balanced k81djs

[philodox]

I think he mentioned some McAlister guy or something like that on Head-fi.

Yep, Peter McAlister... He is the guy that builds that low cost electrostatic amp, the EA-1. He also has a bunch of dynamic tube amps. Inexpensive, but mine is going to be a little more 'overdone' of course. He has some interesting design choices. We talked over the design and I came away very impressed with his knowledge. He is also the first tube designer [other than mikhail] that has not shyed away from balanced.

Personally I like tube rectification, I find it has less hiss & noise in my system and gives a blacker background. I can finally use Grados with my amp without the hiss bugging the hell out of me at night. Smoother sound too. The local surplus shop has hundreds of rectifier tubes lying around so I don't have to worry about tracking down stock on ebay.

He had a bunch of reasons as to why he prefers solid state... but he likes tube regulation. I guess we will just have to wait and see what he comes up with. I'm using a bunch of those metal can caps that you are so fond of in the PSU.

[aerius]

Yep, Peter McAlister... He is the guy that builds that low cost electrostatic amp, the EA-1. He also has a bunch of dynamic tube amps. Inexpensive, but mine is going to be a little more 'overdone' of course. He has some interesting design choices. We talked over the design and I came away very impressed with his knowledge.

Did he send you the schematics by any chance? If so, can we see them?

[philodox]

Did he send you the schematics by any chance? If so, can we see them?

He is working on the balanced version and said he would have something by Friday. Not sure if he is going to send me the schematics or what... if he doesn't I will ask, but I'm not going to push him on it. I can understand if he doesn't want to divulge that.

One thing that he said which sounded interesting is that he uses a seperate tube off the plate of the gain tubes to create an 'infinite plate resistance circuit' [at least I think that is what he said] which allows the tubes to perform quite a bit better and lowers the impact of tuberolling. [ie. crap tubes sound nearly as good as 'great' tubes]

The amp will be using 6H30's [4 of them] and 12sn7's [2 of them] as well as other tubes for regulation and such...

[tkam]

It should be relatively cheap for me though as with the 6H30 there are only 2 types and I would expect them both to sound identical

I've tried both types in my modded philips and to my ear they do sound identical. You are also correct that the only apparent difference are the build years.

How much isolation do the K81DJ provide? They could be a nice pair of phones for use at work for me.

[aerius]

One thing that he said which sounded interesting is that he uses a seperate tube off the plate of the gain tubes to create an 'infinite plate resistance circuit' [at least I think that is what he said] which allows the tubes to perform quite a bit better and lowers the impact of tuberolling. [ie. crap tubes sound nearly as good as 'great' tubes.]

A tube based constant current source, that should be interesting. Though it will make tubes sound better, you still don't want to use a crap-ass tube like the 1970's RCA/GE coin bases. As the saying goes, you can't polish a turd.

[philodox]

I've tried both types in my modded philips and to my ear they do sound identical. You are also correct that the only apparent difference are the build years.

That is great news! The older ones are like 3 times the cost!

As for the K81DJ's, I am a bad judge of isolation... but my wife says she can't hear anything when I listen on them and I listen quite loud.

aerius - Yeah, though I don't know if it is your standard CCS. I asked him if that is what he was talking about and he said. Well... sort of... and then basically said that he could explain it, but it would take a day.