Modern Princeton reverb

[nandrewjackson]

Just a show-and-tell post of my Princeton reverb.  I got it last year from MF/GC, it was a floor model, I got like 10 or 15 percent off, plus it was on sale too. It's burgundy wine color with a 12" Jensen alnico.


I got some more robust metal film resistors for power supply, output tube, and preamp anode/plate positions.


I put some RTV silicone around the tiny wires.
I preemptively reflowed the entire board.
I swapped trem oscillator R/C cathode with a red LED.
I added a raw control with front panel on/off switch, and internal trim pot.
I added passive attenuation using 7, big fat dale 6 Watt resistors, with on/off switch. It changes the impedance from 8 to 4 Ohm, but I'm not too concerned about that. It gives a roughly 14dB attenuation according to my cheap dB meter.


I can get that Princeton grit during daylight hours for a few minutes without the neighbors (apartment) complaining.


Pics in following post

[nandrewjackson]

Pics

[nandrewjackson]

Pics

[nandrewjackson]

Pics

[nandrewjackson]

Pics

[nandrewjackson]

Pic.

[sluckey]

Did you notice a big change in tremolo intensity?

[nandrewjackson]

Yes !


It is really night + day difference from stock with the LED.


Definitely credit to you and others here, Sluckey,  for your posts concerning tremolo.

[dude]

Put an 11 dent trim pot, 100kA, in place of the raw on/off switch. Then you just don’t have full cut in tone stack but a gradual cut with access on back panel, no need to open amp and change trim pot. Mouser has mini 11 dent 100kA pots.

[mresistor]

What is 11 Dent ??

[sluckey]

Why specify 11 detents? A standard pot is all that's needed.

[stratomaster]

Just got one of these myself, well the 68 Custom variant.

I couldn't stand the weird overuse of spade connectors when direct connections would've worked and freed up space around the power tubes/power switch, and OT primaries. 


The power switch in particular is egregious. 4 spade connectors and it's physically wedged into the black cable gland for the OT primaries.

I ended up routing things differently, neutral direct to IEC, hot switched with a single pole that I usually use on vintage Fender repairs, 6.3 and 5v heaters to sockets.  Lots of breathing room now.

Note: I wired the screen resistors unconventionally as they were done before I decided to clean up the wiring.  I'd have put them between 4&6 were I to do this over now that there's room.

[dude]

What is 11 Dent ??

Dent pot, wrong word, l guess l meant dedent (per Sluckey) pot..? Anyway, David Allen recommended the 11 detent pot for a raw control. l liked it much better than a regular pot cause you can dial in the exact same tone stack cut each time rather then turning a regular pot close to the spot you wanted. A dedent pot has 11 clicks, or stop spots, from left to right. Just cutting off the tone stack with an on/off switch, takes it out completely, one or two clicks gives a nice distortion not over the top and TMB, still works a bit.

[sluckey]

Dent pot, wrong word, l guess l meant dedent

The word is detent. Write it on the black board one hundred times.   

[stratomaster]

Have you experimented at all with the grounding scheme or moving the supply node for the reverb to a later one?  The grounding is curious and uses a 10 ohm resistor to isolate preamp and PI from plate/screen/reverb. 

I know why they did it, but I'm not convinced that it couldn't be done better.

The reason I linked the reverb to the grounding question is because if you move the supply node it makes sense that you'd have to move to ground reference to the other side of that 10 ohm resistor. 

[nandrewjackson]

No, stratomaster, I didn't change anything like that.


I actually didn't notice the 10 Ohm separation of ground.


I'll have a look at the schematic and check that out.


I've heard others talk about the reverb being on a less-than-ideal node, but I really don't have any interest in changing that at this time.

[dude]

Dent pot, wrong word, l guess l meant dedent

The word is detent. Write it on the black board one hundred times.   

Ok, 100 times, you keep picking on the dude, no breaks..? 

[sluckey]

Ain't learnin' fun?   

[bmccowan]

you keep picking on the dude, no breaks..? 

Maybe - if the Dude abides.

[sluckey]

Ok, 100 times, you keep picking on the dude, no breaks..? 

Dude, you gotta admit... You kinda asked for that. It's kinda like having a sign on your back that says "KICK ME". What was I supposed to do?