Sunfire Cinema Grand Review (5-channel Amp)

[DonR]

I'd say since the 2 tested channels behave significantly differently, It's probably not fully to specifications. I also have some reluctance to really give meanings to these measurments of old amps, they all have been received different level of work and we never really know. We had a NAD 2200 that was simply superb, It can go in all directions. I feel that someone buying any of those should not assume that he is getting what he sees.

I agree. @amirm should hold off on doing any vintage reviews unless the review unit has been professionally serviced. Otherwise, he is just reviewing a particular example of an unknown state.

 

[Hipster Doofus]

Thanks for the myth busting…

After years of following the herd (and heard). It great to finally find the Consumer Report of audio…you really need to hire a few folks and teach them how to do what you do so we can have a standard so to speak….maybe an IPO.

but when are you going to test some stereo furniture or isolation feet.

i visited a stereo reviewers home once and found solid ribbon copper cables up on several trestle, just like my childhood H.O. trains. Where I was told of an upcoming review of a $30,000.00 stereo table that actuallymade a difference. When I challenged with why don’t you just get some cinder blocks I was met with the shaming that my system or my ears or my manhood did not have enough resolution to hear the difference.

Still happy listening to my tiny, under 1 pound, Toppings PA5 pushing my 1980 B&W Matrix 801 ( when scientist still made speakers for musicians)with 12 in woofers. Clear as light

 

[Cougar]

You can hear the transformer groan when you power the unit on. So definitely a lot of in-rush current.

I have a EDGE M8 (Original Black) that does this same thing. It has two 33,000uF caps in the PS. The draw is so hard it has gone though two power ON switches. The first switch threw out sparks a couple of times before before I replaced it. I did replace the caps for new better ones but may go to two 15,000uF caps for each side to hopefully lessen the turn ON current draw. It does have a CL-90 in line that was part of the original parts but doesn't seem to slow it down much IF at all.

 

[Doodski]

I have a EDGE M8 (Original Black) that does this same thing. It has two 33,000uF caps in the PS. The draw is so hard it has gone though two power ON switches. The first switch threw out sparks a couple of times before before I replaced it. I did replace the caps for new better ones but may go to two 15,000uF caps for each side to hopefully lessen the turn ON current draw. It does have a CL-90 in line that was part of the original parts but doesn't seem to slow it down much IF at all.

One of these amps?

 

[DonR]

One of these amps?

Such a substantial piece of equipment should have had some inrush limiting designed in... you would have thought.

 

[H-713]

Here's a thought:

To any others who regularly work on vintage amps, please chime in if you have found otherwise. In my own experience, I very rarely see an amplifier from a reputable manufacturer that can't meet its published specifications for distortion when working properly. Output power is more hit or miss (and often as not it's a burst rating), but it usually isn't off by too much. We've seen some vintage amps that measure pathetically recently, perhaps any time a used amplifier doesn't meet its published specs it's time for a closer look.

I see old equipment that doesn't meet specs sometimes, and that's usually a sign that it needs maintenance. The usual culprit is that someone decided to modify it, usually someone who is woefully unqualified. Often as not, they screwdriver the bias (or worse yet, the IF coils in a receiver). Given that this forum has a habit of smearing the reputation of the designers and manufacturers of poor-performing equipment, it seems like it'd be worth taking some extra time to verify that the equipment is 1) unmodified and 2) functioning as it should before publishing measurements.

 

[DonR]

Here's a thought:

To any others who regularly work on vintage amps, please chime in if you have found otherwise. In my own experience, I very rarely see an amplifier from a reputable manufacturer that can't meet its published specifications for distortion when working properly. Output power is more hit or miss (and often as not it's a burst rating), but it usually isn't off by too much. We've seen some vintage amps that measure pathetically recently, perhaps any time a used amplifier doesn't meet its published specs it's time for a closer look.

I see old equipment that doesn't meet specs sometimes, and that's usually a sign that it needs maintenance. The usual culprit is that someone decided to modify it, usually someone who is woefully unqualified. Often as not, they screwdriver the bias (or worse yet, the IF coils in a receiver). Given that this forum has a habit of smearing the reputation of the designers and manufacturers of poor-performing equipment, it seems like it'd be worth taking some extra time to verify that the equipment is 1) unmodified and 2) functioning as it should before publishing measurements.

