It's like some type of adhesive to either hold the screws in place or to show any tampering?
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Sunfire Cinema Grand Review (5-channel Amp)
- Thread starter amirm
- Start date
I would really like to see that.
KEFCarver
Active Member
The adhesive is to keep the screws from vibrating loose. I expect to see it in military grade hardware, and good subwoofers, but not so much in a f home audio amplifier
That has an article in it by Tom Nousaine. A good article at that. He also says most (but not all) of the stuff we look at as high end sound is not different than mid price stuff when the blindfolds come out. That is still a big issue even on ASR. But, that is off topic........
I think the last nail in the coffin of expensive mega buck amps is the high performance Class D amps. So, now amps are (still) a commodity. The preamp features and speakers are about all that's left in the system. Then electronic room analyzing software, and room treatments are the last few pieces to fall into place. Looking into my crystal ball, Dirac 10 in 2040 and Audessey version 10 also in 2040 will blow our minds at how good they are. We live in the best times of audio if you can get past all the snake oil!
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Thanks for the review. I read most posts. I have a few comments based on my experiences with Carver and Sunfire amps. I own 2 Sunfire - both very early models for their genre. One is an original 2 channel, the other an early Cinema Grand. Fairly recently acquired. I find the enclosure to be far too large for the guts. The second iteration was a more normal/manageable size. The face is meh ..... they suck to work on.
I've owned many Carver, still have a few. I wouldn't normally go cross products with my comments, but since the review mentions the m1.5t measured performance, now I'm interested. I've owned a bunch of m1.5t. Still have one. Most were repairs.
The results here that stand out the most to me are the noise at idle plots. To me the m1.5t is far inferior in the area of humm..... 60-200HZ content, line cycle harmonics. The m1.5t has a triac driven transformer. The inputs are close to the transformer. It's just a much noisier amp in this regard. The FR plots show otherwise in these reviews. I don't think this is possible if both amps are up to spec. The Sunfire has a conventional toroid. It's quieter by a lot (ears here not meters). You are much more likely to hear noise between songs if you are running a m1.5t.
My 5 channel Sunfire had bad 12V supply caps. This produced noticeable hum at idle in SOME channels.
Second - the results of amplitude/frequency diffs between channels is odd. I've only measured a few Carver stereo amps and found the channels to match quite well. Maybe a bit of a delta in nominal gain, but over frequency, very closely matched. Same components on the same board (in the case of the 5 channel amps). Deltas in this area could also be related to a drooping 12V supply - some op-amps dealing with it better than others ......
I've owned many Carver, still have a few. I wouldn't normally go cross products with my comments, but since the review mentions the m1.5t measured performance, now I'm interested. I've owned a bunch of m1.5t. Still have one. Most were repairs.
The results here that stand out the most to me are the noise at idle plots. To me the m1.5t is far inferior in the area of humm..... 60-200HZ content, line cycle harmonics. The m1.5t has a triac driven transformer. The inputs are close to the transformer. It's just a much noisier amp in this regard. The FR plots show otherwise in these reviews. I don't think this is possible if both amps are up to spec. The Sunfire has a conventional toroid. It's quieter by a lot (ears here not meters). You are much more likely to hear noise between songs if you are running a m1.5t.
My 5 channel Sunfire had bad 12V supply caps. This produced noticeable hum at idle in SOME channels.
Second - the results of amplitude/frequency diffs between channels is odd. I've only measured a few Carver stereo amps and found the channels to match quite well. Maybe a bit of a delta in nominal gain, but over frequency, very closely matched. Same components on the same board (in the case of the 5 channel amps). Deltas in this area could also be related to a drooping 12V supply - some op-amps dealing with it better than others ......
Well, if marketed right, unique SELLS. It did for Carver, especially as in those days nobody was doing serious measurement of this stuff (not even Stereophile as far as I remember or can find)
respice finem
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Yes, this is what the "industry" lived off in its "good old days". The 80s are, however, 40 years ago, so it's increasingly difficult to make something really new in the amp world. An exception "to confirm the rule" being constructions like Purifi.
