and my conclusion on the clipping point is based on not only the measured results but also logic.
 
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ProFan

Enthusiast
I highly doubt the 3.6 Vrm - 4.2 Vrms are tolerance values
As PENG said, no IC I've ever seen has variances like that.
Hmm, there are plenty of them ... just an example:
DAC chip AK4490 (also used in 8805) has maximum output voltage (full scale at 0 dB FS) rated at 2.65Vp-p (min),2.8Vp-p (typ),2.95Vp-p (max)
It is 2.8Vp-p +/-5%. Per it’s data sheet.
Converting those values to Vrms will give us the following range 0.937Vrms (min) - 0.99Vrms (typ) - 1.04Vrms (max).
Those numbers look scary regarding our overloading capabilities, right? What if we have both DAC and volume chips with min numbers?
What if Amir will test such kind of unit?
And we also have multiple resistors with +/-5% tolerance, capacitors with +/-10%, and some other components, right?
Just out of curiosity, do you have analog circuit design experience?
Yes, I do, in both domains. I do not work in the audio industry though.
Below is the graph of Max output voltage rms vs load resistance (ohms):
Well, 10K plus is pretty much standard input resistance / impedance of amplifiers, so nothing to worry about.
 
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P

PENG

Audioholic Overlord
I was able to look at them, but they're not true schematics; too high level. They don't show buffers, but at this 10,000 foot level that doesn't mean they don't exist. I'm not sure what to think, and since I don't know anything about VC ICs, I'm not sure what to think.
The buffer stage is probably shown in the power amp schematics. Time permitting, I'll take another look.
 
P

ProFan

Enthusiast
So the 3.6 Vrms is the minimum guaranteed maximum output voltage of the vol IC, are you still insisting the pre out level is 1.2V/2.4V
Look at the Vrms numbers for the DAC chip ;)
 
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PENG

Audioholic Overlord
Well, 10K plus is pretty much standard input resistance / impedance of amplifiers, so nothing to worry about.
Not me, but you'll be surprised, there are no shortages of SS preamp that has input impedance "rated" just about the 10 k Ohm border line, so the "guaranteed" minimum that you seem to worry about, may be less. Also, for those who use their mid range AVR preouts, a 10 kOhm input impedance could be effectively as low as 5 kOhm due to the parallel effect.

Look at the Vrms numbers for the DAC chip ;)
Wow, what an attitude! No idea what you are implying..

Anyway, I am done, and thank you.
 
P

ProFan

Enthusiast
The buffer stage is probably shown in the power amp schematics. Time permitting, I'll take another look.
They are true schematics, the signal can be traced down to the output socket.
Just no buffer stage in the unbalanced mode, but HDAV can be considered as a buffer in the balanced mode indeed.
Power amps have their own input buffers.
 
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ProFan

Enthusiast
Wow, what an attitude! No idea what you are implying..
Hmm, let me try to explain it again (I previously did it in the other forum). Here is some information to take in consideration:
https://hometheaterhifi.com/reviews/receiver-processor/processors/marantz-av8802-processor-review/
The AV8801 output stage had a gain of two. The AV8802 output stage is now unity gain. ... The signal at the output of the DAC, which is before the volume control, is doubled in the AV8802 to compensate for the gain reduction at the output.
Multiply 0.973Vrms x2=1.946Vrms (min),0.99Vrms x2= 1.98Vrms (typ),1.04Vrms x2 =2.08Vrms (max).
I am “trying to imply” that the “bottleneck” for clipping at the overloading levels is not the volume control chip, it is the DAC chip itself.
 
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ProFan

Enthusiast
As I said before, I apologize if anybody feels abused. My thank you was a sincere response to PENG’s “thank you”, nothing related to sarcasm. Our exchange of opinions was useful for me.
Even request to “google how to read datasheets” was not a sarcasm, as you can see, I did it by myself and provided quotes.
English is my second language, but I have no “attitude” or any intention to make anybody feel unhappy, Pogre.
 
