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Post by stanga on Mar 1, 2014 8:12:31 GMT
Long before I even owned a decent set of headphones, I was already playing about with some expensive cans. I was then a quality control engineer for a now defunct retail group. Since then I have read loads of stuff about headphones, written by knowledgeable and/or technical people. It is fair to say that I agreed with some of that info, and disagreed with others. But ending up in an argument with somebody else on theirs or my technical viewpoint is something that I have started to avoid in the last couple of years. Instead, I put my money where my mouth is and actually go about building a commercial unit based on my own technical perspective.
I have adapted a headphone amplifier circuit that can be modified at the factory end to cater for a wide range of headphones, but what is good enough for one or more cans, might not be suitable for a different set of cans. And this is a problem that many headphone users have had to face since headphones were invented. Few designs on the market offer more than just an on/off switch, headphone socket, and volume control. A couple have added tone controls, or even graphic equalizers. But these solutions only appear to plaster over the cracks, rather than offer a solution. And there is where my alternative perspective on the problem solving comes in to play.
But to solve a problem, you first have to identify the problem. So that's a good place to start as far as this thread is concerned. So what are the problems that I have identified? They are: 1. Variation in headphone impedance giving different sound output levels at different settings on a volume control. A position on the volume dial that is acceptable for a 32 Ohms Can is not going to be acceptable for 300 Ohms. 2. Too forward or too backwards sounding. This is mainly noticeable in the critical part of the musical presentation. That tends to be single vocalists or instrument players, but not confined to just those areas. 3. Too much bass, or too thin sounding. 4. Not enough extension to the bass.
The most common solution recommended to solve one or more of these problems is to use a headphone amplifier that produces more power. But is this the right approach? How would using a headamp that produces say 5amps at its output produce a better sound when the headphone itself is rated at say 100mA at 300 Ohms? My 100Watt integrated amplifier has a headphone socket, but I would not say that it sounds better on headphones. So that approach is not so sound as first suggested. I am more worried that all that excessive output power capability is more than likely to fry the voice coils on my cans.
So where do we go from here, and what are the possible alternative solutions? And that is the object of this thread. Let us see what inputs I get, including any challenges to my identification of the ailments that afflict current headphone amp design approaches.
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alex30
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Post by alex30 on Mar 1, 2014 12:32:34 GMT
Hi, Another issue that you didn't mention is the tendency for cans to polarize the sound much more than speakers do. Modern recordings seem to be better in this respect but older stuff , from the seventies, could go a little overboard with the Stereophonic experience. This is a difficult one because I have built and used a crossover filter but can't say that I was in awe of it and came to regard it as another potential source of distortion in the path.
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Post by PinkFloyd on Mar 1, 2014 14:42:10 GMT
Hi, Another issue that you didn't mention is the tendency for cans to polarize the sound much more than speakers do. Modern recordings seem to be better in this respect but older stuff , from the seventies, could go a little overboard with the Stereophonic experience. This is a difficult one because I have built and used a crossover filter but can't say that I was in awe of it and came to regard it as another potential source of distortion in the path. Hi Alex, Is it a "crossfeed" filter that you made? Mike.
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Post by PinkFloyd on Mar 1, 2014 15:04:38 GMT
low impedance like current, high impedance require more voltage in order to achieve the same loudness as a lower impedance headphone.... no one amplifier can be a jack of all trades for all headphones.
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Post by stanga on Mar 1, 2014 18:08:40 GMT
Hi, Another issue that you didn't mention is the tendency for cans to polarize the sound much more than speakers do. Modern recordings seem to be better in this respect but older stuff , from the seventies, could go a little overboard with the Stereophonic experience. Thanks for bringing that up. In my haste to type out the list I forgot to add that to the mix. Continuing from where I left off, how can these problems be solved or at least reduced to an acceptable level? The SPL Phonitor headphone amplifier is one of the few I know of that attempts to do "something more useful" with the signal in order to tackle some issues like crossfeed. But at more than £1.2K it is more wish list than shopping list. It also lacks any obvious facilities to control any of the other points I mentioned. But are headphone users able to adapt to new control switches or knobs on a front plate of a headamp? Anyone old enough to remember the days when integrated amplifiers were judged by how many knobs and switches they spouted, rather than how few they had, knows what I am on about. Uk HIFI mags started a "IMHO ill conceived" crusade against those extra control knobs, and things have never been the same again. So amp users have found themselves locked into a fixed input/output sound that was deemed to be of a suitable flavour by the amp designer. Changing the sound means changing amp or speakers. Not an ideal solution, since you never know for certain in advance if that is going to provide the solution. It's also an expensive way to find out that got it wrong.
