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I am currently 200% sure my next amp is going to be... 
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The guy from the place with the thing. The one with the stuff.
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Post Re: I am currently 200% sure my next amp is going to be...
Awesome... will report back once i have acquired $$$


dammit... now i really need a job :mad: this thread totally just made my GAS jump up a gazilliongillion% :mad:


Wed Aug 25, 2010 12:21 am
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The guy from the place with the thing. The one with the stuff.
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Post Re: I am currently 200% sure my next amp is going to be...
hmmm was looking at the layout... and 1 question(for now)...

is it 30 watts because each channel uses its own power tube? I noobing around following the signal path through the tubes, and if i'm correct... the clean channel signal goes into the PI's #2 pin and come out of #1 then only goes into the right power tube (following K). :idk:

Can i haz progress or am i super lost? :cop: :facepalm:

Image


Last edited by knope on Thu Aug 26, 2010 1:11 am, edited 2 times in total.



Wed Aug 25, 2010 11:25 pm
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Winston Wolf
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Post Re: I am currently 200% sure my next amp is going to be...
That is why learning about amps by looking at layouts can turn to trouble! :cop:

Here, look at this instead:
Image

To answer some of your questions, no, both channels use both power tubes. The phase inverter basically splits the guitar signal in half, sending half through one EL34, and the other half through the other EL34. Read up about "push-pull" amp operation, for a less simplified version of what i am saying.

As you can see in the schematic, the clean channel goes into one side of the phase inverter (with a circled "G"), and the gain channel goes into the other side (circled "F"). This is also why the two channels cannot be blended as the amp is designed, because they will be out of phase with each other, and unlike some classic Marshall designs, jumpering the channels, will thin the sound out instead of thickening it. The channels will cancel each other out, depending on what each one is doing.

Now each one of those 12AX7s is actually like two tubes. Hence the term dual triode. The phase inverter tube therefore actually has two "inputs" and two "outputs", as seen here:

http://www.ampage.org/td/vtd12ax7.html

In a probably oversimplified/not-quite-accurate version of things, the guitar signal "goes in" to the control grids on pins 2 and 7. The amplification of the signal is determined through the setup of the bias by the power supply through the plate resistors on pins 1 and 6, and the bias resistors on pins 8 and 3(which in a this phase inverter design are tied together to share the one 1k2 resistor). The signal "comes out" at the plates on pins 1 and 6, each of which feed a different power tube.

NOW. THAT IS NOT REALLY HOW THE SIGNAL GOES THROUGH THE AMP. In reality, signal is not being transferred from point A to point B, so much as voltage is being drained or not drained, depending on the signal at the input and the difficulty or ease with which voltage is allowed to travel from the plate through the screens and into the cathode, where it is allowed eventually after some resistance, sweet sweet electrical ground.

But, for the sake of just knowing what the pins on the PI tube are, i think the oversimplification/inaccuracy is okay. For now.

:cop:

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Thu Aug 26, 2010 12:56 am
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The guy from the place with the thing. The one with the stuff.
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Post Re: I am currently 200% sure my next amp is going to be...
GAT DAMMIT!!!!!!!!!

Ax84.com did a good job explaining how preamp tubes work though(need to reread it though)... I already understand that each 12ax7 has two gain stages. The "in" at pin 2 corresponds to the "out" at pin 1 correct? "In" at 7 and "out" at 6? Its pretty clear cut that the clean channel uses only one side of V1 and the gain side uses the other side of V1 + both sides of V2 and V3. I actually figured that out from the layout :dildo:

as for push pull... i read something about that just as i was checking this thread thinking I'm a bit of a dumb ass :facepalm:

for a push/pull amp, the power amp is divided into two parts, one pushes the speaker and the other pulls it. Since they are doing the opposite things, they need the opposite signal or else they would cancel each other out. Oversimplified but true?

In class A there is no phase inverter because the power section isn't divided into two parts, thus it does the pushing and pulling of the speaker as one engine.


