The Amp Garage

Andy, good luck. My brain is overloaded for sure. Just to let you know what I'm thinking, I am trying to design the amp from scratch. I figured out that if I bias the tube at -1.5V and do the load line, I get the same cathode resistor value, and calculated these values for the first half of the 12ax...

A question for the experts please. In the schematic: http://ax84.com/p1x/AX84_P1x_101004.pdf [img:488:429]http://chicagocadcam.com/ChrisHahn/ax84-p1x-pre.jpg[/img] for the preamp stage, there is a single 12ax7 tube with two triodes. The Ra=100k and the resistor between "stages" is 220k. To achieve a...

@SurfsUp Agree with most of your step-by-step above, but I think it is important to create the original dry track while playing through the amp... you get the amp dynamics, etc. and the benefit of the touch/sensitivity feedback for the player. Then you can re-amp. The only drawback to this is if yo...

I know I know its a long post but please, anyone? Please? bumpity bump?

My reservations on the presonus: - if I want to record direct with any electric instrument and listen with my monitors while I play/record along with what I already have - I can't do it. Well, I CAN, but with the main volume up to anything other than zero, static and noise is introduced into the rec...

Making assumptions: You want to sing You want to record guitar You want some drums laid down over it You want some FX You want, want want... Since you are home-recording and probably don't have a ton of cash - I record in a home studio as well. MIC: Don't spend any money here just yet. Use the SM57 ...

Here is the schematic: I am trying to reverse engineer this to figure out what's going on and why. http://ax84.com/p1x/AX84_P1x_101004.pdf This is the AX84 p1 Xtreme schematic. The Transformer is kicking out 388V (i'm using the red value on the schematic here). However I can calculate this from: htt...

Or just drop the mic alltogether. Get the redwire or recab impulses and play to your heart's content with positions, mics, distances, angles, on axis, off, etc. Much better than re-recording every time to find out your mic moved, or was in the wrong spot to capture a good recording, etc. Just record...

A good preamp or soundcard. Both cost $. What's your budget? I use a presonus firestudio but not too happy with it due to reasons other than the preamp.

so just to confirm, the max plate current is 140mA. So you would use 10% of this value = 14mA? So for this example, if you wrote the article, you'd use a value of 28mA instead of the 22mA the author used at valve wizard (because there are two EL34s)? Yes? Do I finally understand the voodoo? I certai...

Okay, thanks so much! Another question. http://www.audiomatica.com/tubes/el34.htm http://tdsl.duncanamps.com/show.php?des=EL34 So here they say the "max plate dissipation" is 25W and a "filament voltage" of 6.3V. So: Two tubes at 25W each = 50W power = I * V 350V out means I = P/V = 0.1428 current T...

Not sure about the article that you reference but....EF-86s and EL-34s are definitely not triodes. They are pentodes. EL-34's, at least in a power amp position anyway, should be drawing a whole lot more than 5 ma. 40 to 50 depending on bias and personal tastes. So....use that "article" carefully! I...

thanks. so the blue volt values would be used to draw the right point of the load line for the tube? So the load line starts at 282Va for the ECC81 for example? The article also states: "Supposing this amp has two ECC81's, an EF86 and two EL34's, the average current drawn by each triode will be abou...

I am trying to figure out tube amp building and have a question (the ax84 forum is rarely visited) and figured I would try to ask it here: http://ax84.com/hioctane/AX84_Hi-Octane_101004.pdf For this schematic, the power supply is a EX269 from Hammond and would like to figure out how the values in re...