Update!
Final version after painting. Holes were off for the tiubes, but I figured I could elongate the hole and use curtain rivets like Stephie suggested in one video to cover up my mistake and make it better looking at the same time.
Also used auto body filler to clean up corners and fill the one accidental hole on the top.
Hooked up one dc rail backwards and blew half my electrolytic capacitors. Luckily I bought 3 extra and had enough to replace. Also had bad hum on the channel that did not blow, but that was the input wire polarity swapped. Still have some hum at louder volume. Seems tp be 60hz and is real bad if phono preamp gnd is disconnected. Will try adding a bulkhead , once I get some aluminum sheet metal.
Also will try some of the notes at the Lenco heaven page..try changing the caps to 33uF and bypass them. I did buy the lowest esr caps I could find at mouser.
https://www.lencoheaven.net/forum/index.php?topic=20984.0
May end up putting it is a really big chassis and put it under my turntable, as I big, short copper strap between my turntable may kill the hum better. But it sounds good.
I scrambled to get the first sounds out of this last night. I still have chassis issues to fix as not happy with placement of holes I punched thru the chassis for the tubes. So I have not bothered installing shielded wire for the audio path yet. I still need to cut a bigger hole around the tubes and add a trim plate with holes for the tubes aligned better, paint, and add the ground screw. Oh and add some shielding for the 60hz hum, but a lot of that goes away with the ground wire pressed to the chassis. I may just make a whole new chassis for it some point. Enjoyable build and your videos helped a lot. Would have never tried this or even thought of making one of these if it was not for your videos. Building this brought a lot of happiness into my life. Thank you!
I am shocked, amazed, the bass is intense. My room is very hard to fill with bass, but this combined with the R8 is amazing. Some reviewers of my Polk R-700 speakers would complain that they can over pressurize the room. I had no idea what they were talking about till now. White Stripes, Ball and Biscuit sounds like the bass drum is in the room!
So much better than my built in pre-amps and Fozi audio tube preamp that previously impressed me with better sound.
I do need to figure out some ultrasonic filtering though.. I will post more photos as I clean it up and finsh the chassis and wiring.
Capacitors. I am having a hard time sourcing capacitors. There is a pair of Mundorf evo oil on the other side, these purple clarity caps were available, so I bought them.
I honestly saw no difference in noise using a bulkhead, even using MU metal. I did notice a difference going to 7025 tubes and I also wonder if you wounded those caps applying reverse polarity even if they didn't explode?
One other thing I found helps is use a LARGE guage solid core wire from the board to the ground, I noticed a difference going from 18g to 14g solid copper. And honestly these are going to have some noise if you hook them up and turn the volume to the max with no signal. I've found with the volume set at a listening level from the listening position, I don't hear anything.
Also I noticed you aren't using shielded wire for the input/output, that could also help.
Here are some updated photos. The hum in my unit went away by correcting the grounding. I think I still have more to cleanup, as I have a ground loop between my phone input gnd to chassis and the input board, and the gnd on the ps broard. I did not have the single point gnd position on the power supply board connected to chassis. There are lots,of good diagrams on the lenco heaven website about how to do the grounding correctly. Regardless, hooking up the power supply board from the gnd with a triangle point on the board to chassis made the the hum go away except at very high volume. I was hearing the sound of the needle dragging on the record. I think from the bad ground it was generating static as my records were suddenly sticking to the mat on the platter.
I made some mistakes reassembling the unit. I hooked up the b+ backwards on one side of the board. I guess it was good at that point I did not have the ps gnd connected to chassis. Eitherway it made let the smoke out of the 22uF caps. So I replaced all the caps on that side. I always order a few extra, and just happened to have the 3 40pv caps as spares. I then had a weird, ridiculous strong hum on one channel. Just touching the rec jack would cause the hum to change. The other channel was fine. Turned out I had the polarity swapped on that channel where the input connects to the board. Swapped the polarity and the hum was back to lower"3vels of the prototype stage. Again, that was later cleared up by connecting the power supply board gnd point to chassis.
I think I need to isolate my phone input ground from chassis, and take it back to the single point ground on the power supply board. But even with the ground loop through the chassis, it it pretty quiet. I guess I will not bother with the metal bulkhead.
The holes were not centered around my tubes. So I elongated them with the hole punch. The curtain rod rivets have a large enough lip to cover the gaps and make it look perfect. Thanks for that great idea in your videos.
The mids still sound a little harsh and have like a static to them. But my HIVI speakers seem to have that quiality, so I need to do more listening to more records and hook up my other speakers.
I will probably continue playing with this seeking diminishing improvements. But I suspect my next improvement should be upgrading my cartridge on my $299 Audio Technia turntable.
Always love the rustoleum "hammered" paints for finishing electronics project boxes. It was a cold 50 deg day, so I used multiple layers of quick dry filling primer, and then put one coat of the rustoleum hammered black paint, and then put it on my propane grill with only one burner on low, and baked the paint on at 150 to 200 degrees for a couple of hours. I would have been waiting a week or two in this weather for the paint to harden up and not scratch off during assembly. It is a great trick, just do it outside, and make sure the temp is low and stable so it does not catch fire and ruin the chassis, and away from your house in case it does catch fire. But inside a metal closed grill, it should be fine. I did this in the house oven once,, the resulting fumes are not recommended. Hence the propane grill outdoors.
Bondo auto body filler fixes accidental holes and the dimples and gaps on the ends from the spot welder.
Every person who has heard one of mine just asks "how much do you want for it?" lol