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I added some tweaking points for those who are not worried about their hearing, or want to bypass the Line out/headphone out switching point for a possible extra bit of detail. Of course, I do need to make sure that those mods would work ;).Quote:
Originally Posted by Puffin
Thanks for the info! This could end up at my order list. :thumbsup:Quote:
Originally Posted by StanleyB
Let me get this straight,
Its a dac that has an external psu but can run off a battery.(or is it powered by battery with external charger ie making it portable)
It has a headphone output (is this passive and requires an additional headphone amp or can I control the volume with my lap top)
No frills or extras...just a high quality dac not silly money..
Is that right.
Regards Tony.
http://www.homehifi.co.uk/aos/bp.jpg
The Bushmaster running off a 12V rechargeable battery pack that I bought off eBay.
Nice tidy design Stan :) Nice load of ground plane & neat track routing.
Why can't everyone do stuff like that? :rolleyes:
Looks superb! SMDs certainly have their advantages with regards to less in the way of stray reactances.
Intriguing, looks full of essential juiciness.
Andrew
Hi Stan,Quote:
Originally Posted by StanleyB
Which battery pack is it? I would like to try one on a Lepai Lp-2020A+ tripath amp. It needs 12v and about 2A min.
Keeping an eye on the new DAC for a stereo setup on my TV. Your new DAC a chipamp and a small pair of speakers looks just the job.
Regards
Chris
It is THIS one. Works very well with the TC-7520 and TC-7510 as well, but don't tell anyone ;). The main reason I don't recommend that as a power supply for those DACs is because they don't have a low power indicator facility built in.
Hi Stan
Will there be any opportunity to purchase the Bushmaster without a case or power supply? I am thinking that there must be others like me who would be quite happy to just have the board and incorporate it into our own case etc. and already have high quality power supplies.
thanks,
Val
I would be happy to find a dac that has no headphone input as I never use them and I would rather have the money spent on it used else where,like maybe upgrading the components.
Sorry,New here,so Im on a steep learning curve.Is it possible to have the bushmaster without a headphone input/board when its released?I would prefer maybe better other components instead.What do you think Stan?
Sure George. But a personalized DAC like that would cost you between £500 to £1000. We would design and build a different PCB and front panel for you and solder each individual component by hand. The bulk of the extra cost will be purely labour.
PM me a list of the components that you would like to be better and I'll PM you a more accurate cost. I'll need a non-refundable deposit as well :).
Ouch.....my middle name is obviously naive...never thought of all that.
I think Ill just wait for the bushmaster..
thanks for the reply though.
Don't let it worry you George, you will soon get used to the "Customer" not always being right!Quote:
Originally Posted by seoirse2002
Regards
Chris
I have had a lot of email correspondence on this whole headphone output thing. Part of the problem is tied to a different thread where a couple of people imply that DACs with inbuilt headphone circuits are inferior in some ways. Some readers of AoS put two and two together and concluded that a DAC without a headphone output is superior. It just goes to show how personal opinions can be seen as established technical facts.
Another point raised on those emails to me is whether the Bushmaster will be sold without a headphone output. The answer to that is NO. I shall be designing a DAC without headphone output however, but it will cost more than the Bushmaster since many of the parts are high end and expensive.
This sounds very interesting, more information needed :stalks:Quote:
Originally Posted by StanleyB
Val
Now that is of interest, although my souped up Caiman sounds so good there is no hurry :)Quote:
Originally Posted by StanleyB
Stanley,
guess I’m part of the “couple of people” you mention, so I would like to put some facts straight here. I always wrote explicitly that I’m not a hardware engineer, and I never claimed to describe facts about the quality of components used in DACs and headphone amplifiers.Quote:
Originally Posted by StanleyB
I expressed that according to my own personal listening experience the stand-alone DAC plus the stand-alone headphone amplifier I use now sound a lot better and pleasing than your DAC/headphone combinations known as (gatorized) Caiman and TC-7520. The headphones used for my A/B tests were the AKG K271, AKG K701, Beyerdynamic DT 990 and Beyerdynamic T1 (both models with an impedance of 600 Ω).
I encourage anyone who considers using high-end, high impedance headphones with any of your DAC/headphone combinations to compare its performance to the playback quality of an audio chain with a stand-alone, bare bones DAC and a stand-alone headphone amplifier and to develop an own opinion afterwards.
Nothing more I stated, but also nothing less.
Werner.
Quote:
Originally Posted by StanleyB
Yes I think I might be a guilty party to ;)Quote:
Originally Posted by Werner Berghofer
If you read what I posted though you'll see that at no point did I say that a DAC will be inferior with a built in headphone amp, though obviously it could be, it depends on the quality of build & components etc.
