A choke will have a single pole high frequency roll off, due to the choke's distributed capacitance.
The 26 tube has an rp of 7300 Ohms.
That rp has to drive the distributed capacitance of the choke plate load.
At 20kHz, 1090 pF is 7300 Ohms. That will be -3dB.
At 20kHz, 545 pF is 14600 Ohms. That will be -1dB
You might not care about -1dB at 20kHz.
But suppose the miller capacitance of the input stage also makes -1dB @ 20kHz.
And suppose the output transformer is also -1dB at 20kHz.
The total of those 3 factors is -3dB @ 20kHz.
Now, perhaps you do care.
Years ago I quit using interstage transformers, and started using IXYS plate loads (just my preference). Yes, you do need more B+ with the IXYS load versus either an interstage transformer or a choke.
I did enjoy listening to those interstage transformer coupled amplifiers.
I do not remember if I ever used a choke plate load.
By the way, interstage transformers have a 2 pole high frequency roll off, versus chokes 1 pole high frequency roll off.
Have fun listening.
The 26 tube has an rp of 7300 Ohms.
That rp has to drive the distributed capacitance of the choke plate load.
At 20kHz, 1090 pF is 7300 Ohms. That will be -3dB.
At 20kHz, 545 pF is 14600 Ohms. That will be -1dB
You might not care about -1dB at 20kHz.
But suppose the miller capacitance of the input stage also makes -1dB @ 20kHz.
And suppose the output transformer is also -1dB at 20kHz.
The total of those 3 factors is -3dB @ 20kHz.
Now, perhaps you do care.
Years ago I quit using interstage transformers, and started using IXYS plate loads (just my preference). Yes, you do need more B+ with the IXYS load versus either an interstage transformer or a choke.
I did enjoy listening to those interstage transformer coupled amplifiers.
I do not remember if I ever used a choke plate load.
By the way, interstage transformers have a 2 pole high frequency roll off, versus chokes 1 pole high frequency roll off.
Have fun listening.
Do not forget, if you have a 160V B+ and a choke load, the plate and choke can go to +320V if the tube cuts off.
Use at least a 400V cap for those voltage numbers above.
Just wait for an RCA plug connector to partly come out, and disconnect the ground, but not the center pin. You likely will clip the tube stages. 320V here we come.
Use at least a 400V cap for those voltage numbers above.
Just wait for an RCA plug connector to partly come out, and disconnect the ground, but not the center pin. You likely will clip the tube stages. 320V here we come.
Hammond 200H@40mA 193A
i use on 6C4C to direct coupled drive 6C33C
psu stackeds
https://www.hammfg.com/files/parts/pdf/193A.pdf
and with every plate choke
do not forget if you need higer DCR a wire resistor can help
like Mr Turner do it
i use on 6C4C to direct coupled drive 6C33C
psu stackeds
https://www.hammfg.com/files/parts/pdf/193A.pdf
and with every plate choke
do not forget if you need higer DCR a wire resistor can help
like Mr Turner do it
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it seems that LL1668 have lower DCR per windings 340R vs 1K2 perhaps a better match for the 26. thanks for the info
Monolith magnetics also seems to make very good choke with low DCR and capacitance suitable for the 26 but quality comes at a price :
3CP/175H10 Multi-section ultra low capacitance anode choke 175H-10mA-420Ω
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Yes, thicker wire, fewer turns, lower dcr and much lower capacitance all lead to better HF performance and much better sound. I have used LL1668 with a few different valves and it can really sound excellent. If budget ever allows I would like to try the amorphous silver version [emoji1787][emoji1787][emoji1787]it seems that LL1668 have lower DCR per windings 340R vs 1K2 perhaps a better match for the 26. thanks for the info
Hello,
I am using Tango plate choke because i bought them long time ago when they were affordable in Japan. It is used for a direct couples e80cc/6085 plus VT25A power amp which will be used full range for some time and later it will be used with a passive 12db/600 hertz filter at its input. So now wired with the two windings in series later maybe in parallel if rewiring van be done without deconstructing to much.
If i would have to buy a choke at this moment i would go for the Vietnamese one that Andy is using. I know that the Vietnamese love to use Tango and Tamura if they can affiord it and they care about quality.
