Also this makes me curious - if the power output doesn't change much with tubes, does that in a way mean that tube rolling on this amp doesn't make quite as much a difference as with the likes of a traditional OTL amp? In many cases I recall tube rolling on other amps not only changed characteristics like tonality, soundstage and extension, but also dynamics/'slam' and I think this dynamic change had something to do with rolling tubes that synergize better/worse with certain headphones according to their varying power output.
Thanks for the kind words Levi!
Well, I was generalizing. Power output will change with different tubes but its not something you'll notice with headphone listening.
Since the bias current will stay the same, the power output will rely on available signal voltage swing. That swing is set by bias voltage (in peak to peak) x mu (gain) of the tube.
This amp will have plenty of power for headphones regardless of tube config. You will notice difference in sound from tube rolling.
One more thing - for the others here would you mind to explain in your own words the function of the two smaller knobs on the front plate?
The left knob is to select the speaker and pre-amp outputs and the right knob is the impedance switch.
The speaker/pre-amp switch has three positions: OFF/speaker/pre-amp
The impedance switch has also three positions: OFF/low/high
- you should reverse measuring point in (toward front)/out (to the back)
Not a problem. To me that doesn't matter.
- have 6j5 socket more in the front (but the big front vue-meter takes space)
Not possible without moving basically everything around. When I plan the layouts I do so with both aesthetics and wire management for least amount of noise/hum in mind. Personally, I like the layout as is.
- will you replace embossed labels ?
It's the only type of label maker I have. I use it as it fits the retro theme of a tube amp. We don't have to use labels on your amp.
Regarding switches at the back. It's a matter of space also. Not everything will fit on the front panel. You could of course mount switches on the top plate as well.
Btw,
@DecentLevi your amp has three different heater windings. Rather than paralleling all of them I kept them separate like this:
Output tubes: 5.4A
6J5 sockets: 3.8A
6SN7 socket: 2.5A
It looks great. I wouldn't change a thing. I know you plan through and give a lot of thought to the layout before the actual build commence.
That's the date I got Oblivion... 2019 I think. Realistically I expect Odyssey in July / August 2021.
