Rabbit
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Post by Rabbit on Jun 2, 2013 7:15:16 GMT
I'd be surprised if you got anywhere near 1.5W Simon. The X-Cans are around 0.5W I believe and they're considered powerful.
Is there a volume warning with Pandas then Frans? It's capable of more volume?
Simon, on your Panda, do you get a very low level hum from one side? Mine has always given out a tiny hum which once I noticed, I stopped using it. Like a transformer hum. I wonder whether an external supply would have been better for them.
The damned thing is so heavy, I can't be bothered to send it to a hospital. I have too many others that don't hum!!
At the time, when I mentioned it, a few people said they had it.
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solderdude
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Post by solderdude on Jun 2, 2013 8:40:09 GMT
Ember and Xcans V2 will have similar output powers (1.3 W) when the Ember Rout is set to 35 Ohm and a 50 Ohm load is applied.
They also have the same output resistance in that case so are exactly equally 'dangerous'.
The Ember will put out 1.5W when set to 0.1 Ohm output R a whopping 0.6 dB louder.
The Panda will be able to deliver 1.2W into 50 Ohm with a 10R out and about 1.6W with a 0 Ohm output R.
So the difference in SPL between a 10 Ohm and 0 Ohm will be 1.2dB.
The 'AK' class A headphone amp (which is inspired by the Silicon Chip amplifier design with some changes) will be capable of delivering 3W into 50 Ohm headphones (not in class A anymore) when no output resistors are fitted.
With a 10 Ohm out it will reach about 2.3W
With the recommended 68 Ohm Rout, however, this is lowered to 0.6W
The Ember (in 120 Ohm setting) will give out 0.4W
The difference between the lowest power ones (X cans V2) with 1.3W and Panda 1.2W as well as 1.5W of the Ember is small (negligible).
So all these amps are equally capable of destroying headphones as well as hearing.
I guess it is up to the user to be the judge of how loud they should play.
After all we are not the loudness Police nor European legislators nor kids that need protection from Ipods (but obviously not Disco's and concerts)
How loud you play ultimately is in the wrist (volume control) and common sense all people that buy/use these amps have.
Since all will be hifi lovers conscious of their ears I reckon they are 'safe' for us to use.
There is little to no difference between 1.2W and 1.6W (just 1.2dB)
For a doubling of perceived loudness (10dB) 12W is needed to play half as loud 0.12W is enough.
There is no reason NOT to have plenty headroom as you do not NEED to use it but can if you want to.
It's what all of the mentioned amps have been designed for.
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Rabbit
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Post by Rabbit on Jun 2, 2013 8:58:46 GMT
Actually, I know it's a mathematical thing, Frans, but power into different headphones is very complex for many people.
Getting your head around the idea that one powerful amp is not so powerful into say a low impedance headphone since they need more current and some work better into higher impedance because of voltage needed. It gets very confusing for many people, which is why Simon is asking about the Panda and trying to compare output power.
I remember seeing a small write up by you somewhere concerning power output, set out in a really concise way concerning the Sunrise, Horizon and Ember.
It may have been called 'Why another amp?' I thought it was excellent since it gave out cold hard numbers for power outputs at different impedances and really highlighted the need to match the headphone with the amp in order to offer maximimum headroom.
I'll have a look for it. It was a really good set of information. I think it included how to calculate power output as well.
You probably remember the surprise I got when I connected the K601 to the Zigis. I commented about the amount of power and authority that it gace to the K601 (which I had considered difficult to drive) and you explained that it was the matching and that 120 ohms was the ideal load for the Zigis.
That's the bit that many can't get their heads around!!
For the Ember:
Headphone Impedance Output Resistance available on amp 1r 35r 120r
32 ohms 1W 920mW 290mW
50 ohms 1.5W 1.3W 380mW
64 ohms 1.8W 1.4W 425mW
120 ohms 1.8W 1.1W 450mW
300 ohms 730mW 580mW 370mW
600 ohms 180mW 33mW 260mW
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Deleted
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Post by Deleted on Jun 2, 2013 16:04:56 GMT
my gut feeling is i will prefer the sound signature of the lcd-2 over the he-6.
the only things that would have been of concern to me regarding the audeze are
1)some reports of poor build quality..... i believe this was sorted on r2.
and 2) the reported lack of high end detail...... which can be sorted by one of Frans' filters.
the so called "crammed soundstage" should not be a problem for me as i will be coming from closed cans.
so the lcd-2 should be less hassle (on the amp front) and its a couple of hundred quid cheaper too.
its just a pain that i will have to wait probably until mid august before i can get them.
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Deleted
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Post by Deleted on Jun 2, 2013 16:13:45 GMT
I'd be surprised if you got anywhere near 1.5W Simon. The X-Cans are around 0.5W I believe and they're considered powerful. Is there a volume warning with Pandas then Frans? It's capable of more volume? Simon, on your Panda, do you get a very low level hum from one side? Mine has always given out a tiny hum which once I noticed, I stopped using it. Like a transformer hum. I wonder whether an external supply would have been better for them. The damned thing is so heavy, I can't be bothered to send it to a hospital. I have too many others that don't hum!! At the time, when I mentioned it, a few people said they had it. to me my panda sounds great with my denons, have not heard the hum you mention. if i max out the volume (nothing playing, of course) there is just a very slight hiss. i am sure i will buy another amp at some point after i have my orthos. i fancy building something myself, hence my interest in the Ember. just not sure if i am upto it (soldering, shakey hands and fading eyesight  ) |
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solderdude
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Post by solderdude on Jun 5, 2013 19:08:31 GMT
a project Ember and Starlight will be coming over to Europe for a tour.
