howie
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Post by howie on Dec 21, 2015 9:48:39 GMT
I think in general some amplifiers can have problems with low impedance cans because of the high current flow demand. Hiss is my main problem with some low impedance cans. Some of my low impedance cans never hiss, others do. It seems related to the sensitivity and frequency outputs of the can as well. Those with higher treble emphasis seem to hiss louder-I suppose that makes sense. Same for me Howard. Low impedance, which seems all the rage nowadays creates another problem. Noise!! I also feel that higher impedance headphones are a little quicker on the whole and give better start/stop information. Maybe that's just me. For home use, I'd rather use higher impedances if I'm honest. Maybe even the th900 would improve at a higher impedance?  I never had the Solstice at home here with the others to compare. I liked it (as I do all of them) a lot, but the Polaris is better than the Ember with low impedance because it has more options with input and output levels. Once you get it down to a reasonable gain, it's actually very quiet. I love it with the dt990 though. Very lively and controlled!! I wonder whether, for any future amps or mods to existing ones, it might be possible to adjust the output gain to a lower level, as with Polaris. Then maybe we could be rid of such hiss with most low impedance cans. |
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Rabbit
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Post by Rabbit on Dec 21, 2015 9:53:12 GMT
That's a shame about the micro. I felt that I should have got a powered 02 TBH. Makes more sense since it's not really well designed as a portable. That's why I originally got an e12.
Sorted out the noise issue with low impedance headphones that way and stuck to high impedance with the Ember. Also, with the Ember, a bigger control knob works well since it gives a slower response on the pot. Can't fit one onto the Polaris though because the case is contoured around the vol pot!
Yes, there are fixes Howard but then it's not so powerful for higher impedances if you make permanent changes to the resistors. The Polaris is actually pretty good with lower impedances though because it has more control over inputs and output gain. It's more malleable. The Ember uses high gain tubes and has less options with regards to gain and is also slightly more noise prone as well what with tubes as well as open frame. It's the nature of tube amps really but often overlooked because of the 'sound' of tubes.
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howie
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Post by howie on Dec 21, 2015 10:53:42 GMT
What I was thinking of was having the ability to move a jumper between High, Medium and Low output gain-exactly as in the Polaris. Maybe it's not feasible with tube amps. Space would be an issue I guess too.
However, like you Ian, applying variable resistance to the output works fine for me as well. I use that Sennheiser volume control we discussed earlier, the one with separate controls for the two channels, which also allows me to adjust the balance in poorly balanced recordings. Don't know what I would do without it now. Usually just a slight nudge is enough to remove any hiss.
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Post by musicman on Dec 22, 2015 15:00:41 GMT
I'm not sure about the gain options for the Ember, but I do remember a resistor being fitted in order to do this. I'm not sure which side of the tube the resistor goes because no matter what input gain you have, tube noise will be consistent. Frans can clarify that. Yes the gain module, or more correctly, attenuation module lowers the input signal. The reason for this is that the tube itself has a rather high gain. Reducing that gain (feedback) also lowers the added harmonics and thus the typical 'tubesound'. The gain of most tubes is a fair bit too high for DAC's with 1V, 2V or even higher output voltages and you would end up using only the first small part of the volpot. L-R tracking isn't the best down there ...  So ... to lower the overall gain (not the gain of the tube) the input attenuator lowers the input voltage. On Ember one the 'overall gain' can be set in 2 steps that are determined by resistors. If one wants more attenuation (= less overall gain) 2 resistors need to be changed. For Ember 2 the attenuation module can easily be changed to another one with more (or less) attenuation... a handy feature making it more 'configurable'. For noise this has no influence at all. The tube amplifier part behind the attenuator (and volpot) will not be influenced by the attenuator. The adapter idea works 100% but it also raises the output impedance which 'could' affect the sound of your headphone. Some it seems to affect more than others. For instance I found the Grados actually improve at high output impedance. So an adapter improves them in two ways; no noise and more mellow sounding. Other headphones don't react that much. You can either use a fixed adapter or one I used was a variable one which you listen on, with no music. Turn up the resistance until the noise has gone, then use the amp. That way, you're just using as much resistance as you need for the headphone. That is also different for each headphone. Not ideal, but at least the hiss goes. I'd stick with higher impedance headphones with it though. I also use the adapter with cheap, crappy digital radios that have amplifier sections in them that hiss like snakes. Techboy, it might make more sense to try an adapter first before doing anything permanent. You might find with some headphones that the value of resistor is a bit critical and the last thing you want is to have an amp that loses its punch. If I increase the adapter, that can be the effect that it gives. It is not difficult to make an output adapter that lowers the output voltage (and thus lowers the gain and noise) and still keep a rather low output resistance. This low output resistance is a MUST for most (but not all) IEM's and high sensitivity (often low impedance) headphones. The recipy for one is