Yes - after 40-50 years of use, they probably do need a change. This thread is a few years old now. I'm still enjoying the AMP - enough that no "upgrade" desires exist, The speakers got finished - the Encore's from GR-Research. The are sounding good - I think the biggest improvement would be room treatments - unfortunately the system is in a fairly large room, with lots of reflective surfaces. I'm thinking of moving everything into a smaller room which will be easier to treat.

Thanks. The resistors do get a little hot, but they are away from caps and the steel case is a pretty good heatsink. I'm using some 40 year old Monitor Audio R252 speakers at the moment (my speakers from college days) - I'm in the process of building some GR-Research X-LS Encores, waiting on some parts they are having problems with. One real improvement for me was getting some of the monoprice monolith speaker stands. Getting the speakers at ear level and away from the wall has helped with the sound. (filled the legs with sand, so the stands are solid) I've been using the AMP a few hours a day, and it's sounding great. It's actually dead silent with just the single choke. It's made me want to investigate my phono stage a bit more as it has a slight hum with ears close to the speaker - which maybe I could eliminate with some better separation of the power board. One additional project in the works is a pre-amp/source selector. I'm going to make the amp portion switchable so I can I can use the box to select a source and select if I want the gain section bypassed or switched in. Trying to have much of the Audio system DIY'ed (The amp/pre-amp/phono stage and speakers).

Autodesk has a free version of Autodesk Eagle - it's a comprehensive package, so may be more than what you are looking for. (It runs on Mac/Windows/Linux) YouTube has tutorials on it - might be worth taking a look to see if it's inline with your expectations. https://www.autodesk.com/products/eagle/free-download

I just built it up from separate parts. I probably should have used brass, but currently it's stainless. I used a knurled nut from Amazon: https://www.amazon.com/gp/product/B07ZF3Y6DP The part is metric, so I also needed a matching metric bolt, nut(s) and washers. I also had to come up with some plastic washer arrangement to isolate from the chassis (I wanted to take it back directly to the star ground). I did find something after I was done that might work, Google "Deltron 351-0000", Mouser.com has them.

The EAR834 board has a spot for a Pot connection (you have to also add a couple of 68K resistors). The marking on the PCB isn't very clear but it does put a box around the 3-pins for each channel and the output is also marked. I don't think it works too well for a volume control. I have a 50K audio taper (log) pot installed and it lets me trim the output voltage some. Maybe just using a 100K audio pot on the full output and taking the output from the wiper/ground would work better. I could never find a schematic showing how the 68K/50K are connected (guess I could have metered it out...). I've had my EAR834 powered up for 5 days now, I did change V1 and V2 to the Mesa SPAX7-A, not sure how much of a change it made as I didn't give the JJ tubes much time to burn in. I've played a bunch of LPs through it and love the sound - it's very detailed and open . The bass is much better than before. My system isn't setup for bass (I'll list components below). I'm going to build the 6SQ7/EL34 amp next and pair it to this. Hopefully my speakers are sensitive enough - I don't listen at loud volume. Turntable: Rotel RP850 Cartridge: Ortofon 2M Bronze phono stage: EAR834 (Was Schiit Mani) Pre-Amp/ Headphone Amp: Schiit Magni Power Amp: Adcom GFA 535 (original not -II) Speakers: Monitor Audio R252 (sensitivity 90db) (Most of this is 30/40yr vintage stuff from my college days, other than the Schiit amp and cartridge. I didn't trust how my Ortofon VMS20E would behave after 40 years, so replaced it ) I'm loving listening to my LPs again - they bring back some memories. I think I might need to invest in a vinyl washer, some of the LPs have a little too much popping (and it's not from any scratches). -Simon.

Thanks, I went the eBay route, managed to get a few used ones for under $6 - hope they work out. I'll have several brands to try.

posted the build update pics to the 'show and tell' forum. Simon.