hi,
can anyone point me towards any schematics for 101d tube with 10M45S CCS on the plate, for a line stage use?
is there any optimal ccs formula for dht tubes that would include 101d?
any help appreciated,
thank you.
can anyone point me towards any schematics for 101d tube with 10M45S CCS on the plate, for a line stage use?
is there any optimal ccs formula for dht tubes that would include 101d?
any help appreciated,
thank you.
Are you using the psvane 101d? Check the datasheet for typical operating points and then see how to set the current with the 10M45. You’ll want a stopper resistor on the 10M45 so pretty much any tube schematic will show that.
Check this website:
Bartola(R) Valves – All about electronic valves and hi-fi
He has many circuits using css. and he sells ccs pcb.
Real nice ,friendly person.
Art
Bartola(R) Valves – All about electronic valves and hi-fi
He has many circuits using css. and he sells ccs pcb.
Real nice ,friendly person.
Art
I have to say… using a semiconductor CCS is all good and well, but it “suffers” from a couple of vexing things.
First, that you can look at the various curves of tubes and the 10M45S, and you can calculate out to 6 digits of precision the in-series current-defining resistor and the operating point, just fine. Then, you gang one up with a real-world valve, and the anode voltage is far, far from where you might have hoped or planned it to be. Drat!
That's because real-world valves, the ones you actually get your mitts onto, have an operating characteristic that depends on the manufacturing run, on the condition of the cathode, on any “spare trace gas” inside, the phase of the moon, and whether you ate Wheaties for breakfast, or not. Moreover, with those variables in play, assuming you can adjust the operating point to where VA is about where you want it, inevitably within a few months-to-seasons, it'll be out of whack again.
By a surprising amount, sometimes.
Anyway, that's my experience. They work. They can be 'set' empirically.
Then they drift. And lord help you when you roll out a tube for another.
The non-finicky solution is kind of interesting. Setting up a very high impedance B+ voltage divider, and feeding that to the sense pin along with the sense-to-source resistance can do wonders. The “perfectness” of the CCS is slightly compromised, but at least you can get a setpoint that doesn't vary so wildly.
In this way, I've gotten away from using the 10M and just using simple depletion mode MOSFETs with suitable junction protecting Zeners. Nowhere near as “steep” (i.e. close to perfection) as a CCS might be, but much less intolerant of little valve-and-phase-of-the-Moon variance.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
First, that you can look at the various curves of tubes and the 10M45S, and you can calculate out to 6 digits of precision the in-series current-defining resistor and the operating point, just fine. Then, you gang one up with a real-world valve, and the anode voltage is far, far from where you might have hoped or planned it to be. Drat!
That's because real-world valves, the ones you actually get your mitts onto, have an operating characteristic that depends on the manufacturing run, on the condition of the cathode, on any “spare trace gas” inside, the phase of the moon, and whether you ate Wheaties for breakfast, or not. Moreover, with those variables in play, assuming you can adjust the operating point to where VA is about where you want it, inevitably within a few months-to-seasons, it'll be out of whack again.
By a surprising amount, sometimes.
Anyway, that's my experience. They work. They can be 'set' empirically.
Then they drift. And lord help you when you roll out a tube for another.
The non-finicky solution is kind of interesting. Setting up a very high impedance B+ voltage divider, and feeding that to the sense pin along with the sense-to-source resistance can do wonders. The “perfectness” of the CCS is slightly compromised, but at least you can get a setpoint that doesn't vary so wildly.
In this way, I've gotten away from using the 10M and just using simple depletion mode MOSFETs with suitable junction protecting Zeners. Nowhere near as “steep” (i.e. close to perfection) as a CCS might be, but much less intolerant of little valve-and-phase-of-the-Moon variance.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
ahhh, that simple, tube curves for current and 10M45 data to calculate the resistor value for above current,...done.
many thanx 🙂
that sounds interesting,
any schematics for that?, my operating point for 101d will be 6mA/130vdc
thank you.