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

[lowmantotempole]

Hey there.

I have a Mako Dorado that needs some work. I have no idea what is wrong with it. I do know it’s got brand new power tubes and decent preamp tubes. Just isn’t working like it should.

Anybody know a good amp tech that could look it over and possibly fix it and maybe even mod it?

Jerry from FJA has been MIA and won’t return emails...

Please PM any suggestions.

Thanks!

 

[napalmdeath]

Maybe your preamp tubes aren't so "decent"?

 

[japetus]

What is it doing, what are the symptoms?

 

[lowmantotempole]

What is it doing, what are the symptoms?

Ok so here we go...

I know enough about tubes and am not a noob. I can change and bias my own amps just fine and have swapped about 20 various preamp tubes in and out of this amp to eliminate bad tubes.

On the low input the volume is really low when cranked and has a lot of hiss.

On the high input I got no signal at all. I looked inside for any burnt components and just can’t find anything visibly wrong. It’s a different PTP design so I’m at a loss there.

 

[SpiderWars]

Andrews Amp Labs in Dunwoody area.

 

[BSRIAudio]

What is it doing, what are the symptoms?

Ok so here we go...

I know enough about tubes and am not a noob. I can change and bias my own amps just fine and have swapped about 20 various preamp tubes in and out of this amp to eliminate bad tubes.

On the low input the volume is really low when cranked and has a lot of hiss.

On the high input I got no signal at all. I looked inside for any burnt components and just can’t find anything visibly wrong. It’s a different PTP design so I’m at a loss there.

Have you cleaned the input jacks and tube sockets with contact cleaner? You likely just have some corrosion that is preventing good contact somewhere in there. Also worth looking closely at all the solder joints. Turret or PTP amps can be built very rigidly and joints can crack or break from shock.

 

[guitarded_1]

I would go with Bakos Ampworks or Andrews. I prefer Jeff Bakos but Andrews is top notch as well.

 

[lowmantotempole]

Atlanta techs apparently don’t need work...

 

[Monomyth]

Sounds like a ground issue, maybe at your input jacks?

 

[lowmantotempole]

Sounds like a ground issue, maybe at your input jacks?

Wanna take a stab at it? Maybe mod it?

 

[guitarded_1]

Take it to Acorn. Tyler knows his stuff.

 

[311boogieman]

Sounds like a ground issue, maybe at your input jacks?

Wanna take a stab at it? Maybe mod it?

If I had to guess he probably has 47 PMs from people asking him to mod their amps

Have you tried some of the suggestions so far? Cleaning ALL sockets with Dioxit (like) contact cleaner would probably go a long way. Can you hear your guitar on the high input if you plug it into the FX return?

 

[lowmantotempole]

Sounds like a ground issue, maybe at your input jacks?

Wanna take a stab at it? Maybe mod it?

If I had to guess he probably has 47 PMs from people asking him to mod their amps

Have you tried some of the suggestions so far? Cleaning ALL sockets with Dioxit (like) contact cleaner would probably go a long way. Can you hear your guitar on the high input if you plug it into the FX return?

I’ve tried everything I’m capable of doing. Yup cleaned it all up, checked for loose tubes, opened it up and looked for any fried components or bad soldered spots. Not sure what you’re saying about plugging into the fx return...

 

[lowmantotempole]

It’s gotta be something in the preamp. I plugged into the FX return and it’s crazy clean and loud. I went through and swapped out every preamp tube with known good tubes. No joy there.

 

[Mr. Willy]

Cold soldering joint?

 

[lowmantotempole]

Cold soldering joint?

That’s what I’m thinking or maybe even a broken solder joint. It came with broken power tubes so it obviously took a hit. Turret boards are pretty rigid so who knows.

I’m getting some signal on the low input jack but absolutely nothing in the high input jack. They are separate. No problem with power getting to the speakers using the FX loop return.

 

[Monomyth]

You’ve isolated where the issue is, no signal usually means a broken connection, luckily in the front of the circuit there’s not much ground to cover.

 

[lowmantotempole]

You’ve isolated where the issue is, no signal usually means a broken connection, luckily in the front of the circuit there’s not much ground to cover.

Can’t find any loose connections. Hope it’s not a bad component not like I can tell because everything is blacked out to protect against copying. Ugh.

 

[lowmantotempole]

Somewhere in here...

 

[BSRIAudio]

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