I'm back. After establishing that I had not destroyed my Lundahl LL 1670 grid chokes I installed them as replacements for 470kohm resistors in a 45 SE output stage. Nothing, nada, zip in terms of output🙁 Put the resistors back in and music😕 Any theories or suggestions would be greatly appreciated🙂
Just a shot in the dark: any chance you wired any of pins 1, 5 and/or 8 together? I think that would short out the choke.
Unlike other Lundahl chokes I've seen, it looks like all the required winding connections are already made internally. And all you need to do is connect pin 1 to grid or ground, and pin 5 to ground or grid.
Not sure if there is a preferred direction of current through the choke -- e.g., from 1 to 5 or vice versa. But I can't see that resulting in no sound.
cheers and good luck, Derek
Unlike other Lundahl chokes I've seen, it looks like all the required winding connections are already made internally. And all you need to do is connect pin 1 to grid or ground, and pin 5 to ground or grid.
Not sure if there is a preferred direction of current through the choke -- e.g., from 1 to 5 or vice versa. But I can't see that resulting in no sound.
cheers and good luck, Derek
Yes I have
Having used other Lundahl products I thought I had to connect pin 1 (high potential) to pin 8 then from 8 to 5. But now that I look at the product data sheet it seems that pin 8 is indeed a center-tap. Too late to remedy that tonight but I will try that tomorrow. Thanks🙂
Having used other Lundahl products I thought I had to connect pin 1 (high potential) to pin 8 then from 8 to 5. But now that I look at the product data sheet it seems that pin 8 is indeed a center-tap. Too late to remedy that tonight but I will try that tomorrow. Thanks🙂
Any choke is going to be a coil of wire. That coil has a certain amount of resistance. If you cooked your choke, then the resistance across the coil would either be very high, infinite (open load), or 0 (shorted out).
In order to determine if you have the choke wired correctly, you simply check the resistance across the choke and see if it matches the spec sheet.
In order to determine if you have the choke wired correctly, you simply check the resistance across the choke and see if it matches the spec sheet.
I agree that without schematic all advice is a "shot to the dark". 😛
If it's DC coupled from driver, the -relative low DCR- grid choke "grounding" the previous stage.
If it's AC (capacitor) coupled from driver, it should work ... if you connect the center tapped LL1670 correctly.
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Try to use only one end and center tap... and after it the other end.
If it's DC coupled from driver, the -relative low DCR- grid choke "grounding" the previous stage.
If it's AC (capacitor) coupled from driver, it should work ... if you connect the center tapped LL1670 correctly.
Empty Page
Try to use only one end and center tap... and after it the other end.
Understanding at last
As Deke609 said I had indeed incorrectly wired the chokes, and they are now installed and making music😎 Initial impressions not much to choose between grid choke and grid resistor, frankly not sure if is worth the expense and bother. Perhaps the chokes need to break in. If others have experience with grid chokes I would love to hear their impressions🙂
As Deke609 said I had indeed incorrectly wired the chokes, and they are now installed and making music😎 Initial impressions not much to choose between grid choke and grid resistor, frankly not sure if is worth the expense and bother. Perhaps the chokes need to break in. If others have experience with grid chokes I would love to hear their impressions🙂
I just recently installed Silk grid chokes in my 300B amp and really like them. Greater detail, punch and they seem to have gotten rid of some treble glare I heard on certain tracks.
The chokes are supermalloy -- which I think means 80% nickel. 7,000H, but can't take any DC current - something like 0.5mA max.
cheers, Derek
The chokes are supermalloy -- which I think means 80% nickel. 7,000H, but can't take any DC current - something like 0.5mA max.
cheers, Derek
