500V on reverb plate

[Colas LeGrippa]

I know this is too hot ! SUPER REVERB SILVERFACE .......any comment ?

Colas

[HotBluePlates]

Why does your Super Reverb even have 500v inside the chassis?

The blackface models ran up around 460v, maybe a bit more with today's wall voltage. The silverface B+ actually dropped around 30v. It should be well under 500v today.

[LooseChange]

Does the amp work? Are there any problems?
I've seen SFSR's with voltages that high.
Check the bias. Is it running cold?
Bias a bit hot and the voltages will go down.

[Colas LeGrippa]

ok let me explain: I am modifying this amp ( but did not touch the reverb yet ) what I did is:  tube recto replaced with SS recto,( that explains high voltage ),  first 12ax7 removed, tremolo intensity pot leads un-soldered and taped individually,  6L6 replaced with KT66 and rebiased at 36mA ( 490V on the plates , for 17W dissipation ), NFB disconnected from ext. speaker jack  . I am here now. When I turn the reverb knob over 8 , with the spring and footswitch disconnected, it starts to squeal very loudly. I started to check the voltages on V3, and I get nearly 500V on the plates ! Now I am to the point of opening the caps cover and check all voltages and resistors value. I NEVER studied a reverb circuit, nor built one, and I don't give a dam about reverb circuits. I want just to unplug it, in order to put it back easily if I want to sell that beautiful beast, eventually. ( sometimes, even if the beast is beautiful, we want to get rid of it for multiple reasons hey hey.........just like I did to Julie ). And sometimes, we are sorry about it.

Colas

[Colas LeGrippa]

THE AMP WORKS BEAUTIFULLY, very loud even at 2. Only problem:the f.........reverb knob and the high voltage on V3 plates ( 490V )
Thanks.

[sluckey]

what I did is:  tube recto replaced with SS recto,( that explains high voltage )

Duh Huh! The reverb driver is supplied from the second B+ node (same as screen grids). The driver is connected to that node thru a SE OT primary. The only thing between the second B+ node  and your SS diodes is a low DCR choke. It's gonna be high! Put the GZ34 back in if you're concerned.

[Colas LeGrippa]

it can't explain 500V on a 12ax7 plate.

[sluckey]

The reverb driver (V3) should be a 12AT7, not a 12AX7, and putting a SS rectifier in the amp IS THE EXPLANATION. Look at the schematic and it should be clear. BTW, did you like my pink fonts? I hated it. I won't do that again.

[Willabe]

BTW, did you like my pink fonts? I hated it. I won't do that again.

Love it!              No wait,          Love it!         

but did not touch the reverb yet When I turn the reverb knob over 8 , with the spring and footswitch disconnected, it starts to squeal very loudly.

Yes you did touch the reverb, you disconnected the spring tank. Now there is _ no _ load on the verb OT.

If you want to kill the verb just pull the verb driver tube, 12AT7 and disconnect the verb OT from the B+ PSU and tape it off, just one blue wire.  

[Willabe]

Did you unplug the verb tank at the tank or at the amp and left the tank cables hanging?

[LooseChange]

If you have nothing in the return of the reverb and turn the reverb all the way up, it will make lot's of noise. But, you won't be doing that if you have no reverb tank. Ground the grid of that half of the tube and all will be good.

IMO, seems like a shame to disable the reverb and the trem in this amp. Couldn't you find a better candidate?

[Colas LeGrippa]

the pink font.....un-readable, I was just wandering what your reply was all about.I didn't even notice you have written.

It is a shame un plugging the verb and trem ? The trem, I'll re-plug it when i receive my 250K pot with an on off switch, so that I can completely disable it for more gain, when not in use. The verb, all my apologies for my lack of knowledge  (that's why I'm a member of this forum, hey hey),  I 'll re hook everything with the good tube.

Thanks for your replies, I love you all

Colas

M A K E  L (o)(o) V E , NOT WAR.

[Colas LeGrippa]

Is there a test I can perform on a reverb spring unit, to see if it is dead or still good ? As far as I know, the circuit is good and the tubes too.

Thank you.

Colas

Make L (o)(o) VE, not war.

[jerrydyer]

what I did is:  tube recto replaced with SS recto,( that explains high voltage )

Duh Huh! The reverb driver is supplied from the second B+ node (same as screen grids). The driver is connected to that node thru a SE OT primary. The only thing between the second B+ node  and your SS diodes is a low DCR choke. It's gonna be high! Put the GZ34 back in if you're concerned.

 

[jerrydyer]

Im laughling because I could not read it until I quoted it.