Brownface Deluxe Owners: What's your Plate Voltage?

IceTre

Member
Messages
895
Calling all TGP Brownface Deluxe owners (1961-1962 Fender Deluxe):

If you've ever measured your plate voltage when replacing power tubes, what did you measure? And what did you set your bias current to? Have you had a problem with power tubes overheating and shutting down, or static noises?

Here's why I'm asking. I have a 1961 Deluxe. I had problems with the amp shutting down. Some expensive NOS 6V6 tubes were damaged. I posted a thread on TGP about 2 years ago, and learned that, when replacing power tubes on a fixed bias amp like this, I need to rebias the tubes. I had a trim pot installed so I could adjust the bias. I then put in JJ 6V6 power tubes, as I didn't want to damage any more NOS tubes. Since then I've been running around 20mA bias current, as recommended by people in that thread. The plate voltages are around 470Vdc with 5AR4 rectifiers. I tried 3 different rectifers, JJ and two NOS ones. The JJ 6V6s have held up, although I haven't run the amp for very long at a time.

On a side note, I also tried a NOS 5R4 rectifier, and at 20mA the plate voltage was around 450dc. The sound wasn't very good. I then tried a NOS 5V4 rectifier, and at 20mA the plate voltage was around 460Vdc. I love how the amp sounds with the 5V4.

I'm curious to know whether my plate voltages are significantly higher than other brownface Deluxes. I'm wondering if something is wrong with my power transformer; if it's putting out voltages higher than it should. I checked the date code and it is EIA606-133, which correlates to a Schumacher 1961 transformer, used by Fender back then, at least according to a website I found.

I don't expect y'all to go measure just for me, but if you recorded what you measured in the past, I'd love to get that info.

Thanks,
 

VJF

Member
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1,620
Those plate voltages are too high.

I built a 6G3 deluxe and here are my readings on startup using a NOS 5R4 rectifier instead of the GZ34 rectifier specified in the original design. I did this to lower plate voltages closer to design.

Slide1_zps5xvewebz.jpg


Here is the link to my build if you want to see how I installed an adjustable bias pot: https://www.thegearpage.net/board/i...e-build-documented-with-lots-of-pics.1579179/
 

IceTre

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895
VJF:Thanks for the reply and info.
I have a bias pot installed. That's how I set the bias to 20mA.
What bias currents are you running at?
Also I'd be interested in knowing what power transformer you used to get the lower voltages. Was it spec'd for 6G3, or something else?
 

IceTre

Member
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895
I'm also curious if anybody uses a variac or similar device (BrownBox, Amp Preserver) to lower the input AC voltage and therefore the plate voltage on your brown deluxe.
 

Blue Strat

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30,722
VJF:Thanks for the reply and info.
I have a bias pot installed. That's how I set the bias to 20mA.
What bias currents are you running at?
Also I'd be interested in knowing what power transformer you used to get the lower voltages. Was it spec'd for 6G3, or something else?

What voltage are you getting for your 6.3V heater connections?
 

slider313

Gold Supporting Member
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8,710
I'm using a GE 6087 rectifier tube in my 1961. The power transformer is a 125P2A. My plate voltage is 410v, screens 406v, current 20 ma per tube (RCA 6V6GTA) , heaters 6.7v ac. My wall voltage is usually 119v-121v.
 
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dex17

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I can't add anything to the conversation, just wanted to say I lol'd at the op's handle. Good one!
 

IceTre

Member
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895
What voltage are you getting for your 6.3V heater connections?

Good question. I measured 6.52VAC. That's a little higher than the standard 6.3VAC. The wall voltage measured 121.2VAC.

I also measured the main secondary voltage coming out of the transformer (red wires) going into the rectifier. One is 366VAC to gnd, the other is 367. The schematic says it should be 333VAC. Once again, the 5V4 rectifier output is 460Vdc.
 

IceTre

Member
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895
I'm using a GE 6087 rectifier tube in my 1961. The power transformer is a 125P2A. My plate voltage is 410v, screens 406v, current 20 ma per tube (RCA 6V6GTA) , heaters 6.7 acv. My wall voltage is usually 119v-121v.