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Post by stanga on Mar 1, 2014 18:22:38 GMT
low impedance like current, high impedance require more voltage in order to achieve the same loudness as a lower impedance headphone.... no one amplifier can be a jack of all trades for all headphones. Would it not be more correct to state that up to now nobody has developed a headphone amplifier that can be a Jack of all trade, or at least a Jack with many strings to its bow?
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Post by PinkFloyd on Mar 1, 2014 19:32:00 GMT
low impedance like current, high impedance require more voltage in order to achieve the same loudness as a lower impedance headphone.... no one amplifier can be a jack of all trades for all headphones. Would it not be more correct to state that up to now nobody has developed a headphone amplifier that can be a Jack of all trade, or at least a Jack with many strings to its bow? Hi Stanga, Yes, that would be quite an accurate statement. There are a few with switchable impedance settings, gain settings etc. but not that many (none that I know of) that cater for ALL headphone impedances in the "correct" way Some of us have dozens of headphone amps and "know" which ones hit the sweet spot with a particular headphone.... if there was a singular amp that could handle every headphone then, yes, it would be a very desirable amp to own. It would possibly be two (or more) amps in one enclosure which could be "switched in" dependant on the load? Or, it would automatically recognise the load and auto switch to the relevant circuit? I don't know, that's why the "?". By the way, before we go any further may I ask your name? Mine is Mike..... All the best, Mike.
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alex30
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Post by alex30 on Mar 1, 2014 19:45:01 GMT
Hi, Another issue that you didn't mention is the tendency for cans to polarize the sound much more than speakers do. Modern recordings seem to be better in this respect but older stuff , from the seventies, could go a little overboard with the Stereophonic experience. This is a difficult one because I have built and used a crossover filter but can't say that I was in awe of it and came to regard it as another potential source of distortion in the path. Hi Alex, Is it a "crossfeed" filter that you made? Mike. Hi, Yes it was a crossfeed filter. Sorry to have confused you there.
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alex30
Been here a while!
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Post by alex30 on Mar 1, 2014 19:54:14 GMT
Hi, Another issue that you didn't mention is the tendency for cans to polarize the sound much more than speakers do. Modern recordings seem to be better in this respect but older stuff , from the seventies, could go a little overboard with the Stereophonic experience. Thanks for bringing that up. In my haste to type out the list I forgot to add that to the mix. Continuing from where I left off, how can these problems be solved or at least reduced to an acceptable level? The SPL Phonitor headphone amplifier is one of the few I know of that attempts to do "something more useful" with the signal in order to tackle some issues like crossfeed. But at more than £1.2K it is more wish list than shopping list. It also lacks any obvious facilities to control any of the other points I mentioned. But are headphone users able to adapt to new control switches or knobs on a front plate of a headamp? Anyone old enough to remember the days when integrated amplifiers were judged by how many knobs and switches they spouted, rather than how few they had, knows what I am on about. Uk HIFI mags started a "IMHO ill conceived" crusade against those extra control knobs, and things have never been the same again. So amp users have found themselves locked into a fixed input/output sound that was deemed to be of a suitable flavour by the amp designer. Changing the sound means changing amp or speakers. Not an ideal solution, since you never know for certain in advance if that is going to provide the solution. It's also an expensive way to find out that got it wrong. I think you make a very valid point here . I tend to like things at what I perceive to be as neutral as possible (but where does that truly lie?) and tend to shy away from any type of tone adjustment but can see it's merits in that at least you can have some control, just as long as it can be bypassed completely if required.
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Post by stanga on Mar 1, 2014 19:57:53 GMT
Hi Stanga, By the way, before we go any further may I ask your name? Mine is Mike..... According to my birth certificate my name is Frank. But my mother put down a list of names on that certificate. So some people also know me as Stan.
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Post by PinkFloyd on Mar 1, 2014 20:40:38 GMT
Hi Stan, I was thinking you may be Eastern European or something so didn't want to say that "Stanga" sounded like I was speaking to a chair lift, that would not have been a good start Stan / Stanley, a good wholesome British name which was brought to the public's attention in the 70's by Slade: Is your amp ready to roll or still in the prototype stage? If in the prototype stage I would SERIOUSLY factor in provision for some kind of MP3 (for want of a better word) input as only the diehards are using sources like CD players these days.... I am 52 years old and couldn't believe it when a young guy asked me what a phono socket was..... ffs! No good to him, apparantly, as he would be using his iphone as a source. The over 40's market is still viable as there are dedicated Vinyl / CD junkies but if you want to make it a truly "Jack of all trades" amp it has to be MP3 "friendly" Mike.