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P

PENG

Audioholic Overlord
As I said before, I apologize if anybody feels abused. My thank you was a sincere response to PENG’s “thank you”, nothing related to sarcasm. Our exchange of opinions was useful for me.
Even request to “google how to read datasheets” was not a sarcasm, as you can see, I did it by myself and provided quotes.
English is my second language, but I have no “attitude” or any intention to make anybody feel unhappy, Pogre.
Okay, as I said, technical discussion is over for me, but I would like to clarify something here so you are clear why I reacted that way in my last couple of posts.

The fact is, I provided you some info about the vol IC, and the availability of the 8805's service manual for download, but evidently from you subsequent posts that you didn't really read my post in any details, but rather, you keep posting as though you were providing me the info, like assuming I had not read what I linked. That's fine, but you can understand why I get frustrated after a while.

Examples of the info I provided, before you sort of posting and/or linking the same:

- that the specified 1.2/2.4V were "rated output", whatever Marantz meant by that, but not "maximum" (citing Yamaha's as an example, that they provided both "Rated" and "Maximum", if they were the same they wouldn't have done so). It appeared you have at least acknowledged that in the beginning but changed you mind again later, back to insisting those were "maximum". So I said I would agree to disagree on that point. When I was good enough to ask you for clarification, you ignored my question, twice iirc.

- I then provided the link to the NJU 72343 vol IC, and I also stated that it does mean the maximum output would be determined by this IC alone. In this case it may well be because the HDAMs of the 8802A and 8805 are designed to be unity gain, the previous versions were not (no idea if you know that prior..)

- I responded first to Irv's point about the buffer, and mentioned HDAM itself was a buffer too, but that his NR1609 does not have HDAM so there may be a buffer that is not shown, or hidden in the block diagram. I have not read the schematics in any detail at that point, even if I did it would have been long time ago and memory does fade over time. We both know that buffer or not, it is a matter of ensuring the driving amp has high enough input impedance and low enough output impedance for the load amp so the buffer stage could well be part of the amp section design and may be shown in the schematic of the power amp section. Then you basically (obviously not in exact words) repeat what I stated in my response to Irv, in your post#93 in which you stated:

"They are true schematics, the signal can be traced down to the output socket.
Just no buffer stage in the unbalanced mode, but HDAV can be considered as a buffer in the balanced mode indeed. Power amps have their own input buffers."


And that's right after I decided to quit and thank you..

I am not going to re-read all the posts so if I missed anything or misstated something, I have decided to move on from this particular discussion. Suffice to say my frustration is from after we seemingly agreed to further discuss the issue of whether the D&M specified rated pre out voltage represents the maximum value or not, the conversation that followed were almost one sided. It just seemed that I read you posts in detail, but you did not, otherwise you wouldn't have repeated more than once a few things I mentioned in different words as though you never read my posts. There is no fun discussing something just with myself lol.. Now I hope you don't take this the wrong way, you obviously know your stuff, and it is your prerogative to simply post without reading or trying to understand others.

Edit: Yes that hometheaterhifi.com article is a good read, I read that a couple times long time ago, and posted the link to it on this site several times in the past, along with links to other informative articles by Dr. Rich who has a PhD in EE iirc.

Good one like that deserved to be shared, and linked often, so thanks for that and I am not upset that you assume I have not read that article. I would have worded it differently but we all have different styles. Oh, didn't I mention I do own a AV8801, one reason I read Dr. Rich review on both AVPs more than once..

PS This is my last post on this topic, and if you don't read it, that's fine for me, others may.:)
 
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T

TankTop5

Full Audioholic
I just read through this thread because I found audio science review several weeks ago and was wondering about their credibility. The Marantz issue aside they do seem to obsess over parameters that you can’t hear. That said I like to read the technical write ups even though I don’t understand most of it, some of it is starting to ‘click’. I also like that they find very inexpensive equipment that is close enough in performance to equipment sometimes 10x the price, especially with Dacs.
 
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PENG

Audioholic Overlord
I don't speak EE but I'm pretty good at interpreting sarcasm and a crappy attitude...

Do you know how to have a regular conversation? If not, Google it.
By the way, I don't know about you and I forgot if you have the Denon or Marantz AVR, but I think guys like HD and ADTG would have read the link I provided to that very article by Dr. Rich on the AV8801 vs AV8802A, and about the damn HDAM that has been discussed to almost the nth degree. So to them, or you included, that's nothing new.. can't resist, but sarcasm not intended..:D:D
 

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