You could calculate with 0.5V at your current of 0.34A. Just in case and also worst case. Add ripple voltage to that. I would pay attention to a choose a regulator that has or can have slow(er) ramp up as filaments are happy with that. They are members of the cold resistance group fighting with inrush current. An extra large output cap with a 0.1 Ohm before it also works but slow ramp up is more elegant. Many LDO regulators have relatively slow ramp up as a bonus (without any action or extra parts) so check that datasheet.
https://www.ti.com/lit/wp/slvafx0/slvafx0.pdf?ts=1730979013380&ref_url=https%3A%2F%2Fwww.google.de%2F
Tubes work fine at 6V but as often with simple things it can be made extremely complex. And vice versa of course. This hobby attracts paradise birds of many colors 🙂
Current filament tubes for series connection exist. PCC88 for instance. The P is the letter that indicates that.
https://www.ti.com/lit/wp/slvafx0/slvafx0.pdf?ts=1730979013380&ref_url=https%3A%2F%2Fwww.google.de%2F
Tubes work fine at 6V but as often with simple things it can be made extremely complex. And vice versa of course. This hobby attracts paradise birds of many colors 🙂
Current filament tubes for series connection exist. PCC88 for instance. The P is the letter that indicates that.
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Thing is I already have a dozen or so 6N2P tubes that only take a 6.3V connection.
A discrete LDO looks quite simple to make, basically a CFP with a voltage reference, PNP output, my early simulation shows < 300mV dropout with OK ripple rejection and slow voltage ramp.
However I know this configuration if prone to oscillation, so careful testing will be needed.
Interesting read here: https://sound-au.com/articles/ldo-regulators.htm
A discrete LDO looks quite simple to make, basically a CFP with a voltage reference, PNP output, my early simulation shows < 300mV dropout with OK ripple rejection and slow voltage ramp.
However I know this configuration if prone to oscillation, so careful testing will be needed.
Interesting read here: https://sound-au.com/articles/ldo-regulators.htm
Thanks for the information and very well might come in useful for another build that is more designed for it,
So I think I'm going to stick with the power supply circuit I already have as it does everything I need it to, regulated filament soft start, low ripple etc.
It seems straight forward with little that can go wrong, with the only down side being 5W off wasted heat that I've already planned for and shouldn't need to much of a big heat sink.
At very least, it will do for testing valve circuits.
I'd rather focus on the next stage, the amp its self:
Seems like a good design to me with obvious high input impedance and a good simulation distortion profile.
I have also simulated it with 6N2P, 6N1P, 12AX7, 12AT7 and 6DJ8 with little change needed to set the bias.
Good for tube-rolling fun? 🙂
Worth a test PCB?
So I think I'm going to stick with the power supply circuit I already have as it does everything I need it to, regulated filament soft start, low ripple etc.
It seems straight forward with little that can go wrong, with the only down side being 5W off wasted heat that I've already planned for and shouldn't need to much of a big heat sink.
At very least, it will do for testing valve circuits.
I'd rather focus on the next stage, the amp its self:
Seems like a good design to me with obvious high input impedance and a good simulation distortion profile.
I have also simulated it with 6N2P, 6N1P, 12AX7, 12AT7 and 6DJ8 with little change needed to set the bias.
Good for tube-rolling fun? 🙂
Worth a test PCB?
I don't have the models for IRF830, it be used in actuality. I don't think there will be much difference.
I may hunt for the models..
I may hunt for the models..
Not to over complicate things, but I wonder if a bass and treble control could be built in the feedback network around R12?
Oh no, just not in the feedback loop. No potentiometers in that area as it is asking for trouble. Old stuff had that and possibly readers recall the sound of scratching 🙂
Even conductive plastic, cermet, stepped stuff can have scratchy contacts. They usually have that as a feature.
Not enough time to check the complete design but you make decoupling caps after a voltage regulator way too high in value IMHO.
Not enough time to check the complete design but you make decoupling caps after a voltage regulator way too high in value IMHO.
So the ripple will be to low? Or the value is that high it won't make a difference anyway?
There's also channel separation to consider.
There's also channel separation to consider.
There is practically no ripple after the regulator. There is ripple voltage before the regulator 😉
I am appreciating this discussion even though I don't understand enough of it. Even though I am on the fence about tone controls (depends how and what frequency that they are implemented), I have a need for balance and find that a stacked set of mono pots serve the need quite nicely. A typical balance control is not the top of my preference list but maybe you should consider that in your design.
Many compliments to what you have come up with so far. Take a peek at some of the GlassWare designs as they might be of service to you.
Many compliments to what you have come up with so far. Take a peek at some of the GlassWare designs as they might be of service to you.
Thank you @Ixnay 🙂
I was also wondering if I can switch the boot-strap capacitor C5 in and out while on and listening, I was thinking a dual pole relay to disconnect it from the MOSFET source then to connect a resistor across C5 to keep the voltage potential the same so when reconnected it shouldn't effect the output to much and have a smooth operation?
I was also wondering if I can switch the boot-strap capacitor C5 in and out while on and listening, I was thinking a dual pole relay to disconnect it from the MOSFET source then to connect a resistor across C5 to keep the voltage potential the same so when reconnected it shouldn't effect the output to much and have a smooth operation?
Funny that you should ask. On the GlassWare website, John sells a little switchboard sort of thing for just such a purpose. See if it can work for your case.
What is the best way to go about grounding and earthing? I'm thinking of leaving the chassis floating (not connected to house earth), but only connecting the chassis to GND from a thick wire to power supply GND. The power supply board would act as a 'star ground' for everything.
There will be a suitable fuse in the mains plug.
Does this sound correct?
There will be a suitable fuse in the mains plug.
Does this sound correct?