Help - electrical advice

[timm]

Hi all. Need advice.

I have a sunfire signature amp. A Cary slp98p. The fuse in the external power supply of the pre continues to blow after anywhere from 5-30 hrs.

To debug it I disconnected everything - let the pre stay on 48 hours straight. No issue. Next hooked up amp - turned it on with no source - nothing playing and nothing other than amp connected. Fuse blew in power supply of pre about 12 hours later. This combo has been playing together for around 10 years.

Can anyone give me a clue how adding the amp to the output would cause the fuse to blow in the power supply of the pre? I've been talking to the mfg and we are scratching our heads.

 

[Speedskater]

Do you have a DMM meter? If so measure the DC voltage on the audio output. Then with no interconnect cables, measure the AC voltage from it's chassis to the amp's chassis.

 

[timm]

Do you have a DMM meter? If so measure the DC voltage on the audio output. Then with no interconnect cables, measure the AC voltage from it's chassis to the amp's chassis.

Yes. I have to get to the store for some measuring devices. In the meantime - I hooked it to a secondary system just to see if things blow on the second system. Same approach - different room different amp nothing else connected

 

[Tosh]

I added an upskirt photo of problem-preamp so those of us at home can follow along.

 

[JonFo]

I added an upskirt photo of problem-preamp so those of us at home can follow along.

OMG, what could possibly go wrong?

 

[RCHeliGuy]

Looks pretty clean with lots of room to probe around.

JUST BE CAREFUL not to short anything out with it powered up!

Another thing that "might" be helpful and has no risk factor would be using a heat gun to see if any of the parts are getting conspicuously hot.

https://www.amazon.com/Etekcity-Las...id=1518982645&sr=8-1&keywords=heat+sensor+gun


I would SERIOUSLY suggest that if you are using a digital multi meter in there put electricians tape on the probes so that only the top 1/8" of the prob is exposed. That will DRAMATICALLY reduce your chances of shorting something out. If you are set up for it using small shrink wrap would be even better.

 

[Bernard]

I know that Cary is popular with a few people here, but I would never buy something where you have to move six components in order to replace one. I heaved a huge sigh of relief when I got rid of my Dynaco stuff, and replaced it with ARC, on PCBs.

 

[timm]

I added an upskirt photo of problem-preamp so those of us at home can follow along.

Tosh. You are the man!! So let me update. The unit went to Cary for...a blown fuse. Fuse didn't look blown to me and I tried a second one - it happened to be bad. So I am told it's just a fuse - I get them to direct couple the unit while it was there and do the hexfreds / diodes mod. Unit sounds great but kept blowing fuses. After going round and round it became obvious it was going to be my job to figure it out.

I suspected phono tubes and asked if I could run linestage without them. I was told yes. So I did that - no fuse blows. So I leap to the brilliant conclusion that it is a bad tube - buy 4 new ones and problem solved.

Now one more thing - remote volume stopped working when it came back. No biggie - - but tosh do you know if that is a clip or soldered? And in your pic - is it visible?

 

[RCHeliGuy]

I know that Cary is popular with a few people here, but I would never buy something where you have to move six components in order to replace one. I heaved a huge sigh of relief when I got rid of my Dynaco stuff, and replaced it with ARC, on PCBs.

I love solid state
BTW not trying to start an argument. I just like the reliability of it. I haven't had an audio equipment failure except for my subwoofer that was likely blown by a lightning strike a while back. It was toast, driver and boards.

 

[timm]

My problem? I love both!!! . The addition of the pre vs going direct from directstream dac to amp was noticeable. And I get those cool glowing lights. Hey... lol. I do like the sound it brings though. So that's why I do it.

 

[amey01]

I love solid state
BTW not trying to start an argument. I just like the reliability of it.

Over the years........the valve equipment I have owned (and currently own) is more reliable than the SS equipment.

What do you do when a PCB fails? Throw the whole thing away.

 

[RCHeliGuy]

Over the years........the valve equipment I have owned (and currently own) is more reliable than the SS equipment.

What do you do when a PCB fails? Throw the whole thing away.

For my sub woofer, they sent me a new board and driver that I replaced.

However for EVERYTHING else I've owned I find that I upgrade them or give them away before they wear out.

I bought a USED Onkyo Integrated Amp in college in 1985. I used it for many years and finally gave it away with my turn table and Boston Acoustic speakers around 2008.

I got a Yamaha AV receiver in the late 90's that I replaced with an UHD AV receiver recently. I now use the old AV receiver to drive the transducers in my car racing rig. My wife still has her integrated stereo that she purchased when she first got out of college.

I have THREE Oppo BD players now! One is the Master Bedroom, One is in the Media Room and the 105D is in the Den driving my amp for my ML speakers. All work great!

I even have a Total Bithead USB D/A headphone amp connected to my computer that has been powered up nearly continuously for the last 16 years!

I have had tape drive systems go out on my Nakamichi tape deck, and Mitsubishi HiFi VHS deck, but I don't think they apply to this conversation.

I think statistically you will find that solid state electronics are much more reliable long term and don't suffer from the same degradation with age. Getting tubes is signing up for maintenance. If you like them, great! That is just part of the bargain when you chose to use them.

 

[Bernard]

I love solid state
BTW not trying to start an argument. I just like the reliability of it. I haven't had an audio equipment failure except for my subwoofer that was likely blown by a lightning strike a while back. It was toast, driver and boards.

I agree with you. I just got seduced by the sound of tubes. My tube preamps have been reliable. Not so my tube power amps. Capacitor failures have been spectacular. I also hate lugging those monsters. You really got me thinking!