The 6087 rectifier is like a 5Y3, right? So I guess you basically converted your Brownface to a Tweed Deluxe-- with tremolo. I haven't tried a 5Y3 in mine yet, cuz I have a Tweed Deluxe, but maybe I should just to see if the plate voltages correlate to yours. Thanks for the reply.
 
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Blue Strat

Member
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30,722
Good question. I measured 6.52VAC. That's a little higher than the standard 6.3VAC. The wall voltage measured 121.2VAC.

I also measured the main secondary voltage coming out of the transformer (red wires) going into the rectifier. One is 366VAC to gnd, the other is 367. The schematic says it should be 333VAC. Once again, the 5V4 rectifier output is 460Vdc.

6.52V is about typical for amps of that era, today. So that rules out a primary partial short that would make all secondary voltages a lot higher than stock.
 

slider313

Gold Supporting Member
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8,710
The 6087 rectifier is like a 5Y3, right? So I guess you basically converted your Brownface to a Tweed Deluxe-- with tremolo. I haven't tried a 5Y3 in mine yet, cuz I have a Tweed Deluxe, but maybe I should just to see if the plate voltages correlate to yours. Thanks for the reply.

The 6G3, even with a 6087/5Y3WGB, will not become a 5E3 Deluxe.
 

IceTre

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895
I can't add anything to the conversation, just wanted to say I lol'd at the op's handle. Good one!

After all these years, I think you're the first one who got it! I assume you've seen the movie, "Fear of a Black Hat"? My favorite music mockumentary.
 

Mattbedrock

A player who collects
Gold Supporting Member
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5,091
'Tre -
I'm back from my trip and found my notes from my build from years ago. I thought I had used Classictones but actually found I used Weber branded transformers in the build - PT W025130 / OT W041318. My notes say the PT puts out 340vac, rectified with a GZ34 to around 430vdc.

I originally had a set of Sylvania 6v6's in it running 396 plate volts biased at 19mv. They lasted a couple of years but then one failed to what I believe was an internal short. I then tried some all black Raytheons that I didn't like. I now have a pair of JJ 6v6's in it, running 390 plate volts biased at 20mv that I really like. I bought another set of NOS's for it but haven't bothered to put them in.
 

IceTre

Member
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895
Thanks Matt, that's helpful.

I'm hoping to hear from some more Brownface Deluxe owners, especially those who have an original with the original 61 or 62 power transformer. I know you're out there. :)
 

IceTre

Member
Messages
895
Last night I put a Sylvania NOS 5Y3 rectifier in. At 20ma bias current, the plate voltage was 430Vdc. That's higher than Slider's 1961 with a 5Y3-- he measured 410Vdc-- but he said his wall voltage was 119-121, mine is 121.2.

btw, the sag with the 5Y3 was very noticable; the sound of the amp was significantly different from the 5AR4 or the 5V4 rectifier. With the 5Y3, it broke up sooner, the midrange was glorious, and the bass was not firm at all, but in a good way, like the greatest fuzz pedal ever invented. With the 5V4 or 5AR4, the bass was much firmer. I like the 5V4 sound the best.

So to recap, with different rectifiers, and bias current always adjusted to 20mA, here's my plate voltages, with a wall voltage of 121.2:

5AR4: 470Vdc
5V4: 460Vdc
5R4: 450Vdc
5Y3: 430Vdc

I'm still hoping to hear from a couple other owners of 1961 or 1962 Deluxes with the original power transformers.
 

swiveltung

Member
Messages
14,483
They run high on plate voltage, the BF do also. My BFD and BFDR both run about 460 or so. The Browns I've had (2) in the last few years have been high also, I dont remember quite 470...I just use JJ's. I've run the gamut on rectifiers, but going too low on the rectifier scale and the amp changes... as you noted with a 5y3.
I have a variac and have tried that prior to going to JJ's. It's a bit of a PITA when gigging. Wires everywhere, fear of the dial getting changed by someone dragging a cord etc around it...
I push the DR pretty hard at a gig, so the JJ's have actually become an asset for me.
 
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IceTre

Member
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895
Thanks Swiveltung, that's valuable info for me. Another one who solved the problem with JJ's. I've heard JJ6v6's criticized as not really sounding like 6v6's, more like 6L6's, but it's looking like that's the only way to go if you want a 5AR4/GZ34 rectifier with modern AC wall voltages. Or buy a variac. I've been thinking about getting a Brownbox Brownie.
 




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