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Post by autiger on Nov 9, 2016 1:01:37 GMT -5
If you ever feel there is still not enough power, but don't want to go with the jumpers, you can open the unit and switch/change the resistors. Simple task but I can't imagine that you would need to do that. And I imagine voids the waranty.
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Post by leonski on Nov 9, 2016 3:22:59 GMT -5
The number of headphones on the market which would actually benefit from yet MORE power is vanishingly small. And many of them are 'high priced' Planar designs.
People who own such headphones sometimes even own headphone ONLY systems with some pretty pricey electronics along with headphones on the elite level.
OPPO, for example, makes 3 levels of planar headphones of which the least expensive goes for about 400$. Top line? Over a grand. But the top line is ALSO listed as very sensitive at OVER 100db @1mw.
Being 32ohms HELPs in regard to power delivery, maybe.
I wonder how BIG the resistors are in the amps attenuator? 1watt? 5watt? Wirewound? Just how much power are they expected to dissipate?
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Post by geebo on Nov 9, 2016 7:54:37 GMT -5
The number of headphones on the market which would actually benefit from yet MORE power is vanishingly small. And many of them are 'high priced' Planar designs. People who own such headphones sometimes even own headphone ONLY systems with some pretty pricey electronics along with headphones on the elite level. OPPO, for example, makes 3 levels of planar headphones of which the least expensive goes for about 400$. Top line? Over a grand. But the top line is ALSO listed as very sensitive at OVER 100db @1mw. Being 32ohms HELPs in regard to power delivery, maybe. I wonder how BIG the resistors are in the amps attenuator? 1watt? 5watt? Wirewound? Just how much power are they expected to dissipate? It depends on the resistance value. If it's high they won't have to dissipate much at all. |
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Post by kewlmunky on Nov 9, 2016 9:00:35 GMT -5
8.5 watts into 50 ohms sounds more than adequate to drive the He 6 (50 Ohms, 83.5 db sensitivity), and that's the good news. Headphone/Amp synergy is, however, not merely about power on tap, and that is the rub. I would reallylike to hear the impressions of someone who gets to try the He-6 on this unit. The mini-x A-100 was excellent for the Hifiman He-500, when the headphone is hooked up using speaker taps. Is the A-100 tuned the same way as the mini-x A-100? I almost want to get this newer unit to compare and see. My Carver M500T is definitely better with the HE-6 than my Gen 1 Mini-x, but I don't feel the Mini-x was a horrible pairing in any way. My friend has been interested in getting either buying my old Mini-x or getting this newer unit for his HE-500. If he gets the newer unit, I will definitely test it out and let you know what I think. |
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KeithL
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Post by KeithL on Nov 9, 2016 9:53:09 GMT -5
Exactly... they're 220 ohms (per channel). And they don't typically DISSIPATE much power at all. However, there are several different things going on here - and they're all cool. 1) The easiest one first. Some few planar headphones are VERY inefficient, and actually require three or four WATTS into 30 ohms or so to drive them. These are the ones you hear about people driving with "speaker amplifiers" - usually by building some sort of adapter cable that connects to the speaker terminals but has a headphone jack wired to it. Very few headphone amplifiers can drive them well, and they're not quite perfectly matched to speaker amps either, so they've always been a bit of a problem. The BasX A-100 will work VERY well with these models. (Remember that you will have to put on the internal jumpers - which also prevents you from doing it unless you really intend to. And also remember that putting this much power into normal headphones would be dangerous to the headphones and your ears.) 2) Really high impedance headphones (like many 300 Ohm and 600 Ohm Beyerdynamic models) require a lot of drive VOLTAGE to really sing. They're actually quite efficient, and don't draw much POWER, but you need enough voltage to drive them. Many headphone amplifiers have trouble with these simply because they don't put out that amount of voltage. (The reason is simply that they aren't designed to. It's not that it's difficult to design an amplifier that can run them well, it's simply that most headphone amplifiers are optimized to run "normal" headphones - which are usually between 30 Ohms and 50 Ohms; and those simply require different optimizations.) You could actually run headphones like these on the A-100 with the jumpers on or off. Most other amps would probably be too noisy to connect their speaker output directly to a pair of 600 Ohm Beyerdynamic cans, but the A-100 is very quiet, and very clean, so it works just fine that way. (However, you don't gain much by bypassing the resistor, so we don't really recommend doing so.) 3) The resistors also serve a very different purpose. In virtually all vintage equipment, the headphone output was derived by using resistors, like we do in the BasX A-100. Back in those days it was simply a matter of saving money; they didn't want to bother with a separate