What I did say is that the headphone amplifiers built into DACs are generally a compromise ;) A DIL IC is not going to be happy to drive low impedance headphones, where as it may drive higher impedances fairly easily. However if the voltage supply is low then it may well not even do that very well.
Hense unless some purpose built headphone amp that doesn't involve the use of a DIL IC (or maybe just as a driver) is built then the headphone output will be a compromise & an external headphone amp would be a wholly better proposition :)
If people can't read properly it is hardly my fault...
As a perfect example of a no-compromise headphone amp take a look at this PDF file :) Low impedance, high impedance it just wouldn't matter... It'll sound the same & drive them all to full level ;)
Definitely guilty along with Mark and Werner :)
It’s not so much a question of the Dac being inferior because of it having a headphone output, it’s that its likely that the headphone output is likely to be inferior to a stand alone dedicated headphone amp.
Cant see why anyone should have a problem with this. :scratch:
You haven't been keeping up to date with headphone amp design technology ;). The TI TPA6120 IC has been used in headphone circuits for many years now by companies like Benchmark in their DAC, and by many others in stand alone headphone amps. Other ICs are also available that can be used for headphone output circuits.Quote:
Originally Posted by Reid Malenfant
As for your point on voltage output: can you expand on this for the benefit of all the readers of AoS? Maybe you can make a simple list of what current and voltage is required from a headmp in order to produce the maximum permitted power output to drive headphones at various impedances?
Can you expand a bit on that in technical terms? How does the separate case and power supply contribute towards making a stand alone headamp sound better compared to a headamp that shares its casing and power supply with a DAC circuit?Quote:
Originally Posted by Welder
I'm not really interested in ICs :eyebrows: A headphone amplifier is going to supply low enough power to make it worthwhile using a discrete circuit in Class A. I don't see many ICs in tube headphone amps so why incorporate one into a solid state version if you want the best quality? :scratch:Quote:
Originally Posted by StanleyB
As for expanding on things, sure!
Beyer Dynamic manufacture a 600 ohm version of the DT990. This has a sensitivity of 96Db/mW & a power handling capacity of 100mW or 0.1W. This means it can reach peak levels of 116Db.
Now if you look as this little screen grab you'll notice the extraordinary sound levels possible with symphonic music...
Attachment 5695
Taken from http://www.soundadvice.info/thewholestory/san12.htm
So lets assume you are sitting 12m away from the orchestra ;) The sound will be approximately 12Db down on those figures as it drops by 6Db when the distance is doubled. That still gives peaks of over 120Db.
Now we aren't going to ask the headphones to do what they can't do so we'll take the peak value of 116Db which they can do...
0.1W x 600 ohms = 60. square root of 60 = 7.7459V RMS neaded to produce this. Peak voltage = 7.7459 x 1.414 = 10.95V PK. So the supply will need to be approximately +/- 15V DC allowing for component losses.
Now type 4 ohm headphone into google, you'll find there are quite a few ;)
As I mentioned previously I'd like a no compromise headphone amp that could drive any headphone to full volume... So lets just assume that these hypothetical 4 ohm headphones have the same 96Db sensitivity & the same maximum power handling. Ok I know it's not likely to be exactly the same but there is no point in sucking eggs...
0.1W x 4 = 0.4. square root of 0.4 = 0.6324V RMS needed to produce peak output. Now comes the interesting bit as I want a class A amp :eyebrows:
0.6324V RMS x 1.414 = 0.8943V Pk. current needed in a push pull class A amp is 0.8943 divided by 4 ohms = 0.223A. Divided by two again as it's push pull = 0.1118A.
Now as we want to drive any headphone from 4 to 600 ohm to full volume we need that +/- 15V supply & the 0.1118A current which works out at 3.353W dissipation per channel or a total of just under 7W both channels.
I don't see any IC being happy with that kind of power dissipation myself :D
Hope that's good enough for you Stan ;)
Now I know you may well come back & say the the EU has restricted the maximum sound level that is allowed to be produced by a set of headphones & thus you have your hands tied, but I'm not interested in what the EU says in all honesty :ner:
Thanks Mark, very thorough and informative. Just need to remember to turn the vol down on one of yours before switch on!
Regards
Chris
:lolsign:
So it is your prejudice against the use of an IC, rather than its current handling ability that you hold;). In a different topic you mentioned that the IC would run out of steam if asked to produce more than 40 or 50mA of current.Quote:
Originally Posted by Reid Malenfant
However, the 600 Ohms DT990 at 120dB only consumes about 18.5mA :scratch:.
I don't really care about using a 4 Ohms headphones on a headamp. That sort of low impedance is for speakers. It would also produce an SPL of 140dB from a 11Vpk line, which would of course wipe out one's eardrums in seconds.
