Transformer question

[AudioAvarice]

I'm slowly building up parts for my Luxman A2003 rebuild, I'm planning on adding separate heater supplies for each section so I don't have to use 8 of the same type of 12AU7.

Can I use this transformer for both the separate supplies, and can I connect the 8v and 5.5v together to get 13.5v (12.6v heater supplies) ?

 

[maxhifi]

I'm slowly building up parts for my Luxman A2003 rebuild, I'm planning on adding separate heater supplies for each section so I don't have to use 8 of the same type of 12AU7.

Can I use this transformer for both the separate supplies, and can I connect the 8v and 5.5v together to get 13.5v (12.6v heater supplies) ?

View attachment 3846664

I don't understand your logic. Why would you need separate heater supplies, if the tubes are different brands? The reason to match tubes is gain, and distortion. Heaters are consistent between brands. Besides the heaters are most likely wired in parallel anyway.

 

[AudioAvarice]

I have some CV4068, and E80CC I want to use in something, obviously I'll try some different tubes to see if changes even effect the sound, as I'm not sure how the tubes are used in an electronic crossover. It definitely uses heaters in series, rather than parallel.

 

[maxhifi]

definitely uses heaters in series, rather than

Weird. Not much hifi gear is built that way, was more common in TVs and radios. Yeah, those tubes you mention use double the heater current of a 12AU7. That transformer would work, but you'd need dropping resistors, or else make a regulated DC supply, and then need to change the resistors depending on if you're using the original 12AU7s or else the higher heater current tube. IMO not worth modifying a desirable vintage piece, but can be done. My other concern is placing a transformer into an amplifier can introduce induced hum, which becomes a new problem.

 

[AudioAvarice]

Weird. Not much hifi gear is built that way, was more common in TVs and radios. Yeah, those tubes you mention use double the heater current of a 12AU7. That transformer would work, but you'd need dropping resistors, or else make a regulated DC supply, and then need to change the resistors depending on if you're using the original 12AU7s or else the higher heater current tube. IMO not worth modifying a desirable vintage piece, but can be done. My other concern is placing a transformer into an amplifier can introduce induced hum, which becomes a new problem.

Yeah Luxman seems to like series heaters, pretty sure my CL32 pre is the same. I'm planning on using a couple of a couple of regulated heater PSU units in a separate box with the transformer, and run it off the 2 pin power out plug on the back. It's a Japanese 100v unit, so not really that desirable here in the UK, but there will be no modification to the case, and I'll make sure the internal wiring changes are easily reversible (if I go ahead).

 

[maxhifi]

Yeah Luxman seems to like series heaters, pretty sure my CL32 pre is the same. I'm planning on using a couple of a couple of regulated heater PSU units in a separate box with the transformer, and run it off the 2 pin power out plug on the back. It's a Japanese 100v unit, so not really that desirable here in the UK, but there will be no modification to the case, and I'll make sure the internal wiring changes are easily reversible (if I go ahead).

Could also use a bench power supply or brick for testing, just to see if it's worth it or not to use the special tubes.

 

[maxhifi]

Cl32 has parallel heaters