Sunfire Signature Stereo DC risk?

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surdo
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Sunfire Signature Stereo DC risk?

Post by surdo » Tue Feb 18, 2014 8:54 am

I'm considering buying a Sunfire Signature stereo power amp to use with a pair of Tannoy System 12 DMT monitors. On another forum, one respondent warned that if the amp fails it may output DC ("go DC") and destroy the speakers. I've read about this risk elsewhere with the old Phase Linear amps, but does this risk exist with the Sunfire Sig. 600? If not, please explain why not. Thanks!

nooshinjohn
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Re: Sunfire Signature Stereo DC risk?

Post by nooshinjohn » Tue Feb 18, 2014 12:39 pm

WOW!!! that is one hell of a first question! Can't answer it, but welcome just the same. There is a guy named Bill Flanery that will eat this kind of question for lunch. You can find him here...


http://www.flannerysvintageaudio.com/

Hopefully you can hang around a bit. There are some smart people her, along with a few smart-asses, but all in all, a great place to hang out.

surdo
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Re: Sunfire Signature Stereo DC risk?

Post by surdo » Tue Feb 18, 2014 12:47 pm

thanks a lot - I just wrote to Bill.

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Snoop65
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Re: Sunfire Signature Stereo DC risk?

Post by Snoop65 » Tue Feb 18, 2014 1:01 pm

Welcome to the forum! :D

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kingman
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Re: Sunfire Signature Stereo DC risk?

Post by kingman » Tue Feb 18, 2014 1:06 pm

surdo wrote:I'm considering buying a Sunfire Signature stereo power amp to use with a pair of Tannoy System 12 DMT monitors. On another forum, one respondent warned that if the amp fails it may output DC ("go DC") and destroy the speakers. I've read about this risk elsewhere with the old Phase Linear amps, but does this risk exist with the Sunfire Sig. 600? If not, please explain why not. Thanks!
I would not figure the risk to be any more to those speakers than any other, but that's just my opinion. BTW Welcome to LA LA land!!! :lol:

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radioeng2
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Re: Sunfire Signature Stereo DC risk?

Post by radioeng2 » Tue Feb 18, 2014 1:11 pm

Just about any solid state amp has the possibility of passing voltage in a mass failure situation. Any rig with output transformers does not have this risk for the most part. I would suspect that's what was being referred to in this situation.

I like the DMT 12's. Had a pair I worked with many years ago. Great point source monitor. I currently have the 8" version of those which were at CF last year.

Mark

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Re: Sunfire Signature Stereo DC risk?

Post by angelod307 » Tue Feb 18, 2014 2:18 pm

The sunfire amps , two channel, are fused to death internally.

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thuffman03
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Re: Sunfire Signature Stereo DC risk?

Post by thuffman03 » Tue Feb 18, 2014 3:37 pm

There is always risk of a failure, that being said, Sunfire amps do have protection built into them to not allow this from happening. The amp will go into protection mode.

surdo
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Re: Sunfire Signature Stereo DC risk?

Post by surdo » Tue Feb 18, 2014 3:58 pm

Thanks for the welcomes and the reassurance. Some amps do seem to be a bit infamous for producing DC (some old crowns for example) , but it wasn't clear whether or not this fellow had specific knowledge of the Sunfire 600x2. That's nice to know there's people here using the DMTs with the sunfires/carvers. My DMTs are being shipped to me at present. Have never used them, but I used some 15” Tannoy Golds many years ago in a studio and loved them. The bi-wiring options on the sunfire look pretty interesting. Radioeng2, I guess you've tried bi-wiring the DMTs? Any observations?

One other doubt I have. I'm looking at lots of used amps. Many of the better ones have THD readings around 0.05%. While the sunfires seem to have universally good reviews I'm surprised to see THD listed as no more than 0.5%. I know spec sheets of some companies are to be taken with a grain of salt but other audiofile amps like the McIntoshes have much lower levels. Any explanation?

If Bill Flanery replies, I'll report back.

Cheers and thanks again.

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radioeng2
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Re: Sunfire Signature Stereo DC risk?

Post by radioeng2 » Tue Feb 18, 2014 4:14 pm

Hi Surdo,

No, have not tried bi-wiring. No reason not to. The crossover is complex enough in the typical Tannoy I'm not sure how much you would gain.

At CF I was running a 6C33 tube amp thru Red Rock Audio cables.

I'm not a believer that you help yourself having monster power amps when it can't possibly be used. I've even heard such a situation and on a more efficient speaker, a good amp may actually sound like crap. I have no idea how the Sunfire would sound in this situation. Others will no doubt speculate. :lol:

The Tannoy's (you have experience and probably knowledge of such) have complex enough typical crossover, that they often are run with more power than the listed eff would suggest.

The single THD number is a bullcrap spec. Meaningless to the extreme. :shock: Tells you nothing about sonic sound quality. Takes a much deeper dive into specs to get a hint from them as to sonics. And in the end, they tell you more what is wrong, not right so much. IMHO.

Mark

surdo
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Re: Sunfire Signature Stereo DC risk?

Post by surdo » Tue Feb 18, 2014 4:30 pm

Yes perhaps the signature is too big or a waste of power, I don't know either. The DMT series manual recommends amps between 50 and 300 watts for the system 12, but later in the manual suggests 150 WBC should be the minimum for series 12 and above. This sunfire signature has popped up as a option, the other amps I'm looking at are between 150 and 300. Cheers and thanks

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Re: Sunfire Signature Stereo DC risk?

Post by angelod307 » Tue Feb 18, 2014 8:26 pm

I have yet to hear anything short of amazement with the lightstars, or even the 300/2. You never go wrong as bob built a sound quality product that has it were it counts. But like all things, there are many reasons one has to like this or that. Sunfire 300/2 hands down the most bang, best sounding amplifier a man , woman or child can own with having a lean on the house to own it.

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Re: Sunfire Signature Stereo DC risk?

Post by angelod307 » Tue Feb 18, 2014 8:30 pm

Unless you are in for some tubes. Glorious tubes.

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Re: Sunfire Signature Stereo DC risk?

Post by angelod307 » Tue Feb 18, 2014 8:32 pm

I did not mention although worthy, the sunfires that i have have a cap on the rca for not passing dc from a defective pre, so theres that ad well.

surdo
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Re: Sunfire Signature Stereo DC risk?

Post by surdo » Wed Feb 19, 2014 5:21 am

I read about this somewhere that the "lab" RCA input doesn't have any protection from DC coming from a faulty pre-amp. Sorry I don't know much about electronics, by "cap" do you mean capacitor? I guess the balanced inputs are OK and I'll be using these mainly with a mixer.

Another doubt I have about the sunfire. I read in various posts about people sending their amps to very specific people for repair and that circuit diagrams are held by a select few. I live in Brazil and won't be able to send my amp to the states if something breaks. Do you think I'll be left with a lame duck if the amp needs repair, or are these amps pretty simple to fix by a good tech?

Cheers

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