Can I use a 5Y3 instead of a 5AR4 in my Heathkit AA-100 amplifier? Do you have another idea? I have a couple of rectifier types in stock but not 5AR4.

Thank you

Probably best to purchase a 5AR4. The are currently made.

:Can I use a 5Y3 instead of a 5AR4 in my Heathkit AA-100 amplifier? Do you have another idea? I have a couple of rectifier types in stock but not 5AR4.
:
:Thank you
:

Agreed. The 5Y3 would most likely be pushed beyond it's limits for this amp, plus it lacks the indirectly heated cathode. The idea here is to limit the flow of current until the rest of the tubes warm up.

The 5AR4 is otherwise known as GZ34. It should be easy to get one.

By the way, these tubes have a very long service life, so bring it up slowly on a variac, or otherwise predetermine why you are replacing this tube. This vintage amp probably needs a total recap job.

Best of luck.

:Probably best to purchase a 5AR4. The are currently made.
:
::Can I use a 5Y3 instead of a 5AR4 in my Heathkit AA-100 amplifier? Do you have another idea? I have a couple of rectifier types in stock but not 5AR4.
::
::Thank you
::
:

I had this amp from a friend. Did not powered it up, but the 5AR4 is dead (tube is white inside). Other tubes are OK and mostly original. It's a future project with it's fm stereo tuner. I want to test it with another rectifier. If 5Y3 is good, will use this type. I have full of them and it fit.

:Agreed. The 5Y3 would most likely be pushed beyond it's limits for this amp, plus it lacks the indirectly heated cathode. The idea here is to limit the flow of current until the rest of the tubes warm up.
:
:The 5AR4 is otherwise known as GZ34. It should be easy to get one.
:
:By the way, these tubes have a very long service life, so bring it up slowly on a variac, or otherwise predetermine why you are replacing this tube. This vintage amp probably needs a total recap job.
:
:Best of luck.
:
::Probably best to purchase a 5AR4. The are currently made.
::
:::Can I use a 5Y3 instead of a 5AR4 in my Heathkit AA-100 amplifier? Do you have another idea? I have a couple of rectifier types in stock but not 5AR4.
:::
:::Thank you
:::
::
:

I wouldn't do it. The 5Y3 has half the current rating of a 5AR4. A new 5AR4 (Chinese) sells for only $12: http://www.tubedepot.com/5ar4.html?gclid=CLDZ06CC6aECFQPyDAodlAFtIg

Did you check the existing 5AR4's filament with an ohmmeter or tube tester? I wouldn't go only by appearance.

:I had this amp from a friend. Did not powered it up, but the 5AR4 is dead (tube is white inside. I want to test it with another rectifier. If 5Y3 is good, will use this type. I have full of them and it fit.
:

A 5U4G or 5V3 might be a better sub for testing

Only problem with that is you probably won't be able to get the amp back in the case, if you've got one. If that's not a problem, a 5V4 would be a better choice. It's got an indirectly heated cathode just like the GZ34/5AR4, but it's size is also larger.

:A 5U4G or 5V3 might be a better sub for testing
:

A 5AR4 has a maximum current rating of 825 mA per plate. The 5V4 is rated at 525 mA per plate. I assume that a 5AR4 was used for a reason.

The risk is that a lower rated tube will short out, particularly at turn on. That could damage the power transformer.