If you take the far more popular and common 300 Ohms cans, then a 9Vpk signal will still be able to produce a 120dB SPL output, and a 32 Ohms can would be able to produce a 130dB SPL output. High enough to make you permanently deaf.
And at the end of the day the majority of headamps cater for the most common headphone impedances :),
If I want to live in a prefab then I'll use prefabricated parts yes.Quote:
Originally Posted by StanleyB
While I'm sure that they measure very well due to having loads of feedback to lower distortion, I'd rather build a discrete circuit that only requires a small amount of feedback to control things.
A triple emitter follower circuit biased into class A on it's own is likely to have about 0.1% distortion (-60Db) driving it's respective load. That's with no front end or voltage amplifier.
In the case of a headphone amp & the worst case 4 ohm load only a two stage output would be needed. That would produce less distortion than a triple. A few transistors making a circuit that gives say 25Db gain open loop & 15db gain closed loop would reduce that output stage distortion to miniscule levels. Yes more than the IC would give, but then it would be a heck of a lot more musical :)
Now while I can fully understand why people use ICs for DACs is pretty obvious & I'd do the same thing, but for something as simple as an amplifier I think there are better ways of going about things.
Sorry, I had to attend to the postman for a minute and today's dispatches.
Coming back to your point about the 120dB dynamic range of the orchestra: where are you going to get that extra 24dB out of the CD format :scratch:?
There are res formats Stan as I'm sure you are aware.
I don't think any orchestral music has that kind of dynamic range anyway, not whilst playing, so I fail to see what dynamic range has to do with anything?
If you'd have said peak to average ratio of volume of sound I think it would have made more sense. If you look back at that screen shot it shows about 25db peaks (not being silly & giving the 137Db peak figure) over the average content.
Stanley,
I don’t think that SPL (= sound pressure level, so that other non-techies may be able to fully understand what you’re talking about) is the most important criteria to evaluate the playback quality of a headphone amplifier. While of course a bicycle with an auxiliary engine may reach similar speeds (when driving downhill), there is no doubt that riding a fully equipped motorbike with enough horsepower reserve is much more fun – and more safe, in case the extra power needs to be available unexpectedly and immediately.Quote:
Originally Posted by StanleyB
When talking about low impedance headphones like the AKG K701 (62 Ω) or the AKG K271 (55 Ω) both you and I know that I’m not the only one who considers their sound rather thin, anemic and weak when they are used on the headphone socket of your Caiman or TC-7520. The moment these headphones are connected to a real headphone amplifier, they really start to shine and bloom, even if one of your DACs is used to feed the head amp.
Werner.
You should have addressed that to Mark. I didn't want to pull him up on the use of SPL as a measurement of a headamp, but replied nonetheless to his calculations.Quote:
Originally Posted by Werner Berghofer
Where did I do this? I simply said about driving the headphones to realistic levels on peaks when listening to symphonic music at a fairly realistic level most of the time.Quote:
Originally Posted by StanleyB
I can't see at any point I mentioned that a headphone amp has to produce X amount of SPL, that's down to the headphones & nothing to do with headphone amp other than being able to cleanly supply enough voltage & current to achieve it :)
So what were all those calculations of the headamp calculations all about? Was that not to drive the headphone to a certain sound pressure level in order to cover the dynamic range of an orchestra at 12m?
Stanley,
sorry for this, I stand corrected, but I see that Mark already has replied. However, I still miss an explanation from you why even headphones with far more popular and common impedances of 300 Ω or less sound better when driven by a stand-alone headphone amplifier.Quote:
Originally Posted by StanleyB
Now, I fully understand that your DACs are budget products which are targeted for different buyers, and I’m pretty aware of marketing speech, but I wouldn’t dare to claim:
“The new generations of high-end headphones have up to now only been able to operate properly on expensive stand-alone headphone amplifiers. The Caiman inbuilt headphone amplifier is designed to drive even the latest range of high-end headphones and reproduce musical detail that these new headphones are capable of.” (quoted from your website)
You see, last year I really tried hard to believe this was true. Then I found out that at least for me and my demands your statement is slightly exaggerated.
Werner.
If you go back & take a look you'll notice it was to supply the headphones with there full power capabilty. IE 600 ohms at 100mW in the case of the Beyer Dynamic DT990 (600 ohm version).
The calculations were about the voltage needed to fulfil that & the current needed to run a full class A push pull output stage into lower impedance headphones (in this case 4 ohms).
In other words a headphone amplifier that will drive any standard moving coil headphones without compromise in either current or voltage.
