Experimenting a Solid state rectifier - Readings

[tweed]

Hi guys,
Today, I have installed a solid state rectifier, weber WY3GT to replace a NOS 5Y3GT.

This is what happened, I toke some voltage readings with a tube and a tube rectifier ;

Rectifier socket:
Vacuum tube rectifier: Pin 2 and 3: 388v
Solid state rectifier: Pin 2 and 3: 323V

Power tubes:
Vacuum tube rectifier: Pin 3 to 8: 383v
Solid state rectifier: Pin 3 to 8: 303V

Also, I checked the cathode current on power tubes in the probe:
Vacuum tube rectifier: 37.5Ma
Solid state rectifier: 30.5Ma

I don't understand what is happening here. I though that solid state rectifiers would increase voltages not bring them lower?!

In the end of the day I liked the way the amp behavior. I notice that the amp sounded cleaner with more dynamics.
Thanks one more time for your support..

Regards

[Tonewood]

I believe typical ss diodes don't drop much voltage (about 0.7v per diode) for a common one. I have read the Weber WY3GT drops about 50v, maybe to help simulate sag??

I plan on ordering a Weber to play with so I would be interested in hearing the answers to your questions. Also, I'm not understanding your last sentence, is the 5y3 or the WY3 cleaner?

Thanks

[Bruce / Mission Amps]

Originally Posted by tweed

Hi guys,
Today, I have installed a solid state rectifier, weber WY3GT to replace a NOS 5Y3GT.

This is what happened, I toke some voltage readings with a tube and a tube rectifier ;

Rectifier socket:
Vacuum tube rectifier: Pin 2 and 3: 388v
Solid state rectifier: Pin 2 and 3: 323V

Power tubes:
Vacuum tube rectifier: Pin 3 to 8: 383v
Solid state rectifier: Pin 3 to 8: 303V

Also, I checked the cathode current on power tubes in the probe:
Vacuum tube rectifier: 37.5Ma
Solid state rectifier: 30.5Ma

I don't understand what is happening here. I though that solid state rectifiers would increase voltages not bring them lower?!

In the end of the day I liked the way the amp behavior. I notice that the amp sounded cleaner with more dynamics.
Thanks one more time for your support..

Regards

Hmmm... you have something wrong there chief.
Maybe you just misquoted.
Only even numbered lugs are used with 5Y3s, 5V4s, 5U4s, 5R4s, 5AR4s, GZ34s and probably others I can't think of... 2, 4, 6 and 8.
2 and 8 are the heaters and cathode, while 4 and 6 are the high voltage anodes.
Many years ago, I did quite a bit of the beta testing sag resistor tweaking adjustments for Weber on and inside those copper cap rectifiers.
They were/are pretty close to vacuum tube parameters when used within normal current load levels.
The only problem I ever really had was that at very high current levels they drop more voltage and they get hotter then a $2.00 pistol on Saturday night in a back alley off Bourbon Street, LA.
Also, if the solder sags out and a resistor or diode lead touches the copper somehow... pow... B+ all over the place on the outside of your copper cap.

[tubeswell]

Yep those copper caps have 'sag resistor(s)' in them to drop more voltage. Maybe they put the wrong value resistor in that particular one (perhaps)??