It depends on the choke value. If it is too small, then the rectifier can still be pushed outside its comfort zone by too much capacitance.
Be careful with the heater/cathode voltage. I had some tube failures including voltage about one half the maximum published in data sheets resulting in tube catastrophic destruction. So I suggest to use an independent 6.3V winding in the transformer, and wire one end to the cathode, so always that difference is only 3.15V. Also this is applicable to the 6X4.
+1
sheet says Rt>300R @ 350~ (cap input)
i suppose after >1H choke you could go unlimited (XL 315R @50Hz)
which for example is 36W lamp choke..
Yes, they have air gap. I used them as reactor to modulate a 6DQ6 transmitter with another using a 40W fluorescent ballast without audio problems. Perhaps the iron is not the best to handle audio signals, but it did the job very well.
In fact, as the cathodes of any fluorescent lamp never are equal, always there is a DC imbalance flowing through ballast and line.
I've tested 5 ballasts so far, and used one of them. I haven't been able to get hold of lower wattage ballasts - which should be even better for many valve amps. The inductance is not up there for perhaps hifi applications, but great for guitar etc. Also not too aesthetic unless hidden under the chassis, or behind a PT. The voltage rating is typically fine if the ballast is rated for 240VAC usage.
ATCO EC40: 1.2H @ 104mAdc: 1.1H @ 300mAdc; 0.96H @ 500mAdc; DCR=40.
ATCO EC18/20: 1.88H @ 147mAdc: 1.69H @ 260mAdc: 1.45H @ 420mAdc; 1.26H @ 517mAdc; DCR=54.
VS LN 18.162: 1.66H @ 165mAdc: 1.57H @ 288mAdc: 1.22H @ 458mAdc; 0.49H @ 740mAdc; DCR=47.
VS LN 18/20.129: 1.69H @ 145mAdc: 1.61H @ 254mAdc: 1.42H @ 407mAdc; 1.2H @ 509mAdc; DCR=47.
VS LN 36.505: 1.08H @ 295mAdc: 0.73H @ 517mAdc; 0.3H @ 825mAdc; DCR=21.
Ciao, Tim
The Lundahl LL1685 data sheet indicates it saturates at 230mApk in series, but does provide 10H of effective inductance. It could be used in choke input mode if it doesn't exceed that pk level. It may provide common mode attenuation when applied in some configurations, but I can't see how any 'common mode' characteristic is going to make an iota of difference in a choke input configuration - but that is just quick thought.
I don't get it why the current would mind if a 20H coil is split up and put in both legs of the circuit....the rectifier will see less capacitance if it is placed behind the inductor....also in this case....No?
I believe that a 20Hy to a common mode choke is very unusual. The more I saw was in the order of millihenries, almost in switching power supplies.
Common mode aren't designed to support DC in its core, nor low frequency ripple trough it. They are like a bifilar winding in which currents in both conductors are canceled, so no net low frequency or DC is not present in the core.
Common mode aren't designed to support DC in its core, nor low frequency ripple trough it. They are like a bifilar winding in which currents in both conductors are canceled, so no net low frequency or DC is not present in the core.
A common-mode choke couples two inductors together, it is not two separate inductors. Two separate inductors in both legs of the circuit would work fine.Arno Pf said:
A CM choke does not notice the balanced current circulating around the charging loop as that current balances out in the two windings of the choke. Hence it does not function as a choke for the purposes of the PSU. All it does is remove any CM noise from the input.
There is a modern fashion for using CM chokes where they are useless or even, as here, potentially damaging to the circuit components. A choke input PSU needs a choke; just a choke, not a CM choke or a differential mode choke or any other special choke - just an ordinary common-or-garden choke. You can split the choke in two if you want, provided the two chokes can't magnetically see each other.
lets talk about costBy the way...I use the Lundahl common mode choke 2x10H
The Lundahl choke seems to put two windings on the same core. It isn't specified as a common-mode choke, but does show an example where it may provide some common-mode attenuation - I think the 'common-mode choke' moniker given to that choke is just Arno's description, not Lundahls - it is not a common-mode choke in the normal sense of the description (as df96 has assumed).
Perhaps it is a two winding "differential" style choke, where the leakage inductance provides some low level of common-mode inductance (sort of the opposite of a common-mode choke that provides some low level of differential inductance).
Perhaps it is a two winding "differential" style choke, where the leakage inductance provides some low level of common-mode inductance (sort of the opposite of a common-mode choke that provides some low level of differential inductance).
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.