headphone amplifier. By using dropping resistors, the same amplifiers that you use for the speakers can run your headphones. The main drawback is that speaker amplifiers tend to be slightly noisier than good headphone amplifiers. That's not a problem with the A-100 because we've designed it to be really quiet. Another thing is that, by driving the headphones through a large value resistor, the impedance of the headphones is allowed to interact with signal. Most modern headphone amplifiers specifically aim to have a very low output impedance. This minimizes this interaction, and helps ensure that a given pair of headphones will sound very much the same with different headphone outputs and different headphone amplifiers. However, it is this variation that gives each headphone and amp combination its "distinctive personality", so wiping it away may not be a good thing after all. THIS is what contributes to the "great sound of vintage headphone outputs" that some audiophiles rave about so much (and we've brought it back). The resistors also serve to "even out" the level between various headphones. While there's a lot of variation between both the impedance and the efficiency of different models of headphones, in general lower impedance models tend to be more efficient. If you work out the math, by delivering a certain signal level through a large value resistor, lower impedance headphones end up getting less signal. As a result, with the resistor, when you unplug and plug in different headphones, you are more likely to end up with similar output levels. (You may be surprised to know that the "standard" for equipment back in the old days was for the headphone output to have a resistor..... often 120 or 220 Ohms.) Check out the output power the A-100 delivers into headphones of various impedances (with the resistors). You'll notice that it lines up VERY well with the actual needs of typical headphones. Remember that these are MAXIMUM OUTPUT CAPABILITIES; so don't worry about "too much power for your headphones". The number of headphones on the market which would actually benefit from yet MORE power is vanishingly small. And many of them are 'high priced' Planar designs. People who own such headphones sometimes even own headphone ONLY systems with some pretty pricey electronics along with headphones on the elite level. OPPO, for example, makes 3 levels of planar headphones of which the least expensive goes for about 400$. Top line? Over a grand. But the top line is ALSO listed as very sensitive at OVER 100db @1mw. Being 32ohms HELPs in regard to power delivery, maybe. I wonder how BIG the resistors are in the amps attenuator? 1watt? 5watt? Wirewound? Just how much power are they expected to dissipate? It depends on the resistance value. If it's high they won't have to dissipate much at all. |
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KeithL
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Post by KeithL on Nov 9, 2016 9:56:34 GMT -5
If you're curious, they're 5 watt and flameproof (but they won't ever get that warm).  Note that the Oppo phones are very efficient, AND they're pretty much the optimum impedance for most headphone amps, so they should be easy for any headphone amp to drive. Also, because planars are more or less resistive, they probably won't interact very much with different amps. Of course, quality headphones will always sound better if you drive them with a high quality amplifier.  The number of headphones on the market which would actually benefit from yet MORE power is vanishingly small. And many of them are 'high priced' Planar designs. People who own such headphones sometimes even own headphone ONLY systems with some pretty pricey electronics along with headphones on the elite level. OPPO, for example, makes 3 levels of planar headphones of which the least expensive goes for about 400$. Top line? Over a grand. But the top line is ALSO listed as very sensitive at OVER 100db @1mw. Being 32ohms HELPs in regard to power delivery, maybe. I wonder how BIG the resistors are in the amps attenuator? 1watt? 5watt? Wirewound? Just how much power are they expected to dissipate? |
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Post by sahmen on Nov 9, 2016 10:05:34 GMT -5
If he gets the newer unit, I will definitely test it out and let you know what I think. kewlmunky: I'd really appreciate that. |
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Post by leonski on Nov 9, 2016 15:59:42 GMT -5
In regards to Keith's point #1, above, it should be possible to use an IMPEDANCE MATCHING transformer to even out the load to the amp. This is a tried and true technique. I dont' know that SS amps have a problem with 32 ohms, but may start getting weird as impedance RISES. I wonder what happens as the impedance driven rises to some fraction of the INPUT impedance of the final amp stage? www.diyaudio.com/forums/pass-labs/134249-impedance-matching-transformer.htmlMy original and immediately discarded thought was to use a rotary attenuator, the Stepped Fixed Resistor type for headphone matching, But they are typically 1/4watt resistors and not available in such a low value with any resolution, anyway. I'd still think the QUIETEST amp rules. |
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Post by Dan Laufman on Nov 9, 2016 16:32:04 GMT -5
The A-100 amplifier is very happy driving high impedance loads... no worries.
Try it, you'll like it!
