dumbleator

[jestaudio]

Anyone got a sugestion for the trannie in good old blighty, i can,t seem to find one with the right specs

[ToneMerc]

see here

https://tubeamparchive.com/viewtopic.ph ... ght=button

[markusw]

http://www.musikding.de/product_info.ph ... --14V.html

Fits nicely into a 1U rack enclosure.

Regards,

Markus

[jestaudio]

thanks for the replys, i may be missing something or maybe its just cause its a sunday but the heater supply on the diagram is 6.3 but the transformers quoted are 14v, am i mkeing a silly noob oversite

[martin manning]

You would have to wire the 12AX7 filaments in series so they would nominally run at 12.6VAC. The 14VAC of the transformer linked above is a bit on the high side IMO, and will shorten the tube's life.

[markusw]

thanks for the replys, i may be missing something or maybe its just cause its a sunday but the heater supply on the diagram is 6.3 but the transformers quoted are 14v, am i mkeing a silly noob oversite

I used regulated 12.6VDC for the heaters.
Alternatively, you might go for 12.6VAC and drop the voltage with two power resistors in series with the heater wires. Should be something like 4-5R each.

Here are some images of the xfmr in my build.

https://tubeamparchive.com/viewtopic.ph ... t=%2Alator

Edit:

some more details on dropping heater voltage with series resistors
http://www.tubecad.com/july2000/page2.html

and on current limiting DC heaters with regulators:

http://www.tubecad.com/july2000/page6.html


Peace,

Markus