Sunfire 300 Turn-off Squeal

Sunfire Home Audio (Stereo) Discussions and Questions
Post Reply
User avatar
kmanusa
Newbie 50+
Posts: 54
Joined: Sat Jan 23, 2010 9:35 am
Location: Northern Virginia

Sunfire 300 Turn-off Squeal

Post by kmanusa » Sat Jun 22, 2013 9:54 am

I have a Sunfire 300 amp that I sent to Bob Carver's Audio repair shop in 2011 for a refurb. Upon getting it back I noticed that when I power down the amp, it makes a squealing noise that slowly fades away. I wonder if this is typical of a refurbed amplifier or is it a symptom of a problem that needs attention? For the record Bob's replaced a bunch of power supply electrolytic caps on the downconverter board and burned-in and tested all functions. It seems to work fine with my Martin Logan CLS speakers but that turn-off squeal makes me wonder since I don't recall it doing that before I sent it in for refurb.

Keith

User avatar
Don
SILVER-7 TUBE AMP
Posts: 2695
Joined: Tue Oct 28, 2008 10:46 am

Re: Sunfire 300 Turn-off Squeal

Post by Don » Sat Jun 22, 2013 10:29 am

kmanusa wrote:I have a Sunfire 300 amp that I sent to Bob Carver's Audio repair shop in 2011 for a refurb. Upon getting it back I noticed that when I power down the amp, it makes a squealing noise that slowly fades away. I wonder if this is typical of a refurbed amplifier or is it a symptom of a problem that needs attention? For the record Bob's replaced a bunch of power supply electrolytic caps on the downconverter board and burned-in and tested all functions. It seems to work fine with my Martin Logan CLS speakers but that turn-off squeal makes me wonder since I don't recall it doing that before I sent it in for refurb.

Keith

Not familiar with your model. But my 400 X 7 has no squeal on turnoff. Sure someone will chime in that has your model. Is the squeal coming from the amp itself or through the speakers during shutdown?
To argue with a person who has renounced the use of reason is like administering medicine to the dead.
— Thomas Paine


"Try not to become a man of success, but rather a man of value" Albert Einstein

"Politicians are the only people in the world who create problems and then campaign against them". Charlie Reese

"The problems we face today exist because the people who work for a living are outnumbered by those who vote for a living." Brad Shurett


"Kindness is a language that the Deaf can hear and the Blind can see." Mark Twain

RIP BILL D. RIP WRABBIT

User avatar
jjptkd
SILVER-7 TUBE AMP
Posts: 3057
Joined: Wed Sep 22, 2010 4:50 pm
Location: Snohomish, WA

Re: Sunfire 300 Turn-off Squeal

Post by jjptkd » Sat Jun 22, 2013 10:57 am

I've had several units do the exact same thing but only when they're being unplugged. I believe there's a muting circuit which is suppose to prevent that. The early models were pretty much designed to be left on at all times because of the extremely low idle current, that's why they didn't have a power switch.

Bill Flannery (worked for Bob Carver) is still doing Sunfire repairs, you might want to give him a call and discuss the situation.
Attachments
Bill's info.JPG
Oppo Sonica DAC
Sunfire TG-III
Sunfire 300x2
Klipsch Chorus II

User avatar
radioeng2
SILVER-7 TUBE AMP
Posts: 2700
Joined: Fri Jan 26, 2007 7:06 pm
Location: E TN

Re: Sunfire 300 Turn-off Squeal

Post by radioeng2 » Sat Jun 22, 2013 11:46 am

I ran Carver Silver 9T's for years with Martin Logan Monoliths. At power down, they'd give out a small squeal or squeak going up sound, kind of like your talking about I think. It wasn't very loud, pretty quick and they always did it forever. Didn't change over time.

That's if I turned them off for some reason, which I very rarely ever did. I left them on all time unless going of vacation or maybe a big thunderstorm with lots of close lightning.

Mark
I was there "At the Fest!" Hope you were too!

User avatar
kmanusa
Newbie 50+
Posts: 54
Joined: Sat Jan 23, 2010 9:35 am
Location: Northern Virginia

Re: Sunfire 300 Turn-off Squeal

Post by kmanusa » Sun Jun 23, 2013 10:42 am

The squeal is heard through the speakers. It is not real loud but I was just concerned that if it got much worse it might take out a transformer in the CLS speakers. I toasted a transformer due to a malfunctioning amp a few years ago but I was able to get a replacement transformer from Martin Logan thanks to their service guy Jim Power. However, I understand there are no more replacement transformers for this model. It seemed like the squeal was a bit less loud when I had the amp connected to my other speakers, JBL 250ti, but who knows-- I can't put them side by side to compare.

I suppose I could just leave them on, they should otherwise last a long time now that the low voltage caps have been replaced.

Maybe I'll give Bill a call, thanks for the info and responses!

User avatar
jjptkd
SILVER-7 TUBE AMP
Posts: 3057
Joined: Wed Sep 22, 2010 4:50 pm
Location: Snohomish, WA

Re: Sunfire 300 Turn-off Squeal

Post by jjptkd » Sun Jun 23, 2013 11:57 am

I spoke with Bill about the situation, apparently there's not much he can do about it but he did say it wouldn't hurt anything. He rambled off a bunch of technical mumbo jumbo that I won't try to repeat as to why it happens with some amps and not others. I'm sure he'd be happy to explain it all to you if you wanted to give him a call.
Oppo Sonica DAC
Sunfire TG-III
Sunfire 300x2
Klipsch Chorus II

User avatar
kmanusa
Newbie 50+
Posts: 54
Joined: Sat Jan 23, 2010 9:35 am
Location: Northern Virginia

Re: Sunfire 300 Turn-off Squeal

Post by kmanusa » Sun Jun 23, 2013 12:59 pm

jjptkd wrote:I spoke with Bill about the situation, apparently there's not much he can do about it but he did say it wouldn't hurt anything. He rambled off a bunch of technical mumbo jumbo that I won't try to repeat as to why it happens with some amps and not others. I'm sure he'd be happy to explain it all to you if you wanted to give him a call.
Thanks for closing the loop with Bill, I appreciate it! And I'm especially happy about it not hurting anything ! :D

Post Reply

Return to “Sunfire Home Audio”