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Lonnie
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Post by Lonnie on Nov 9, 2016 16:49:30 GMT -5
In regards to Keith's point #1, above, it should be possible to use an IMPEDANCE MATCHING transformer to even out the load to the amp. This is a tried and true technique. I dont' know that SS amps have a problem with 32 ohms, but may start getting weird as impedance RISES. I wonder what happens as the impedance driven rises to some fraction of the INPUT impedance of the final amp stage? www.diyaudio.com/forums/pass-labs/134249-impedance-matching-transformer.htmlMy original and immediately discarded thought was to use a rotary attenuator, the Stepped Fixed Resistor type for headphone matching, But they are typically 1/4watt resistors and not available in such a low value with any resolution, anyway. I'd still think the QUIETEST amp rules. All of our amp designs are load invariant. Basically what that means is the amp doesn't care if the load is 4 ohms or 4 million ohms. The frequency response, THD, S/N etc. will all remain the same. The only thing that will change is the output power as it relates to the load impedance. So high impedance loads, not a problem. Lonnie |
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KeithL
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Post by KeithL on Nov 10, 2016 12:23:12 GMT -5
I just want to .... amplify.... a little bit on what Dan and Lonnie said.  Matching transformers are generally used when you have an amplifier that is designed to work optimally with a specific load impedance. Tube amplifiers use output transformers to match the load impedance of typical modern speakers (4 to 8 Ohms) to the load preferred by tubes (different for each tube number, but on the order of a few thousand Ohms). And some early solid state amps with limited power used transformers to allow them to deliver their maximum power into speakers of differing impedances (an amp that's rated at 50 watts into 8 Ohms and 90 watts into 4 Ohms can deliver 90 watts into 8 Ohms with a matching transformer). In the old days, transformers were also used to step up the voltage of the audio signal for PA systems where very long wire runs were required. However, since transformers themselves introduce added distortion, and are heavy and expensive, and "power is now cheap", they are rarely used in modern solid state amplifiers. In the past transformers were also often used with microphone preamps for a similar reason. With the minuscule signal levels delivered by microphones, the best signal-to-noise ratio can be achieved by ensuring a near-perfect transfer of power between the microphone and the input of the preamp, which in turn is achieved by matching the impedance of the microphone to that of the preamp. (Modern solid state preamps are quiet enough that this is no longer a significant issue, but there are other benefits of using transformers with microphones, and the tiny transformers required have fewer drawbacks that high powered ones.) And you'll also hear impedance matching talked about with radio equipment, However, when you're using an amplifier like the A-100 (which can deliver 50 watts into an 8 Ohm load), with a headphone that requires somewhere between a few watts and a few milliwatts, none of these issues matters. (And while, historically, tube amplifiers had problems operating into high impedance or open loads, solid state amps like the A-100 don't mind at all.) The output impedance of the BasX A-100 is actually very low - on the order of a very small fraction of one Ohm. This is the output impedance your headphones will "see" when the internal jumper is used to bypass the resistors. However, when you operate it with the resistor in place, the source impedance seen by your headphones is almost entirely the value of the resistor. Electrically, when you put a resistor in series with the output of an amplifier, the overall "source impedance" becomes the combination of the output impedance of the amplifier and the value of the resistor. (With a voltage divider it becomes somewhat more complicated.) In this case, when you add the resistance of the 220 Ohm dropping resistor to the negligible output impedance of the A-100, the overall source impedance (output impedance) is 220 Ohms. And it is this source impedance that interacts with the impedance of the headphones to create a "sonic signature" unique to the combination. (The output of the A-100 remains the same, but the voltage that reaches the drivers in the headphones is altered by how the headphones interact with the resistor along the way.) Any additional attenuator or matching transformer that you might put between the output of the A-100 and your headphones will further alter that situation. (But probably not for the better - since we've planned it the way it is pretty carefully.) In regards to Keith's point #1, above, it should be possible to use an IMPEDANCE MATCHING transformer to even out the load to the amp. This is a tried and true technique. I dont' know that SS amps have a problem with 32 ohms, but may start getting weird as impedance RISES. I wonder what happens as the impedance driven rises to some fraction of the INPUT impedance of the final amp stage? www.diyaudio.com/forums/pass-labs/134249-impedance-matching-transformer.htmlMy original and immediately discarded thought was to use a rotary attenuator, the Stepped Fixed Resistor type for headphone matching, But they are typically 1/4watt resistors and not available in such a low value with any resolution, anyway. I'd still think the QUIETEST amp rules. |
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Post by monkumonku on Nov 10, 2016 13:26:44 GMT -5
Just ordered one to use as a headphone amp, hopefully it will ship out today!  |
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Post by garbulky on Nov 10, 2016 13:29:38 GMT -5
Just ordered one to use as a headphone amp, hopefully it will ship out today! Do let me know what you think! Oh and WHEN DID YOU GET THE HD-800?!?!? Tell me all about it please! |
