MX-1000 rebuild

[rottalpha]

I see, so you are piggy-backing on the meter 15VDC supply, with D521, D522 as rectifiers. Even better than what I was thinking....the LED's should not add any substantial load, those diodes should be able to handle it. Will do some calculations, but I think that your solution is most optimal.
Now as a "want", it would be really cool to have a variable pot to adjust those LEDs just peachy....I have to think about that

 

[amr2]

Yes, the load is minimal. And if you put some leds in series, the load is even less.

Now as a "want", it would be really cool to have a variable pot to adjust those LEDs just peachy....I have to think about that

You could add a cheap PWM controller. I have tested this and it works great.

 

[amr2]

I used wide angle leds (140 degrees)

 

[rottalpha]

I used wide angle leds (140 degrees)

View attachment 870600

thank you, I will change my setup for the next patient. As far as the PWM, shouldn't I be concerned about introducing some line noise??

 

[amr2]

As far as the PWM, shouldn't I be concerned about introducing some line noise??

I had very little time to test it properly, but I think you shouldn't be concerned about the noise.

 

[amr2]

And finally, the speaker connectors. I decided to repair the originals:



I used two-part adhesive with epoxy to fill and join the parts. Bakelite as reinforcement.



And this is the result

 

[rottalpha]

really nice job, but what a pain!
Why didn't you go for a replacement solution? These posts are not the greatest by any standards.

 

[amr2]

This amplifier is for a friend of mine, and I decided to keep it as original as possible. Although I do not like these connectors at all...

 

[rottalpha]

This amplifier is for a friend of mine, and I decided to keep it as original as possible. Although I do not like these connectors at all...

did you get to play some tunes with that bad boy?

 

[amr2]

oh yes. it sounds just awesome. I want one for myself!

 

[Mark B]

really nice job, but what a pain!
Why didn't you go for a replacement solution? These posts are not the greatest by any standards.

They are however excellent from a conductor standpoint as the signal path is all copper.

 

[rottalpha]

They are however excellent from a conductor standpoint as the signal path is all copper.

The MX posts are not bad, but if you go to the extent he did to repair them, might as well replace them, unless the original look was in scope.
The "thongs" connecting the posts to the board are not copper.

 

[Mark B]

The MX posts are not bad, but if you go to the extent he did to repair them, might as well replace them, unless the original look was in scope.
The "thongs" connecting the posts to the board are not copper.

I think the "thongs" are tinned copper. The B-2x uses the same terminals and after replacing the original speaker terminals with WBT's I cut one of the "thongs" in half and it was copper inside.

 

[rottalpha]

I think the "thongs" are tinned copper. The B-2x uses the same terminals and after replacing the original speaker terminals with WBT's I cut one of the "thongs" in half and it was copper inside.

I would not be surprised...is just that they seemed so rigid to be copper.

Edit: just snapped one in half. It looks like it is tinned brass. Certainly not copper. I am not sure how long the thongs are in the B-2X. On the MX they look to also play a mechanical role, since they are the only support for the relay board. If you noticed they are flat and aligned in both axis so that provide lateral and vertical support.

When replacing speaker posts, the mechanical support would have to be addressed separately....unless modding to use the same thongs.

 

[Mark B]

I would not be surprised...is just that they seemed so rigid to be copper.

Edit: just snapped one in half. It looks like it is tinned brass. Certainly not copper. I am not sure how long the thongs are in the B-2X. On the MX they look to also play a mechanical role, since they are the only support for the relay board. If you noticed they are flat and aligned in both axis so that provide lateral and vertical support.

When replacing speaker posts, the mechanical support would have to be addressed separately....unless modding to use the same thongs.

Interesting. They're definitely copper on the B-2x.