Thanks freediver for responding. There are tweaks next to each tube (4), and there's a switch on the side to select 1 thru 4 (tubes, I'm assuming), it's currently setting on 4. Then, there's a removable plate, next to the 1-4 switch, behind it has four RCA connectors, labeled 1-4. That's what I got. The meter is definitely for biasing, it's inside the cage, and calibrated in mA, 0-100 mA. So the switch surely connects the meter to each tube, but I don't know what to do with the RCAs. I've measured them. with power off. Grounds are ground, and the plus lead reads 10.3 ohms. Kinda sounds like a cathode biasing resistor? But who knows? This is a ZERO feedback amp, and it sounds unbelievable. It set new standards for me, and made most of my other amps crappy in comparison. Gotta keep it running!!! Let me know if you can help.
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Thanks Peter, good idea. Here's a url with photo's and detailed description - except how to bias. http://www.stereoknight.com/S-40.html |
Sounds like the meter acts as test point.Disregard RCA's for now.They shouldn't have anything to do with biasing.Try setting switch to #1,then slowly turn tweak(your word)next to tubes & see if meter changes.NOTE setting before moving tweak so it can go back.Pics in your link don't work.Maybe you could post pics in a virtual system so we can see it. |
Thanks freediver. FYI - I'm a bit of an idiot, the amp is an S-40, not an M-40, sorry for any confusion. I've set the switch to each number (1-4), with the amp on (its an integrated), with no inputs, and volume set to 0, the meter always reads 0. I also tried turning the pots (tweaks) next to each tube, but the meter doesn't move. I'm thinking the RCAs are used to "insert" the meter's "other lead", with the 1-4 switch being one, and the RCA's being the other. If it's a true current reading, it'll need to be in series with the cathode, somehow they have to "break and insert" the meter in series. Perhaps the switch is set to 1 and RCA #1 is shorted? |
- 15 posts total