Chinese WY2P tube same as a OB3/VR-90?

inperson

inperson

Active Member
I have another thread (the one about my 300B meters) with this question but maybe nobody noticed so I will ask in a separate thread.

The amp uses WY2P regulator tubes and I bought some NOS OB3 tubes to roll in but when I got them I realized that the OB3 tubes are 6 pin and the WY2P tubes are 4 pin. Did I get the wrong info from the OB3 seller? Which US or western tube is the same as a Chinese WY2P?
 
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I found a schematic on line using the WY2P, and the pinout matches an OB3.

Both are octal tubes. The only "Active" pins are 2 (K) and 5 (P). Pins 3 and 7 are jumpered together. This was sometimes used as a disconnect - if you accidentally pulled the voltage regulator tube you'd disconnect the output as a safety feature.

The US made OB3 also has pins 1 and 8, but they are not electrically connected.

Assuming that the voltage drop is correct (90v) and the current ratings are similar then an OB3 should substitute fine.

- Gary
 
Yesterday I stuck the OB3's in and when I turned the amp on it had a buzzing sound and the meters jumped, almost into the red, so I switched the amp off.

After reading what you wrote Gary I stuck the NOS Toshiba OB3's in and let the meters jump again but I didn't switch the amp off. The mA meters jumped and then settled back into the normal area. It is that sudden jump that got me worried. Is that okay?

Thanks Gary!
 
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Hiya,

Since you are editing your thread making mine look dumb :) I will answer your new query and edit away mine.

The mA meters jumped and then settled back into the normal area. It is that sudden jump that got me worried. Is that okay?
Click to expand...

Sounds like to me that the Tubes you subbed in don't "soft start" (Wish I had a better term). Meaning they conduct faster than the Chinese ones supplying full plate current faster.

Also after thinking about this. Maybe they just change the circuitry in a way that screws with the factory soft start.

I have OB3's coming out of the woodwork here. I can send you a pair if you want and you can see if maybe its just the Toshiba's ??

Frannie
 
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Two thoughts....

I can't imagine something that would affect the sound less than the regulators for the screen supply of the driver circuit. Stick in the Chinese WY2P if they're working properly and be done with it. Since we don't have full specs on the WY2P's there may be a difference in striking voltage etc. Also the capacitor across a gas regulator can cause oscillation big time - ask me how I know :).

If you really wanted to, you could play with decreasing the value of R5/6 a bit and see if the OB3's will fire more reliably/quickly.

Secondly, "matched" is perhaps the most incorrectly used word in the world of tubes. I've seen some supposedly factory matched tubes that weren't even close. As others have hinted - matched for what? GM, Plate current, Appearance??

- Gary
 
Hiya,

I can't imagine something that would affect the sound less than the regulators for the screen supply of the driver circuit.
Click to expand...

Well they could regulate B+ higher or lower I guess swapping them and I guess in a weird parallel universe that could affect sound.

This is SET land after all where the slightest circuitry twitch affects things it seems :)

Kidding aside.

But they could conduct differently and that could effect how fast B+ is generated which was all I was angling at.

Frannie
 
I know it says WY2P but the schematic shows 74 (72) volts in both locations which would indicate a 0A3 instead of a 0B3. 0B3 is a 90 volt regulator 0A3 is 75 volts.
The first character is a zero, by the way. No heater so no voltage.

see this for WY2P data: http://data.zuoshi.com/audiodata/cn/WY2P.png
 
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You need to calculate the voltage drop over the set resistor to get the tube to regulate properly. Ohms law is all that's needed: http://www.the12volt.com/ohm/ohmslaw.asp
The drop is the supply voltage minus the regulator tube voltage, in this case it should be 150 volts in my opinion which would indicate a 0D3 for 150volts for a 6sj7 because the plate voltage is 280 volts in this application. The resistor R5 should be 127K to drop 280 volts from 430 volts with .0022amps (2.2mA) as noted in the schematic for the 6SJ7. That seems unreasonable to me for good regulation. Someone please check my math. This might be a nice idea poorly implemented
The regulator needs about 30 volts to start and it helps if there is a light available - seriously. They need light to start. There was some military versions that used a radio-active source to start in the the dark at nominal voltages.
 
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This morning I got up switched on the amp and no problems. The OB3's fired right up with no noise and no peaking of the meters. Could they have just been acting up and were a bit grumpy after sleeping for 30+ years? This morning it seemed they were better prepared.
 
