5E3 original voltages question

[Jazzcab]

Hey all, does anyone know what the internal voltages where in the 5E3 on 110V votages back in the day? Trying to piece together a BOM for a 5E3 project and want to source a PT that can deliver those voltage on the plates. TIA!

[pdf64]

I think that the nominal domestic voltage in the USA was 120V when the 5E3 was designed / built, with an assumed 117V at the wall outlet, to account for losses in the house wiring etc.

[shooter]

also note Fenders note on everything being +/-20% 

[bmccowan]

Here is a discussion on that with some recorded voltages.
https://www.tdpri.com/threads/using-proper-voltages-with-5e3-what-a-difference.692627/

[bmccowan]

And Classictone claims this PT was reverse engineered from an original. http://www.classictone.net/40-18021.html I wouldn't hesitate to use it, but I also wouldn't sweat the exact voltage; 20% tolerance as Shooter pointed out.

[66Strat]

According to this source, the standard wall voltage in the US from 1938 until 1984 was 115 volts AC.
https://www.quora.com/Is-the-power-system-in-the-US-technically-110-115-or-120VAC-How-about-220-or-is-it-240-or-235VAC?share=1
I once attempted to measure the voltage at the fuse box when I was about 3 years old using a key hole saw, but was unsuccessful in my efforts.

[shooter]

I once attempted to

I was 8 when I soldered a lamp cord to a speaker to here the 60hz 

[bmccowan]

At 5, Dad taught me what batteries were. I had a cow jumped over the moon nightlight in my room and figured electricity/electricity what could go wrong? I unscrewed the candelabra lamp and dropped a battery in the socket. It was extremely interesting.

[pdf64]

Note that some early Fender schematics show a mains supply voltage of 110Vac but by the 5Fxx series, where noted, it's up to 117Vac.
https://el34world.com/charts/Schematics/files/Fender/Fender_white_model80.pdf
https://el34world.com/charts/Schematics/files/Fender/Fender_bassman_5f6a.pdf

Regarding to 20% voltage tolerance, I don't think it credible that given like primary voltage and similar loadings, it would be acceptable for PT secondary voltages to have a 20% variance, one to the next; consider that tube heaters have a 10% voltage limit, and normal mains variance must take up most of that. And it would be bizarre for each winding to have its own voltage tolerance spec.
Rather the 20% tolerance on voltages realistically can only apply where tube variance controls such things, eg bias voltage, resistively loaded plate voltage.

[shooter]

Rather the 20% tolerance on voltages realistically can only apply where tube variance controls such things

agree
my point, reproducing "that sound" has a 20% margin of error on a good day 

[bmccowan]

Yep - I took the point to simply mean that it might not make sense to try and hit the voltage spec right on the money. A recent thread on the 6G3 discussed voltages being off spec by a least 20%. Not necessarily varying all over the place, but just not what Fender recorded on their schematics. Who did they think they were; Gibson?

[DummyLoad]

Note that some early Fender schematics show a mains supply voltage of 110Vac but by the 5Fxx series, where noted, it's up to 117Vac.
https://el34world.com/charts/Schematics/files/Fender/Fender_white_model80.pdf
https://el34world.com/charts/Schematics/files/Fender/Fender_bassman_5f6a.pdf

Regarding to 20% voltage tolerance, I don't think it credible that given like primary voltage and similar loadings, it would be acceptable for PT secondary voltages to have a 20% variance, one to the next; consider that tube heaters have a 10% voltage limit, and normal mains variance must take up most of that. And it would be bizarre for each winding to have its own voltage tolerance spec.
Rather the 20% tolerance on voltages realistically can only apply where tube variance controls such things, eg bias voltage, resistively loaded plate voltage.

US standard from WWII to 1967 was 117V +/-10% - from 1967 onward 120V/240VCT 1ph became the current standard delivered as the residential service. many parts of the country lagged behind in adopting the 117V standard, so 110V/115V was commonly the specified line voltage for quite some time, well into the early sixties.

attached is a 1959 5E3 tube location chart that clearly states 110V 50/60Hz. so, if you own an original, it WILL be running a bit hotter.

why do folks fret over this anyway? everything is supposed to work within +/-10% of specified, so even at 120V we are still within the +/-10% of the 110V specified by leo on his 5e3 from 1959.
 
--pete

[pdf64]

Yep - I took the point to simply mean that it might not make sense to try and hit the voltage spec right on the money. A recent thread on the 6G3 discussed voltages being off spec by a least 20%. Not necessarily varying all over the place, but just not what Fender recorded on their schematics. Who did they think they were; Gibson?

When working with those old schematics, we should bear in mind that they could only accurately represent things at a particular point in time, ie their date code. Probably were done at the transfer from prototype to manufacture. After that, it’s completely normal for things to change as design tweaks etc were made over the course of that model’s production life. Maybe new drawings were done and they’re not in the public domain, or perhaps the changes were only ever hand annotations.
That’s probably why there’s a few schematic discrepancies between the 5F6-A Bassman schematic and  the 59 Tweed Bassman RI. The date code on the former is Sept 57, and things changed between then and the 59 production that the RI was modelled after.