[MatsudaMan]

I drive my headphones with my Atoll IN100 integrated when the wife wants it quiet. I'm very happy with it, as it's very musical and has a lot of headroom/dynamics. The only issue is a little bit of background hiss. Come to think of it, I've always wondered how much better a dedicated headphone amp like a little dot mkv would be. Can you better a decent headphone out on an integrated with a sub 500 dollar dedicated headphone amplifier?

 

[scompton]

Quote:

Originally Posted by MatsudaMan /img/forum/go_quote.gif I drive my headphones with my Atoll IN100 integrated when the wife wants it quiet. I'm very happy with it, as it's very musical and has a lot of headroom/dynamics. The only issue is a little bit of background hiss. Come to think of it, I've always wondered how much better a dedicated headphone amp like a little dot mkv would be. Can you better a decent headphone out on an integrated with a sub 500 dollar dedicated headphone amplifier?

There's a thread that's an offshoot of this thread that's discussing just that. It's an interesting read and experiences are mixed.

http://www.head-fi.org/forums/f5/man...-jacks-338299/

 

[pp312]

Quote:

Originally Posted by Headdie /img/forum/go_quote.gif PP312 : My NAD C720BEE is based on a C320BEE, so you got my full attention here ! I may change my mind, but actually I'd prefer upgrading my receiver than buying a dedicated headphone amplifier. So, could you briefly compare the sound of the C320BEE against the PM6010 OSE? Could you also tell us wich headphone(s) you've used with the C320BEE and wich on you actually use with the PM6010 OSE? That would be helpfull, at least to me... Thanks,

Good question, but please don't base any buying decisions on my experience; synergy, music choice and personal preference are very much at play here. However, my experience was that the C320BEE was a little dark sounding for my Senn HD650, with a slight bias toward the upper mid/lower treble area at the expense of extreme treble (this has been remarked on in user reviews--check Audioreview). The HD650 benefits from a lighter, more open, more neutral amp. To be honest, I've been surprised at how good the PM6010 is after having a PM66K1 as the visual layout is very similar and probably both were designed by the same team; but there you go--that's the black art for you. One thing I'll say for the NAD: it had a very honest sound with good orchestral timbre. Some swear by it as a HP amp, but I found it just a little harsh and closed in with the Senn. However, there again, my Senns are still burning in though I've had them six months, and that may be a factor too. See how difficult it is to make subjective judgements, let alone objective ones.

I'll say this about the PM6010. If I were blind and had no hands, and someone told me I was listening to an MF X-Can v3, I would believe it. I've never heard the latter amp, but the 6010 gives me the sound I would have hoped to hear had I bought one.

 

[Headdie]

Thank you pp312 !

I did some mining for old C320BEE threads and reach a message with this little text:

"I believe the general rule of thumb is that the headphone jack's output impedance should be lower than the headphone's impedance. The BEE's headphone jack output impedance is high, something like 220 ohms. As a result, the bass was pretty sloppy with my old SR-80s (32 ohms)."

Is this impedance rule and its consequence widely accepted? Could we fix such a problem efficiently with a 200 ohms impedance adapter?

BTW, I don't understand how an impedance adapter can work anyway. If you add serial resistance, then you would have to turn up the volume to keep an arbitrary sound level... But, if you turn up the volume, then you increase resistance inside the amplifier (with the volume control). Increasing restistance just inside vs outside the cabinet seems the same to me... Hopefully, someone will correct me...

 

[tfarney]

Quote:

One thing I'll say for the NAD: it had a very honest sound with good orchestral timbre. Some swear by it as a HP amp, but I found it just a little harsh and closed in with the Senn. However, there again, my Senns are still burning in though I've had them six months, and that may be a factor too. See how difficult it is to make subjective judgements, let alone objective ones.

No problem. My Senns are 10-11 years old. Just send me the NAD and I'll let you know how it does.

Tim

 

[Headdie]

HiRes
LowRes

 

[pp312]

"No problem. My Senns are 10-11 years old. Just send me the NAD and I'll let you know how it does."

Sorry, Tim, Ebay claimed it long ago.

But you'd have been my first choice if I'd still had it.

 

[Headdie]

I'm not an electronic engineer or technician, but here's what I see looking into the C720BEE :

1. The headphone jack (front left on the previous image) has two resistors and two connectors on it.

2. A first connector goes to the front right of the machine, close to the volume pot, so I suppose it's for volume control and it adds even mor resistance some way.

3. A second connector (with a ground) goes to the rear left, close to the speaker terminals, so I suppose it's for the signal. The wires are not that big, so I wonder if the signal is not already attenuated from that point...

For the rest, I don't know if there is an OPAMP somewhere on the main board. There's not a lot of ICs, but mainly resistors, capacitors, transistors on the board. There is a huge hole on the floor for ventilation. I'll have to pay attention, cause it may be a risk for mouse to get inside...