Those that want to audition one can make this known.
The only costs (a hobby is costly) will be forwarding the amp after a while to the next person or back to it's home (i.e. me)
I noticed some Scandinavian friends might also be interested.
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Crispy
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Post by Crispy on Jun 6, 2013 19:10:44 GMT
The one that is touring is ready built but at Jeremy's website both a kit and ready made version is available. In all cases the SMD output devices have been pre-soldered. Frans, I have just read this thread and looked at Jeremy's website, the amp sure looks good and hopefully it will live up to expectations sound wise. I downloaded the build manual just to see if I might be able tackle a kit build - me being a novice.  I noticed one very small mistake in the manual - page two: "Tubes / Valves that can be used in project Sunrise" Needs to be altered to Ember Only a minor error that is easily overlooked - you only see what you want to see  |
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Post by jhelms on Jun 6, 2013 19:23:42 GMT
Good catch  Hard to see the forest for the trees sometimes |
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solderdude
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Post by solderdude on Jun 8, 2013 22:29:38 GMT
What did surprise me was the supply you sent to me with the Horizon really isn't bad and to look at it, you'd think there's nothing much there. It's perfectly adequate for the job..... so something similar? It's a decent SMPS with not too much common mode garbage and despite of it's size and weight is quite powerful. The lin supply will be at least as powerful but have much lower common mode nasties which may be needed in some situations. |
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Post by dragnet32 on Jun 11, 2013 3:02:41 GMT
I am contemplating purchase of the Ember but question: on Garage17 website, under Project Ember user manual - operation guide - it says there may be 'some channel imbalance below 9 o'clock on the volume this is normal & solution seems to be to adjust the source output level so can use with volume setting of 9 o'clock or greater'. First, how do you adjust the source volume when you are using RCA line out from a CD player?? Also, it has been my experience with portable amplifers that slight increases in volume can be more than my ears can take. I suspect that it depends on the gain jumpers and whether you are using low or high impedance headphones. In a previous comment on this thread, Rabbit said he was using the Horizon (not Ember) with Beyer DT990 and his volume level was at 8 o'clock. Thanks to anyone for info, I like to listen at relatively low volume levels but channel imbalance would be a problem.
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solderdude
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Post by solderdude on Jun 11, 2013 6:04:21 GMT
The reason for the possible imbalance (not all potmeters are created equal) is the physical size of the potmeter.
With small potmeters the tracking (difference between L and R channel) is bound to differ a bit.
When using a CDP you cannot adjust the output voltage but the gain of the amplifier can be altered by the jumpers.
If the gain is still too high AND you are always listening at the potmeter below 9 o'clock AND your potmeter has a noticeable imbalance you can always lower the gain of the amp even further by:
a: changing the value of a resistor
b: choosing a tube with lower gain
Portable amplifiers, more often than not, have linear volume controls as they are more or less intended as 'gain control' instead of volume control.
In these cases the potmeter reacts a lot from 0 to 30% setting and very little between 50% and 100%
The potmeter in Ember (etc) are log type and do not have this behavior.
The horizon didn't have the gain setting and because the gain of tubes that have no feedback is rather high we added the gain jumper.
Before ordering you can contact Jeremy and ask him to select the best possible potmeter (I know he tests each potmeter individually!) and lower the gain of the amp even further by changing the resistors.
Jeremy knows where to find me to get the proper values.
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Post by jhelms on Jun 11, 2013 15:12:18 GMT
All of our factory built amplifiers receive what we call A grade pots. I literally hand test them in batches of 100qty. Only excellent potentiometers make cut, the rest go to ebay, used for projects and so forth. In fact, only about 1/3 of all tested make this cut. All A grades match excellent down low. There is a threshold however generally between the lowest volume and just a few degrees of turn where even an A grade may have a slight imbalance. That only makes up about maybe 3-5% of the volpots actual range. Keep the amplifier in the low input gain default setting and I highly doubt you will ever want to listen in this range as it is close to zero.
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Rabbit
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Post by Rabbit on Jun 11, 2013 15:49:10 GMT
I don't listen that loud and so it can be a problem with some amps but it's negligible on the Horizon. I don't have any issues with imbalance down low. The DT990 is 250 ohms and I also use the T50 and T40 which do take some driving even at 50 ohms. I think it's more a question of matching the headphone and amp. Any imbalance must be really low down since I sometimes fade things up and down too.
Dragnet, most amps will have slight imbalances at the bottom end but a lot also depends on the sensitivity and impedance of your headphone. Some amps go down really smoothly; much smoother than users or even manufacturers say. What headphone are you going to be using with the Ember?
No issues with the Horizon pot. I wouldn't use a highly sensitive, low impedance headphone with it though since it has such a lot of power. I'm using an O2 for lower impedance, sensitive headphones and the Horizon for things that need more driving.
Once I try the Ember, I can let you know what it's like down there. It would be useful to know what headphone you're going to use though.
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Post by dragnet32 on Jun 11, 2013 17:26:05 GMT
I plan to use the HD650 with either Horizon or Ember, and am becoming interested in the DT990 as per your review comments! Dragnet. Lacey, Washington.
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Post by jhelms on Jun 11, 2013 17:40:20 GMT
I would recommend the 250ohm version of the DT990 if you plan to use an amplifier with them, both headphones work excellent with Ember. Unless you have abnormally high source voltage - output, you will not have any issues at low volume.
The little blurb is in the manual for the rare cases when someone with extremely efficient headphones (some iem's for example) want to attempt to listen by turning the volpot 1/8th from zero.
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)
Hard to see the forest for the trees sometimes