JRC 8080 slew rate 5V/μs that explains a lot
What per chance does 5V/μs explain or are you hiding your head after you reconsidered that statement?
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Denon AVR-X4700 AVR Review (Updated)
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What per chance does 5V/μs explain or are you hiding your head after you reconsidered that statement?
If they put these menial slow op amps there, it explains why these AVRs (Denon) sound so tragic to me. I returned Denon because it had a flat, indistinct sound without bass, even in the cinema. I wrote somewhere that SR6013 (HDAM) sounds better to me than AVC4700 (probably OP) and best SR8015 (latest HDAM) but it's still not enough for my stereo because OPs in my dac have a slew rate of 27V and 28V and in the power amplifier I have jfet and mosfet power transistors, so the luxury slew rate of the whole stereo. HDAM is made of discrete transistors and it is possible that it has a higher slew rate despite having worse measurements than Denon. A higher slew rate means a higher impulse response, dynamics, separation of musical instruments and their colors ..... etc. That's probably why Marantz sounds better to someone, which would mean that Marantz users can hear better
The measurements here are important and useful, but the slew rate is an equally important parameter. But if you connect a high-quality and expensive power amplifier for such an OP, you are declassifying it.
I am adding examples of use from the JRC8080 datasheet:
home audio, car audio, active filters, servo controls amplifiers, headphones amplifiers.
And an example from the popular OPA1612 (Chinese Topping):
professional audio equipment, microphones preamplifiers, analog and digital mixing consoles, broadcast studio equipment, audio test and measurement, high-end A / V Receivers.
I think I wrote something here somewhere in the sense that these receivers play like a stereo for a few bucks. Today I would write that they play as car audio
I'm sorry it was ironic though from the datasheet. I don't want to and I won't argue with anyone. Thanks to the JRC8080, I have already made up my mind and no one will change it. PeaceHerbertThePervert
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Sine this is the audiosciencereview forum you propably verified that in a blind listening test, right?
A blind test? I made an opinion on the sound of Denon after ten seconds of listening to my favorite music that I have been listening to for several years. I am rather surprised by how many people are satisfied with the sound of Denon, or rather it proves that most people are deaf and parrot the opinions of others. Search the youtube slew rate and watch a few videos. Such OPs cannot properly monitor the input signal and basically average it. This is basically the end of all discussions as to why Marantz is a bit more expensive and sounds better than Denon, and it shows the absurdity of the results of the local AVR and AV processor tests. Until the slew rate is measured here and the squarewave response is useless.
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Bear123
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I had/have no knowledge of slew rate so I did a quick google search as far as whether or not 5V/µs would result in poor sound quality. Can you show us the math on why this value is not adequate, and if so, what would be better, and why? Thanks.
For example, I plugged in values on what an acceptable slew rate would be for a 20 volt signal(50 watts, a lot for a tweeter AFAIK) at 15KHz and came up with 1.8, which is far below the slew rate of the Denon OP amp. Also, I read that too high of a slew rate can be detrimental as it increases current and EMI. I used high frequency because it seems this is where slew rate is meaningful/applicable.
Also, you specifically commented that the Denon AVR sounded deficient in the *bass*, but it seems lower frequencies don't have a very high slew rate requirement, so it seems highly unlikely that a slew rate of 5V/µs would have any audible affect on low frequencies? Again, perhaps my understanding is incorrect, so any clarification on your part would be helpful. Thanks!
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I have posted more once about oupee's bias expectation, Placebo, something went wrong such as settings, hardware defects etc., might have been the real reason for his bad experience with the Denon vs his Marantz, but his mind seemed made up, so I gave up..
Below is not for you as you already know, but for oupee in case he is open minded and interested in the science.
Op Amp Slew Rate - Details Formula Calculator » Electronics Notes (electronics-notes.com)
To quote the above linked article:
"As an example, take the scenario where an op amp is required to amplify a signal with a peak amplitude of 5 volts at a frequency of 25kHz. An op amp with a slew rate of at least 2 π x 25 000 x 5 = 0.785V/µs would be required."
So 5V/µs is not going to be a bottleneck for an AVR that has pre out voltage maximum no more or not much more than 4V. And note that the example is based on 25,000 Hz!
