why so many Fender Princeton Reverbs for sale?

[statorvane]

Here's a silverface that just came up here: http://binghamton.craigslist.org/msg/3935782646.html Seems ridiculously overpriced for a modded silverface with shattered tubes.

There's a link there to some Rivera mods.

[Cygnus X1]

Rectifier, again don't be hesitant to swap from 5AR4 to 5U4.

I'm still wondering about this.
Whether it's really safe.

Seems 5U4 would pull too much current?

[Structo]

I found this a few years ago.

[Milkmansound]

thanks for that file! I will be posting that on my shop wall

[Reeltarded]

Ditto on the thanks for that one, Tom. Everything annoying and all in one place! Yeah!

[Firestorm]

The one caveat with the rectifier data (and the one that most disappoints people who were expecting a different result) is that the voltage drop figures are typically calculated at each tube's maximum current. If you have an amp designed for a 5Y3 and you swap in a 5U4 to get a little less sag, you wind up with no sag at all because the 5U4 isn't even breaking a sweat at the 5Y3's 125mA max.

[Cygnus X1]

Already have that chart.
Doesn't tell me what safe current rating of the DR (or PR) is for the 5U4GB 5V filament is.

Just wondering why the assertion is that it is a valid substitute.

[M Fowler]

I think the answer is: probably safe to run the 3A rectifier tube 5u4 but if you think the PT is running to warm well then it may not be safe. Not sure if the spec on the Princeton PT is 3A or 2A personnally.

Mark

[Reeltarded]

I want to put one in a JTM but I know better. I have a PT for 2 and a quad of 6L6 that I want to run EL34s in but I kind of know better than that for now too.

Damnit! I want the whole other way! 5u4GBs and EL34s! Why!!? Whyhahahahayyy?

Ok. Carry on.

[M Fowler]

Well the 5V4 recto tube is 2A and drops voltage between 5AR4 and 5U4 but the above chart shows different?

For lots of drop use the 5R4 it's 2amps.

[Cygnus X1]

I figure 2 amps for 5V4 off the top o' me head.

Am running a 40 year old Telefunken GZ34 in the Deluxe Reverb.
Probably safest to keep using it until it decides the "time has come".

But I have boatloads of 5U4GB's.
Not looking to change the tone either.

Sorry for the temporary derail.

[pula58]

what strikes me as weird about the Princeton reverb is its feedback circuit. The 2700 ohm feedback resistor from the output (speaker) connects back to what is (at audio frequencies) the junction between the 47 ohm resistor to ground, and the cathode of the 12AX7 that drives the phase splitter. So, most of the feedback current from the 2700 resistor is heading straight to ground through the 47 ohm resistor since that path has so much less resistance than the impedance "seen" looking up into the cathode of said 12AX7.

[10thTx]

I found this a few years ago.

That was put together yrs ago by LooseChange and Tubenit on the Hoffman forum.

Most (not all) of the data came from "NJ7P Tube Database"

With respect, 10thtx