I think they’ll be more surprised we got to the moon once.
Went bowling with the kids yesterday morning. I was on “team turd” so yes everything comes down to poo.
Ok it's Sunday afternoon, I've had a couple of beers and I'm now looking at boat anchors with
valves in them
This thread is definitely an enabling thread.
Edit: my excuse is that winter is coming and of course I need something to keep the place warm
Edit: this looks fun
https://www.ebay.co.uk/itm/323883516377
BTW....see that large object in the center of the pix that looks like a transformer? It's actually a filter choke. It looks like a transformer but only has 2 leads coming out the same side. It's used in a vacuum tube B+ supply to provide additional filtering in addition to the capacitors.
I need one, about that size. New ones are quite pricey. If someone has one floating around in their junk box I'll gladly take it off your hands for cost of shipping plus. Note that it must be a small one, not the huge filter chokes typically used in audio amps or bench supplies.
10H and 20H chokes are freaking huge.
I'm talking something in the mH range.
Ahh. How much current? If it’s up to about 30mA then Bourns do some cheap ones. Also look out for Epcos common mode chokes. They can be used as well.
Assume that’s for caveman HT smoothing?
Time for a huge toroid and some 18ga Kynar wire...
mnem
*visiting the in-laws*
LOL you'd be there a week doing a toroid at that inductance
Ahh. How much current? If it’s up to about 30mA then Bourns do some cheap ones. Also look out for Epcos common mode chokes. They can be used as well.
Assume that’s for caveman HT smoothing?
No, I want to rebuild the B+ supply in the Heath OL-1 proper, with a filter choke like it should have been done when designed. Heath left one out to keep the price down. So the trace has a very small, but noticeable, ripple on it that I want to get rid of. Adding capacitance is a double-edged sword in that it increases the load on the rectifier and may burn it out. I guess I'm just too anal about it. That scope currently has a better trace than any other OL-1 ever built due to my mods so far.
Edit, we're talking about 400VDC and I'm assuming less than 100mA.
LOL you'd be there a week doing a toroid at that inductance
Oh, yeah. You said mH, not uH.
mnem
*at the in-laws with the ‘lurgy*
Ahh. How much current? If it’s up to about 30mA then Bourns do some cheap ones. Also look out for Epcos common mode chokes. They can be used as well.
Assume that’s for caveman HT smoothing?
No, I want to rebuild the B+ supply in the Heath OL-1 proper, with a filter choke like it should have been done when designed. Heath left one out to keep the price down. So the trace has a very small, but noticeable, ripple on it that I want to get rid of. Adding capacitance is a double-edged sword in that it increases the load on the rectifier and may burn it out. I guess I'm just too anal about it. That scope currently has a better trace than any other OL-1 ever built due to my mods so far.
Edit, we're talking about 400VDC and I'm assuming less than 100mA.
Im a cheap ass too, possibly slightly less than Heathkit so had a look at the schematic. It uses mostly differential stages. In theory (not necessarily in implementation with Griefkit) these should have a decent (for the age) power supply rejection ratio. I’d pull V1 out then measure ripple on the plates. Get the feeling that’s where it’s actually coming from.
Disclaimer: may be wrong but worth a check
Ahh. How much current? If it’s up to about 30mA then Bourns do some cheap ones. Also look out for Epcos common mode chokes. They can be used as well.
Assume that’s for caveman HT smoothing?
No, I want to rebuild the B+ supply in the Heath OL-1 proper, with a filter choke like it should have been done when designed. Heath left one out to keep the price down. So the trace has a very small, but noticeable, ripple on it that I want to get rid of. Adding capacitance is a double-edged sword in that it increases the load on the rectifier and may burn it out. I guess I'm just too anal about it. That scope currently has a better trace than any other OL-1 ever built due to my mods so far.
Edit, we're talking about 400VDC and I'm assuming less than 100mA.
Im a cheap ass too, possibly slightly less than Heathkit so had a look at the schematic. It uses mostly differential stages. In theory (not necessarily in implementation with Griefkit) these should have a decent (for the age) power supply rejection ratio. I’d pull V1 out then measure ripple on the plates. Get the feeling that’s where it’s actually coming from.
Disclaimer: may be wrong but worth a check
That's exactly where it's coming from. I've already determined that. It's a high gain pre-amp with a somewhat shitty supply. Any quality audio pre-amp wouldn't be like that.
Gotcha. All makes sense. Bourns radial ones then. Cheap and cheerful. Series a few up to make a bigger one.
Gotcha. All makes sense. Bourns radial ones then. Cheap and cheerful. Series a few up to make a bigger one.
Can you give me an example of what you mean?
@bd139
So, finally you've sniped the HP 209A oscillator? Congrats
Fuck! Completely forgot about that! Wasn’t me