Sansui 3300 hiss

[PlayDead]

I just picked up a Sansui 3300 in working order! The problem is that it has a fairly loud hiss, more so on the left channel. The hiss is on all inputs and raises and lowers with volume it doesn’t overpower the volume of music but is definitely auditable during play back, just curious what to replace? I did order this kit to “recap” this unit https://www.audio-high-store.com/product/sansui-3300-upgrade-kit-audio-capacitors/ just wondering if this is going to rectify my buzzing noises

 

[RonnieBiggs]

I'm not sure whether recapping will solve the issue completely.
If the volume pot does change the volume of the noise, then the source has to be in front of it. It might be a noise transistor. Candidates here are the 2SC871 - I think they are known to get noise. I would also replace the 2SC632 and SC1124 and maybe do some more research whether one of the other transistors are also known to have issues...

 

[Hyperion]

1. Dirty controls, switches or connectors, 2. noisy transistors or diodes (there is a list), and coming a poor 3rd, a small number of problems might be caused by a small handful of electrolytic capacitors.

Shotgunning all the electrolytic capacitors in a unit with faults is a very poor way to deal with those faults. And if you are not skilled in this activity, you could introduce more faults. Add to that schematic errors introducing doubts, and mistakes made by the people you bought the capacitor kit from, and you have a recipe for disaster.

I also personally think that these 'capacitor kits' provide the wrong types of capacitor too.

 

[PlayDead]

Thanks so much for the reply’s. I am definitely looking to get her back to blazing again! I am good at soldering and can halfassed read a schematics, so that helps. This thing does sound great and it is rocking but that left channel hiss will drive me up a wall, lol. the right channel isn’t so bad, but it does make sense to me that The problem is pre volume knob so a recap is probably not going to help much. I am going to take a look at it and consider changing out the 2sc871,2sc632 and sc1124 If I could source these parts. I am not opposed to having it worked on if anyone knows a good shop or tech in the NW Indiana area

 

[Trw]

From my personal experience and something that i will certainly do in the future is to clean all of the trimmers before changing anything be sure to mark them before hand

 

[JHoffman]

I just picked up a Sansui 3300 in working order! The problem is that it has a fairly loud hiss, more so on the left channel. The hiss is on all inputs and raises and lowers with volume it doesn’t overpower the volume of music but is definitely auditable during play back, just curious what to replace? I did order this kit to “recap” this unit https://www.audio-high-store.com/product/sansui-3300-upgrade-kit-audio-capacitors/ just wondering if this is going to rectify my buzzing noises

I just replaced all of the electrolytic capacitors in my Dads 3300 on the power and driver block with hardware from Mouser. Also replaced the off board large capacitors and a couple transitors, known for noise, on the driver block. The left channel was very weak which turned out to be several failed electrolytic capacitors; they are at the end of life for sure. I scanned my Manual and schematic, they are posted at akdatabase.com. Take a look at the field effect transitors on the mic block, F-1430, FET651 and FET652 as a potential source of noise. Both can be replaced with a J113. It’s pretty easy to trace the signal through the circuit with an oscilloscope to find the source of noise. Good luck and keep us up to date.

 

[dly66]

Hiss going up and down with volume would indicate the main hiss source is upstream of the volume control, so not likely in the amp and tone circuit. If like the 2000A everything seemed to run through that input board except the tape monitor (Phono, AM, FM, and AUX).

Push the tape monitor button in to see if the hiss is still there and moves up and down with the volume control. If hiss no longer noticeable my best bet would be transistors on the F-1267C input board and maybe the pair in the mic circuit.

I think the 2SC458, 2SC631, and 2SC632 were largely interchangeable Sansui would use what they apparently got a deal on or was available, Conrad Hoffman on his 2000X etc web page indicates they could all get noisy, the 2SC458 probably the most infamous of the vintage problem transistors.

 

[PlayDead]

Ok, so far on the driver block 1180 I have replaced TR806&TR801(2sc1124 replaced c2690A) and TR802&TR807(2sc458 replaced ksc1845) the noise has got softer but is still present, early post stating onboard f1430 the transistors maybe the problem or on f1267 transistor , just curious if this is where I should go next?

 

[PlayDead]

Is a NTE133 a good substitute for a 2SK24E? I have a couple on hand or should I order J113 instead?