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Post by emodarlington on Aug 1, 2017 13:28:08 GMT -5
Guys,
I wonder if someone can tell me for sure whether the BasX amplifiers have triple darlington output stages or not.
I have already posted on the BasX section but no one has replied yet. Maybe here it gets the necessary visibility in order for someone, who can actually answer the question, to chime in.
I have been thinking about purchase one of these amplifiers and I really would like to know that, since Emotiva used to market their former X-Series amps explicitly saying "Output topology: discrete triple Darlington with On Semi output devices", whereas now they just say "short signal path Class A/B output circuits", regardless of the series.
Much appreciated!
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klinemj
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Post by klinemj on Aug 1, 2017 15:20:25 GMT -5
Guys,
I wonder if someone can tell me for sure whether the BasX amplifiers have triple darlington output stages or not.
I have already posted on the BasX section but no one has replied yet. Maybe here it gets the necessary visibility in order for someone, who can actually answer the question, to chime in.
I have been thinking about purchase one of these amplifiers and I really would like to know that, since Emotiva used to market their former X-Series amps explicitly saying "Output topology: discrete triple Darlington with On Semi output devices", whereas now they just say "short signal path Class A/B output circuits", regardless of the series.
Much appreciated! If you call them, they will likely tell you. Mark
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Post by emodarlington on Aug 1, 2017 16:29:26 GMT -5
If you call them, they will likely tell you. Mark Hi Mark, Thank you for your reply. I have already emailed them but no luck either. I'm based overseas. I'm sure that someone here more technically inclined can help me. It's intriguing why they drop the "triple darlington" designation and replaced it for "Class A/B output amplifier". I'm hopping that it's only a question of marketing. If I decide to go with one of these BasX amps I won't be able to listen to it before purchase. Hence, the reason why this question interests me so much!
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klinemj
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Post by klinemj on Aug 1, 2017 16:44:18 GMT -5
If you call them, they will likely tell you. Mark Hi Mark, Thank you for your reply. I have already emailed them but no luck either. I'm based overseas. I'm sure that someone here more technically inclined can help me. It's intriguing why they drop the "triple darlington" designation and replaced it for "Class A/B output amplifier". I'm hopping that it's only a question of marketing. If I decide to go with one of these BasX amps I won't be able to listen to it before purchase. Hence, the reason why this question interests me so much! I understand the overseas part...they are known to be most responsive by phone, though. In any case - give your question is sound - maybe instead of sweating the details on what all the various parts are - how about asking people to compare their sound to something known to you. I suspect what people are going to say is that the Emotiva amps all tend to have a similar sound, and the main difference between them is what your power needs are. Speaking of that...what are your power needs? What are you driving? Mostly music or mostly video? How loud do you tend to listen? Mark
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hemster
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Post by hemster on Aug 1, 2017 19:23:17 GMT -5
If you call them, they will likely tell you. Mark Hi Mark, Thank you for your reply. I have already emailed them but no luck either. I'm based overseas. I'm sure that someone here more technically inclined can help me. It's intriguing why they drop the "triple darlington" designation and replaced it for "Class A/B output amplifier". I'm hopping that it's only a question of marketing. If I decide to go with one of these BasX amps I won't be able to listen to it before purchase. Hence, the reason why this question interests me so much! Compared to bipolar transistors, MOSFETs have a much lower ON resistance which typically results in a little better efficiency at higher power levels. The Darlington design was common in the 1990s but now has been largely superseded by MOSFETs. Also, compared to the 3rd order harmonics of bipolar transistors, MOSFETs produce 2nd order harmonic distortion so they sound a little more tube like when driven hard. Hope this helps, Hemz
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Post by emodarlington on Aug 1, 2017 19:42:42 GMT -5
Fairly sensitive (90 dB) Monitor Audio floorstanders. Two-channel music and video. As for loudness... it depends on the music type! That's precisely my point Mark... depending on the amp's output stage topology, all those questions may be or maybe not relevant, as far as sheer power from the amp is concerned. Can someone please give me a definitive answer?
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hemster
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Post by hemster on Aug 1, 2017 19:57:38 GMT -5
Fairly sensitive (90 dB) Monitor Audio floorstanders. Two-channel music and video. As for loudness... it depends on the music type! That's precisely my point Mark... depending on the amp's output stage topology, all those questions may be or maybe not relevant, as far as sheer power from the amp is concerned. Can someone please give me a definitive answer? I know you're abroad but did you email them?