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Post by stanga on Mar 1, 2014 21:14:18 GMT
I assume that when you mention mp3, you mean a 3.5mm input socket?
I have been using/playing with the prototype for some years now. Primarily to drive my HD800 and K701. Anyone familiar with those knows how much of a strain on the wallet it is to find an amp that produces a satisfactory listening experience for either of them let alone both of them. Out of desperation it was then when I decided to tear up the rule book and do some lateral thinking to find a solution that could satisfy my needs. My main requirement was that I could come up with something that could take into account a wide range of impedance requirements. But then I started to come across other headphone listening problems that could also benefit with a solution. That's how I initially ended up joining RG in order to see what path other people were following. But I was on a different track and quest, so I continued the journey on my own. But the time has come to turn this prototype into a commercial unit for others to also enjoy. I am waiting on an answer from a particular component manufacturer to see if they do indeed make a standard 90 degrees stereo rotary switch. Those things were common in years gone by, but are now hard to source for some odd reason. The ones that are available tend to be HEX types, which won't do the job in my application.
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Post by PinkFloyd on Mar 1, 2014 22:11:17 GMT
I assume that when you mention mp3, you mean a 3.5mm input socket? I have been using/playing with the prototype for some years now. Primarily to drive my HD800 and K701. Anyone familiar with those knows how much of a strain on the wallet it is to find an amp that produces a satisfactory listening experience for either of them let alone both of them. Out of desperation it was then when I decided to tear up the rule book and do some lateral thinking to find a solution that could satisfy my needs. My main requirement was that I could come up with something that could take into account a wide range of impedance requirements. But then I started to come across other headphone listening problems that could also benefit with a solution. That's how I initially ended up joining RG in order to see what path other people were following. But I was on a different track and quest, so I continued the journey on my own. But the time has come to turn this prototype into a commercial unit for others to also enjoy. I am waiting on an answer from a particular component manufacturer to see if they do indeed make a standard 90 degrees stereo rotary switch. Those things were common in years gone by, but are now hard to source for some odd reason. The ones that are available tend to be HEX types, which won't do the job in my application. Yes, a 3.5mm socket and possibly a USB socket (dependant on where you are taking this)..... I have a few of those rotary switches kicking about somewhere, new old stock from the 70's, I'll see if I can find them and am happy to send you one for evaluation. Mike.
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Post by stanga on Mar 1, 2014 23:45:52 GMT
I think you make a very valid point here . I tend to like things at what I perceive to be as neutral as possible (but where does that truly lie?) and tend to shy away from any type of tone adjustment but can see it's merits in that at least you can have some control, just as long as it can be bypassed completely if required. I have looked at tone controls, but I was not convinced that they offer an acceptable solution for headphone amps. What I ended up trying out is a combination of voltage and current amplification. Voltage to handle the SPL, and current to handle the damping of the voice coil and to take care of the differences in diameter of the diaphragms. One reason why the HD800 sounds bass light on many headamps is down to those 55mm diamater drivers. They need more energy to get them to move and to stop in the bass region. It's like a heavy car that needs more torque to move off, and bigger breaks to stop when compared to a smaller car. Just using a bigger engine doesn't guarantee you more torque where you need it, and certainly not better breaking.
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alex30
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Post by alex30 on Mar 2, 2014 11:33:40 GMT
Hi stanga, I have seen a number of headamps that feature two outputs,one for high impedance cans and the second for low. Is this the sort of thing you are thinking of but in a dial in solution to offer more controlled output ?
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rowuk
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Post by rowuk on Aug 20, 2014 7:51:38 GMT
Did Stan ever get a can amp off the ground? Nothing that I read here sounded like alternative, product development or a business plan........
I do agree that EQ would be a nice thing to have. 2 parametric controls would be enough to flatten out most decent cans. If this was a commercial venture, measure a bunch of headphones and publish the frequency response and suggested correction.
In a previous life, I learned that it was even possible to optimise phono preamps for a specific cartridge. It can't be that tough to figure out if the issue is "driving" the headphones or frequency response due to impedance issues. I am sure that we don't "need" 6 amps for 6 headphones if music is our final goal.
