dsavitsk

You are welcome to borrow my HD800s to try it if you like.

Hard to know exactly. Any tube is going to slowly degrade over time, and at the point where it is too compromised to work well in one circuit, it may be fine in another. Or it may still meet its specs, but not be sufficient in certain circuits. But it is generally not a hard line of good vs. bad. In the case of the L-2, the tubes are run only moderately hard, but they do need to maintain their Gm to work well. I'd venture that 1000 hours is a reasonable expectancy, but that will vary from tube to tube. I've personally never used a 6c45 for long enough to kill it, but then I have a lot of different amps so that is not necessarily surprising.

With another pair. It sounded like they were just getting old.

Yup, no problem. Shoot me an email and we'll discuss.

The circuit is horrible, the build is horrible, the layout is horrible, etc. But if there is proper ventilation, the upside down tubes does not bother me so much. Guitar amps do this and it has been working fine for 100 years.

It rains 1 in 5 days in the Bay area.

Happy Birthday!

There are a couple out on loan right now. I am of course hoping that the people who have them buy them, but in the event that that does not happen, we can do a little loaner program. Just PM or email (my user name at ecpaudio.com) me. Dibs to people who might want one permanently, but I am happy to send them around to anyone willing to cover shipping expenses.

The Dickies' cover of the Banana Splits theme

Happy Birthday!

I see. I like the O.E. picture better

A picture of Hank Rollins from Black Flag, a quote from a bad Descendents song (is there any other kind?) attributed to the singer from the Sex Pistols who had nothing to do with Dead Kennedys ... I don't get it.

Yes, the front switch. On the DSHA-1 it changes whether the two output windings are in parallel or series. The transformers are 1+1:1+1 (quadfilar). The inputs are always in parallel, so when the outputs are in parallel, the transformer is 1:1. When they are in series, they are 1:2. The Zout of the circuit itself is very low. The Z difference is due to the copper in the transformer. This is true with all transformer coupled amps -- they all have added Z due tot he copper. The jumpers change the gain. As a byproduct, they also change the input impedance, but not in a way that will make any difference for 99% of sources.

The high Z out is right around where the Senn amp is. The Lo is about 1/4 as much. I tend to think they sound better with the high one, but it is really a matter of preference.

A transformer coupled tube amp with a 300R secondary is likely going to be right in this ball park.

This has been in the back of my head -- this build reminds me of one of my favorite builds I've seen. http://www.diyaudio.com/forums/attachments/tubes-valves/144849d1256750797-photo-gallery-dsc_0617.jpg

It's a really beautiful build. Ask 10 designers how to build an amp with those parts, and you might get 20 designs. 9 of them will give you the same design, and one will give you 11 different ones. The point being that if this is a "traditional" amp, then what the schematic looks like is probably pretty easy to deduce, but there are lots of ways of tinkering with the details.

Happy Birthday Ari!

Happy Birthday!

The availability of inexpensive circuit boards has been a blessing, and a curse. This is just the crap I don't know what to do with. Note the original Millett Hybrid on the far left

I don't totally disagree. I did a very basic version of the mod just using some wool felt I had left over from a speaker project. There was definitely less treble energy, but there was also a flatness that made them a bit boring (hence the HD650 comment). And bass seemed to be reduced. Since the mod can clearly be implemented better, I'll reserve any judgment until I actually do it right. I do like them stock with the right amp. Tyll -- have you measured them with different amps, or just with some low Z high feedback type?

It was a facetious comment.

Not sure if it is useful to anyone, but I edited Tyll's pattern to make the lines thicker and get rid of the extra stuff. The reason being that you can use the toner transfer method to transfer this directly onto (wool) felt to make cutting easier. The moment between a decently transferred image, and burned piece of felt is short. These now sound more like my HD650s ... not sure that's a good thing here SennheiserHD800modTemplateEDIT.pdf

I finally bought some HD800s. I don't buy many headphones so this was a big deal. I was talking to someone today, and he asked if the whole cup was the speaker. I then realized that the whole outer shell is supposed to look like a speaker cone. Maybe everyone else knew this, but I had never noticed. They still sound good, but they went from ugly to lame.

It's perfect here today -- we only get a few of these each year. I'm quitting early to go play tennis. It looks like typical Chicago spring weather for the next week or so.