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Post by emodarlington on Aug 1, 2017 20:00:08 GMT -5
Compared to bipolar transistors, MOSFETs have a much lower ON resistance which typically results in a little better efficiency at higher power levels. The Darlington design was common in the 1990s but now has been largely superseded by MOSFETs. Also, compared to the 3rd order harmonics of bipolar transistors, MOSFETs produce 2nd order harmonic distortion so they sound a little more tube like when driven hard. Hope this helps, Hemz Very 2000's to me ... The XPA-2: Power and Finesse. FEATURES: Modular channel design for greater channel separation. Automatic 120/230 AC voltage detection and switching. Multi segment bar graph output level meters with clip detect. Metering and status LED on/off switches. Advanced microprocessor operating system. Discrete front end, no integrated circuits. Output topology: discrete triple Darlington with On Semi output devices. Input topology: dual differential input. External trigger turn on. Fully protected from all fault conditions. Input: balanced (XLR) and unbalanced (RCA), switchable. Soft touch power switch. 4RU chassis w/ 15mm solid milled aluminum faceplate. IEC power inlet. Display type: digital status indicators
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Post by emodarlington on Aug 1, 2017 20:03:41 GMT -5
I know you're abroad but did you email them? Do you mean should I email them again?
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Post by Jim on Aug 1, 2017 20:14:06 GMT -5
Are we still in the 2000s?
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klinemj
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Post by klinemj on Aug 1, 2017 20:16:07 GMT -5
yes - you should. Given you are running fairly sensitive speakers, a lot of different amps should be fine unless you want to get to ear bleeding levels (so, if that's what you mean about "depends on the music"). Sound wise, I've not personally heard the BasX line myself, but their A-300 looks like a nice little beast for just $399. From what I've read around - people seem pleased with its sound.
For my needs in critical listening in 2-channel, I had an XPA-2 Gen 1. It packed quite a punch and friends were impressed that it was "fast" (I always find that description odd but I get their point...it hit hard and moved on...). however, I did notice a little harshness in the high end and sought other solutions. See my signature for what those are. Each of those (the hypex ncores and the PrimaLuna) sound, to me, every bit as powerful and just that much smoother in the high end.
If you want into the Emotiva lineup and are concerned that for your "depends on the music" loudness preference the A-300 won't be enough - step up to the XPA-1's and lack of power will "not be an issue".
Mark
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hemster
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Post by hemster on Aug 1, 2017 20:55:57 GMT -5
I know you're abroad but did you email them? Do you mean should I email them again? ...Only if you haven't heard from them. ...YES! Email them again!
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hemster
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Post by hemster on Aug 1, 2017 20:59:03 GMT -5
Are we still in the 2000s? Some of us are ahead of our times... but, yes, still in the 2000s last time I checked.
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hemster
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Post by hemster on Aug 1, 2017 21:02:07 GMT -5
Compared to bipolar transistors, MOSFETs have a much lower ON resistance which typically results in a little better efficiency at higher power levels. The Darlington design was common in the 1990s but now has been largely superseded by MOSFETs. Also, compared to the 3rd order harmonics of bipolar transistors, MOSFETs produce 2nd order harmonic distortion so they sound a little more tube like when driven hard. Hope this helps, Hemz Very 2000's to me ... The XPA-2: Power and Finesse. FEATURES: Modular channel design for greater channel separation. Automatic 120/230 AC voltage detection and switching. Multi segment bar graph output level meters with clip detect. Metering and status LED on/off switches. Advanced microprocessor operating system. Discrete front end, no integrated circuits. Output topology: discrete triple Darlington with On Semi output devices. Input topology: dual differential input. External trigger turn on. Fully protected from all fault conditions. Input: balanced (XLR) and unbalanced (RCA), switchable. Soft touch power switch. 4RU chassis w/ 15mm solid milled aluminum faceplate. IEC power inlet. Display type: digital status indicators See my word in red above. I did not say Darlington was defunct. Unless it's about people's screen names!
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Post by emodarlington on Aug 2, 2017 6:05:30 GMT -5
Are we still in the 2000s? Back in 2008, sure we were Jim! That was when the Emo XPA-2 appeared...
