Fun with Rectifiers 6X5 to 5Y3?

[Toxophilite]

Hello all
I'm new here so salutations and Merry Christmas where applicable!

My question is regarding rectifiers
I've built one vibrolux head (5F11) and really quite like it . It was my first entire emp build. using an existing 50s homebuilt PA chassis with accompanying nice Hammond transformers), Originally I built it as a tweed deluxe but wasn't keen on it so I switched it to a vibrolux but added a negative feedback switch for fun.

I want to build another and have a nice stereo pair!
I have another bit of chassis with all the right sockets (3 large octal 2 small 9 pin)that has a usable power transformer but with a 6X5 rectifier, I also have a push pull 6V6 transformer from an organ.
So I have most of the bits
I've read not so great things about the 6X5. Can I use a 5Y3 instead if do some fiddling with the power coming from the transformer(for the rectifier filaments)? I know the 5Y3 normally has it's own filament power supply separate from the 12AX7 and 6V6 heaters)
On this amp as it currently is (before I gut it) it uses the same heaters for everything
Thanks

[Tom Phillips]

...I've read not so great things about the 6X5. Can I use a 5Y3 instead if do some fiddling with the power coming from the transformer(for the rectifier filaments)? I know the 5Y3 normally has it's own filament power supply separate from the 12AX7 and 6V6 heaters)
On this amp as it currently is (before I gut it) it uses the same heaters for everything...

If you want to use a 5Y3 then you absolutely must power the 5Y3 filament from a dedicated 5V winding. I'm not sure what "not so great things" you have heard about the 6X5 but they have been reliable for me in various circuits. The 6X5 does have a lower plate current rating so you cannot build as powerful an amp with the 6X5 as you could with a 5Y3. However, the plate winding on your existing power transformer is probably designed for the 6X5 anyway. Since your final amp power will be determined by the weakest factor then, as I see it, you have at least the following choices. 1) Give up a little power and use the 6X5 and your existing salvaged power transformer. 2) Find a different transformer with a 5V rectifier winding that is appropriately sized for the Vibrolux you want to build and use a 5Y3.
Cheers,
Tom

[loudthud]

On the 5Y3, the heater is connected directly to B+ (high voltage). It has no cathode. On the 6X4, the heater is isolated from B+. Not many tubes are designed like this. The 5Y3 REQUIRES it's own independent heater winding because most tubes like 6V6 and 12AX7 cannot withstand more than about 100V between the heater and cathode. If the power transformer does not have the isolated 5V winding, a separate transformer rated at 5V 2A will have to be provided.

[Toxophilite]

Thanks
I'm not familiar with the 6X5
Apparently antique radio guys say that some makes of 6X5 have a tendency to short (on the cathode I think) and then they burn the power transformer.

I've done a lot of work on my own amps and have converted a few mono hifis to guitar as well as building preamps out of reel to reels
Still I have gaping holes in my knowledge, so thanks very much ! Happily I do know how not to get electrocuted!..so far!
I believe I will put aside that project for now until an appropriate power tranny comes along and work on an 18 watt conversion that has all the appropriate bits
Onward

[Rhodesplyr]

Hammond -2 and -3 series organs all use 6X5s and 6X4s in their preamps. Checking these for heater-cathode leakage is a standard test I perform on every one of these I service. It's usually measurable as leakage before it becomes a catastrophic short. Most are still OK after many years in service, but I do find some with high leakage. Complete h-k shorts are rare, but they can happen. I've seen one in the last two years.

Appropriate fusing can serve as an effective insurance policy if you want to use a 6X5 instead of adding a 5V filament transformer.

[g1]

Apparently antique radio guys say that some makes of 6X5 have a tendency to short (on the cathode I think) and then they burn the power transformer.

Very early 6X5 versions (ST shape) from the '40's may have this problem, 6X5GT's do not, unless the heater to cathode voltage (450V) is exceeded.
Unless you are dealing with an antique radio with very old tubes you will not have the problem.
There are plenty of low power guitar amps that use 6X5 rectifiers, they do not suffer any common failure of rectifier tubes.