I have fixed a few in my time and usually it's (in order of frequency) failing capacitors, bias drift, failing resistors, failing diodes. Apart from that, there is always the odd catastrophic failure of output transistors. After repair, they tend to work as good as new.

 

[levimax]

I have a EDGE M8 (Original Black) that does this same thing. It has two 33,000uF caps in the PS. The draw is so hard it has gone though two power ON switches. The first switch threw out sparks a couple of times before before I replaced it. I did replace the caps for new better ones but may go to two 15,000uF caps for each side to hopefully lessen the turn ON current draw. It does have a CL-90 in line that was part of the original parts but doesn't seem to slow it down much IF at all.

You can add a "soft start" circuit which should be done for any transformer over 300 va. Here is one example https://neurochrome.com/products/intelligent-soft-start

 

[Spocko]

Another in the long line of amps of which at one time I coveted , later to be shown for its true self.

HERE HERE - in the gold ol' days when all you had were subjective reviews with zero measurements, this was an object that many budding audiophiles hoped one day to own. Boy am I glad I didn't save up for this!

 

[Cougar]

One of these amps?

The First edition of that amp when they were made in CO and Mr. Nober was there. They were Black with handles on the front. They were known as the "Krell Killer" back in the late 90's. Massive power supply transformer and caps. Never has a problem pushing any speaker and never stressed when puched hard. The lights in the house would dim when I would power it on. I have it waiting to be worked on, I need to find time to recap it and make sure everything is working properly. The last time me and Mr. Nober exchanged emails, he gave me some ideas on how to make this amp even better sounding. Very nice guy.

Once I get the M8 back up and running, I will do a side by side test against a nice class D amp and see how it goes in the same system. I already have a good idea which one I will prefer.

 

[Cougar]

You can add a "soft start" circuit which should be done for any transformer over 300 va. Here is one example https://neurochrome.com/products/intelligent-soft-start

@levimax We are both here in SD, what a coincidence!

Thank You for the link! I will order it this this week. I wanted a Velleman soft start unit but they dont make it anymore cause I wasn't able to find it a few years back when I wanted to go this route with a soft start.

Have you used this unit in any amps you have/had?

 

[Cougar]

Such a substantial piece of equipment should have had some inrush limiting designed in... you would have thought.

Yes, I agree. I guess they thought the CL-90 was good enough. This amp wasn't cheap either back then. I got mine used but new there were expensive.

 

[Cougar]

You can add a "soft start" circuit which should be done for any transformer over 300 va. Here is one example https://neurochrome.com/products/intelligent-soft-start

I have to double check since it's been a while since I last seen the specs on the transformer inside my M8. but I'm pretty sure it had a 1.5kVA power transformer in it.

 

[respice finem]

With very limited information on the older equipment being tested makes this seem much more like a "hey, lets bash this old stuff that people like".
Even if one agrees that the numbers tell the complete story on an amplifiers performance, we would need the background on the equipment for it to be at all 'scientific'. The results fit the hypothesis so why question the methods, is bad science.

Well... IMHO there is not much science to achieve with testing one old and somehow "revised" amp, and I think everybody here knows it.
One might argue if testing old stuff which was "tampered with" makes sense at all, IDK... Even with new stuff, what would be a significant number of units to check for sample variation? Mission impossible, except for the manufacturers themselves (who might be doing it, but aren't too eager to publish).

But, all this aside, is there really such a hypothesis from Amir, or is this yours (to prove)?

 

[Cougar]

You can add a "soft start" circuit which should be done for any transformer over 300 va. Here is one example https://neurochrome.com/products/intelligent-soft-start

I just order the unit a few mins. ago. Again, Thank You for the link!

 

[Cougar]

Here's a thought:

To any others who regularly work on vintage amps, please chime in if you have found otherwise. In my own experience, I very rarely see an amplifier from a reputable manufacturer that can't meet its published specifications for distortion when working properly. Output power is more hit or miss (and often as not it's a burst rating), but it usually isn't off by too much. We've seen some vintage amps that measure pathetically recently, perhaps any time a used amplifier doesn't meet its published specs it's time for a closer look.

