The differance between...
- Thread starter WildWest
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Thatch_Ear
Addicted Member
Could be wrong about this but think the 37 is a larger bottle, lower voltage version of the newer 34.
Thatch_Ear
Addicted Member
Told you it was a guess, but typically the earlier versions of a tube have lower specs. Like the difference between a coke bottle 6L6G and a straight bottle 6L6GT. You can always put a GT where a G would go but not always the other way around. I made an assumption because I believe the 37s have the older shape and probably had easier operating conditions.
Course all you have to do is drop one in and watch for smoke. I for one would be interested.
My books don't go that deep into the Euros or I could tell you more. I bet the 37s sound great but if it breaks you are indeed in the deep DoDo. That is a very Technicle term.
Course all you have to do is drop one in and watch for smoke. I for one would be interested.
My books don't go that deep into the Euros or I could tell you more. I bet the 37s sound great but if it breaks you are indeed in the deep DoDo. That is a very Technicle term.
MikE
Color Me Gone
Same pinout, but NOT the same tube
The voltage drop is very different between a GZ37 and GZ34, so the bias point on the power tubes will be different when using either one. Every rectifier type will either raise or lower the bias voltage depending on the rectifier's voltage drop. This will change the sound, but also, may be over extending your power tubes, leading to there premature death. The GZ37 has a greater current draw (3 amp) than the GZ34 (2 amp), and the voltage drop is about 10 to 20 V greater than a GZ34. If your transformer allows for 3 amps of heater current at 5 v then the gz37 should work giving different output voltage and load characteristics. If the power stage of the amp is self-biased, it will settle itself with either tube... The sonic difference is primarily due to placing the bias at a different point.
Still the specific issue of subbing a gz37 or 5u4 rectifier in a amplifier that has 3 amp capability has been the source of much debate with at least one person I know experienced in the subject. The bottom line: it's best to use the tube that your circuit was designed for and when deviating from that standard to proceed with caution. As you can either prematurely waste a tube or smoke a transformer.
MikE
The voltage drop is very different between a GZ37 and GZ34, so the bias point on the power tubes will be different when using either one. Every rectifier type will either raise or lower the bias voltage depending on the rectifier's voltage drop. This will change the sound, but also, may be over extending your power tubes, leading to there premature death. The GZ37 has a greater current draw (3 amp) than the GZ34 (2 amp), and the voltage drop is about 10 to 20 V greater than a GZ34. If your transformer allows for 3 amps of heater current at 5 v then the gz37 should work giving different output voltage and load characteristics. If the power stage of the amp is self-biased, it will settle itself with either tube... The sonic difference is primarily due to placing the bias at a different point.
Still the specific issue of subbing a gz37 or 5u4 rectifier in a amplifier that has 3 amp capability has been the source of much debate with at least one person I know experienced in the subject. The bottom line: it's best to use the tube that your circuit was designed for and when deviating from that standard to proceed with caution. As you can either prematurely waste a tube or smoke a transformer.
MikE
Thatch_Ear
Addicted Member
So the GZ37 is more akin to a 5U4 than a 5AR4? I know the GZ32 is like a 5V4 which will not stand up to what a 5AR4 or 5U4 can. My duplication book shows the GZ37 to ge able to slide into a 5AR4s slot, but then again a 5U4 should be able to also as far as voltages and amps go from the top of my head.
I think that 5AR4s were made to fit into smaller places than the other larger diodes but still handle the heavy loads of 4 large pentodes.
So much to learn about this.
I think that 5AR4s were made to fit into smaller places than the other larger diodes but still handle the heavy loads of 4 large pentodes.
So much to learn about this.