The 90volts from the 0B3 isn't a problem for the screens obviously, but you should still change the resistor for the voltage drop that is required for the 0D3.
Read a bit about implementing gas regulators, it's handy info.
 
kyle said:
The 90volts from the 0B3 isn't a problem for the screens obviously, but you should still change the resistor for the voltage drop that is required for the 0D3.
Read a bit about implementing gas regulators, it's handy info.
Click to expand...

Is this more for a safety reason or will this also allow for better sound from the amp?
 
buglegirl said:
Hiya,

Since you are editing your thread making mine look dumb :) I will answer your new query and edit away mine.



Sounds like to me that the Tubes you subbed in don't "soft start" (Wish I had a better term). Meaning they conduct faster than the Chinese ones supplying full plate current faster.

Also after thinking about this. Maybe they just change the circuitry in a way that screws with the factory soft start.

I have OB3's coming out of the woodwork here. I can send you a pair if you want and you can see if maybe its just the Toshiba's ??

Frannie
Click to expand...

Wow! I never meant to make anyone look dumb. If anyone is dumb here it is me :) I really appreciate your thoughts and the tube offer. I am in China now so I wouldn't want you spend so much on shipping me your tubes :P In fact back home in the US I live pretty close to a place full of tubes.

I think you were right about the hard start when I first turned them on but since then they have started softly. :thmbsp:
 
I bought some 5783 tubes: also regulator tubes, at 90 volts.
But they are quite different from the OB3.

The 5783 is a neon-type --> like to call it such because of the red gas glow.
The OB3 glows blue or purple.
The 5783 are quite noisy like a zener compared to the silence of the OB3.
And they have a smooth warm-up characteristic, with out a 'pop' (ignition of OB3 is 105 volt for a fraction of a sec.)

Maybe the chinese tube internally looks like the 5783 but octal.
My 2¢.
 
inperson said:
I have another thread (the one about my 300B meters) with this question but maybe nobody noticed so I will ask in a separate thread.

The amp uses WY2P regulator tubes and I bought some NOS OB3 tubes to roll in but when I got them I realized that the OB3 tubes are 6 pin and the WY2P tubes are 4 pin. Did I get the wrong info from the OB3 seller? Which US or western tube is the same as a Chinese WY2P?
Click to expand...
Analog metric lists 2 cross matches for the WY2P
CV3798, which is an European designation
QS1205, which I have no idea about.[emoji12]
Gary Kaufman said:
I found a schematic on line using the WY2P, and the pinout matches an OB3.

Both are octal tubes. The only "Active" pins are 2 (K) and 5 (P). Pins 3 and 7 are jumpered together. This was sometimes used as a disconnect - if you accidentally pulled the voltage regulator tube you'd disconnect the output as a safety feature.

The US made OB3 also has pins 1 and 8, but they are not electrically connected.

Assuming that the voltage drop is correct (90v) and the current ratings are similar then an OB3 should substitute fine.

- Gary
Click to expand...

inperson said:
Yesterday I stuck the OB3's in and when I turned the amp on it had a buzzing sound and the meters jumped, almost into the red, so I switched the amp off.

After reading what you wrote Gary I stuck the NOS Toshiba OB3's in and let the meters jump again but I didn't switch the amp off. The mA meters jumped and then settled back into the normal area. It is that sudden jump that got me worried. Is that okay?

Thanks Gary!
Click to expand...

Gary Kaufman said:
Two thoughts....

I can't imagine something that would affect the sound less than the regulators for the screen supply of the driver circuit. Stick in the Chinese WY2P if they're working properly and be done with it. Since we don't have full specs on the WY2P's there may be a difference in striking voltage etc. Also the capacitor across a gas regulator can cause oscillation big time - ask me how I know :).

If you really wanted to, you could play with decreasing the value of R5/6 a bit and see if the OB3's will fire more reliably/quickly.

Secondly, "matched" is perhaps the most incorrectly used word in the world of tubes. I've seen some supposedly factory matched tubes that weren't even close. As others have hinted - matched for what? GM, Plate current, Appearance??

- Gary
Click to expand...

kyle said:
I know it says WY2P but the schematic shows 74 (72) volts in both locations which would indicate a 0A3 instead of a 0B3. 0B3 is a 90 volt regulator 0A3 is 75 volts.
The first character is a zero, by the way. No heater so no voltage.

see this for WY2P data: http://data.zuoshi.com/audiodata/cn/WY2P.png
Click to expand...

inperson said:
This morning I got up switched on the amp and no problems. The OB3's fired right up with no noise and no peaking of the meters. Could they have just been acting up and were a bit grumpy after sleeping for 30+ years? This morning it seemed they were better prepared.
Click to expand...


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