 

[scompton]

Quote:

Originally Posted by Headdie /img/forum/go_quote.gif I'm not an electronic engineer or technician, but here's what I see looking into the C720BEE : 1. The headphone jack (front left on the previous image) has two resistors and two connectors on it. 2. A first connector goes to the front right of the machine, close to the volume pot, so I suppose it's for volume control and it adds even mor resistance some way. 3. A second connector (with a ground) goes to the rear left, close to the speaker terminals, so I suppose it's for the signal. The wires are not that big, so I wonder if the signal is not already attenuated from that point... For the rest, I don't know if there is an OPAMP somewhere on the main board. There's not a lot of ICs, but mainly resistors, capacitors, transistors on the board. There is a huge hole on the floor for ventilation. I'll have to pay attention, cause it may be a risk for mouse to get inside...

There are at least 4 ICs in there that look like op amps, but I'm no expert. The chips with 8 connections may be op amps. For example, on the right, next to the heat sinks, under the wires going to the headphone jack. Also directly up from the same heat sinks, the IC between the heat sinks and the 2 ICs with 16 connections.

On the other had, the resistors could be adapting the speaker out to the headphone out.

You need a schematic to know for sure

 

[odigg]

Well here's a surprise. I looked at the schematics on hifiengine.com and guess what? The 320BEE uses an opamp circuit. The PM6010 is right off the main speaker terminals. I only glanced at the diagrams so I suggest you look yourself to verify. billbillw was the one who pointed out the 320BEE uses an opamp circuit in the other thread.

Maybe that's why you like the PM6010 better than the 320BEE.

And just so you know, the 720BEE uses the 320BEE amp.

Edit!

billbillw stated that he read the 320BEE circuit wrong. I checked again and I think I either mixed up the 317 and 320BEE circuit or I read the circuit wrong as well. The 320BEE uses resistors. Thanks billbillw

 

[Headdie]

Great ! Great ! Let's keep this thread pleasant and constructive.

Our goal is not pretending that we can replace dedicated head amps with integrated. We have to get real. I don't expect from a NAD receiver costing around 300$ to have an headphone output as good as a specialized product at the same price, like Little Dot MK4 or MK5. After all, NAD have to spread money on all parts of the receiver, (hopefully) not just the phone jack, which is not the case for most head amp makers.

Our goal is rather to pinpoint good integrated amplifiers, identify proper match with some headphones, and even be creative to get the most out of those big box. That's the fun part of it, no?

So let me ask a few more questions... Apparently, my NAD C720BEE is good, without being great as an headphone amplifier. It's ok for me, but I'd like to get the most out of it anyway.

First, it's not a tube amplifier (snif)... but do you think that I could get a taste of it with this thing,

Pacific Valve & Electric Company Yaqin Tube Buffer

Moreover, I suppose that we can also tweak integrated amps, maybe even the headphone output circuit... Do you know about any mods done on a C320BEE or C720BEE ?

BTW, I'd be interested to know what you guys have done to improve the sound of your integrated or receivers. New jumpers, opamp rolling, power cords, power conditionners, impedance adapters or whatever that really works... Go ahead with your suggestions!

Thanks again,

 

[tfarney]

Quote:

Originally Posted by Headdie /img/forum/go_quote.gif Our goal is not pretending that we can replace dedicated head amps with integrated. We have to get real. I don't expect from a NAD receiver costing around 300$ to have an headphone output as good as a specialized product at the same price, like Little Dot MK4 or MK5. After all, NAD have to spread money on all parts of the receiver, (hopefully) not just the phone jack, which is not the case for most head amp makers.

I'm not sure your reasoning is completely sound, Headdie. NAD, Marantz, Cambridge, etc. are international companies with international markets that sell millions of units per year. That means they source millions of parts a year. Probably at a good bit less than most small headphone amp companies (and they're all very small, relatively speaking). They're able to buy components at a lower cost; they're abIe to sell products at a lower margin, and in between, they probably have much more automation and manufacturing efficiency. It may be completely realistic to expect a company like that to be able to produce an integrated amp that includes a headphone stage as good as a dedicated headphone amp that costs as much as the entire integrated amp. And that's if we're talking about separate circuits for the headphone sections.

If we're talking about the speaker amps stepped down through nests of resistors, the only additional parts are the resistors and the jack. Of course we have heard from a couple of sources that this method can cause impedance changes at output, resulting in changes in the sound of some phones. But this is not unique to integrated amps. Resistors are used to step down the ouput of headphone amps with multiple gain sections. Resistors are used to step down the output in audiophile stepped attenuators. And these are often solutions included in the most expensive and respected amps. So we can't assume a nest of resistors automatically degrades signal quality, it must come down to proper implementation. And why would companies like NAD, Marantz and Cambridge Audio implement something so simple improperly? There could be a reason. But we haven't heard it yet. And even if the ohms at output are a bit high, what we've heard so far is that will have little to no audible effect on high-ohm phones. That synergy thing again, but not the clear superiority of one method over another. An awful lot of the best reference phones are high-ohm.

Discrete circuits powered by op amps, or main amps through resistors -- I suspect either approach can result in a headphone section as good as any $300 or $400 headphone amp. With a good match of headphones and output, I can't imagine any reason why the headphone jack of your NAD isn't every bit as good as your NAD. Period. Does this put it in the true high end with silver coated wire and the finest audiophile parts? No. But the cost of diminishing returns up there is too dear for me anyway.

I could be all wrong about what modern integrated amps can deliver from their headphone jacks. It could be that any $300 dedicated headphone amp is better than the output of the jack of any integrated amp. But I sure have a lot of reason to doubt that conventional wisdom today. So I will go find out what I can on my own.

Tim

 

[pp312]

Quote:

Originally Posted by tfarney /img/forum/go_quote.gif Discrete circuits powered by op amps, or main amps through resistors -- I suspect either approach can result in a headphone section as good as any $300 or $400 headphone amp. With a good match of headphones and output, I can't imagine any reason why the headphone jack of your NAD isn't every bit as good as your NAD. Period. Does this put it in the true high end with silver coated wire and the finest audiophile parts? No. But the cost of diminishing returns up there is too dear for me anyway. Tim

I guess this relates to what I was saying about the only honest approach of speaker amp manufacturers toward headphone users is to use the resistors-off-the-main-amp approach. So the headphone jack of the NAD or any amp SHOULD be outputting a stepped-down version of the speaker output if the buyer is to get the sound he read about in reviews and subsequently bought the product for. After all, why should he get the "What Hi-Fi" 5 Star sound through his speakers, and the sound of a different amp entirely through his headphones? That'd be dishonest marketing, surely.

So..couple that with the fact that it's simpler and cheaper to use the resistor approach, plus the testimony of some of the major manufacturers themselves, and I think we have good cause to believe the resistor approach is now and probably has been for many years in general use. However, since myths die hard, I will not rule out more posts along the lines of "I've opened heaps of integrated amps and the HP jacks were all driven by op amps". It seems to comfort some people to believe this, though I fail to see why as it proves nothing.

Incidentally, Tim, I like your reasoned reply to the suggestion that an integrated at a certain price point could never be expected to sound as good as a dedicated at the same price point. Economies of scale indeed, and buying a Marantz or NAD is tapping into the vast buying power of those companies and the incredible pricing structure pressures they're under. And that's if you're buying new. Even putting aside Ebay, there are some incredible bargains in superceded integrateds and receivers in online shops. In England, the PM6010 can still be bought for around GBP120 new. To my ears, that would make it the bargain of the century.

 

[tfarney]

Quote:

I guess this relates to what I was saying about the only honest approach of speaker amp manufacturers toward headphone users is to use the resistors-off-the-main-amp approach. So the headphone jack of the NAD or any amp SHOULD be outputting a stepped-down version of the speaker output if the buyer is to get the sound he read about in reviews and subsequently bought the product for. After all, why should he get the "What Hi-Fi" 5 Star sound through his speakers, and the sound of a different amp entirely through his headphones? That'd be dishonest marketing, surely.

Interestingly, in doing a bit of research online yesterday, I found several of the more expensive integrateds used separate headamp circuits. In particular, the expensive and highly-praised new Yamaha A-S1000 and the even more expensive A-S2000, which not only uses a separate headphone amp, but one with a selectable gain for low impedence/high impedence phones. But that's not to say that the resistor approach shouldn't be able to deliver to the headphone jack a signal that mirrors the one delivered to the speaker terminals. As far as I know, it should. Of course we'll never be sure if it sounds the same because our speakers and our headphones will always be different. So once again, it's down to listening. I have my old Harman Kardon as evidence. It drives my Senn 580s very well and sounds great. I don't have a bunch of dedicated headamps to compare it with, but I know what good audio sounds like, and the old HK is good enough to reveal subtle differences in recording masters and even changes in cable (something I wasn't sure I quite believed in until yesterday, but that's another story). But the old HK has 30-something specs. It is outclassed by the better modern integrateds. Is it something I'd really hear? I don't know, but even if it is subtle, and there is a chance that I could get the quality of a $400 - $500 headphone amp and upgrade my speaker amp with the same money, why would I not investigate?

Tim

 

[Dobro]

Tim said:
Quote:

... and even changes in cable (something I wasn't sure I quite believed in until yesterday, but that's another story).

A story I'd very much like to hear, knowing your aversion to Kool-aid. I'm still very much a cable agnostic.

To all who have contributed to this thread, a big thank you! I've been following closely and find this thread both interesting and edifying. Again, thanks!