Electronics > Projects, Designs, and Technical Stuff
Tube amp questions
<< < (3/6) > >>
sahko123:
Now I have another question not to do with impedance. This question is to do with powering the tubes. I was wondering of I could use rectified mains for the high voltage line and use a smaller transformer just for the filament voltage.(I live in Ireland with a 220v mains)
T3sl4co1l:
Not directly, that would be stupid.

You can, however, use two transformers, back-to-back, to get filament and high voltage, both isolated, without having to find a specialty part. :-+

That said, Hammond (and a couple of smaller manufacturers I think) make standard transformers for just this sort of thing, that aren't much more expensive than a standard (single output) transformer, and are carried by most distributors.  YMMV.

Tim
sahko123:
k I found well priced transformers that push both filament and plate voltage I thought that would be possible to go for a cheaper option
spec:

--- Quote from: sahko123 on November 05, 2018, 04:49:03 pm ---Now I have another question not to do with impedance. This question is to do with powering the tubes. I was wondering of I could use rectified mains for the high voltage line and use a smaller transformer just for the filament voltage.(I live in Ireland with a 220v mains)

--- End quote ---

Your best bet is to use an off-line switch-mode power supply to get a nice stabilized supply line of anywhere between 200V and 400V. These off line switch mode PSUs are compact, will work off any voltage from 90V to 270V and are reasonably cheap too. You can use another mains PSU to provide 6.3V or 12.6 DC for the heaters. 

As you are building a headphone amp, you can consider going full class A single ended.

You could also consider doing away with the output transformer.

If you are interested in the off-line switch-mode PSU approach, I can post a schematic of one of the designs I did a few months ago, which may give you a few ideas.
schmitt trigger:

--- Quote from: Circlotron on November 04, 2018, 10:39:42 pm ---6550s for a headphone amp?
Nothing exceeds like excess.

--- End quote ---

He could have used KT88s  ;D

Now seriously......in the mid 1960s vacuum tube amplifiers seldom came with headphone amplifiers. A popular hobby shop at the time, Calectro Electronics, would sell a headphone adapter box. It was essentially a DPDT switch, to select either the speaker or the headphones. In headphone mode it had -you guessed it- a pair of 8 ohm power resistors in parallel with the headphone jack.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod