Re: LN 1530 Wellbrook amplifier replica deaf on LW - MW
|
I think you may have a oscillation problem that is causing your problem on the lower frequencies. You need to make the board more compact and you need double sided copper shielding on the board.
?
I have designed several PCBs for the ALA1530LN and they all work fine, with no oscillation issues.
?
Everett N4CY
In a message dated 1/2/2025 12:55:57 PM Central Standard Time, netsmo62@... writes:
?
Good morning, I'm wondering if anyone like me has made a full working Wellbrook 1530 LN amplifier based on the schematic found in the files section named "Wellbrook_Loops.Kicad_sch." with smd 2SK932 jfets (but others schematics are very similar) I'm asking because I made a couple of them over time, one even with the original 2SK715 jfets but in the end they have the same problem, that is, they seem completely deaf up on LW and MW to the shortwave range, where they work much better...a classic amplifier with only two transistors (BFU590QX) works regularly. I tested the jfets (taken from the European electronics e-commerce portal TME) and they are all ok, the absorption is normal at about 115 mA at 12V. The toroid windings are the ones described on the schematic: input P3/S12 (plus the two single turns) secondary with crossed wires - output P9/S5. Test loop hang from a tree in my garden at about 2 mt. from ground.? I'm adding the link with a short video and I've put two photos of the boards so you can see the construction. Thanks in advance, F.
?
?
?
|
Everett N4CY