Hello,
I have an issue with my Sansui AU-70 where right channel is silent (almost) when Tone Defeat switch is OFF. Once I turn Tone Defeat ON, then everything works fine (except I'm left without tone adjustments).
Here's a quick video to showcase it: https://photos.app.goo.gl/kHmQUfcoy44AQGWn9
I was told to apply some DeoxIT into the switch, but I'm hesitant that this just won't address the issue long term.
Would you guys have any advice on what may be the root cause as well as what are the potential solutions?
Best,
Kamil
I have an issue with my Sansui AU-70 where right channel is silent (almost) when Tone Defeat switch is OFF. Once I turn Tone Defeat ON, then everything works fine (except I'm left without tone adjustments).
Here's a quick video to showcase it: https://photos.app.goo.gl/kHmQUfcoy44AQGWn9
I was told to apply some DeoxIT into the switch, but I'm hesitant that this just won't address the issue long term.
Would you guys have any advice on what may be the root cause as well as what are the potential solutions?
Best,
Kamil
Deoxit is your first and simplest port of call. If it's a dirty switch that will probably cure it long term.
If it isn't the switch, then start investigating further.
If it isn't the switch, then start investigating further.
Maybe you can locate the tone circuit, and short different points to the tone disable output to trace the tone circuit, and locate where the circuit is broken. Also clean the tone controls too.
Cleaning switches is usually the best place to start.
There's one tube in the tone path, shared between channels, so also check that tube.
There's one tube in the tone path, shared between channels, so also check that tube.
Thanks. I played around with swapping the three 12ax7s. Nothing has changed in terms of the symptoms. Having said that, I just shipped my amp back to the shop I bought it from (in Colorado). They promised to fix all the issues at their own expense (as I bought the amp as fully functional). I'll wait and see what the issue and fix was. I'm also considering full recap, as advised by some folks. Stay tuned!
The amp is finally back and fixed. Meaning all the controls are working properly. There's two issues and questions that I have:
1. the shop installed EL84 (JJ Electronics) NOS matched quad and when asked multiple times about them not being rated for 400v - they stated this is measuring really well in this particular amp. It does work perfectly, and I don't really crank it up loud. What can go wrong? Will it just use up faster compared to 7189?
2. I hear a buzz in the right channel when the volume is very low. Once I crank up the volume (12 o'clock) the buzz goes away. However my regular volume during sessions is between 9 and 10. What could be the issue here? I've switched my speakers etc. this is in the amp.
Thanks in advance.
1. the shop installed EL84 (JJ Electronics) NOS matched quad and when asked multiple times about them not being rated for 400v - they stated this is measuring really well in this particular amp. It does work perfectly, and I don't really crank it up loud. What can go wrong? Will it just use up faster compared to 7189?
2. I hear a buzz in the right channel when the volume is very low. Once I crank up the volume (12 o'clock) the buzz goes away. However my regular volume during sessions is between 9 and 10. What could be the issue here? I've switched my speakers etc. this is in the amp.
Thanks in advance.