Hipster Doofus
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yes the downside of the truth is that....we have to face it
This amp was defective, out of alignment & needed love. To judge all others by this (very limited) review sample is pretty ridiculous. While Amir tested what was sent to him, this should have been noted in the review.
I am glad to see a few others that are sharp enough to have caught what should be some glaring issues to anybody with a technical background. Those that aren't technically savvy will no doubt accept these results & dismiss this entire product line based on these measurements.
The Audio Critic review linked to on page 8 of this thread sums things up pretty well. Julian Hirsch also did a review of the original non-Signature 2 channel Sunfire in Stereo Review. The measurements there also speak for themselves.
As far as output capacity goes, the early versions of these amps had captive power cords. Quite bluntly, these cords were less than sufficient to say the least. Upgrade the cord & go to a heavy gauge multi-conductor self-shielded design.
On top of that, and even though these amps are pretty efficient, they really do need a dedicated 20+ amp circuit to feed them. While many may scoff at this, these amps are capable of sucking a standard 15A circuit dry. Gets even worse if it is a shared circuit. This issue results in a lack of dynamics, high frequency smearing & "wooly" bass. This becomes more evident as both speaker impedance & sensitivity drop while wanting to throttle the output.
The original design lacked sufficient PS capacitance. I bitched about this to Sunfire incessantly & had repeated battles with them over the phone about this. While they kept telling me that I did not understand the design, a few months after these conversations, they upped the filter capacitance on the revised "Architectural Series" using the smaller 17" chassis. I count that as a "win" for my side in the long run.
As to line noise, besides using a properly designed low impedance self-shielding power cord, try adding "snubbers" in the power supply across your rectifiers. This is beneficial to all gear.
Careful attention to circuit design, ground paths & eddy currents are important too. Any component that ties Earth aka safety ground to signal ground using the chassis as a common connection is poorly designed. I say this NOT in specific to the two-pronged Sunfire gear, but the mating gear that it may be connected to.
And one more issue that is pretty important but I never see mentioned. Bob wired the XLR's on the Sunfire's "old school" as was used in the 1960's & early 1970's. The pin-out is NOT the same as most all other gear using XLR's. This standard was changed in the later 1970's.
As such, one can be using XLR cables but not really be obtaining the full benefits of balanced operation. This can most assuredly alter the S/N measurements along with a few other factors. As such, you might have to rewire one end of the XLR cabling when mating a non-Sunfire component to a Sunfire component in order to achieve proper pinning / polarity.
I am glad to see a few others that are sharp enough to have caught what should be some glaring issues to anybody with a technical background. Those that aren't technically savvy will no doubt accept these results & dismiss this entire product line based on these measurements.
The Audio Critic review linked to on page 8 of this thread sums things up pretty well. Julian Hirsch also did a review of the original non-Signature 2 channel Sunfire in Stereo Review. The measurements there also speak for themselves.
As far as output capacity goes, the early versions of these amps had captive power cords. Quite bluntly, these cords were less than sufficient to say the least. Upgrade the cord & go to a heavy gauge multi-conductor self-shielded design.
On top of that, and even though these amps are pretty efficient, they really do need a dedicated 20+ amp circuit to feed them. While many may scoff at this, these amps are capable of sucking a standard 15A circuit dry. Gets even worse if it is a shared circuit. This issue results in a lack of dynamics, high frequency smearing & "wooly" bass. This becomes more evident as both speaker impedance & sensitivity drop while wanting to throttle the output.
The original design lacked sufficient PS capacitance. I bitched about this to Sunfire incessantly & had repeated battles with them over the phone about this. While they kept telling me that I did not understand the design, a few months after these conversations, they upped the filter capacitance on the revised "Architectural Series" using the smaller 17" chassis. I count that as a "win" for my side in the long run.
As to line noise, besides using a properly designed low impedance self-shielding power cord, try adding "snubbers" in the power supply across your rectifiers. This is beneficial to all gear.
Careful attention to circuit design, ground paths & eddy currents are important too. Any component that ties Earth aka safety ground to signal ground using the chassis as a common connection is poorly designed. I say this NOT in specific to the two-pronged Sunfire gear, but the mating gear that it may be connected to.
