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Discussion in 'Amp Tech Center' started by deadbeat son, Aug 20, 2015.
I imagine it only exists on the Custom channel
You are correct.
I finally got around to doing the 18k resistor mod and it makes a huge difference. I didnt experience any thinning of the sound, just better control of the bass and a lower plateau. The amp is way more clear and tight now.
For any other noobs attempting it, a piece of advice: you cant simply remove the resistor and call it a day, there needs to be a connection at r34. If you simply remove the resistor altogether the bass response is actually worse...I know because I did this lol
So either jumper the resistor or solder in a wire in its place
I did not. I originally jumped the 18k resistor and didn't care for it.
Did you parallel an additional 18k, or simply jumper the existing resistor?
The resistor is removed and a jumper wire is in its place.
18k mod + RCA 12ax7a in v1 + eminence blue frame = killer tone
Hey everyone, I hate to bring this thread back up, but I'm considering getting a used 68' Princeton Reissue. How much bass does that jumper wire mod take out? Like if you could put a number to it, would it be -2 or -3 with the bass at zero after the mod? My jazz box has a lot of low end with my Vintage Sound 35sc (35watt single channel PTP wired Deluxe Reverb circuit in a Princeton cab) I have the bass at 0, pretty much all the time, I can't remember the last time I actually used the bass knob. Amazing amp, but at 42 pounds, not amazing to carry, and a double bills south of 2k, doesn't put my heart at ease to use a handcart on rough pavement. What 10" speaker will have the least amount of bass response?
try a 10K in there and see what you think, or use a jumper so you do not lift pads off the fragile pc board,
and don't let it get too hot, there is a non reset thermal fused burried deep in the pwr xfmr that will nail you for 100 bucks>
From what I recall, after jumping R34, you would need to turn your bass up to 4 or 5 to get the same sound as 0 on the stock amp. Why are you interested in the 68? A 65 PRRI wouldn’t need this mod.
Good luck with your search!
With that handwired circuit, a good tech can do a lot more to customize that Vintage Sound amp to your needs.
The vintage sound isn't the issue besides the weight. I rarely have issues of it being too boomy. The mid knob can help control the bass too. It's kind of like a 65' Twin but cut in half lol. It's funny how I find you can get tighter, less boomy bass, and a more usable bass knob with a Twin when compared to a Princeton Reveeb.
Upon looking on the web some more, it seems the 65' reissue princeton is about the same price as the '68 one. Maybe $100 more at the most. The 68' apparently has less clean headroom too, so I'll probably keep my eyes peeled for a used 65' reissue on Craigslist or Offerup.
you can jumper both channels, so maybe they wanted one channel different so that you could set up on channel for one sound and blend that with a different sound, kind of like a Sunn Beta Bass/Lead, or not.
There aren't 2 channels in a Princeton. What amp are you referring to?
dang, my mind is gone. sorry about that, thinkin of 68 deluxe reverb,
No worries, I was just confused.