Need an amp tech... Mako Dorado...

[311boogieman]

If you knew the preamp tube gain stages (block layout) you could look for issues surrounding those pins/trace/socket (Edit: ...that drive the Hi input jack). That's just a guess though, I'm not an amp tech.

you know...

V1a=
V1b=
V2a=
V2b=
V3a=
V3b=

I looked (Googled) but couldn't find such a description.

 

[lowmantotempole]

I know one is for the loop...

 

[SpiderWars]

Get a chopstick and gently poke some of the wires/connections in that area you think it is. Do it while amp is ON (one hand only! other hand NOT touching anything!). There are also some unshielded leads (like on that ceramic disc cap that goes from the jack to the volume) that look really close to other things that they are not soldered to, perhaps making contact.

 

[lowmantotempole]

Get a chopstick and gently poke some of the wires/connections in that area you think it is. Do it while amp is ON (one hand only! other hand NOT touching anything!). There are also some unshielded leads (like on that ceramic disc cap that goes from the jack to the volume) that look really close to other things that they are not soldered to, perhaps making contact.

You know I was actually trying that last night. I just wish I knew enough about amp engineering to figure it out myself. Dave Friedman said he’d fix it for me but man that’s like $300 in shipping ugh. It’s an odd design for sure.

 

[lowmantotempole]

And years after going silent I get this email...

I wonder if he sold the company/name?

 

[SpiderWars]

Once you've powered down the amp and let it sit a few minutes, then unplug it, then verify NO voltage with a known good multimeter...you could then measure/verify all the grounds relative to the chassis are common (0 ohms or extremly close to it). If you can bias it and I'm sure you've stared at it for a while...you should be able to tell what is supposed to be grounded.

It seems you've isolated it to very early in the circuit so you don't have to go thru the whole amp, just that stuff at the jacks and first couple of preamp tubes. Divide and conquer.

 

[Mr. Willy]

Always nice when a builder paints over all their parts and completely disappears.

What happened to him? I had a Dorado several years ago.

 

[lowmantotempole]

Always nice when a builder paints over all their parts and completely disappears.

What happened to him? I had a Dorado several years ago.

Dunno he just kinda wandered off. I got in contact with him. So I’m trying to work it out...

 

[savant421]

Lowell Hunt at Hunt Amplification in Phoenix....amazing tech

 

[SpiderWars]

Just got back from lowmantotempole's house and if you look closely at the shorting 'tongue' (I don't know what it's called) of the input jacks you can see the problem. Both input jacks and both FX loop jacks were like this. I have no idea how they could get bent so much, they were closer to shorting when plugged in rather than when unplugged as designed. I think the guy he got it from really pissed off his wife/gf or something. It almost has to have been intentional right?

I used a chopstick to temporarily make/break contact but could not fix them and the jacks have been compromised anyway so he said he will replace them.

 

[lowmantotempole]

Just got back from lowmantotempole's house and if you look closely at the shorting 'tongue' (I don't know what it's called) of the input jacks you can see the problem. Both input jacks and both FX loop jacks were like this. I have no idea how they could get bent so much, they were closer to shorting when plugged in rather than when unplugged as designed. I think the guy he got it from really pissed off his wife/gf or something. It almost has to have been intentional right?

I used a chopstick to temporarily make/break contact but could not fix them and the jacks have been compromised anyway so he said he will replace them.

Dude thank you so much for taking a look. I owe you. Don’t forget you’ll be getting an invite once I finish my project.

 

[SpiderWars]

Dude thank you so much for taking a look. I owe you. Don’t forget you’ll be getting an invite once I finish my project.

All good brother! Look forward to seeing it. Dibs on that Langner if you decide to sell!