I fixed a '78 Ray with a dead preamp...

[Basstech]

Hi all. I thought you guys might be interested in a bass I recently worked on. It was a 1978 StingRay with a dead preamp.

As a tech, I've worked on quite a few early stingrays in the last few years, but I've never seen one with a dead biasing resistor before.

I ended up also replacing the current set resistor since it had drifted a long way from 1M5.

I also shifted the negative battery wire and put in a reverse polarity protection diode, to bring it up to modern standard.

 

[Rod Trussbroken]

Hi Rob. I searched for the amended schematic you did but cant find it on your site. Can you give me a direct link to it.

Edit: No need. I already have the variations.

 

[Jef]

Very instructive, thanks for sharing

 

[Basstech]

@Rod Trussbroken Sorry mate, I didn't see your post. Should be on the "Rob Mods Extras" page.

The differences are very minor, academic really. Even the output cap at 1u wouldn't make much of a difference unless you were driving a very low z load.

Very instructive, thanks for sharing

Thanks Jef.

 

[tbonesullivan]

That's great to see! Love seeing old gear like that brought back to life. Even the best components can drift over the decades.

 

[Rod Trussbroken]

@Rod Trussbroken Sorry mate, I didn't see your post. Should be on the "Rob Mods Extras" page.

The differences are very minor, academic really. Even the output cap at 1u wouldn't make much of a difference unless you were driving a very low z load.

Cheers.