And one more issue that is pretty important but I never see mentioned. Bob wired the XLR's on the Sunfire's "old school" as was used in the 1960's & early 1970's. The pin-out is NOT the same as most all other gear using XLR's. This standard was changed in the later 1970's.
As such, one can be using XLR cables but not really be obtaining the full benefits of balanced operation. This can most assuredly alter the S/N measurements along with a few other factors. As such, you might have to rewire one end of the XLR cabling when mating a non-Sunfire component to a Sunfire component in order to achieve proper pinning / polarity.
"As far as output capacity goes, the early versions of these amps had captive power cords. Quite bluntly, these cords were less than sufficient to say the least. Upgrade the cord & go to a heavy gauge multi-conductor self-shielded design."
Lol. No, power cords do not make any difference.
Lol. No, power cords do not make any difference.
They do when the amp can drain a 20 amp circuit & you have a 16 gauge cord feeding it from the factory.
On top of that, Amir mentions the AC line noise being fed right through the power supply into the amp. Power cords can be designed with specific electrical attributes, can they not?
They could be, but not for audio excellence. Power cords that actually modify the electrical signals after the amp incoming power supply would have to be so different the unit would probably just fault out. A power cord can't effect the output sound if it is a little off. No magic sauce can be added with a power cord. Any magic would be negative. Power cords are and have always been snake oil.
I am not a EE, but it seems like a power cord (or power conditioner) could limit current, the result would be lower power output and increased distortion because of that.
Obviously, Bob Carver figured out the power cord gage.
The @amirm measurements are a bit disappointing, especially as the amp owner, but this amp doubles down into 4 ohms and is a bit of a beast.
It delivers power into tough loads. It would be interesting if this and other amps were also measured into 2 Ohm (short duration) to help assess the ability to drive difficult (reactive) loads.
- Rich
Spkrdctr: For me to educate you as to how a power cord CAN alter sonics (beyond required ampacity) would be to give away potential trade secrets. Mind you, I'm not in the field of "high fidelity" audio products, but that doesn't mean that I'm not entertaining the thought of entering the field.
The fact that Amir stated that he was seeing a bunch of feed-through via the power supply with this defective amp means that it would be a good candidate to use for such testing. While the testing could measure SOME attributes of changes upstream, it would still not be able to quantify everything that was audible. Unfortunately, we can't measure or quantify everything that we hear.
If you read my response above, simply using well tuned "snubbers" across the rectifiers negates the need for "fancy" power cords, although those using specific geometries could still be of benefit. Just not near as much benefit.
So you are saying that you can alter the electricity after the incoming power supply and it will benefit the sound coming out of the speakers so that a person can hear the difference? I just want to make sure I understand you.
RichB I think that Mr Carver has always left WAY TOO MUCH to the "bean counters". This is primarily what has handicapped most of his designs. The lack of expenditure to gain match & assure quality of internal componentry is most of the reason that the units don't sound as good as they could / should & have a high rate of failure / reduced longevity out in the field. So long as it didn't ad production cost or complication and it worked within tolerance , it went out the door. The fact that most of his customers are "bang for the buck" kind of guys that tend to thrash their systems with intensive throttling doesn't help either.I am not a EE, but it seems like a power cord (or power conditioner) could limit current, the result would be lower power output and increased distortion because of that.
Obviously, Bob Carver figured out the power cord gage.
The @amirm measurements are a bit disappointing, especially as the amp owner, but this amp doubles down into 4 ohms and is a bit of a beast.
It delivers power into tough loads. It would be interesting if this and other amps were also measured into 2 Ohm (short duration) to help assess the ability to drive difficult (reactive) loads.
- Rich
As to the amp "doubling down", that's what gave the problem with the amp away. The fact that it did MORE than twice the power into 4 ohms as it did into 8 ohms AT CLIPPING is a sure sign that something isn't adjusted or tracking properly. Why Amir didn't catch this is beyond me.
How does the 50m or perhaps even 150m of solid core copper wire between the fancy AC mains cable and the component affect the sound? Adding 2m of expensive AC mains cable is not going to change all that copper core conductor.
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