Pro Jr. Layout?

[jrdamien]

Fair enough.
But is the phase inverter stage about he same? Fender schematic shows LTP as do the 18watt pix. The push pull output stage ought to be the same or darn close. That leaves the other 12AX7 to program. It is at least a short cut through part of it.

It certainly is that. You seem inspired to put it together.

[nosaj]

Fair enough.
But is the phase inverter stage about he same? Fender schematic shows LTP as do the 18watt pix. The push pull output stage ought to be the same or darn close. That leaves the other 12AX7 to program. It is at least a short cut through part of it.

So basically he could take the layouts of the 18watters and adjust values from the schematic of the pro jr (after looking at the similarites). Would be a good exercise. Maybe the OP can show us what he can do.
nosaj

[Enzo]

OH three four years ago, I'd hop right in and build something. My shop is just a memory, my parts and gear are in a storage unit, and I have no delusions I will ever operate a shop again. My shop work is done vicariously through others these days.

[jrdamien]

So basically he could take the layouts of the 18watters and adjust values from the schematic of the pro jr (after looking at the similarites). Would be a good exercise. Maybe the OP can show us what he can do.
nosaj

No, there are component differences above and beyond voltages. I haven't looked into how significant those are.

If I was good at turning a schematic into a layout I'd just do it. But I am not good at it.

[J M Fahey]

Point to point would not require a layout as everything is connected component to component.

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Of course you need a layout, you can´t randomly throw a bucketful of parts inside a chassis and solder them where they fall or plain *try* to interconnect them without further thought.

I used to build guitar amps on terminal strips before using eyeletted or printed boards and had to spend a good afternoon or two with pencil, paper and a good eraser to layout what I was about to build.
And if you need to build more than one unit, you need a layout for consistency and repeatability, because "there´s more than one way to skin a cat".

[Enzo]

The 18 watt schematic shows the input 12AX7 paralleled for one triode effectively. The Fender has two stages in that tube. So it would be a matter of keeping the input stage but using one triode, then adding part board space for the second triode stuff. So the part board would be a little larger.

[jrdamien]

?????????????????????????????
Of course you need a layout, you can´t randomly throw a bucketful of parts inside a chassis and solder them where they fall or plain *try* to interconnect them without further thought.

I used to build guitar amps on terminal strips before using eyeletted or printed boards and had to spend a good afternoon or two with pencil, paper and a good eraser to layout what I was about to build.
And if you need to build more than one unit, you need a layout for consistency and repeatability, because "there´s more than one way to skin a cat".

Every once and awhile, for practice and for fun, I'll try to put together a really simple circuit like an 5f2 using just term strips and the sockets. I have yet to get it right the first time. Some day...

[vintagekiki]

Hey all. I'm looking for a Pro Jr. layout of any kind. I can't seem to find anything online.

http://www.thetubestore.com/Resources/Fender-Amp-Schematics/Recent-Fender-Amp-Schematics

http://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-Pro-Junior-Schematic.pdf

http://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-ProJunior-III-Schematic-Rev-F.pdf

http://www.nodevice.com/manual/pro-junior/get126275.html

http://web.archive.org/web/20150905225324/http://support.fender.com/schematics/guitar_amplifiers/ProJuniorIII_schematic_Rev-F.pdf

[jrdamien]

http://www.thetubestore.com/Resources/Fender-Amp-Schematics/Recent-Fender-Amp-Schematics

http://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-Pro-Junior-Schematic.pdf

http://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-ProJunior-III-Schematic-Rev-F.pdf

http://www.nodevice.com/manual/pro-junior/get126275.html

http://web.archive.org/web/20150905225324/http://support.fender.com/schematics/guitar_amplifiers/ProJuniorIII_schematic_Rev-F.pdf

Unfortunately none of these are layouts. Fortunately no one googling "Pro Jr Schematic" will ever be wanting for links to said schematic.

[Enzo]

The fender literature - at least the service manuals - includes layouts, but for the printed circuit board, which doesn;t help you.

[olddawg]

Every time I see one of these threads I wonder "why" ? I can see maybe doing it if you have a hopelessly buggered board. But to gut a functioning amp just to rebuild it point to point always seems a bit ludicrous to me. Will it really sound different with the same component values, speaker, PT, OT, and tubes? I mean the amp might age better than a board after 20 years... but other than that... what is the advantage?

[J M Fahey]

Every time I see one of these threads I wonder "why" ? I can see maybe doing it if you have a hopelessly buggered board. But to gut a functioning amp just to rebuild it point to point always seems a bit ludicrous to me. Will it really sound different with the same component values, speaker, PT, OT, and tubes? I mean the amp might age better than a board after 20 years... but other than that... what is the advantage?

With exact same components, it will sound the same.
Only advantage of rebuilding on, say, eyeletted board is ease of modding; eyelets tolerate hundreds of leg/wire removals and resoldering, while PCB pads get destroyed after a few replacements.
In fact, when I build something on eyeletted board I add a few "unused" eyelets on free spaces, they may prove handy later on.

If you have a complex amp replacing its PCB is hopeless and frustrating, ; yet I often recommend junking a PCB on some amps, not to rebuild the same but to junk a buzzy crappy sounding high gain multi mode monstrosity and build instead a simple but killer sounding classic.

It will sound better not because of construction technology but because *the design* is better, as simple as that.

[vintagekiki]

Unfortunately none of these are layouts. Fortunately no one googling "Pro Jr Schematic" will ever be wanting for links to said schematic.

See the detailed attached links.
Layout is on the next page after schematics.

Fender Pro Junior- A Look "Under the Hood"

[jrdamien]

See the detailed attached links.
Layout is on the next page after schematics.

You're referring to the PCB layout, yes?

[jrdamien]

Every time I see one of these threads I wonder "why" ? I can see maybe doing it if you have a hopelessly buggered board. But to gut a functioning amp just to rebuild it point to point always seems a bit ludicrous to me. Will it really sound different with the same component values, speaker, PT, OT, and tubes? I mean the amp might age better than a board after 20 years... but other than that... what is the advantage?

Kids these days, with there doing things differently than other people do them.

What you're talking about isn't happening. But I don't know who wouldn't rather have a ptp circuit and discreet components (jacks, sockets, etc) over a pcb. It makes it endlessly easier to work on and to repair.