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Guys, I'm sorry, but I don't have time right now, just in speed. Nowhere did I write that my power amplifier has 28V/µs. This is ridiculous for a power amplifier, but unfortunately still a common value today. I wrote .... because OPs in my dac have a slew rate of 27V and 28V ..... This means that I have two OPs in the DAC signal path (OPA1612, OPA827). For completeness, I will add that my power amplifier has a slew rate at 100W/4Ω 90V / µs. It's a custom version of the 200-watt version I didn't want(only less power because I have a sensitive speaker). 200W version has a measured slew rate of 200W/4Ω 185V/µs.
I use google translator for reading and writing, so I understand that sometimes it can make nonsense, especially in technical terms.
I use google translator for reading and writing, so I understand that sometimes it can make nonsense, especially in technical terms.
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Okay then I misread your post, my apology, post edited accordingly. Still, slew rate many times higher than that required is enough, like damping factor, higher doesn't hurt but beyond a certain point it become a moot point. Your suggestion of the 5 V/µs spec for a preamp output buffer being the reason for it to sound "tragic" still doesn't sound logical, unless I misunderstood your point again.
If your 100 W into 4 Ohms power amp has slew rate rated 90V / µs, then it is quite high. I have a power amp that has slew rate spec 130 V/µs, but it is rated 250 W 8 Ohms, while my other power amp rated 300 W 8 Ohms has slew rate 60 V/ µs. The best measured (by ASR, Stereophile, and others) Benchmark AHB2 power amp, rated 100 W 8 Ohms apparently has slew rate of just 16 V/µs (reported by ASR members including at least one owner). So they are all over the map, but again, all more than high enough, not an issue in most cases.
Now this is getting really funny! We (not just me) have told you the Marantz has the same preamp/volume control ICs and DACs, but has an extra HDAM buffer stage at the end. So whatever the slew rate of the HDAM, let's assume it is infinite, or 100,000 V/µs , it doesn't matter because it will still be limited by the parts upstream, in fact it can only slow things down as the signal has to go through an extra stage. And by the way, in fact some Marantz models such as the SR6014 (so quite possibly the SR7015 as well), just like the Denon AVR-X3600H and X4500H, have the same OPA used right behind the HDAMs, and are also used in other parts of the signal chain.
So logically speaking, this is another proof that based on what you have said about those OPAs being the reasons, your claim of the "Denon" sound being horrible, tragic vs the "Marantz" sound cannot be real, but your Placebo, expectation bias induced imaginary!! Still, logic aside, I believe you heard what you heard, but it would have to be for other reasons, such as messed up settings, not comparing apples to apples, some defective parts involved etc.
@peng - sometimes you have to let the crazy posts go.
Anyone whose actually setup a Denon 3700/4700 knows there are lots of settings to configure besides just an Audyssey run to attain the exact sound you are looking for. It's not like my Hegel H90 where you simply turn it on and that's what you get.
If the user doesn't spend some time understanding and trying the various settings I can see how after 10 seconds he might make a snap judgement out of a lack of understanding.
That occurred to me too. Unfortunately, I can't get to the service manual of the new receivers, so I don't know a lot of details. HDAM is only an operational amplifier composed of discrete transistors, but no one knows the parameters. The only thing I found was this:@peng - sometimes you have to let the crazy posts go.
Anyone whose actually setup a Denon 3700/4700 knows there are lots of settings to configure besides just an Audyssey run to attain the exact sound you are looking for. It's not like my Hegel H90 where you simply turn it on and that's what you get.
If the user doesn't spend some time understanding and trying the various settings I can see how after 10 seconds he might make a snap judgement out of a lack of understanding.
1992 - HDAM
The original Hyper Dynamic Amplifier Module (HDAM) was first used in the PM-99SE integrated amplifier in 1992. The HDAM is a stamp-sized high-performance amp unit with approximately 70dB of raw gain, with a slew gate of 70 to 80 V per microsecond that can be utilized throughout the audio signal chain.
I tried different receivers and connections but the only thing I didn't try was to turn on my power amplifier and stereo box in the SR8015 preout front. I think this will be a crucial test. I plan it permanently as HT bypass so that I don't have a special front speaker for cinema and stereo, but there is no time.
Just don't accuse me of bias expectation. I haven't had an oscilloscope in a long time, but I'm just demanding and I'm not deaf.