I see old equipment that doesn't meet specs sometimes, and that's usually a sign that it needs maintenance. The usual culprit is that someone decided to modify it, usually someone who is woefully unqualified. Often as not, they screwdriver the bias (or worse yet, the IF coils in a receiver). Given that this forum has a habit of smearing the reputation of the designers and manufacturers of poor-performing equipment, it seems like it'd be worth taking some extra time to verify that the equipment is 1) unmodified and 2) functioning as it should before publishing measurements.

I had a few preamps and amps that I repaired that when I saw the inside, someone had been inside trying to modify the unit and I would just return it if they lied about it being modified or I would inform the owner I would be returning it back to Its original state when doing the repair. Even when I was buying gear that was broke off ebay, I would ask if the unit had been modified in any way and most of the time it had or it was broken not working after being said it was in proper working order.

The last piece of gear I bought was McIntosh MR-80 tuner that wasn't working properly and in very good condition. The guys said it was in original form with no modifications or repairs. I open it up when I got it and sure enough it was tampered with. Look like someone tried to recap the tuner but most of the caps were wrong values according to the service manual. I had to put it back into original form and is awaiting to be aligned by a local guy who knows Mac tuners. As of now, it sounds better than it did when I first received it. The person I bought it from said he was not the original owner and had not looked inside of it. Even though this was a bad situation, the tuner was in great condition and was at a very good price when I bought. It just only cost me a little time to put better quality caps that what was in it when it came with the correct values. So after that I was done buying anything off ebay plus the packaging of gear is horrendous! Forget about buying turntables off ebay!

 

[RichB]

You can hear the transformer groan when you power the unit on. So definitely a lot of in-rush current.

I also had the Sunfire Cinema Grand Signature that is the 400 WPC version. It is identified by a gold Bob Carver Signature on the front.

At the time, I went to Tweeter Etc and bought a Monster Power conditioners and plugged it into the amplifier "High Current" outlet.
The Monster fried immediately. I took it back to Tweeter, telling them, that it could not handle the amp.
The salesman insisted I take a replacement, it fried as well and they gave me my money back.

So, yes these require tremendous cosmic power when turned on

- Rich

 

[Prana Ferox]

I'm curious what the FR transfer function looks like through the 'current outputs' and some random set of multiway speakers.

 

[RichB]

What does the term "upgraded" mean in this context? I see a fair amount of threads on old amps where the power capacitors are replaced with larger values to 'improve' the amp and where electrolytic capacitors are replaced with film capacitors. Since capacitors have more specs than just farads it is easy to alter the function of the circuit with different ESR, ripple current, etc.

Also, do these amps need more than just capacitor replacement after this much time? Are there bias adjustments that need done?

Sure, it may not have started out as a great amplifier; but then again we don't know how different from its original design it is running now.


See above about 'upgrading' the power capacitor(s).

With very limited information on the older equipment being tested makes this seem much more like a "hey, lets bash this old stuff that people like".
Even if one agrees that the numbers tell the complete story on an amplifiers performance, we would need the background on the equipment for it to be at all 'scientific'. The results fit the hypothesis so why question the methods, is bad science.

This is my amplifier but looking at the measurements, I wonder, if this was a complete repair. There are a lot of parts and if it still buzzes at the speaker, than I think I did not get my monies worth. I am surprised by the channel difference measurement.

At the time, this was the only choice for a cool running, high powered amplifier. Honestly, I expected better but the review makes me pleased that I replaced it with an ATI AT522NC amplifier. Smaller form factor, cool running, and reliability where the main features required.

- Rich

 

[RichB]

Couple of questions - what does "normal use either' mean?

View attachment 187992

Also, why does it say 'Center' top left, but the input/output is on the opposite side?

Are those fuses either side of the power lead?

The internal layout is not the best I have seen and that is weird.
Unbalanced was "Normal" at the time.

The meters and current outputs were, of course, gimmickry and I am surprised that the lamp still works after 20 years.

- Rich