Reducing B+ required? Newport "Vibrolux" Copy

[MrPink]

Hello!

I'm new here but have been reading multiple discussions here these weeks, so Hello everyone and thx for sharing all that knowledge!

I've been repairing a broken Newport Fender Copy I found. I'm a beginner (at max) in tube amp repairs to but done electronics before, so basics work

Thing i talk about says Fuji Electron Musical Instrument on the back. It's only the actual amp, no boxing. I have a link to the schematic, scroll down on this site and there it is:
https://www.musiker-board.de/threads/newport-top-wer-kennt-das-teil.330890/

Ground switch and death cap were removed, three prong cable installed
Filter capacitors were replaced as they were obviously blown, red plating was tamed by replacing coupling caps, biasing worked fine with matched new el34s and realising that really all those original oil capacitors (Atlas was the brand) turned out to be noisy and leaky i ended up replacing every single capacitor. Resistors turned out to be mostly same values as in schematics exept for grid stoppers between pins 5&6, them beeing 2,2k where schematic says 1k.   
Also, blown original filter capacitors were 450v ones whereas schematic asked for 500v ones.
It now is 500V ones.

That beeing sad, It's been working properly with some space for upgrades still (slight tremolo ticking) and it sounds Amazing! I've been playing it alot these days, sometimes up to 5 hours. No noise, no nothing, fenderish sound, beautiful!

What worrys me though is that turning on the amp, I do get peak 510V down to 498V on the first filter capacitor.  Switching off standby and completing the circuit then reduces my b+ to 470 V. All Tubes installed (exept V1, as i only use tremolo channel)
That first capacitor getting 500V beeing 50uf/500V, i dont like this.

The Power Transformer has a 350V out, which is connected now, and an unsused 300V out, which i could resolder to. So there would be an easy solution at hand, i guess? 
I'm not sure if I should do that though, for everything else is perfectly fine right now and I'm not sure about the consequences of reducing by 50V.  Might even consider using the unconnected ground switch to switch voltages, but I'm looking for more experienced opinions here..  Never change a running system vs dont exeed your capacitors voltage ratings on a regular basis

Plate Voltages of the El34's now are 461 and 464 V. Currents is 38 and 43ma. Guess it's in the hotter range but it does sound nice. Open for all suggestions though
So, what shall I do? Can i ignore that i exeed Voltage on my cap in standby? I'm getting a bit lost here, and very thankful for

[sluckey]

Replace that first filter cap with two 100µF@350V. Use two 220K resistors too. Look at this schematic for guidance...

     https://el34world.com/charts/Schematics/files/Fender/Fender_super_reverb_ab763_schem.pdf

[Dave]

You're right about it being a Fender copy. They even copied and edited the schematic. What Sluckey says is right. 2X100uf@350 plus resistors.


Not much you can do to reduce the voltages without major surgery from looking at the schematic.


Dave

[sluckey]

That schematic should not have a FWB rectifier. And the PT should have a center tap. Post some hi-rez pics of this amp, especially the PT and rectifier/bias board.

[MrPink]

Beautiful! 

Thanks for the replies! nice to see that the voltages i got actually fit fine to those in the fender schematic to... so i guess nothing wrong here except someone making the newport design never thought about what happens to that lonely capacitor in standby 

out of curiosity; what would be the effects of reducing my power transformers output to 300v? Like i said, there is a solder point right there with that output, not beeing used

think your suggestions is perfect as i can see fender handled it that way
really glad
i think it will need a lot of crafting and space making in the amp as now the 4 filter caps are stuck together in 2 "cans" each containing 2 caps at 50uf500v. so i will need to redesign some inside to get another one fitting there.  is there a value i could add in parallel to the already existing one? might make things easier
thanks!

ay and
I guess its a super reverb then and not a vibrolux? Was referred to as a vibrolux copy online

edit: just read your answer
I will try to make some pictures tomorrow

[sluckey]

out of curiosity; what would be the effects of reducing my power transformers output to 300v?

Kinda like stepping down from a Super Reverb to a Deluxe Reverb. Try it and see if you like it.

is there a value i could add in parallel to the already existing one? might make things easier

NO! Adding caps in parallel means the voltage rating will still be the rating of the lower voltage rated cap.

Adding caps in series causes the overall voltage rating to be the sum of the two series caps. So, two series connected 100µF@350V will be equivalent to a single cap rated 50µF@700V.

[PRR]

520V for 30 seconds is entirely tolerable within "surge" rating on large e-caps.

But "360V" * 1.414 is 509V. On 450V caps? This is the stuff of 30-day warranties. (On 450V caps??? Maybe that's why I never heard of Fuji Newport??)

If you retap for 300VAC it will be 424V, IMHO still high for 450V parts but everybody does it. You get about 70% power or maybe 35W (say a hot DeLuxe) which is not a lot of drop but still lame for the weight.

[HotBluePlates]

You're right about it being a Fender copy. They even copied and edited the schematic. ...

I don't know for sure, but I believe I see hallmarks of digital editing/drawing on that schematic.  Meaning "Fuji Electron" didn't draw the schematic, someone in modern times edited a Fender schematic to match their no-schematic Fuji Electron amp.

[MrPink]

out of curiosity; what would be the effects of reducing my power transformers output to 300v?

Kinda like stepping down from a Super Reverb to a Deluxe Reverb. Try it and see if you like it.

so making that switchable sounds fun

But "360V" * 1.414 is 509V. On 450V caps? This is the stuff of 30-day warranties. (On 450V caps??? Maybe that's why I never heard of Fuji Newport??)

They exported to european markets in the 60's. people argue it's the same as guyatone, only earlier
as i can confirm, amazing quality (in terms of sound) tubes is matsuhita japan

Pictures added, don't kill me for undersized mkp's, they were free

bias potentiometer included on the board

[MrPink]

520V for 30 seconds is entirely tolerable within "surge" rating on large e-caps.

suggesting i worry too much and leave it be for now? easiest way out so I'd take that

And thx again for help