What tube amp to build.

[Jeff429]

How expensive does iron get for higher watts per channel?
Say 20 to 40 WPC. Still has to be cheaper than buying a commercial amp.

[Schmitz77]

It can cost from $50 upwards the sky is the limit.
If you want good quality 40W push pull (Lundahl), it would cost roughly $500 for the pair. But thats not best quality, only good quality.
Go for asians and get two for $50.
Remember, with just a normal quality tube amp with 40W your right in the range to miss all that tube excitement a high efficiency speaker could give with a low powered, simple tube amp and may not be able to made up for that loss of sparkle. You will end with an amp that may cost you much more, and still not excellent enough for high quality listening pleasure.

[Demonkleaner]

Klipsch "Heresy"

[Eli Duttman]

Originally Posted by Jeff429

How expensive does iron get for higher watts per channel?
Say 20 to 40 WPC. Still has to be cheaper than buying a commercial amp.

That sort of power falls squarely in "El Cheapo Grande" (ECG) range. PP designs, which ECG is, frequently employ global NFB loops and ECG does employ such a loop. For reasons of avoiding core saturation, the O/P "iron" has to provide power handling capability above the design's full power O/P.

Edcor's product has a reputation for being a solid, if unspectacular performer, and an all around good value. This Edcor model will be fine in a 7591 based ECG or a Mullard style circuit employing Russian 6Π3C-E (6p3s-e) O/P tubes. FWIW, the tube sold by New Sensor as a 5881 is 6Π3C-E and it's pretty darned good.

[Brinkman]

I would definitely consider a loudspeaker kit from DIYSG, though covid has disrupted their kit inventory supply chain.

Both the Vortex-12 and Vortex-15 offer high sensitivity, constant directivity and point source dispersion. Either can be build as ported designs for full acoustic bandwidth. The frequency response measurements of these speakers (esp the 15) is superb.

Doing so would allow you to consider the vast majority of tube amplifier builds, regardless of topology.

I used a modified ST-70 with Klipsch Fortes for years. It was the bug that bit me. I have subsequently built many of the DIYSG speaker kits. Currently building the Helix Dome MTM (92dB/W/M) which turns out is tube friendly due to its flat impedance (wasn’t aware at the time of purchase). I have a Vortex-15 in the build queue after that.

[invaderzim]

It looks like the Vortex ones are, at least for a while, no longer offered.

"I believe only 2 people ordered the Vortex-12's in the 1.5 years they were on the site. I'll likely put them back up at some point but I probably need to document them better with a better explanation on why they were made up and what makes them good."

They still have several other offerings that look quite interesting though. As soon as the supply chain gets moving at speed again.

[baudouin0]

You could do worse than a Mullard 5-20 amp. EL34 PP.
Or a kit such as a ST-70

[Brinkman]

Originally Posted by invaderzim

It looks like the Vortex ones are, at least for a while, no longer offered.

Hopefully it will only be temporary. There’s a backstory and the short version of it is the guys who cut flat packs for DIYSG are/were prioritizing covid-related hospital work over non-essential clients. Erich is reserving the drivers for when he can make flatpacks available. Other supply-chain reasons too but you get the idea.

[pl802]

hi Jeff429.
If you are going to build with vacuum tubes go Single-ended,which by extension mate well with Full-range Drivers.
The sound of a simple SE EL84 amp driving a pair of Goodmans Axiom80s.....set me on a journey of record buying that needs to stop.
All the best with your exploits.