I think the better chokes also will allow you to position the choke closer to the tube so i would go for the covered ones. Lundahl chokes can be put close to the circuit because of their constructing. I did the well know test with an ac meter across the choke and placing the choke close to a power transformer. I am using Lundhal chokes in lot of my power supplies even some with 1A . I would load the supply with a big resistor and move a 100 henry 25 mA Lundahl plate choke close to the input choke which are famous for their disturbing behaviour. The more the Henry the more it will pick up. No problem at all. Mounted closely to the transformer and in all angles readings would very low. One reading was a little better but forgot which one. I can imagine for a plate choke this tecnique can give an improvement. Usually the better the choke the less the less the differences will be. Also did check with a normal EI choke 100H 30 mA. There the best orientation would be 3 times worse than the worst orientation with the Lundahl.
Greetings, eduard
I am using Tango plate choke because i bought them long time ago when they were affordable in Japan. It is used for a direct couples e80cc/6085 plus VT25A power amp which will be used full range for some time and later it will be used with a passive 12db/600 hertz filter at its input. So now wired with the two windings in series later maybe in parallel if rewiring van be done without deconstructing to much.
If i would have to buy a choke at this moment i would go for the Vietnamese one that Andy is using. I know that the Vietnamese love to use Tango and Tamura if they can affiord it and they care about quality.
I think the better chokes also will allow you to position the choke closer to the tube so i would go for the covered ones. Lundahl chokes can be put close to the circuit because of their constructing. I did the well know test with an ac meter across the choke and placing the choke close to a power transformer. I am using Lundhal chokes in lot of my power supplies even some with 1A . I would load the supply with a big resistor and move a 100 henry 25 mA Lundahl plate choke close to the input choke which are famous for their disturbing behaviour. The more the Henry the more it will pick up. No problem at all. Mounted closely to the transformer and in all angles readings would very low. One reading was a little better but forgot which one. I can imagine for a plate choke this tecnique can give an improvement. Usually the better the choke the less the less the differences will be. Also did check with a normal EI choke 100H 30 mA. There the best orientation would be 3 times worse than the worst orientation with the Lundahl.
Greetings, eduard
Attachments
no , but you can ask them directly , they respond very quickly and are very helpfull ..
Contact Email | MONOLITH MAGNETICS
I have four Electra-Print #8037 (70 H, 20 mA) for sale here: https://www.diyaudio.com/forums/swa...s-pots-toms-bargain-basement.html#post6168463
They should be pretty good for the #26. At 20 Hz, they'd present an 8.8 kΩ load. Maybe that's a tad low for the #26, but I thought I'd toss it out there. You could put two in series for 140 H...
Tom
They should be pretty good for the #26. At 20 Hz, they'd present an 8.8 kΩ load. Maybe that's a tad low for the #26, but I thought I'd toss it out there. You could put two in series for 140 H...
Tom
Hello France,this one could also be part of the game 450H 15ma
big and heavy but not expensive .
how good is the Audionote choke ? anyone
As a non expert i would think.
WOW, impressive 450 Henry. But if your circuit needs 150 Henry to work as it should work so with the right Henry for your tube why you pay extra for more Henry. It is easier to make a 150 Henry choke than a 450 Henry one.
Same like if your power tube will run at 25 mA and you can choose between a 50 mA and 125 MA being double the seize. Which one?
Greetings
more henry wouldn't hurt , the capacitance and DCR will , it's just for the info
and 70£ is an unusualy low price for an AudioNote product
Hello,
Sure 450 Henry is nice but it will come with other specs that will be less spectacular than the ones of a 150 Henry.
Probably they had it made in China. I remember buying chokes in Paris 3 decades ago made in France and if you would correct the prices to have an honest comparison. Like how many hours i had to work to buy the French choke and how many hours i have to work to get the Audio Note the last one is double the price.
Greetings, Eduard
final price is more then 30% up70£ is an unusualy low price for an AudioNote product
yes your are right , not so a bargain
at the end i think my choice will be between :
the Lundhal LL1668 wich has the lower Dcr of all with 680R
for 250H in 10ma gap or 167H with 15ma . 200€ for a pair
the NP acoustics with 180H 40ma 1K2 or 136H 15ma 2.4K 250€ for a pair
TANGO RC-160-15W 160H 15mA 1K2 360€ for pair.
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