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Post by mgbpuff on Nov 22, 2019 11:28:34 GMT -5
After 18 years, I’ve been unable to “kill” my Signature Sunfire. And that perfectly functioning 18 year old amp uses an SMPS. Just more proof that SMPS's aren't bad, it's how they're implemented that matters.  Not true at all! As you can see, the Sunfire Signature amp has a HUGE toroidal transformer. The power supply is a down tracking power supply (essentially another power amp just for the power supply rail). The rail voltage is kept a constant 6 VDC higher level than the music demands of the signal. There is no SMPS power supply in the unit as far as I know. |
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Post by 405x5 on Nov 22, 2019 11:29:39 GMT -5
After 18 years, I’ve been unable to “kill” my Signature Sunfire. And that perfectly functioning 18 year old amp uses an SMPS. Just more proof that SMPS's aren't bad, it's how they're implemented that matters. Yes....it’s always got power to it and warmed up. It’s own trigger mates well with the XMC as it did with my former TG 2. Additionally, all my speakers are set to small with the sub. delivering much of the “horsepower”. Small wonder the thing is still here. Bill |
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Post by rbk123 on Nov 22, 2019 11:35:39 GMT -5
Not true at all! As you can see, the Sunfire Signature amp has a HUGE toroidal transformer. The power supply is a down tracking power supply (essentially another power amp just for the power supply rail). The rail voltage is kept a constant 6 VDC higher level than the music demands of the signal. There is no SMPS power supply in the unit as far as I know. Welllllll..... I'm not sure what amp is in that picture, but as you can see by the review here they mention it's power supply: hometheaterhifi.com/volume_6_3/sunfire-cinema-grand-signature.htmlI have a friend with the same amp and his is definitely an SMPS. |
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Post by 405x5 on Nov 22, 2019 11:41:50 GMT -5
And that perfectly functioning 18 year old amp uses an SMPS. Just more proof that SMPS's aren't bad, it's how they're implemented that matters. Not true at all! As you can see, the Sunfire Signature amp has a HUGE toroidal transformer. The power supply is a down tracking power supply (essentially another power amp just for the power supply rail). The rail voltage is kept a constant 6 VDC higher level than the music demands of the signal. There is no SMPS power supply in the unit as far as I know. You may be right, but that picture is the newer version of the original I’ve got which has a square transformer and a different amp. Channel arrangement. So what I heard about this, was that my early model has a VERY small hum at idle (normal operation) but enough to go forward with the newer version you have pictured. Totally inaudible at the quietest music or film listening levels. Bill |
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Post by rbk123 on Nov 22, 2019 12:03:39 GMT -5
So what I heard about this, was that my early model has a VERY small hum at idle (normal operation) but enough to go forward with the newer version you have pictured. Totally inaudible at the quietest music or film listening levels. My friend's has the similar hum which he also can't hear unless he turns the volume way up and the sources off. |
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Post by brutiarti on Nov 22, 2019 12:14:48 GMT -5
In my experience the DR-1's were a disappointment. Lack of microdynamics and bass control of my epicon's 6. I had high hopes for them.  |
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Post by 405x5 on Nov 22, 2019 12:28:07 GMT -5
So what I heard about this, was that my early model has a VERY small hum at idle (normal operation) but enough to go forward with the newer version you have pictured. Totally inaudible at the quietest music or film listening levels. My friend's has the similar hum which he also can't hear unless he turns the volume way up and the sources off. I've never before tried that...…….it would scare the crap out of me Bill |
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Post by routlaw on Nov 22, 2019 12:32:15 GMT -5
In my experience the DR-1's were a disappointment. Lack of microdynamics and bass control of my epicon's 6. I had high hopes for them. Thanks, I remember you making a similar post recently in another thread. Sorry they didn't work out for you though. What little information there is about these amps seem to conflict with your results however, which I find perplexing, given that their rating of 650/1000 WPC into 8/4 ohm loads should handily perform well on any speaker load. One would have to assume your speakers are a very difficult load to drive apparently. |
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Post by brutiarti on Nov 22, 2019 12:51:20 GMT -5
Thanks, I remember you making a similar post recently in another thread. Sorry they didn't work out for you though. What little information there is about these amps seem to conflict with your results however, which I find perplexing, given that their rating of 650/1000 WPC into 8/4 ohm loads should handily perform well on any speaker load. One would have to assume your speakers are a very difficult load to drive apparently. I was trying to replace the XPR-1's that were the best monos that I've ever heard. Didn't try the XPA-'1's tough. Good luck and hope you like the DR-1's. In paper they were perfect |
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Post by rockman85 on Nov 22, 2019 12:53:43 GMT -5
I haven't even read the post yet, but I literally came to the site right now to see if anyone had some impressions of the DR1 and BAM, first on the newest threads list. Don't you love it when stuff like that happens?