As I said, let's assume the HDAM is as good as an ideal OPA so it is totally transparent. Even then, my point is, it is an extra buffer stage so it cannot really improve on what's done upstream. You can see the logic I assume, if not, then all I can say it, believe what you believe. As ampere42 suggested that I should just let it go, I have hard time letting it go not because I wanted to win an argument, but wanted to share the facts that I know from the info in the service manual. You can buy the service manuals for the AV8805, SR6014 and other older models and see it for yourself. The service manuals of the 2020 models are not available yet as far as I can tell, but may be biggerguyca has access to some of those, don't really know.
Regarding the HDAM details, the service manuals do show the schematics, and if I remember right bigguyca might have posted some info of the different versions, do a search if you want to see them.
Lastly, I don't think anyone is accusing you of bias expectation. For me, I simply included "expectation bias" as a possibility of the reasons why you had such experience with that one Denon AVR. In fact, I also included other scenarios such as settings and defective parts. Experts like Dr. Toole has said more than once, people are not immune to such effects.
On the other hand, how about your repeated post of something like "I am rather surprised by how many people are satisfied with the sound of Denon, or rather it proves that most people are deaf and parrot the opinions of others. " Is that "accusation" then? I would think not, hope not..
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@oupee, your reaction to the 5V/μs deal is probably because you thought Marantz uses the HDAM instead of the OPA IC NJM8080 that bigguyca mentioned in his post#1619, or for other reasons? I am just curious. Anyway, if you compare the signal flow for say the AVR-X4500H and the SR6014, and likely the SR7013, you will see that it is not the case. The signal flow from the volume control IC to pre out for the front left and right channels look like the following: (again, service manuals are available if you want to see them.
SR6014:
AVR-X4500H:
Same but no HDAM. The HDAMs are reportedly wired as a unity gain buffer (see the hometheaterhifi.com) reviews on the AV8802A and AV8805 if you are interested in what the reviewer said.
The vol IC and the OPA IC buffer (yet another extra stage) for the SR6014 and AVR-X4500H are the same. So you can see that the HDAM is both preceded and followed by another IC and that's why I said it could not possibly improve the overall slew rate of the pre out voltage, even if we assume the HDAM is perfect and have infinite slew rate. The best those two additional buffers after the volume IC can do to the overall slew rate is being transparent, that is, not making it worse.
That's just logic, not disputing the benefits of the HDAM technology at all, and the fact is, the overall results, to a large extent is only as good as the weakest link. Then the question is, why would Marantz even bother, for what benefits? That's a different ball of wax I would rather leave alone for the experts to comment.
SR6014:
AVR-X4500H:
Same but no HDAM. The HDAMs are reportedly wired as a unity gain buffer (see the hometheaterhifi.com) reviews on the AV8802A and AV8805 if you are interested in what the reviewer said.
The vol IC and the OPA IC buffer (yet another extra stage) for the SR6014 and AVR-X4500H are the same. So you can see that the HDAM is both preceded and followed by another IC and that's why I said it could not possibly improve the overall slew rate of the pre out voltage, even if we assume the HDAM is perfect and have infinite slew rate. The best those two additional buffers after the volume IC can do to the overall slew rate is being transparent, that is, not making it worse.
That's just logic, not disputing the benefits of the HDAM technology at all, and the fact is, the overall results, to a large extent is only as good as the weakest link. Then the question is, why would Marantz even bother, for what benefits? That's a different ball of wax I would rather leave alone for the experts to comment.
@peng This isn't an argument or word ward. So I didn't have bad expectations from Denon. I bought it for a review here and sold the SR6013 pointlessly cheaply. I like the Denon design much more, it has a nicer and more practical front panel, but the front panel doesn't play. The first thing I did was turn on pure direct and play hires music. That was the first ten seconds I almost had a heart attack. Denon cost one and a half of what I earn in a month (it's expensive in Europe). I enclose two old photos setting levels Denon4700 vs Marantz6013. It needs to be related to the front L. Watch the woofer and it still didn't play really bass. After buying the SR8015, everything was ok again.
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Good morning oupee, let me be 100% clear, I have said from the beginning that I believe you heard what you heard. So no, I would never say you imagined the difference, other than it could be a "possibility", and even that, I mainly meant to say it is often a good possibility in general but to me it is obvious that you heard something that is quite unexpected, otherwise you wouldn't have used description such as horrible, tragic, now even heart attack, and within the first ten seconds. So like I have said before, something isn't right, and "settings" are much more than just the "levels" you attached, an AVR is quite a complicated device, something (again setting is just one example, another possibility..).
