5Y3 in PR?

[mresistor]

Wondering if anyone here has run a 5Y3GT in their Hoffman boarded Princeton Reverb? My first set of 6V6 flashed out on me, and I had to re-tube and re-bias, not a biggie, but the plate (pin 3 and 8) is running 405 VDc and the wall voltage is 119.5vac. I have it biased at 18ma so it's kind of medium. But I can barely turn up the vol as it gets really loud. ( I was running through a Weber Mini-Mass but I'd like to not do that as it wears out tubes prematurely. )
I thought I might like to lower the plate V and thought of a 5Y3. Could also go 5R4 but I'd have to purchase one.

[mresistor]

Oh never mind   - I got the answer. Nope, they can't handle the AC voltage. I had better go with the 5R4 .  It might still be as loud but at least I can get the plate voltage down a little.

[Willabe]

Oh never mind   - I got the answer. Nope, they can't handle the AC voltage.

Yes it can.

You could also try a 5V4, Doug has new 1's that are spot on voltage wise at a very good price. And it has a slow warm up time, easy on the other tubes.

[Fresh_Start]

I haven't looked at rectifier tube data sheets for more than max capacitor. Issues are voltage input and peak signal plate and screen current, correct?  This is an ignorant question:  does the output transformer draw additional current?  (IOW in addition to current drawn by tubes)

GZ34 rated for 250ma while 5Y3GT only 125ma (in our voltage range). Isn't 125ma still plenty to run two 6V6s plus four 12A?7s?

 Do remember that real 5Y3GTs put out significantly lower voltage than modern production.

Also know that while data sheets say 20uf is max reservoir capacitor for 5Y3, plenty of amps use 32uf and some even more.

Cheers,
Chip

[mresistor]

Thanks guys,  I think I will be fine with a 5R4GA JAN has about the same specs as a 5U4GB and it will  drop around 63-65 volts as opposed to 50 with the latter.
I'm running a Deluxe OT into a 2x12 cab with this Hoffman PR Chip. Although a 5Y3 would work, I want to stay with a rectifier that has similar or better specs.
Just wanted to know if anyone had used one in a PR. Wonder how long it would last?
Willabe, how many volts does the 5V4 drop? What I could find is it drops about half of the 5U4GB and that is going in the wrong direction for what i'm trying to accomplish.

[Willabe]

Willabe, how many volts does the 5V4 drop? What I could find is it drops about half of the 5U4GB and that is going in the wrong direction for what i'm trying to accomplish.

I don't know exactly how much, you'd have to try it in the amp. In a GE book I have it says; 25v@175mA.

I brought it up as another possible option.



 

[mresistor]

You know, I think the solution to my problem is to find and purchase a Mercury Magnetics Tone Clone Plus FBFPP-MM power transformer with 250-0-250 rating.
cha ching!! 

[mresistor]

Nope   that's not the solution, Too brown. Guess I'll have to explore the Marshall 18 watt circuit.

[punkykatt]

Ran a 5y3 in a pr build for over 200 gigs with no problems.

[Fresh_Start]

You know, I think the solution to my problem is to find and purchase a Mercury Magnetics Tone Clone Plus FBFPP-MM power transformer with 250-0-250 rating.
cha ching!! 

Much cheaper solutions:
1) Add reservoir cap and dropping resistor before the cap feeding your power tube plates.  Shouldn't produce too much extra sag as long as the plate node cap is big enough (40uf? 60uf?)  Has bonus of greatly improved filtering.
2) Zener diodes, either in a string on power rail or between PT ground and chassis (yes, I know some hate the idea of putting anything between PT ground and chassis)

Cheers,
Chip

[mresistor]

Thanks Chip    # 1 is a considerable option. I've done it on Champs where I've used that 4th cap in the JJ cap can and it does a great job. Pi filter I guess.
Drops the volts efficiently and the better filtering doesn't hurt even if it's dead quiet already.


I've done # 2 as well, but there isn't a lot of real estate left in the chassis so I would have to be very creative.   


I like #1.

[mresistor]

Well,  I have a large stash of 12AU7 Sylvanias from an organ, so it finally occurred to me to try one up front in my PR. 


VIOLA!!!      I like it. It has less gain than a 12AX7 but I can use a distortion effect to accomplish over-driven sound at reasonable volume levels.. 


I will just have to live with the high voltage on the plates of the 6V6.   Another thought was to try some JJ EL34s in this amp.   And I might just do that.

[Willabe]

I will just have to live with the high voltage on the plates of the 6V6.   Another thought was to try some JJ EL34s in this amp.   

The PT can't handle the extra heater load from a pair of EL34's.

[PRR]

What is wrong with 405V on 6V6?

Yes, it exceeds the sheet specification. But that was always somewhat bogus. Fender ran millions of 6V6 near 400V, the foundation of modern music.

[mresistor]

Hi Willabe  - My PT in this one is an Allen (Heyboer) TP25. It has 6.3Vac filaments at 4.5A.   


Upgrade Power Transformer for BF/SF Champ™, VibroChamp™, Bronco™, and Princeton™. 310V-0-310V @ 150ma, 6.3V at 4.5A, 5V at 2A. 50V bias tap, center-tapped heater winding and internal hum shield brought out to a lead for grounding. 2" by 2-1/2" mounting centers, 5.1lbs. Unit is approximately 1" taller than a stock transformer. Supports the use of both 6L6 and EL34 power tubes (with proper socket wiring). Now featuring M-6 grain oriented lamination steel for cooler operation.

[mresistor]

PRR - I guess it's OK. It was up to 416 when I was checking Bias again. So I set it around 18ma and that seems good with HV around 410. My line volts fluctuates during the day. I suppose it was mainly the the attenuator that is wearing out the tubes. Guess I was just freaking out a little with voltages over 400 volts.