Thanks Vunce, fun is guaranteedGreat looking beefy inductor Plott!
I’ll be looking forward to your progress updates. Enjoy
But I need a forklift for that piece
As I have been listening to my VFET amp with some of the new FE cards by Mark J., it occurs to me that the Dreadnought and Marauder designs would be worth trying. They both can handle 60V power (single-ended one way or another), and will swing enough output voltage to drive this amp to full power.
They happen to include on-board DC-DC converters, and may be Ok running of the main 28V rail. Otherwise, there are several other DC-DC converter solutions available..
They happen to include on-board DC-DC converters, and may be Ok running of the main 28V rail. Otherwise, there are several other DC-DC converter solutions available..
If you are looking for LD1014 (LU1014) parts, I have a bunch available here:
https://www.diyaudio.com/community/threads/ld1014d-lu1014d-matched-by-vgs-and-curve-tracing.381338/
https://www.diyaudio.com/community/threads/ld1014d-lu1014d-matched-by-vgs-and-curve-tracing.381338/
Good you did not buy the Mundorf fairy-**** caps, they are not worth the money. Just use some no-nonsense MKP caps. The standard Mundorfs are fine, and Mouser has many more, whiich will not cost an arm and a leg. Once you have the amps up and running put a temporary jumper across the input DC blocking caps (if your source has no DC). I am pretty sure your ears will not be able to tell the difference without the help of your eyes telling your brain if the jumper is in place or not.
I received my LuFo boards yesterday, and am looking forward to building a new amp with these.
I have been working with output capacitor coupled amps for a few years, beginning with the original ACA and most recently with the DIYA (lottery) VFET amp. I haven't found electrolytics in the audio path to necessarily be an issue. I do take care in selecting which types are used, and frequently use two or more in parallel with each other to achieve a tonal balance.
Starting with the ACA, I found that the Nichicon LKG series sound good. They are designed for audio use. One will notice that the pictures of the LuFo amp show big Nichicon electrolytic caps with gold lettering. These are examples of the LKG series. I recently ordered a few of the Nichicon LKS series for the next couple amps in the queue. These are compact, high quality Type-1 versions of the LKG series.
https://www.mouser.com/ProductDetail/647-LKS1K103MESCThe big electrolytics that are included with the VFET amp kits are these. Papa seems to like them, and I do as well:
https://www.digikey.com/en/products...5438?s=N4IgTCBcDaIIxwBwE4C0YDsBmNA5AIiALoC+QA
Beyond the big electrolytics, there are a few film caps that are used in the new VFET amps and their various front ends cards.
These polypropylene caps are used in several places in the new VFET amp front end cards. They sound quite good in signal coupling applications:
https://www.mouser.com/ProductDetail/80-F461BY225K160LHere are the 0.33 uF capacitors used in both the input and output stages of the latest VFET amps. The VFET output stage boards use one of these in parallel with the big Rubycon electrolytics:
https://www.mouser.com/ProductDetail/505-MKP20.33-100-5
I have been working with output capacitor coupled amps for a few years, beginning with the original ACA and most recently with the DIYA (lottery) VFET amp. I haven't found electrolytics in the audio path to necessarily be an issue. I do take care in selecting which types are used, and frequently use two or more in parallel with each other to achieve a tonal balance.
Starting with the ACA, I found that the Nichicon LKG series sound good. They are designed for audio use. One will notice that the pictures of the LuFo amp show big Nichicon electrolytic caps with gold lettering. These are examples of the LKG series. I recently ordered a few of the Nichicon LKS series for the next couple amps in the queue. These are compact, high quality Type-1 versions of the LKG series.
https://www.mouser.com/ProductDetail/647-LKS1K103MESCThe big electrolytics that are included with the VFET amp kits are these. Papa seems to like them, and I do as well:
https://www.digikey.com/en/products...5438?s=N4IgTCBcDaIIxwBwE4C0YDsBmNA5AIiALoC+QA
Beyond the big electrolytics, there are a few film caps that are used in the new VFET amps and their various front ends cards.
These polypropylene caps are used in several places in the new VFET amp front end cards. They sound quite good in signal coupling applications:
https://www.mouser.com/ProductDetail/80-F461BY225K160LHere are the 0.33 uF capacitors used in both the input and output stages of the latest VFET amps. The VFET output stage boards use one of these in parallel with the big Rubycon electrolytics:
https://www.mouser.com/ProductDetail/505-MKP20.33-100-5
On LuFo I would recommend a cap multiplier to reduce ripple. On SuSyLu it’s balanced so good PSRR and only CRCRC needed. I used my own CRC cap Mx board for the LuFo and that worked well. It does impose a 3v drop in the rail voltage so keep that in mind when sizing transformers.
You can try CRCRC with a high ripple current high ESR 105C rated 15,000uF cap on first C. Use 22,000 on the others. So that’s about 59,000uF total per amp. About 0.1ohm 5W resistors. First cap gets hit with a lot of ripple at 3A current so gets hot.
You can try CRCRC with a high ripple current high ESR 105C rated 15,000uF cap on first C. Use 22,000 on the others. So that’s about 59,000uF total per amp. About 0.1ohm 5W resistors. First cap gets hit with a lot of ripple at 3A current so gets hot.