Gibsonian's Cherry Pl 700 Ser I, soon to be a PLWO-1000

[laatsch55]

Last 2 times I hit the power switch , sparks flew from the BR. Not a good sign. Capping a new one up now,

 

[laatsch55]

And that's never a good sign, don't care who you are!!

 

[mlucitt]

But... a video of the sparks flying would have been cool. C'mon, you know it would have.

Mark

 

[laatsch55]

it would have been tits. Got my attention though. Bad solder joint on the transformer side.

 

[laatsch55]

The Giddings-Lewis horizontal mill is acting up again in the shop, with all kinds of work backed up. So, I stay at the shop till it's fixed tonight, just stopped by the house for dinner.


BTW-- the new BR did not fix my hum problem....

 

[laatsch55]

Cathy is now exhibiting saevere distortion on the left channel, which is consistent with what I think is a problem in the front end and could very well explain the severe buzz when I plug in an RCA interconnect.

 

[mlucitt]

Do you need any help? My son was wondering about the job opportunities north of Colorado. His in-law family is in Ft. Collins. He could be a roughneck although he is kinda skinny, good with tool tho'

Mark

 

[laatsch55]

Skinny just means the wind will takew you a little further. The Denver basin is busy with Anadarko drilling up the countryside, shouldn't have a problem finding work as a roustabout or rig hand.

 

[laatsch55]

The Giddings-Lewis has some 60 year old Allen Bradley motor startersin it. Starter coil was burnt, 60 years ain't a bad run for a coil. Oh, happened to have 4 of those in the Rozet shop, 2-120 volt, 2-480 volt.

 

[NavLinear]

Well shiiiit - dosen't everyone have four or five Allen Bradley starter coils in their private stash?

Where do you come up with this stuff anyways? Glad you got it fixed. Were you at least in a heated shop? You don't want to know what our weather is like here.

 

[laatsch55]

I have hundreds of AB coils, only 4 that are 60 years old though.

 

[speakerman1]

I have hundreds of AB coils, only 4 that are 60 years old though.

That's Nice. LOL

 

[laatsch55]

It is if you have 60 year old starters...

 

[speakerman1]

I have a 53 year old non-starter. LOL

 

[Gepetto]

Like the old joke...

That's when your semi-annual turns into your annual-semi.

 

[laatsch55]

An update. The right channel is now clear and quiet. The left is giving me grief. I got the right straoghtened out by isolating the ground from the AC feed to the protect board from the speaker grounds. The meter drive is now getting my attention. The lefty channel has that screech that ya get from a half plugged in patch cord.

 

[laatsch55]

Had the left and right meter drive feeds backwards, BUT, and this is embarrassing............................................
....................................................................................................................................................................
........

For testing amps I have a hook up panel brought out to the front of the rack. The speaker outs go to the back of the Spec2 where they are piggy backed with the Spec's speaker outputs. I switched the left and right speaker feeds going to the Spec and thge problem moves to the right. Both channels are quiet, like church mouse and clean as clear creek. Am doing low level listening now, as soon as Jani wakes up we'll shake it down.


It's done Scott. A better amp than when it got here in spite of me.....

 

[Gepetto]

You didn't wipe out your Spec 2 I hope Lee

 

[laatsch55]

Joe I don't think so , but I haven't pulled the rack out to see what the problem is. The Spec sounds Ok when I run it, but not GOOD. I' was told the power supply caps i put in it were counterfeit, and the bass has been deteriorating slowly./

 

[Gepetto]

Some advice on using MJ15024 transistors in the pre-driver position (where the RCA 410 usually goes) in combination with MJ15024 transistors in the main output position (where the PL909s usually go). In the lower half of the output configuration, this is a marginally stable configuration, there is local feedback in the configuration that Phase Linear uses for the bottom half of the signal between the pre-driver and the main outputs. I have observed transient oscillation birdies on the lower half signal when the MJ/MJ combination is used. I have not captured a scope trace yet due to the transient nature of this event. This also shows up as a slightly higher distortion reading when the MJ/MJ combination is used compared to the RCA/MJ combination.

Not recommended. Recommend that the original RCA 410 device be used instead if you are using MJ15024 main outputs.