Yet another 12B4 line stage, or is the 12B4 better than the Grounded Grid.....

[Mark A. Gulbrandsen]

Thanks for the link Planet 10!! I had read stuff on that site a couple of years back but had forgotten all about it. 125 euro for the kit???? Pretty pricy but could be done for less by DIY. I would be more tempted to buy the book and build it myself.... the book would be good to have anyway.

Thanks,
Mark

[kooltubes]

You can buy a tube regulator pcb for $20 (no tubes though) it's a Lite audio you will need an EF86 and an El 84 or EL86; the board comes with a filament regulator. Check on ebay or www.liteaudio.com

[planet10]

Originally posted by Mark A. Gulbrandsen
.... the book would be good to have anyway.

Yes... it is a hoot, gives some solid info & lays out AWs philosophy. Even having the book, i'd probably buy the reg kit myself...

dave

[Mark A. Gulbrandsen]

Even having the book, i'd probably buy the reg kit myself...

Aw, thats no fun..... Kits are way too easy..... Unless there are some special spec'd out parts I can't see why not to build it DIY?

You can buy a tube regulator pcb for $20 (no tubes though) it's a Lite audio you will need an EF86 and an El 84 or EL86; the board comes with a filament regulator.

I have one of those boards here. I don't think it can supply 60ma of current for both channels, so you would probably require one board per channel. The board by the way is extremely nice!!

Mark

[Looneytunes]

Thanks everyone for the great power supply discussion. I definitely have some research (and a lot of catching-up) to do.

From Dave:

...You can buy the book (Preamp Cookbook -- one of my top 3 recommended tube books)...

Dave, I'll definitely get the Cookbook. What are your other two top books? Does anyone have any other "highly-recommendeds" to add to the list?

I'll probably start with Brian's or Kool's power supply. Lots of iron, but by the time I get the parts , I should have a basic understanding of what is going on. Can anyone suggest a good source (and manufacturer) of pio capacitors? Is quality critical considering where the parts are used?

From Bryan:

I do have a very slight amount of hum, but this is caused by the physical proximity of all the iron of the PS chassis ...

Bryan, how far would you recommend separating the tranny & chokes to get rid of this hum? Also (and please excuse the NewB question), but I remember reading that all of the iron needs to be rotated 90 degrees from each other to minimize coupling. If I remember correctly, your design places a tranny plus 2 chokes (per channel) on the power supply box. Can I "decouple" (I hope this is the right word) the three pieces by rotating them by 90 degrees over all three axes?

From Evan:

Any thoughts as to stuff I should read before doing this project besides the newbie pages?

Evan, I found the "Online Tube Audio Resource Guide" a virtual treasure trove of information. If you haven't found it already, you can find it at: http://www.tubeseller.com/docs/tube_links.pdf. You'll even find links to complete texts there.

Thanks to everyone for the help and great information.

Wynn

[Zen Mod]

http://geek.scorpiorising.ca/GeeK_Zo...php?board=33.0

[VT67]

O.K. guys, to make it even harder here's another compact regulated power supply.

Welborne-Labs PS10

Regards

[bordins]

Originally posted by Mark
Some claim that alot of iron sounds best while others say regulated is best. Supplies definately do affect how a unit sounds to some degree but in the end its still a matter of taste.

It always comes to a subjective conclusion in the audiophile world.

Originally posted by Mark
I don't experience that forwordness that you experienced with your borrowed 12B4. .... what I've experienced is massively more detail much better imaging and a wider deeper sound stage over my Grounded Grid line stage.

I had similar experiences at first when I auditioned a 12B4 preamp. But when I took it to my friend's place where 3-4 experienced audiophile arrived on different times, they all said the same thing, without knowing others' comment.

They commented that my "first sighted love" because my ears got attracted by so revealing sonics. But if I listen to it for a long period of time, it might introduce hearing stress.

Originally posted by kooltubes
I have experienced the same thing before and I came to the conclusion that the sound is affected by the operating point and the PSU!

I agree that the PSU is the key. I'll have some tweaks on it.

If you listen it for relaxation, soundstage shouldn't be any concern. 12B4 is so marverlous! But for serious audiophiles, there is still a long journey to go.

[planet10]

Originally posted by Mark A. Gulbrandsen
Aw, thats no fun..... Kits are way too easy..... Unless there are some special spec'd out parts I can't see why not to build it DIY?

SS makes me quesy... nice to have the boards.

dave

[planet10]

Originally posted by Looneytunes
What are your other two top books?

Morgan Jones Valve Amplifiers and RHD 4 which can be downloaded from Geek's website http://geek.scorpiorising.ca/RDH4.html

dave

A copy of the RCA tube manual should be on the list too....