Wear rubber gloves, wait for it to properly discharge before touching it, DC burns really bloody hurt, tell me how I know I almost did this stuff for a living, tho god knows how you make one doing it, must be like fixing other people's Buses @zedders?
Without a schematic it is hard to say. The valve has a gain of up to 17, but the circuit may have it running as a follower e.g. unity gain.
My first loud amp was a Selmer "Treble and bass" valve amp. It was old when I got it in the 70's. I had a 4x10 cabinet too. Damn that was loud. eventually it stopped working and my dad being an electronics engineer set about testing it to see what had gone wrong. There was an almighty bang and he had exploded a huge capacitor... in the living room. The entire ceiling was coated with little bits of tar and silver paper "snow" was still falling when I came down to see what was going on. That had to go in the bin.
So...in English... it doesn't "do" anything at all and all I've gained is a better impedance match for my headphones? Or does it "colour" the sound? It definitely sounds much nicer than the mismatched headphone output I was using previously.
Yes, we're guessing it's giving you better impedance matching and possibly a nice bit of second harmonic
Output buffer...drives the line (cable) and the load. Christ on a bike, it's all coming back to me, I better go have a lie down...can we talk about engines now?
You only fix posh stuff for people who do not care what it costs, to put in their "listening rooms" that probably look great but are full of nulls and reflections making the £100K of equipment sound no better than my headphones. expectation bias is a wonderful thing.
Capacitors are the things that need replacing most often in vintage kit. They decay over time. Some can be "reformed" by gently applying a gradually increasing voltage, others just end up as a puddle of wax on the floor. A common trick with unknown mains powered radios is to connect a 60w filament bulb in series when you first switch it on.
Hahahaha, have you met some of the HiFi press by any chance? I must admit, I do miss the shows this past 18 months, there's some absolute nutters in the HiFi industry
No - he shorted something. The amp itself just didn't work one day when I switched it on. No great loss - as a guitar amp it didn't sound good until it was on full volume which was rather impractical.
That's HiFi for you, it is whatever you want it to be when you have "expectation bias" but I don't think you do @zedders, you're feet are firmly planted earthwards.
Don't need to - the recording world is worse. There are people who truly believe £20 software can make their £100 headphones sound like £20,000 speakers in a famous producer's £100,000 treated mix room and a free convolution reverb plug in sound like a £5,000 reverb unit. It doesn't take much thinking to realise these things are pure marketing BS. Silk purse/sow's ear. Once they've spent the money, it's even harder for them to admit they've been conned.
The orange thing is just a relay. The things on heatsinks might - might - be IC power amps that might - might - use the valve as a preamp. Have they got numbers on?
