n_maher

Is that the filament trafo I see in the center of the case? If so that's a bad location for it, right next to the output of one of the beta channels. Of course in that chassis there's no good location for it so eff it. And Gary, if I were you I'd get busy with the drill and start perforating much of the open space in that bottom panel, you're not going to get much airflow the way it is now.

I'm curious what "easy to drive" means? I keep looking at Headroom's Impedance vs. Frequency graph and seeing that 600+ ohm peak at ~100Hz.

I would recommend doing the real math before firing up both amps at the same time. I have no idea how much current the EHHA draws but it makes me uncomfortable to think about the tube heaters and what they must be drawing (if 6GM8s that's .33A each).

There are a couple of bottom lines here: 1. If you don't know and don't know how to check how your speaker amp's outputs are configured you shouldn't be messing with it. The Grado adapter picture clearly shows 4 conductors so that it doesn't have to worry whether or not the output of the amp has a common ground connection. 2. It's pretty likely that the Grado adapter had its resistor values chosen for a Grado headphones (all of which are 32ohm). Assuming that it'd be either appropriate or useful with headphones of varying impedances is a "at your own risk/peril" type of deal. It may work great, it may load your amp in such a way as to cause it to go into thermonuclear meltdown. Me, I'm content to have a separate speaker and headphone amplifier.

Just tell Jack you want an OTL version of the WA22 with a single ended output.

I would agree with this, it's my solder of choice purely for workability reasons.

Happy Birthday!

I find it hard to believe that you're an EE asking that question.

I put it on and Lily started to dance.

All I'm really sure of is that the 2ohm and 20ohm resistors form a voltage divider on the output that will give you about 1/10th the output V. As far as the load the amp sees I would think that the 20ohm and 32ohm (nominal impedance of the Grados) would be in series for an effective resistance of 52ohm and that this resistance is also in parallel with the 2ohm resistor. Not sure what this accomplishes but I do believe that the amplifier will effectively see a 2ohm load (actually a little less) which hardly seems like a good thing to me. A more informed opinion is definitely needed.

I love me some J5. Lily is a huge Kanye fan, if she's upset in the car all I have to do is put that on and she chills out.

Happy Birthday!

Quick question: have you ever built anything before? I'm not sure I'd recommend the M3 you're proposing as a first (or even second) project.

I agree completely, I'm hopeful that fixing the power supply is all that will be required.

Kevin, I think that the 278X is a single primary, not a universal.

Hmmmm, 6 tubes on the amp section... we could run [2] 6SN7 input tubes and use a quad of 6AS7/6080/5998s on the outputs and turn this f'er into the uber balanced Menace. Lord save us for the PS that it would need but you just might have room in that hulking chassis for it...

I know some of the build team have the resources and knowledge to do it, I was just pointing it out to those that might not. Carry on.

Part of what makes gives the Extreme the potential to sound good is running the 6080/6AS7 in parallel on the output, OTL's with a single tube are not going to perform well into low ohm loads in my experience. And of course none of them run the output tubes as hard as I do in the Menace.

Aren't you going to need a 4-wire meter to match the 2ohm resistors?

Where is this post?

I'd be shocked if there was a distinct audible difference between the two supplies. Both are exceptionally low ripple and well designed.

Regina Spektor - Far Upon careful listening I think I'm hearing just a touch of distortion in the L channel on some songs but I'm doing my best to just ignore it. Sounds pretty damn good on Mr. Menace, that's for sure.

There's little doubt that I have "special needs" but thankfully not in the computer department.

I don't think it was a very wise to choice to use the chassis, and only the bottom panel at that, as the heat sink for the power supply.

Regina Spektor Hears Magic In The Inexplicable : NPR Music This will take you to NPR's Morning Edition interview with Regina Spektor from this morning, just click "Listen Now".