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Post by KeithL on Aug 2, 2017 10:06:42 GMT -5
There are all sorts of different topologies that can be used for an amplifier output stage..... and many of them are describing different aspects of the circuit. (For example, my car could be described as "a hatchback" or "a passenger car" or "having an internal combustion engine" or "having fuel injection" or "having a CVT transmission"...) Many of the different types of circuits have specific advantages and disadvantages which may be important in some applications and unimportant in others. Many of our previous amplifiers used "complementary bipolar output transistors and drivers connected in a triple-Darlington configuration". (The term "Darlington" refers to how the three transistors are "stacked" together - you can buy single-package "Darlington transistors" - but ours was comprised of separate devices). Our current XPA Gen3 amps use "a short signal path Class A/B output stage with a Class H power supply topology". Our current BasX amps use "a short signal path Class A/B output stage" but not the Class H power supply topology. (Terms like "fully-complementary" and "push-pull" refer to all of the amps we're talking about.) All of those options have specific benefits in specific applications. As far as I know we have never used MOSFETs in our output stages (at least not in any recent products). I would also disagree about MOSFETs being more efficient in AUDIO applications. MOSFETs excel at high speed switching, and do sometimes have a lower on-resistance in switching applications, but that is not relevant in audio applications. In switching applications the output device is not intended to dissipate power... and dissipates less power if it switches very quickly and cleanly. In any sort of linear amplifier circuit, the output device must drop the difference between the rail supply voltage and the output voltage. This requires the device to dissipate a certain amount of power as heat.... and there's no way that can be done "more or less efficiently". (In our Class H output stages, we reduce the amount of heat by reducing the power supply rail voltages when the full high voltage isn't needed.) In a switching circuit, where the output device is either on or off, and an ideal device would be dissipating zero power, a MOSFET may do better. MOSFETs do have different distortion characteristics, and tend to have higher bandwidth, which is why some designers have historically preferred them in audio amplifiers. However, they also have some serious drawbacks. The bottom line is that none of the topologies we're talking about are universally better than the others, and you get the best results by choosing a topology that works well for a particular application. (In the past there have been topologies which are inappropriate for audio circuits, or which universally performed poorly in audio circuits, but nobody uses them any more .) So, in that sense, other than how the amp performs, and how it sounds, and personal preferences of some design engineers, all of this is "just marketing". Hi Mark, Thank you for your reply. I have already emailed them but no luck either. I'm based overseas. I'm sure that someone here more technically inclined can help me. It's intriguing why they drop the "triple darlington" designation and replaced it for "Class A/B output amplifier". I'm hopping that it's only a question of marketing. If I decide to go with one of these BasX amps I won't be able to listen to it before purchase. Hence, the reason why this question interests me so much! Compared to bipolar transistors, MOSFETs have a much lower ON resistance which typically results in a little better efficiency at higher power levels. The Darlington design was common in the 1990s but now has been largely superseded by MOSFETs. Also, compared to the 3rd order harmonics of bipolar transistors, MOSFETs produce 2nd order harmonic distortion so they sound a little more tube like when driven hard. Hope this helps, Hemz
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Post by garbulky on Aug 2, 2017 11:38:38 GMT -5
So if I'm reading right, the new amps don't have the Darlington topology.
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KeithL
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Post by KeithL on Aug 2, 2017 11:54:33 GMT -5
That is correct..... neither the XPA Gen3 nor the BasX amps use a classic Darlington topology. So if I'm reading right, the new amps don't have the Darlington topology.
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Post by leonski on Aug 2, 2017 13:26:47 GMT -5
As kind of an aside to what Keith said, I worked for a semiconductor manufacturer. They made the proprietary HEXFET device which is a unique GEOMETRY of MOSFET. One of the advertising claims involves very LOW RDon which is resistance of device in its ON state. For applications like motor speed controllers and other high current applications, this is a REAL good idea. For those applicatons involving high current, the 'device' in question heats less and lasts longer. Bob Carver made use of another type of device from the SAME manufacturer in some of his SunFire amps. I think he used a version of the BiPolar transistor in some of his designs.
The other thing Keith said which may get passed over and is of really little importance is that a Darlington pair can be made up of Discrete devices or made at the Wafer Fab on a single slice of silicon. Using one or the other might be a design decision of the end user. Costs? Space available? Reliability? And in a piece of Audio Gear.......the vital Listening Tests.
The people that design the devices, NOT the circuits they are used in are very ingenious. Many variations exist of both BiPolar and MOSFET devices. Nelson Pass, for example, is a fan of what is called the VFET. All sorts of variations exist and claims and counter-claims are all over the place.
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Post by emodarlington on Aug 2, 2017 16:50:36 GMT -5
That is correct..... neither the XPA Gen3 nor the BasX amps use a classic Darlington topology. I think Keith is playing with words... since an image is worth a thousand words, the only thing I really would like to know is this: do the BasX amps use IN ANY WAY the non-classical Darlington (aka "Triple Darlington") configuration for the output stage, as pictured below? This is a very simple question, with a very simple answer: yes or no! Keith, can you please give me a straight answer? PS: The last transistor in the picture can also represent several paralleled transistors. So take this into account when answering. Also, please ignore any resistor between any of the transistor's emitter and the base of the next transistor if that is the case.
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