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Post subject: deluxe reverb power tubes
Posted: Thu Nov 17, 2011 2:39 pm
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hello could someone recommend power tubes that would handle 450 at the plates? seems my amp has a newer power tranny and runs high even with changing the rectifier value. thanks jim


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Post subject: Re: deluxe reverb power tubes
Posted: Thu Nov 17, 2011 3:16 pm
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Was this PT made for the Deluxe Reverb? By running nearly 35 VDC higher B+ voltages (and perhaps more current load, too), you not only stress the power tubes, but the output tranny, gain stages, and perhaps the rectifier.

What maybe a solution (if you want to keep the PT)... is get a heavy duty Variac (at least 15 amps). And dial the voltage down so that 415 VDC is being apply to the power tubes plates. Then, all the other tubes should also be reading around nominal value.

I'd then remove the Variac's know to keep it from being twisted "accidentally" while playing. Note though, Variac can sometimes "squish" the tone a bit. It's adding another device to the link.


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Post subject: Re: deluxe reverb power tubes
Posted: Thu Nov 17, 2011 3:32 pm
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yes the tranny is a early 71 schumacher for a deluxe reverb. I was told that the silverface trannys tend to run higher. not shure why this should be a problem as there should be some good tubes out there that can handle the load. what about nos rcas from the 60s or 70s?


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Post subject: Re: deluxe reverb power tubes
Posted: Thu Nov 17, 2011 4:07 pm
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FBT, 450 VDC on the plate is about the max for 6V6GT (NOS or not). Heck, my Twin Reverb puts about 475 VDC onto the 7581A's. You could try 1950-1960 JAN mil spec 6V6GTY or 1970's 6V6GTA. May want to measure the voltages on the 12AX7 and 12AT7.

That OPT might be "seeing" close to 460 VDC. Be sure to rebias the power tubes.

http://www.webphix.com/schematic%20heav ... _schem.pdf


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Post subject: Re: deluxe reverb power tubes
Posted: Thu Nov 17, 2011 4:38 pm
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fenderbeenthere wrote:
hello could someone recommend power tubes that would handle 450 at the plates? seems my amp has a newer power tranny and runs high even with changing the rectifier value. thanks jim


What rectifier tube?

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Post subject: Re: deluxe reverb power tubes
Posted: Thu Nov 17, 2011 6:25 pm
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5ur4


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Post subject: Re: deluxe reverb power tubes
Posted: Thu Nov 17, 2011 7:22 pm
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5U4GB? It almost sounds like you got a PT for a Pro Reverb (or some similar dual 6L6GC circuit), instead of one for a DR.


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Post subject: Re: deluxe reverb power tubes
Posted: Thu Nov 17, 2011 7:29 pm
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I'd like to know the Fender P/N of that power tranny.

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Post subject: Re: deluxe reverb power tubes
Posted: Fri Nov 18, 2011 1:18 am
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025130 606-5071-7


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Post subject: Re: deluxe reverb power tubes
Posted: Fri Nov 18, 2011 8:11 am
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The "025130" P/N is legitimate -- it's the correct PT for a DR (also a Tremolux).

Arjay

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Post subject: Re: deluxe reverb power tubes
Posted: Fri Nov 18, 2011 8:25 am
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FBT, sorry after much ado. You better run good 1950-60's NOS 6V6GT. The 6V6GTY is a mil spec JAN designated tube with a brown micanol base. This base insulates better in various temperature than the black bakelite. So it can handle a bit more current.

I like Raytheon, Sylvania, TungSol, Canadian made JAN-6V6GTY.

https://www.tubeworld.com/6v6gtycan.jpg

The 6V6GTA can handle a bit more current. And may work in your amp.

https://www.tubeworld.com/6v6gta3940.jpg

At 450 VDC on the plates, better bias the amp to around 15-18 mA per tube (6.75 to 8 watts per tube).

Good luck! Tell us how it sounds. And if there is an early OD issue.


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Post subject: Re: deluxe reverb power tubes
Posted: Sat Nov 19, 2011 1:54 pm
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hey bmw thanks for the input, will have amp back from service today, been setup with vintage sylvania 6v6 power tubes and biased, Seems that a brand new cap let loose taking out the rectifier tube with it. It wasn't a power tube failure at all. Amp guy said he has only seen a brand new cap go twice on him in 30 years just so happens it was my amp. I will put it through its paces tonight with the new weber speaker and let you know how it sounds . jim


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Post subject: Re: deluxe reverb power tubes
Posted: Sat Nov 19, 2011 2:07 pm
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" brand new cap go twice on him in 30 years "

I've seen a lot of "generic" brand caps go bad on first fire up. Esp those made in China and other countries in the area. It's why I prefer Sprauge Atoms, F&T, Panasonic, Black Gates... established brands.


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Post subject: Re: deluxe reverb power tubes
Posted: Sat Nov 19, 2011 2:22 pm
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BMW2002Ti wrote:
" brand new cap go twice on him in 30 years "

I've seen a lot of "generic" brand caps go bad on first fire up. Esp those made in China and other countries in the area. It's why I prefer Sprauge Atoms, F&T, Panasonic, Black Gates... established brands.


+1

Resistors as well. Which is why I generally stick to NOS Allen-Bradley's where it counts the most.

Arjay

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Post subject: Re: deluxe reverb power tubes
Posted: Sat Nov 19, 2011 3:53 pm
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was a sprauge atom that let loose from the side not the end, told me that it was a rare thing especially with this brand.


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