spritzer

They do matter but not as much as you'd get with a more basic amp. I always run XF2's but use SED's for testing. Good news on the tubes Todd.

I'd certainly try it. It is a single ended triode amp so it is not balanced but it will accept a balanced input. Been looking at the interior shots...

That's a cue for Kevin to show his Single Power rig...

Should take a set amount of time based on the 555 timer. Could be a bad chip?

That hum has to be a ground issue as at the extreme left there is max resistance between the input, viper and ground.

Being grounded grid and with fixed operating points the tubes are less of a factor but their construction still matters. I'm vary of the Psvane tubes given the quality issues of other Shuguang models which is why I still recommend the SED's. Same sturdy build quality as the late Mullard tubes which is also why they are expensive.

The B22 would not be my first choice for the HD800. It is a bit on the bright side.

True in many ways but even Sennheiser aren't Ultrasone cheap when it comes to the build quality. Fake Neutrik plug on a 3.5K$ headphone speaks volumes about the company. I'd still like to get an ED10 and Stax-ify it...

That is true but they are more similar than not minus the usual Krell overindulgence. They really are transistor mad, didn't the old CDP's have something like 200+ transistors in the output stage?

A balanced version of this would be very, very big so that is the first major issue. There are also a lot of parts needed and to match all of them. Not under 2K$ with free labor would be my guess built to our standards. For a balanced amp the Dynalo Mk2 would be a better fit as it is cheaper to build, it's super symmetry so you can use either a SE or balanced source for balanced output and it's performance should be on par or even superior to the KSA-5.

Sketched up front and back panels for the KSA-5V just now: They will naturally not be colored like that...

Anybody who wants to order unproven PCB's is free to do so but none of these have been operational yet.

Some progress on my end but now I have to wait for the panels to be laser marked.

I get that but it doesn't change the fact that an electrolytic capacitor only has a shelf life of about 20 years. Doesn't matter if it is used or not... There is also the small matter of the massive improvements in capacitor technology over the last 20 years.

Krell used Motorola sand in the stock amp but they should be identical to the current ON Semi stuff.

I didn't fare any better with the output devices but this amp will be as close to stock as is possible. Most of that doesn't make any sense to me. Rolling caps which look mostly vintage... why would anybody do that?

I try the HD700 from time to time and they never cease to suck quite badly. I'll have to try them with some electrical damping though as that seems to be Senn's new thing. I also hate the fit and finish of them. That fake rubber crap...

...and here is that PSU. As soon as we are both happy with the design then I'll have some proto's made.

I used Panasonic FM's which pretty much the best you can buy at a sane price.

Some progress on this as well: I've moved the 10uf servo caps to make the oversized Wima caps a better fit but tantalum's will be far smaller so not an issue.

That is indeed true but it's still better than most of the commercial amps.

Just basic matching, nothing more than that. Mostly because I didn't have enough to do any major testing and sorting.

I got some parts in and it is almost ready.

Yup, the mini PSU is just the same supply but the only thing that was added was a spot for a 270V zener. It's there so you can use the KSA1156 instead of the 2SA1486 which is stock at Mouser and quite cheap. The simplified PSU will be polished over the next few days and then I'll order a prototype run. It cuts out a lot of parts but should be similar enough in performance.

The word pure does mean very different things to people. Some claim it applies to simple amps even if the end performance of a single fet or a triode could be abysmal. To some it is a short signal path, never mind if it is a chip amp with hundreds of components. Then we this craziness...