I'm surprised you'd need me to explain this to you Stan? I thought it was plainly obvious to an electronics engineer :confused:
The above two paragraphs are an example of what I was originally referring to when mentioning the fact that customers were asking for the removal of the headphone section on the Bushmaster. You are mixing a discussion about headphone circuit design and my DACs. This is what is giving many readers the impression that the headphone amp section on my DACs must be crap.Quote:
Originally Posted by Werner Berghofer
However, quite a few people have tried the headphone output of my DACs against stand alone headamps and were pleasantly surprised how good they were on most circumstances when stacked against the standalone headamps. Of course, using the K701 as a yard stick of performance is in itself questionable. The K701 is notoriously poor in its ability to reproduce bass properly. The cone tends to exhibit sound break up quite easily when driven with bass heavy audio. That observation has been made many times over by numerous K701 owners using a variety of DACs and headamps.
You consider 4 and 600 Ohms headphones standard?Quote:
Originally Posted by Reid Malenfant
I don't think you are quite getting my point Stan. I mentioned that If I built a headphone amplifier I'd design it to drive just about anything.Quote:
Originally Posted by StanleyB
I find it a bit silly to make something that will only work on more generally available stuff & then find you can't drive something properly just because it's non standard ;)
I'm talking about myself, what anyone else does is entirely up to themselves.
Nobody is condemning you for designing a headphone amp that can drive just about anything. But for the general commercial market it is not a practical option. Like everything else, products are designed for a particular level of use and options, not an all encompassing one. To wish otherwise only goes to show your total lack of knowledge on a commercial scale. The more options a product offer, the more expensive it is, and the more customers look for a product that does cover their needs without crippling them financially.Quote:
Originally Posted by Reid Malenfant
Thank you :) I also agree with your last sentence, though it does depend on what market you are aiming for of course. As I pointed out with the KSA5 though, some manufacturers do go the whole hog (though that thing is simply OTT).
Stan,
Please continue to design, build and sell products for normal people and as previously please do not take too much notice of those who seem to appear to just trying to make it harder to get *products* to market by constantly asking for an extra wibble or wobble widget.
Peter
And all I was asking was if it was possible to have the bushmaster without a headphone board,as,
A: I never,ever,use headphones and
B: Having limited funds I thought it would be cheaper,without the board and extra work involved,and if not cheaper,maybe using better other components instead. Sorry for my ignorance,but if Im buying my first DAC,and never use headphones,I see it as a waste of money to have a headphone board and would rather see the money spent elsewhere,where I would benefit from it.
All the facts and figures and graphs and tests etc. are all meaningless to me.
Ive been constantly told that a dac will make a great difference to what I like to do....listen to music...and having spent over 30years wearing headphones(I was a radio presenter) The last thing I want to do is wear them at home as well....so Im truly sorry Stan for opening this can of worms,but you see I didnt read any posts about headphone amps or the like as I couldent care less about them....
Based on what I can afford now to put my toe in the water with the DAC(S)
Stans DAC seems to be what I need and after a certain age there are frequencies that the human ear can no longer hear,so Im hoping the dac will make my music sound better.
Im not too much into wearing the emperors new clothes,but if it makes the improvement that everyones talking about Ill be very happy.Im already enjoying my music as I write this,so STAN,please hurry with the Bushmaster.
I cant wait to try it.
George,
be assured: it will make your music sound better, even much better. Be prepared to discover fine details, layers and textures of sound you might have never heard before.Quote:
Originally Posted by seoirse2002
Kind regards,
Werner.
So can I have a Bushie without a headphone but with a preamp bit?
:stalks: = :steam: = :lolsign:
Only joking Stan as it is Christmas.
Regards
Chris
From what I can gather the Bushmaster will suit me very well.
A head phone output that exceeds the ability of the caiman.....
A straight forward co-ax/optical input dac with no filters/displays/pre-amp.
Priced very reasonably.
I have on order a FIIO E10 that can be utilised as a spdif convertor, I dare say when the bushmaster becomes available I will treat myself to one.
It strikes me that Stan is very generous with help and information to the less technically minded like myself.
I look forward to trying one in my set up and posting my findings.
Tony.
I have not been paying attention recently, and have just tried to catch up.
Fascinating but for me disappointing. The lack of a variable output is for me a deal-breaker. I have no pre-amp I use my Caiman as a Dac-Pre, and it drives my Quad power amp very well.
I will continue to watch.
Where's my USB!
;)
Andrew
No USB either?Quote:
Originally Posted by AndrewR
Mind you, what will the price be?
looks a good price :)Quote:
Originally Posted by StanleyB
You can build a passive pre using an Alps Blue and top quality resistors, in a nice box, for £20-£40 depending on choice of parts. If the Bushmaster is that good, the lack of a variable output isn't really a problem.Quote:
Originally Posted by Labarum
I too use a Caiman as a pre for my Leaks.
Val