Vacuum Tube Audio Gear

Thanks for all the info

This setup was all new to me but seemed to be recommended by various YouTube channels. As I was starting to get paranoid after changing all my electrolytics I thought I’d give it a go. Great fun making it but an extra cost for more or less a one off. The information I had was if the bulb glowed you had a short circuit. Being in the UK I got up to half voltage and the bulb glowed. Now I was worried. I went onto forums and now I was told that was normal and I might need a second 100W bulb-confused or what. I juggled the resistance figures in my head not knowing how much current my power amplifier needed. I tried again and the bulbs started to light before my voltage reference tube would strike-which I was used to seeing immediately on normal power up. Looking at the voltages I was getting nothing seemed untoward and I then checked the current. It seemed that the 200W of bulb seemed to cut in too early and choke the supply of current. Stephe kindly reassured me that she tends to use this method for initial testing. As I knew I’d wired everything correctly and there was no smoke smells or bangs I then went for a normal power up and rely on the fuse to blow. All went OK and sound emerged from the speakers-phew! After finally receiving my power plug it showed the amplifier takes about 1.4A at 240V so unfortunately it seems that when the bulbs illuminate they’re restricting the current to well under an amp max. Maybe if I’d have been brave enough and pumped the variac up to 240V I might have got a signal through the amp but I was too scared of the Big Bang theory! 🙂

It was happy when I shorted out the light socket. Even 2x100W seemed to choke the current quite a bit especially with my preamp 🤷

All up and running now, thanks 👍

Just connected an Ammeter to the mains input and it seems the 100W bulb is limiting the current to 0.2A. Think I need another 100W bulb in parallel at least?

Just received my Nichicon Capacitors and a couple of Kemet’s. 385V changed for 400V as no choice now and a couple of 600uF had to be 680uF. Digging out my foam weather strip where necessary to pad the dimensions out. Just watched videos about Variacs and Dim Bulb Limiters. Didn’t want the expense of a Variac and I’d probably risk an Amazon Chinese one if I decide I need one. The Amps were working fine before I gave it a lobotomy 🙂