A really simple starved plate tube booster?

[JimRayden]

OK, i found something. I chose to build the 18watt preamp for my next project (after the tube driver). I'm planning on building it as a preamp running into the preamp of any amp. Kind of like a stompbox but I'm going to built it bigger and for placing on the amp. No stomping. And lots of room for big trannies and lotsa tubes. Here's the schem:

http://www.18watt.com/storage/18wattLite2b.gif

Now, I see that the section around the first tube and before the volume control could be built separately. Is the second stage necessary?

What if I want nice smooth tube saturation? Isn't the preamp circuit designed for saturating the power amp. So I'm guessing it will have a huge boost on the signal and an ugly clipping when I run it into an SS preamp? Can I use a booster or another identical tube circuit in front of the actual preamp to saturate the preamp tubes? Would it sound bad?


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Jimbo

[luix]

Hi Jim, the page you post is mine so I try to reply:
The test I do is a test to show the tipical distortion of a tube, at 12V the tube is very non linear and the gain is about 10 per triode.
The sound you get from a single stage of 12AX7 is a little overdriven and you can't use for a buffer or a clean buffer.
At 12V the anode voltage seem to be dependent on the grid resistor, I can't polarize the anode at 1/2Vcc with a grid resistor greather than 180k, very strange !!!!!
The tubedriver has an opamp gain of about 300 so the distortion is all from the IC, lowering the gain you get the distortion from the tube.

[JimRayden]

But what do I get when I remove one of the SS gain stages?

Thanks alot, man.


Ok... another obstacle on my Quest To Tone...

http://www.generalguitargadgets.com/index.php?option=content&task=view&id=89&Itemid=117

"Please Note: this project has some problems with noise, build it at your own risk."  :shock:

DAMN I didn't see that before.  :x

does the noise appear at higher gain levels or is it constant? I can sacrifice some gain... but if it's constant, then I'm F-d I think...

Any help?

---------------
Jimbo

[Mike Burgundy]

its a lot less if you use a well regulated supply and a more quiet IC at less gain
hih

[JimRayden]

I read that the layout could be a big factor for hum. Are there any tips to follow when making my own layout?


-----------
Jimbo

[puretube]

probably some answers are given when you search this forum for:
" hum " and  " tube " (click "search all terms")