$30 tube preamp kit? What do you think?

[jeffhamman]

tube buffer?

What exactly does a tube buffer do?, I saw that too but did say it had any gain like l was looking for. Any way I will post on my results with this whin it arrives.

 

[Gary Indiana]

...it uses 110 and 6 ac so I might go with it instead of the 90v and 9v or do you think it is basically the same

The one I bought was little cheaper, it (mis)spelled "Peramplifier" instead of Preamplifier. 110V for anode should be just fine, and 6 VAC for the heaters should do OK. Especially if that's what the seller specifies. I came across some data sheet for the 6N11 that said 90VDC anode voltage. But tubes allow for "wiggle" room.

Personally I would suggest little more than 6 VAC to supply the heaters' regulator chips (7806). Preferably between 7 and 9 VAC. And here's why: 6 VAC after rectification and filtration will get bumped to about 8 VDC and the 7806 chips need minimum 9 VDC input for proper ripple rejection. In other words, too low AC voltage fed to the heaters' circuit might result in imperfect regulation and audible buzz.

What exactly does a tube buffer do?, I saw that too but did say it had any gain like l was looking for.

I theory, a buffer's amplification is 1. Its main purpose is not to amplify but to match two differing impedances - from low to high or the other way around.

These circuits however do have a nice gain. It was on a par with the opamp chips in my CD player.

 

[Jlux]

Hey, I'm thinking 'bout getting a Chinese amp/buffer? comparable to the one in this thread, RE: Gary Indiana, from ePay or Amazoon. ePay's $10 cheaper with shipping. They are going for $49.00 now. The one I'm looking at seems a little more well built & put together & comes WITH the tranny INCLUDED. I don't know what would be the problem with buying with the trans. made for the piece? It looks fairly beefy, and finding one here stateside will cost me as much as the preamp, if not more.
here's a link: http://www.amazon.com/dp/B008BGLN5G?tag=thanayud044-20
Anyone have any thoughts, comments? This is my first tube rodeo by the way, so even if I screw it up it was a learning experiance. BUT, I don't plan on screwing it up!
My intentions are to build an amp that I found on the Instructibles site, or restore a Dynaco ST 70. Ether way, I'll need a preamp for my Phono, Tuner, Cd, etc...
Thanks, Johnny.