Noisy background on TEAC 3340S R2R

[gary7]

Been working on a Teac 3340S open reel. Transports functions, Recording & playback functions. Then I noticed noise in the background, kind of a hiss-crackle sound. It increases and decreases with the output control knobs. Did the deox and seemed to help briefly. Very annoying on an other wise nice deck. Any suggestions?

 

[r_brumett61]

A certain amount of background noise is normal. But you may have some noisy components. When playing a tape where are the VU meters reading when you hear the noise and is the noise present when no tape is playing?

 

[sixthday]

sounds like a failing transistor.

 

[gary7]

A certain amount of background noise is normal. But you may have some noisy components. When playing a tape where are the VU meters reading when you hear the noise and is the noise present when no tape is playing?

My thought. When it warms up a few minutes the noise appears at idle. Another Teac & Revox same vintage hooked up to same cables dead silent.

 

[audiojones]

A couple of thing that may help narrow it down:

Which channel is it coming from or is it in all channels?

What position is the tape /source switch in when you hear it and does changing it make the noise go away?

If it happens when the tape / source switch is set to source does the noise increase or decrease with the line input volume knob or with the microphone input volume knob? Lower them both all the way and try them individually while the output knob is turned up. Make sure nothing is connected to the input of the deck that may be causing it too.

Once you know which channel is doing it and which amp section it’s originating from it should be a lot easier to narrow down. I agree with sixthday, it does sound like a failing transistor but finding out where it’s coming from is the first thing on the list.

 

[gary7]

Noise is in both channels. Seems worse in right channel with switch to monitor. Worse in both channels when switched to source. Output controls raises & lowers the volume in both tape & source.

 

[audiojones]

What about the other two channels, same noise in those? Also see if the line input or the microphone input level affect it when it's in source mode. When it's in tape (monitor) mode see if the Simul-Synch switches have any effect on it, sometimes they get dirty and cause issues. Also see if there's any evidence that the deck has fallen forward and damaged the Simul-Synch switch board, that sometimes happens with these decks. Try listening with headphones plugged directly into the deck if you can.

 

[gary7]

Hard to say, getting hiss & gargling noises from both sets, F & R. Sprayed Deox in to the Synch switches. Synch board doesn't look damaged. Worked back and forth. Seemed to calm down the hiss & noise somewhat. Now getting playback distortion in the right channel, F & R. Damn. Going to leave it tonight and see how it is tomorrow after work.

 

[tapetech]

It's a 46 year old tape deck. It may need all new transistors. Even all new capacitors! That would be a long, involved project.

 

[gary7]

I know. Shame. At least the distortion cleared up when I checked later. At least the 3300SR I got with the lot seems to not have the noise issue.