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Princeton Reverb Rectifier-GZ34 or 5U4?

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10/15/1999 4:03 PM

Princeton Reverb Rectifier-GZ34 or 5U4?

Greetings,
I have been rebuilding a '67 PR that calls for a GZ-34 recto on the tube chart...and it probably has had a GZ-34 in it all of it's life.
But, when I measure the voltage at the plates of the 6v6s it reads 446 volts. I have tried a 5u4 and it drops the voltage to around 420v. The 446v seems to me to be a bit high. I tell myself that it has been running these voltages for years, so don't worry. It does sound good, and I like the GZ-34 due to the slow warm up. Should I not worry about it? Any Opinions/experiences/advice are welcome.
Thanks
Bob Cassen

10/15/1999 4:13 PM
keith	I started a thread on this subject about a year ago and I was advised to keep the GZ34. My '66 BFPR has been sounding great with no problems.

10/15/1999 5:39 PM
BC	Keith, Do you know what voltages your PR is seeing at the plates? BC

10/15/1999 6:37 PM
Troy	BC: I would keep the 5AR4 in there if you've got good NOS 6V6's. I have a '70PR and mine originally came with a 5U4, but I replaced that with a 5AR4 and my plate voltage runs about 435-440Vdc. The 5U4 will draw higher current and stress your PT (although it probably will handle it). The 5AR4 sounds better to me. Troy

10/16/1999 9:15 AM
John Stokes	Yikes. That is the highest I've seen in a PR. Jeez, mine is a 69 and the plates run at about 410 and that is with a GZ34. If you want the slow warmup (which is a good idea) and yet want to drop the voltage a tad, use a 5V4.

10/16/1999 12:51 PM

Thanks for the 5v4 tip. I thinks I'll get one and try it out. I did install 470k screen resistors, but I still feel uncomfortable with 446v on the plates of (NOS) 6v6s...call me paranoid:}
On a slightly different subject, I have been thinking about installing a Delux Reverb OT in this princeton for improved bass. This PR currently has a 12" V-30 speaker and is a little shy in the bass area. Any experiences with a DR OT in a PR?
Thanks,
BC

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