HEREEven do-able for beginners to soldering. I suggested to Jeremy that he should be making them so the waaaayyyy to powerful (and noisy tube) amps can also be used safely and noise free on IEM's and sensitive headphones. So far he didn't have time to make something nice for it but think it would be a useful addition. I would have to disagree your statement that Jeremy that he should be making them so the waaaayyyy to powerful (and noisy tube) amps can also be used safely and noise free on IEM's and sensitive headphones. After all is said and done, this product is a headphone amplifier. It can be used with IEM's I have done it myself, safely, baring in mind that it is more than the iem could handle should I be dumb enough to go full gain at the vol pot. I don't do that with headphones either. The adapter FOR iem's is a better idea, unless you want to reverse engineer it and make it and iem amp, with an optional amplification module. I like it like it is, don't mess with success! |
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Deleted
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Post by Deleted on Dec 22, 2015 15:50:50 GMT
I think you've perhaps misinterpreted Frans' last comment (assuming that's what you were referring to? - if not ignore me). He's previously spoken to Jeremy about Garage1217 making an impedance adapter so folk can buy one. Believe it is on the 'to do' list but not yet made it to the top. I don't think there is any desire to 'neuter' the Ember  |
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Rabbit
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Post by Rabbit on Dec 22, 2015 17:54:59 GMT
Well, IMO. It's not a great match to use an iem with tubes. Tubes tend to be better with headphones that require more voltage to drive them. That's not saying that it doesn't work though. I've also used an iem from it but it's not great.
My th900 is only slightly higher than an iem and that works as well, but I do get noise from most of the tubes that I have. Nothing at all with higher impedances though.
I don't think anyone would want to make a tube amp match an iem really. Most people wouldn't be listening at home with an iem, but low impedance headphones are all over the place nowadays, so it is something to consider I think, before buying an Ember as well as any other tube amp.
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solderdude
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Post by solderdude on Dec 23, 2015 10:33:47 GMT
I wonder whether, for any future amps or mods to existing ones, it might be possible to adjust the output gain to a lower level, as with Polaris. Then maybe we could be rid of such hiss with most low impedance cans. I just happened to 'discuss' this topic with Jeremy 2 days ago. MAYBE the future Ember-II revision could have an extra 3.5mm output jack on the front with a built-in (output) attenuator so all sensitive (high and low impedance) headphones can be connected safely and noise free from Ember-2.1. BUT it is also possible that Jeremy decides to offer attenuators as an accessory. |
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oldson
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Post by oldson on Dec 23, 2015 19:49:35 GMT
 these sorted my hiss with the d7000/Ember. the top adapter is 60 ohm and the lower one 120 ohm |
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Post by techboy on Dec 24, 2015 5:58:25 GMT
Where can I buy something like above old son?
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oldson
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Post by oldson on Dec 24, 2015 16:01:45 GMT
Where can I buy something like above old son? i got these from Moon audio www.moon-audio.com/they no longer keep them ready made in stock, but will make to order if you contact them with requirements. to be honest , shipping would make it expensive. if you could make one as per Frans' a few posts back, that would be a fraction of the cost. |
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Post by techboy on Dec 24, 2015 17:24:40 GMT
How much did they cost from Moon Audio? Can't find on their website. I am certainly not looking to spend a 100 odd bucks on that adapter.
Also, you said 60 ohm and 120 ohm. Doesn't that screw up the sound?
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Rabbit
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Post by Rabbit on Dec 24, 2015 18:30:28 GMT
How much did they cost from Moon Audio? Can't find on their website. I am certainly not looking to spend a 100 odd bucks on that adapter. Also, you said 60 ohm and 120 ohm. Doesn't that screw up the sound? 'They no longer keep them ready made in stock, but will make to order if you contact them with requirements.' 'To be honest, shipping would make it expensive.' The issue of output impedance was talked about earlier in this thread, but I think that this one might have been an adapter not just added resistance. |
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oldson
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Post by oldson on Dec 28, 2015 18:40:11 GMT
How much did they cost from Moon Audio? Can't find on their website. I am certainly not looking to spend a 100 odd bucks on that adapter. Also, you said 60 ohm and 120 ohm. Doesn't that screw up the sound? it did not, not to my ears. i used these for my sensitive d7000, now sold. |
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Post by musicman on Jan 9, 2016 2:14:11 GMT
Just traded a pair of my Senn 650's for a pair of Nad Visio hp 50's and even though they are only 32 ohm they sound very nice with the Ember. Nad's will be great for travel, fold nice and flat
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Post by husafreak on Jan 10, 2016 1:27:40 GMT
Too cool, I recently purchased a set of NAD HP50's to compliment my HD600's and of course an Ember II as well. Could you tell me what settings you liked, for either of those phones? Making adjustments to this amp and rolling tubes is going to be my new hobby for a while... Jeremy suggested a 6n6p tube to get me started.
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