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Post by routlaw on Nov 22, 2019 13:24:35 GMT -5
BAM? No idea what you're talking about, padon my ignorance.
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KeithL
Administrator 
Posts: 10,264
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Post by KeithL on Nov 22, 2019 14:20:59 GMT -5
In point of fact an amplifier and a power supply are simply different aspects of the same circuit function. A regulated power supply is really just "an amplifier that amplifies and outputs a fixed voltage" (and, to get that output voltage, it "amplifies" a DC reference voltage)... And an amplifier is just "a power supply that delivers an output voltage that is varied to follow an input signal"... (The main difference in design is that an amplifier is optimized to deliver a rapidly changing output voltage while a power supply is optimized not to do so.)
Over the years, various Carver and Sunfire amps have used a variety of different circuit topologies, and the descriptions they give tend to be rather obtuse (and sometimes just plain confusing).
The "tracking down-converter" that provides power for many of them is in fact a variable voltage switch mode power supply. That's what enables them to be more efficient than a standard Class A/B design.
(Unlike a Class H design, where the output stage switches between two or three fixed rails, the rails are actually varied as required.)
At lower audio frequencies the rail voltage tracks the shape of the signal waveform - which reduces the amount of power that has to be dissipated by the Class A/B output stage. At higher frequencies, where the waveform itself varies too quickly to be "tracked", they deliver a rail voltage that tracks the shape of the signal envelope. This delivers a lesser, but still significant, improvement in efficiency at higher frequencies, especially at relatively low signal levels. (A fair description of the whole arrangement would be "a Class A/B output stage that uses a Class D amplifier as its power supply"...) Unfortunately, while the idea itself is quite sensible, it requires a lot of work to fine tune it to work properly, without messing something up.
(For starters, most typical amplifiers are optimized to run from power supply rails that don't vary along the way.)
I had one of the original "Sunfire Load Invariant Power Amplifiers" a long time ago... It sounded just fine and ran quite cool under normal operating conditions... (And, yes, it proved eminently reliable over the period of time I owned it, and was working just fine when I sold it.)
Note that, while SOME switch mode power supplies, and SOME Class D amplifiers work directly from rectified AC line voltage... Some still use 60 Hz line power transformers, either to provide an operating voltage they prefer, or to provide isolation from the line.
(The SMPS we use in the XPA Gen3 and XPA-DR amps enables us to avoid a big heavy line transformer... but that is not always the case.)
Not true at all! As you can see, the Sunfire Signature amp has a HUGE toroidal transformer. The power supply is a down tracking power supply (essentially another power amp just for the power supply rail). The rail voltage is kept a constant 6 VDC higher level than the music demands of the signal. There is no SMPS power supply in the unit as far as I know. You may be right, but that picture is the newer version of the original I’ve got which has a square transformer and a different amp. Channel arrangement. So what I heard about this, was that my early model has a VERY small hum at idle (normal operation) but enough to go forward with the newer version you have pictured. Totally inaudible at the quietest music or film listening levels. Bill |
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Post by mgbpuff on Nov 22, 2019 15:24:53 GMT -5
In point of fact an amplifier and a power supply are simply different aspects of the same circuit function. A regulated power supply is really just "an amplifier that amplifies and outputs a fixed voltage" (and, to get that output voltage, it "amplifies" a DC reference voltage)... And an amplifier is just "a power supply that delivers an output voltage that is varied to follow an input signal"... (The main difference in design is that an amplifier is optimized to deliver a rapidly changing output voltage while a power supply is optimized not to do so.)
Over the years, various Carver and Sunfire amps have used a variety of different circuit topologies, and the descriptions they give tend to be rather obtuse (and sometimes just plain confusing). The "tracking down-converter" that provides power for many of them is in fact a variable voltage switch mode power supply. That's what enables them to be more efficient than a standard Class A/B design.
(Unlike a Class H design, where the output stage switches between two or three fixed rails, the rails are actually varied as required.)
