Voltage doubler is OK (since power consumption of the gain stage is very small, couple of mA max) but gain stage has very small PSRR so it's recommended to use the clean PS.
I decided to focus less on scrap from now on 
since this is beginning to look better I will buy two small print board trafos
one 2x 12V, and one 24V( or another 2x12V)
up to 5VA they don't cost much
since this is beginning to look better I will buy two small print board trafos
one 2x 12V, and one 24V( or another 2x12V)
up to 5VA they don't cost much
picking up the pieces
this have taken a slightly different turn, and I decided that the original box will be a stereo preamp, with two optional outputs
2 channels tube output, and another 2 channels balanced output with BA-3
might need this later for planned tube amp project
since its now a balanced BA-3 I need more space
cut a small piece off the previous tube 'board', and turned it 90 degr
this have taken a slightly different turn, and I decided that the original box will be a stereo preamp, with two optional outputs
2 channels tube output, and another 2 channels balanced output with BA-3
might need this later for planned tube amp project
since its now a balanced BA-3 I need more space
cut a small piece off the previous tube 'board', and turned it 90 degr
Attachments
Hi Tinitus,
Nice to see your continuing development. I have been checking your updates. Just thought I should send a quick post, I didn't have much to add to previous progress. Looks like you are pretty close to final for the Fet preamp.
Nice to see your continuing development. I have been checking your updates. Just thought I should send a quick post, I didn't have much to add to previous progress. Looks like you are pretty close to final for the Fet preamp.
when ordering parts for my Salas reflektor I found theres a higher voltage LM317HV
will start out with that one, until I get the more complicated reflektor done
thats from the 28Vac down to +30Vdc
and I might also use 2x LM317HV as pre regs for 2x TO92 regs, to get the 2x 24Vac down to the +/12V I also need
the TO92 will be with the buffer
but man this is looking 'costly'
will start out with that one, until I get the more complicated reflektor done
thats from the 28Vac down to +30Vdc
and I might also use 2x LM317HV as pre regs for 2x TO92 regs, to get the 2x 24Vac down to the +/12V I also need
the TO92 will be with the buffer
but man this is looking 'costly'
thinking about dumping the LM regulators
and run the 'sensitive' single j310 gain stages directly from caps smoothing only 😀
at least I won't have to worry about 'unstable' power supply
and the TO-92 regs might just be able to bring it down to the other needed +/-12V
or... would it still be better to use two different print trafos, and dump all regs entirely
but those small trafos ? I dont know....with their 'different regulation' it could be tricky without regulator
at least I know the voltage on the C-core I already have
and with its 1.5A rating it won't change voltage one bit
and run the 'sensitive' single j310 gain stages directly from caps smoothing only 😀
at least I won't have to worry about 'unstable' power supply
and the TO-92 regs might just be able to bring it down to the other needed +/-12V
or... would it still be better to use two different print trafos, and dump all regs entirely
but those small trafos ? I dont know....with their 'different regulation' it could be tricky without regulator
at least I know the voltage on the C-core I already have
and with its 1.5A rating it won't change voltage one bit
Attachments
and there might be one big advantage without the LM regs
reason, the HV positive regs all the way made my ground appear...problematic
and the advantage without, I can use seperate diode bridges
I suppose thats a very good thing if you have 'sensitive' curcuits
and maybe especially in this case, mixing SE and symmetric curcuits
and I will only need to buy one type supply cap, 50 small ones are cheaper 😀
reason, the HV positive regs all the way made my ground appear...problematic
and the advantage without, I can use seperate diode bridges
I suppose thats a very good thing if you have 'sensitive' curcuits
and maybe especially in this case, mixing SE and symmetric curcuits
and I will only need to buy one type supply cap, 50 small ones are cheaper 😀
Attachments
look here what I just found 
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