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Post by stanga on Nov 4, 2014 23:09:22 GMT
Did Stan ever get a can amp off the ground? Nothing that I read here sounded like alternative, product development or a business plan........ Hi guys, just to update you on this new headphone amp of mine. I managed to get it off the ground, and with a bit of luck it will be ready as a commercial product by the end of the month. I am busy right now waiting for the silk screen printers to complete the front and rear panel printing. The thread was a bit slow here, so I put it on another forum, where I got enough encouragement to just go ahead and build a prototype. After that I invited guys round from various forums to come and listen and give me some input. The outcome was positive enough for me to risk building a small production run for now. Some of you might know me as StanleyB on some forums.
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jc
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Post by jc on Nov 5, 2014 16:51:54 GMT
Any links to said information?
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Post by stanga on Nov 5, 2014 18:00:41 GMT
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Post by Deleted on Nov 5, 2014 21:38:08 GMT
Stanley Without any basic technical information posted here , unfortunately it comes across more as an advertisement. One shouldn't need to link to another forum and spend heaps of time reading through a thread with > 10 pages. I gave up after reading numerous suggestions about a suitable name, and the first basic subjective report from somebody else where noise obscured low level detail, presumably because it wasn't enclosed in a suitable metal case. I got the impression too, that perhaps the suggested price was a little too optimistic for a HA with such claimed performance ? To get such claimed performance would imply a little more technical finesse than average, when compared with products from Graham Slee etc. Perhaps you are just testing the waters ?
Regards Alex
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Post by freddypipsqueek on Nov 5, 2014 23:19:27 GMT
I think it probably is a bit of an advertisement however Stanley Beresford has a very good pedigree (particularly the Caiman DAC - www.homehifi.co.uk/S2/home.htm) and I'm sure the finished article will be well worth looking at, and listening too, and be a welcome option to the HA's already available.
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Post by stanga on Nov 6, 2014 7:59:44 GMT
Stanley Without any basic technical information posted here , unfortunately it comes across more as an advertisement. One shouldn't need to link to another forum and spend heaps of time reading through a thread with > 10 pages. I gave up after reading numerous suggestions about a suitable name, and the first basic subjective report from somebody else where noise obscured low level detail, presumably because it wasn't enclosed in a suitable metal case. I got the impression too, that perhaps the suggested price was a little too optimistic for a HA with such claimed performance ? To get such claimed performance would imply a little more technical finesse than average, when compared with products from Graham Slee etc. Perhaps you are just testing the waters ?
Regards Alex
I am disappointed to see these suggestions that it is a bit of advertisement. I was asked for a link, which I provided. If I wasn't asked for one I would not have given any. Damn if you do provide a link, damn if you don't it seems. The idea for the headphone amp started in a thread here. And as I already wrote just above your comments, I built a prototype on a PCB and a couple of forum guys came round to listen to it and offer advise etc. A few posted their comments online after hearing the first prototype. I am at a loss why you are comparing the performance of a DIY prototype to a Graham Slee finished product, especially since you have not heard them side by side. Even talking about price comparisons are far fetched. Jumping the gun to attack me in order to come up smelling of roses? And one wonders why this forum is now avoided like the plague by many? With the kind of helpful comments like yours it is easy to see where it all stems from.
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Deleted
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Post by Deleted on Nov 6, 2014 9:44:21 GMT
If the thread was a little slow here, perhaps it was at least in part due to you not posting anything further here on the subject, and the fact that you didn't even respond to a post directed to you from 2nd March by alex30 ? Neither did you respond to Rowuk's query on 20th August until yesterday.
That's 8 months since your last posts on the subject, without apparently even checking out the thread that you started here. We would have welcomed further input from you in order to stimulate discussion, at least perhaps even that block diagram. BTW, I was suggesting that the price I saw quoted seemed quite optimistic on your part, and was unlikely to come in that low after manufacturing costs and margins. I didn't word that as well as I should have.
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Deleted
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Post by Deleted on Nov 6, 2014 15:46:42 GMT
Come on boys, settle down. Stanga was asked for the link so he replied with it. And threads stop, start and falter for all sorts of reasons.. usually because we have real lives to be getting on with. Things like paying bills, earning money.... ?
Stop being so hard on eachother.
Derek
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Post by Deleted on Nov 6, 2014 20:50:53 GMT
Come on boys, settle down. Stanga was asked for the link so he replied with it. And threads stop, start and falter for all sorts of reasons.. usually because we have real lives to be getting on with. Things like paying bills, earning money.... ? Stop being so hard on eachother. Derek Derek Just a simple link to a 15 page thread elsewhere (8 months later) when the product is about to be sold , is not very nice. At the very least we deserved a few posted highlights about the new design, perhaps a few technical details followed by the link to the other forum for those who wanted more in-depth information.( Even if only posted yesterday.) Alex
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