Sansui 771 with hum.
- Thread starter marvil2k
- Start date
Register to hide this ad
I agree that generally that's what causes a constant hum in both channels of an amp, but believe it or not I have come across a couple of Sansui 771 receivers that hum (quietly when the volume is down) no matter what. I wondered if it had something to do with the enormous transformer used in that model (looks like a transformer for a 100 wpc power amp!) or if there was some sort of shielding design issue.
I think there were also a few posts about that particular model humming very quietly in the background when the volume was all the way down and new caps didn't solve the problem. I re-capped one of them and it still did it, so I didn't bother with the other assuming it was a design issue. I don't know if this applies to your receiver, just something I've observed.
Last edited:
661
I recapped a 661 chasing a hum and didn't get it. Threads lean toward a design issue. Finally reached a "need an o-scope to find it sort of finish". I missed a chance to hear another 661 to see it the hum was there. It is only with no volume on all inputs and both channels. I shelved it until I want to try again.
I can't believe its actually a design thing. It's slight, but its there.
I recapped a 661 chasing a hum and didn't get it. Threads lean toward a design issue. Finally reached a "need an o-scope to find it sort of finish". I missed a chance to hear another 661 to see it the hum was there. It is only with no volume on all inputs and both channels. I shelved it until I want to try again.
I can't believe its actually a design thing. It's slight, but its there.
tiga
Super Member
Thanks for that info. My 771 hums as well and I thought it was going to need a re-cap. I've put it aside for another day thinking it needed a recap but this sounds like an easy fix (if that's what the problem is). These are very nice sounding receivers.
Hmmmm,
Well, that is certainly worth a try. Mine looks clean enough but a funky connection there could be it. God knows I've had weirder things occur.
Well, that is certainly worth a try. Mine looks clean enough but a funky connection there could be it. God knows I've had weirder things occur.
Metrobilly
Member
My 881 that I bought new a loooong time ago has a hum. Sure would be nice if someone told me why ans simplify troubleshooting.
Great receiver that survived many collage party.
Great receiver that survived many collage party.
peterfranks
Super Member
This thread is a couple years old but I'm resurrecting it because it just saved my Sansui 771 which was sitting in my shop for the last year until I decided to make things right today (or hoped they would be right).
I had the problem as described by others in this thread: A fairly loud hum when the unit was powered on - present regardless of volume, selector setting, thru speakers or headphones - steady hum and nothing would affect it. I pulled the F-1499 driver board and used Deoxit on the blue connector. Re-assembled and the unit is as quiet as it could possibly be. Not often a fix is this simple. The hum made the receiver unusable. I'll even go as far and say this unit rivals my Marantz 2238B especially on low end frequencies. Powering Polk Monitor 5Bs along with EPI A70s - the bass is amazing. Below are pics of the boards and the 771 as my main receiver for my Sony TTS-3000.
It's been a good day .....
Last edited:
Hi Peter,
When you sprayed Deoxit the blue connector, did you brush it (with toothbrush?) or just spray and leave it till dry?
thanks
peterfranks
Super Member
Just saw this post - for what's it worth - just sprayed the connector then worked the card in and out - brushing would work too I suppose. Deoxit does a good job on contacts.
duckland 23
Active Member
I also own a Sansui 771 that me and my father bought for my uncle that's now dead .The most hum I had was from the turntable cartridge leads being lose on the headshell .But Im also thinking of selling it , but there's a broken push in silver knob on it so I think I cant place iot on eBay and get a good price for it .Its just too dam powerful for my jamo speakers . I don't want to blow out the cones on it . But I would like to get the a replacement switch for it ,but I can find it .
iamthejeff
Active Member
Wish I knew about the F-1499 board fix when I had my 881. I couldn't stand the hum, so I sold it as-is.
djprohaska
New Member
found this thread on 3/2/22
thought "there's no way this is going to solve my hum"
10 seconds later: "holy h*ll - the hum is GONE"
THANK YOU, Audio Gods
thought "there's no way this is going to solve my hum"
10 seconds later: "holy h*ll - the hum is GONE"
THANK YOU, Audio Gods
Auster
New Member
Here l am in 2025, looking to solve a 17 year old hum problem in my 771. It seems that patience is a virtue. I stumbled across this thread this morning, and l have just fixed it in about 5 min, as per the directions posted by various members over the last 15 years. I was originally advised it would require a full restoration, so l boxed it up, until today. It is now DEAD silent and sounding magnificent. l can’t believe it.
Thanks to all the members and their input over the years in keeping this thread alive.
Thanks to all the members and their input over the years in keeping this thread alive.