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Post by monkumonku on Nov 10, 2016 13:36:52 GMT -5
Just ordered one to use as a headphone amp, hopefully it will ship out today! Do let me know what you think! Oh and WHEN DID YOU GET THE HD-800?!?!? Tell me all about it please! I'll definitely post a review. LC's and Keith's comments were enough to make me want to give it a try. I got the HD-800's earlier this year around March or April. They're my favorites of all the headphones I've had (Grado 80, 325i, Senn 580, 650, AKG 701, Oppo PM-3 and Beyerdynamic 880). To me they sound very balanced with lots of detail, not at all fatiguing either ear-wise or comfort wise. Some complain about a lack of bass but I really like them and think the balance is fine - to me they sound natural. They do need a lot of power. The 650's are warmer in sound, the 800's brighter and more "open" sounding. I like them both but the 800's are definitely preferred. |
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Post by garbulky on Nov 10, 2016 13:41:15 GMT -5
Do let me know what you think! Oh and WHEN DID YOU GET THE HD-800?!?!? Tell me all about it please! I'll definitely post a review. LC's and Keith's comments were enough to make me want to give it a try. I got the HD-800's earlier this year around March or April. They're my favorites of all the headphones I've had (Grado 80, 325i, Senn 580, 650, AKG 701, Oppo PM-3 and Beyerdynamic 880). To me they sound very balanced with lots of detail, not at all fatiguing either ear-wise or comfort wise. Some complain about a lack of bass but I really like them and think the balance is fine - to me they sound natural. They do need a lot of power. The 650's are warmer in sound, the 800's brighter and more "open" sounding. I like them both but the 800's are definitely preferred. Very nice! Currently which amp do you like with the 800? The Lyr? |
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Post by monkumonku on Nov 10, 2016 13:52:46 GMT -5
I'll definitely post a review. LC's and Keith's comments were enough to make me want to give it a try. I got the HD-800's earlier this year around March or April. They're my favorites of all the headphones I've had (Grado 80, 325i, Senn 580, 650, AKG 701, Oppo PM-3 and Beyerdynamic 880). To me they sound very balanced with lots of detail, not at all fatiguing either ear-wise or comfort wise. Some complain about a lack of bass but I really like them and think the balance is fine - to me they sound natural. They do need a lot of power. The 650's are warmer in sound, the 800's brighter and more "open" sounding. I like them both but the 800's are definitely preferred. Very nice! Currently which amp do you like with the 800? The Lyr? I'm using the Oppo HA-1. I also have a Valhalla 2 that works well with it but what I did was get a balanced cable for the 800 so I could use it with the balanced headphone output of the HA-1. Based on LC's favorable report of the A-100 and how it compares nicely with the HA-1 in terms of ability to control his HD600's, curiosity got the better of me and I ordered an A-100 to try out. You may be seeing an HA-1 in the Emporium soon if it turns out to be as good as what the comments have been so far. |
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LCSeminole
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Post by LCSeminole on Nov 10, 2016 16:50:58 GMT -5
Very nice! Currently which amp do you like with the 800? The Lyr? I'm using the Oppo HA-1. I also have a Valhalla 2 that works well with it but what I did was get a balanced cable for the 800 so I could use it with the balanced headphone output of the HA-1. Based on LC's favorable report of the A-100 and how it compares nicely with the HA-1 in terms of ability to control his HD600's, curiosity got the better of me and I ordered an A-100 to try out. You may be seeing an HA-1 in the Emporium soon if it turns out to be as good as what the comments have been so far. .............like you needed an excuse to try the A-100 out! |
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Post by srpawski on Nov 10, 2016 19:26:16 GMT -5
Ok, so now I have a question, Not really thread related, but since most all of the heavy hitters on this forum have responded to this thread and are likely to see my reply, I'm gonna let er rip.
Insurance-wise, do you guys carry a separate rider on insuring just your electronics above and beyond the standard content insured value of your home so you have an extra buffer to ensure that you can replace your goods at market value? Just curious, as it seems that it could be something serious to think about.
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Post by geebo on Nov 10, 2016 20:49:18 GMT -5
Ok, so now I have a question, Not really thread related, but since most all of the heavy hitters on this forum have responded to this thread and are likely to see my reply, I'm gonna let er rip. Insurance-wise, do you guys carry a separate rider on insuring just your electronics above and beyond the standard content insured value of your home so you have an extra buffer to ensure that you can replace your goods at market value? Just curious, as it seems that it could be something serious to think about. That would be a really good topic for a new thread. It really deserves it's own. |
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Post by novisnick on Nov 10, 2016 21:03:29 GMT -5
Ok, so now I have a question, Not really thread related, but since most all of the heavy hitters on this forum have responded to this thread and are likely to see my reply, I'm gonna let er rip. Insurance-wise, do you guys carry a separate rider on insuring just your electronics above and beyond the standard content insured value of your home so you have an extra buffer to ensure that you can replace your goods at market value? Just curious, as it seems that it could be something serious to think about. That would be a really good topic for a new thread. It really deserves it's own. I concur! |
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