PSE Studio Two: The Unmodification

[hopeless]

I didn't start this at the beginning before I tore it apart, but what was done to this amplifier should have been a capital offense. Twisted pairs of 12ga wire were used to both power the boards, but as internal speaker wire as well. Kimber 4TC was used for line level input. It was a horrible mess, held together with blobs of solder. I'm going to attempt to rebuild this thing to something approaching normalcy.



With a nod to modernization, some things needed to be changed. To fit modern day binding posts, I had to move the line level inputs into the bottom speaker post holes.


It looks a little weird, but a whole lot easier than adding a plate and drilling new holes.



Always thought that spacing was odd. The originals were destroyed in removal, slathered in solder.

Back to work, need to find my wire stash and get the power supply situated, then back to the boards.

 

[hopeless]

More discoveries. The power switch had always seemed under-speced for the inrush current. Turns out the inside was largely goo.



So, she's going to get a triac switch to permanently solve that problem. I relocated the rectifier to the far right end of the amplifier, the transformer junction strip will remain in place. The triac will be placed where the rectifier was.



Here's a picture of some of the carnage. Still developing workarounds for some of the issues. Time consuming, especially when it takes so much time to not only move stuff, but to extend wires that were cut incredibly short, I imagine as part of the mod.



More carnage. I'm going to have to run 12ga wire just to fill in the holes so I can solder the speaker and power wires in.

It's going to be a while until this is completely finished up. Mouser just let me know that the 1302 outputs won't be in until June 10th. I should be ready for them by then.


For now, here's where we sit. Time for dinner.

 

[hopeless]

Shutting it down for the night. All that's left in the "back of the house" is to run the speaker ground wires, install the positive binding posts and wire them, then install the power wires to go to the boards.



Then we turn our attention to the boards. Mine is apparently a later model that adapted TO-3P devices instead of cans. It made for some interesting workarounds.

 

[hopeless]

It took 8ga wire to fill the holes

 

[RVT1K]

AAAHHH!! AAAHHH!!! My Mil-Spec-trained eyes can't take it!!

 

[gadget73]

I'm really curious what sort of magic they thought this was going to produce. Looks like someone did a nice job of making a mess for no good reason.

 

[hopeless]

AAAHHH!! AAAHHH!!! My Mil-Spec-trained eyes can't take it!!

That wire is stiff, and cut short. I'll revisit wiring once it's put together and running.

 

[RVT1K]

That wire is stiff, and cut short. I'll revisit wiring once it's put together and running.

I'm looking forward to seeing what some skilled TLC can do.

 

[hopeless]

I'm looking forward to seeing what some skilled TLC can do.

Then you are looking in the wrong place

 

[dogwan]

I feel your pain. I've had a few Studio II's with similar butchery!

Are you replacing outputs? If so, which ones are you ordering? I have a couple of II's that I need to order replacements for and was just thinking about getting back to working on them.

If you haven't seen it yet, check out this thread....

PSE owner's thread (Professional Systems Engineering)

Hey all, I know there's not many owners of this gear out there. I have been digging around and there are a few disparate threads, so I thought it might be useful to get us all in one spot! One thing that seems to be a problem is that there is not much documentation. Owner's manuals are...

audiokarma.org

 

[hopeless]

I feel your pain. I've had a few Studio II's with similar butchery!

Are you replacing outputs? If so, which ones are you ordering? I have a couple of II's that I need to order replacements for and was just thinking about getting back to working on them.

If you haven't seen it yet, check out this thread....

PSE owner's thread (Professional Systems Engineering)

Hey all, I know there's not many owners of this gear out there. I have been digging around and there are a few disparate threads, so I thought it might be useful to get us all in one spot! One thing that seems to be a problem is that there is not much documentation. Owner's manuals are...

audiokarma.org

I didn't want to plug up your thread, it's a reference for me. You have helped me out on this one in the past. Its been sitting a while until my skill level got somewhere in the ballpark.
MJW1302AG/MJW3281AG are replacements I'm going to try. Since there are no schematics, I'm flying a bit blind, but much more experienced. You will likely hear from me again.

 

[dogwan]

Ahh. Now I think I remember talking about this amp. It's early. The dogs got me up before I was ready.

I need to find replacements for the TO-3 cased 2n6229 and 2n5632 outputs. Haven't done much research yet. Maybe this weekend. Apparently MJ15015/15016 are recommended but seem hard to find these days.

 

[RVT1K]

Haven't done much research yet. Maybe this weekend. Apparently MJ15015/15016 are recommended but seem hard to find these days.

Mouser shows a large stock of the MJ15015G and MJ15016G

 

[dogwan]

Mouser shows a large stock of the MJ15015G and MJ15016G

Yeah, I just saw that this morning. Last time I checked (6-8 mo. ago) they were all back ordered everywhere I looked. Unless I wanted to pay approx double Mouser's price.

Looks like I need to need to gather a bunch of loose ends this weekend and assemble a Mouser order.

 

[hopeless]

Yeah, I just saw that this morning. Last time I checked (6-8 mo. ago) they were all back ordered everywhere I looked. Unless I wanted to pay approx double Mouser's price.

Looks like I need to need to gather a bunch of loose ends this weekend and assemble a Mouser order.

I've got a big Digikey order nearly ready to send Sunday. Found a Citation 16 that has a weird collection of Motorola transistors, like the PSE. Just starting a Mouser order. Have to wait for new projects to arrive. Hate it when freight is a big fraction of the bill.

 

[hopeless]

Well, got a little time in today. Not much, but I got the outputs mounted on the first card.
Before:



After:



Waiting for some hardware bits to come in. I'll pick up some #4 screws and nuts tomorrow to get these finished, but I'm going to swap out the slotted screws for Phillips. Easier to deal with.

 

[hopeless]

Nearly completed board fit for power wires on right channel. A bit more tidying up, but the back of the house is pretty much together. Now t get after the left channel. Should have all necessary hardware by Thursday. Should have time to finish up one or both of the Citation 12 Deluxes by then.
This is coming along pretty quickly since the outputs came in a month earlier than expected. Hoping I don't have to take it apart again. These are less fun than an hk870.