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

[pengboon]

Hey Zekk, sure, let's take this offline. Drop me a email or PM.

[coffeedj]

Send me an email off line at djc1t@comcast.net and I can help you get up and running with parts and schematics. I'll try to post a schematic on my website soon and notify the group when done. Right now www GalaxySETlabs dot com is pretty much in a holding pattern while I get my lab in order.

[blaaberg]

Hey,
I`ll like to see this schematics and parts too, can`t you post it in the group
so I can take a watch?

Cheers Jan Jensen

[bequerel]

Coffeedj,
I noticed that you have made provision for a shop section on your website.
I think that there could be a market for a simple 12B4A kit.

Cool website btw.

[coffeedj]

I'm going to start a new thread on this topic and post design finding there--ending with a (hopefully) decent design for the 12B4 as a line stage amplifier.

[blaaberg]

Originally posted by coffeedj
I'm going to start a new thread on this topic and post design finding there--ending with a (hopefully) decent design for the 12B4 as a line stage amplifier.

Coffedj, thanks....

[coffeedj]

You can see that I've finished the first rev in the new post.

I'm really impressed with the bench performance--now I'll have to build it for real and see if it sounds as good as it looks.

12B4 Line Stage Amp

[ray bronk]

Originally Posted by coffeedj

You can see that I've finished the first rev in the new post.

I'm really impressed with the bench performance--now I'll have to build it for real and see if it sounds as good as it looks.

12B4 Line Stage Amp

That sure sounds good.


I have read this whole big thread. I did seem to get a concensus that somewhere between 17 and say 22 MA might be best.

Now, to bring this full circle, could the "Grounded Grid preamp be reoriented to be anode driven as opposed to being Cathode driven? Now, I'm a real newbie here, so if I understand rightly, the anode is the plate? As anyone explored that idea?

Ray Bronk

[Mark Allen]

Ray, The best place for you to start might be by building Rosenblats Grounded Grid in kit form. This will teach you the basics. You can then experiment and modify from there.

For those that were curious about my 12B4 line stage I powered it with an Eico High Voltage tube regulated variable supply. That supply fed the a pair of local 0D3 gas regulators for each channel. A seperate lab grade variable DC supply powered the filaments. I will complete mine soon but with a more practical tube regulated supply... but still will feed the local gas regulators as well. They do make an audible positive difference and who can resist the purple glow! I've absolutely no interest in adding the phono stage at my end. I got out of the LP end of things a number of years back... Really good LP playback gear is too $$ wasteful.

Mark

[ray bronk]

Originally Posted by Mark Allen

Ray, The best place for you to start might be by building Rosenblats Grounded Grid in kit form. This will teach you the basics. You can then experiment and modify from there.

For those that were curious about my 12B4 line stage I powered it with an Eico High Voltage tube regulated variable supply. That supply fed the a pair of local 0D3 gas regulators for each channel. A seperate lab grade variable DC supply powered the filaments. I will complete mine soon but with a more practical tube regulated supply... but still will feed the local gas regulators as well. They do make an audible positive difference and who can resist the purple glow! I've absolutely no interest in adding the phono stage at my end. I got out of the LP end of things a number of years back... Really good LP playback gear is too $$ wasteful.

Mark

Hi Mark,

\i seem to recall somewhere in this thread, someone had posted a schematic showing tube rectification along with the 12B4.

\yeah, \i thought about building his preamp, but \i'd rather build something that will sound better and presumably cost less to build than Bruce's GG. Besides, \i was kicked off his board for "socializing" like asking for help with parts layout. Being blind is tough enough, and \i think what really pissed him off is when \i challenged anyone on that forum to close there eyes and see if they can solder anything. Well, \i did eventually hear someone's homebrew GG, and well, it was ok. \i could \i guess live with it, even though my TVC had better resolution, but not that tube magic. So that's why i want to build the 12B4. Thanks for letting me rant just a bit.

Ray Bronk