At lower audio frequencies the rail voltage tracks the shape of the signal waveform - which reduces the amount of power that has to be dissipated by the Class A/B output stage. At higher frequencies, where the waveform itself varies too quickly to be "tracked", they deliver a rail voltage that tracks the shape of the signal envelope. This delivers a lesser, but still significant, improvement in efficiency at higher frequencies, especially at relatively low signal levels. (A fair description of the whole arrangement would be "a Class A/B output stage that uses a Class D amplifier as its power supply"...) Unfortunately, while the idea itself is quite sensible, it requires a lot of work to fine tune it to work properly, without messing something up.
(For starters, most typical amplifiers are optimized to run from power supply rails that don't vary along the way.)
I had one of the original "Sunfire Load Invariant Power Amplifiers" a long time ago... It sounded just fine and ran quite cool under normal operating conditions... (And, yes, it proved eminently reliable over the period of time I owned it, and was working just fine when I sold it.) Note that, while SOME switch mode power supplies, and SOME Class D amplifiers work directly from rectified AC line voltage... Some still use 60 Hz line power transformers, either to provide an operating voltage they prefer, or to provide isolation from the line.
(The SMPS we use in the XPA Gen3 and XPA-DR amps enables us to avoid a big heavy line transformer... but that is not always the case.)
You may be right, but that picture is the newer version of the original I’ve got which has a square transformer and a different amp. Channel arrangement. So what I heard about this, was that my early model has a VERY small hum at idle (normal operation) but enough to go forward with the newer version you have pictured. Totally inaudible at the quietest music or film listening levels. Bill SMPS envolves high frequency switching, this is a PWM and does not require such high frequency switching. The source for the PWM is a standard DC supply provided by the transformer and large caps. It is a little different, but I admit that switching is going on. |
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Post by jdmusante on Nov 22, 2019 20:02:19 GMT -5
You must have found a pair used. Congratulations! I’m sure you will like them. I agree there wasn’t much review info on the DR amps, not enough one could really sink there teeth into. Less than a dozen consumer reviews on the Emotiva website but that’s it, yet still helpful. To answer your question, if the Class A switch is off they will be fairly warm at idle, but with switch on they are downright hot. You couldn’t keep your hands on them but for a quick touch. Some people do not hear the difference with the switch on, but to me it’s very noticeable in my system. There will I’ll certainly be a measurable difference, but whether or not you can hear the difference between monos and stereo amps in your system will be up to you. It’s a very immersive experience in my setup. Don’t think I would ever go back to a stereo amp. I actually bought them directly from Emotiva. I emailed them a couple of weeks ago and they got back to me that they had 3 pair in stock, brand new. I probably could have waited out someone ditching a used pair for cheaper but they don't come around often and I get a 5 year warranty. I don't have the space for amp stands where my current set up is but we'll be moving in February. I can run them in AB until then. I don't have a heat issue with the XPA-2. |
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Post by brutiarti on Nov 22, 2019 20:47:38 GMT -5
I’m currently running my analog rig with a pair of PA-1’s. Time for evaluation
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Post by routlaw on Nov 23, 2019 10:56:39 GMT -5
I actually bought them directly from Emotiva. I emailed them a couple of weeks ago and they got back to me that they had 3 pair in stock, brand new. I probably could have waited out someone ditching a used pair for cheaper but they don't come around often and I get a 5 year warranty. I don't have the space for amp stands where my current set up is but we'll be moving in February. I can run them in AB until then. I don't have a heat issue with the XPA-2. That XPA-2 and the mono blocs you ordered are nothing alike, especially when it comes to heat. I also have the XPA-3 Gen 2 which is more like your XPA-2 and by comparison it runs quite a bit cooler than those mono blocs. Regardless thats awesome you got a brand new pair had no idea they had any left, certainly not listed on their website. Good luck with them. |
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Post by jdmusante on Nov 24, 2019 12:24:19 GMT -5
I’m currently running my analog rig with a pair of PA-1’s. Time for evaluation What are your thoughts on the PA-1s? |
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Post by brutiarti on Nov 24, 2019 15:18:52 GMT -5
I’m currently running my analog rig with a pair of PA-1’s. Time for evaluation What are your thoughts on the PA-1s? Great amps for not demanding speakers. I have a pair of Music Culture RCL21, at low/medium levels sounds good/excellent. Higher levels I rather my Bryston amps. |
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Not true at all! As you can see, the Sunfire Signature amp has a HUGE toroidal transformer. The power supply is a down tracking power supply (essentially another power amp just for the power supply rail). The rail voltage is kept a constant 6 VDC higher level than the music demands of the signal. There is no SMPS power supply in the unit as far as I know.