Think about it, if it really was so bad that would almost give you a heart attack in the first 10 seconds (I know you are emphasizing it to make point..), then why would there be so many users including some who has experience with comparable Marantz, Arcam and other models, who did not have similarly bad experience like yours?
I repeated myself several times now that I believe what you heard, who am I to say otherwise? I just wish you don't keep making blanket statement that Denon is so bad.., or perhaps that's not your intention, but Google translate did it..
Okay now I am really done as I have tried my best to suggest that it may just be a "one off" case, that it is not true that Denon is so bad, just that you have had a bad one. Enjoy whatever you have, the SR8015 is a beautiful device to look at, and I am sure it is among the best AVR currently available.
Don't distort what I wrote. My stereo is without bass and treble corrections, room corrections and without channel balance. That's what I've listened to, and with AVRs it's like Pure Direct mode. I wrote that the first thing I did after turning on Denon was to set up Pure Direct. That was the stereo shock. Somewhere I wrote something like it was a boring, dull, lifeless, non-dynamic sound from an old radio, that's true. The fact that most people add volume and a second subwoofer, especially that it clinks and bangs, is another matter and it's just their business. So don't tell me that there are different setting options, including levels, it only concerned home theater settings and you can see it in that photo.
In 95% of all audio devices, the most dusty is the OP NE5532, which has a slew rate of 9V and is almost twice as fast as the JRC8080, with the overview that it could be written that it is twice as good. The JRC8080 does not belong to the Hi-Fi signal path and is a disgrace. If you do not know how the slew rate will affect the sound, then we will not solve it and I take it as a finished thing.
I only have one personal question and don't take it wrong or offensive! We are from several countries and continents and there is a different mentality and expression everywhere, so I don't want to be misunderstood but I would like to know what your Hi-Fi setup is. Sometimes I meet teenagers on the forums who have old, repaired Marantz, NAD, Rotel .... but they have learned a few theories, formulas ... etc. I would just like to know what I am up to and whatever answer I take, thank you and peace.
I found the results using Direct mode can be amazingly different with different speakers connected and based on the crossover setting selected in Audyssey.
When I had my Sierra Towers setup they sound 100% better with Dynamic EQ and an 80Hz crossover to my dual HSU subs. When I would use Direct mode for playback they would sound flat in comparison. But once I setup Dynamic EQ and the dual subs were crossed over at 80Hz. The sound was amazing.
In contrast, when I setup my Revel F328Be with the Denon 4700 in Direct mode it was the reverse. I loved the Direct mode sound as it offered a HUGE fat sound even without my subs. When I engaged Audyssey it tamed some of the lower end of the F328Be and elevated highs 2dB over 5K so the FR was less of a wedge (with a slant down from 30Hz to 20KHz) and made the FR flatter in comparison. I love being able to select the curve I'm in the mood for by switching between Direct and Stereo modes with Dynamic EQ off.
This is the thing about the Denon 3700/4700... there are a ton of options. Dynamic EQ, Audyssey custom curves, flat versus custom - it's all up to you. If you don't read English and don't have access to a user manual in your native tongue it can be quite difficult to understand all the options. If when I got my Denon 4500 a year ago, I only put it in Direct or Pure/Direct mode and listened, I would be disappointed if I didn't know about the various options. But now that I understand how to configure the settings I can make it sound any way I want it.
It's probably hard to understand this if you haven't been exposed to the learning curve or don't want to mess with it. If that's the case I would stay with my Hegel H90. Turn it on and that's the majority of options besides connecting the Mac via USB.
Bear123
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Stereo without bass and treble control and room correction = low fidelity. I'm ok with such lo-fi music reproduction in my workout room while I'm clanging weights around, but now that I've heard high fidelity sound in room(i.e. room corrected +/- 1-2 dB response to below 20 Hz), it would be difficult for me to settle for the low fidelity sound of two speakers in a room without eq no matter how expensive or "audiophile" the "gear" is. So different strokes for different folks. Pure Direct = low fidelity unless someone has a way to address room issues in this mode. But I haven't seen anything that shows this button in any way improves sound quality. It seems to appeal to a necessary audience and is therefore included.
Thank you, I don't know much, but have been reading a lot, and learning. It helps a little being an EE and have worked in related field for many years.