Thanks for finding the schematic :love:
Still have a LONG way to go before I start poking my Carvin... I CAN"T WAIT!!!!! :D


Thu Aug 26, 2010 2:15 am
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Winston Wolf
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Post Re: I am currently 200% sure my next amp is going to be...
You CAN have a class A amp with a phase inverter. Push/pull operation requires a phase inverter. Operating class is about something else. The class is more about how much of the signal is transmitted in a cycle.

Image

Read more about that, but be aware that some of it can get tricky/confusing, especially when so many ampmakers have been incorrectly using so many of the terms for so long...




Anyhow. One design that *doesn't* require a phase inverter, would be a design for Single-Ended operation. This type of amp would often(but not always) have only one output tube. The output transformer also needs to be constructed in a specific manner, so as not to fry itself during normal operation.

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Thu Aug 26, 2010 8:52 am
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Winston Wolf
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Post Re: I am currently 200% sure my next amp is going to be...
:hypno:


tor plugs guitar into amp. it makes noize, tor happy.

no noize, tor kicks it, see if that helps. :neanderthal:

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Thu Aug 26, 2010 8:59 am
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Simethicone
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Post Re: I am currently 200% sure my next amp is going to be...
Aaarrgh! Tor BASH! :cop:

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Thu Aug 26, 2010 5:48 pm
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Jeremiah Johnson
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Post Re: I am currently 200% sure my next amp is going to be...
Heh you guys are so cute :fag:

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Indeed


Thu Aug 26, 2010 5:52 pm
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Simethicone
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Post Re: I am currently 200% sure my next amp is going to be...
When I think "cute", I think "Maps". :love: :dildo:

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Thu Aug 26, 2010 6:18 pm
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The guy from the place with the thing. The one with the stuff.
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Post Re: I am currently 200% sure my next amp is going to be...
Class AB

Sound is a wave like a sine wave. So that where the angle comes from... Class A amplifies the 100% of wave( zero crossover distortion) but is inefficient at it and can get very hot very fast one you pass 30w, which is why in general they aren't seen very often past 30w mapz. I think I read that at super awesome best, for every watt the map sends to the speaker, a Class A amp would have to dissipate 1watt in heat so most of the time they run much less efficiently(low out put lots of heat). Class B only amplifies 50% of the wave (lots of crossover distortion) but is more efficient(lots of output, low heat) . Class AB is like a combination of both and amplifies between 51-99% and is efficient enough to use at higher wattages. The amount of crossover distortion in a properly biased class AB is not audible and thus ok for mapz.
Edit: this amp is cathode biased aka self biasing :cop: :love:

:huzzah: or :poop:



Quick preamp question....

The first gain stage on the gain channel... it haz like a lot of gain right because it doesn't have a resistor on the cathode?
Edit: By connecting the cathode directly to ground, that mean it has no voltage. Saturation occurs when the gird voltage is 0V(which is always at idle). To counter act this we up the cathode voltage, so that the grid bias is negative (grid bias =grid v - cath v). But since everything is zero then the tube is in saturation right?

Or did I misread the ax84 info? P1 Theory Doc @ http://www.ax84.com/p1.html

edit edit: so maybe not so much as a lot of gain at that stage but the gain is distributed across all frequencies

edit edit edit: http://metroamp.com/wiki/index.php/Cate ... structions obviously not the same amp, but more less the same thing on putting it together... maybe if I could find instructions on how to put a matchless or a vox kit together :love:


Thu Aug 26, 2010 10:55 pm
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The guy from the place with the thing. The one with the stuff.
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Post Re: I am currently 200% sure my next amp is going to be...
chris_d wrote:
The biggest thing that i found was just reading everything. I found a couple of forums that i liked, and i just read back through several years worth of posts, troubleshooting, design problems, whatever. And then i read everything that people suggesting solutions posted, and every article that they posted about technical stuff, etc etc.


forget the previous post as most of that I eventually can (or have on a few points I haven't edited) figure it out. What were the forums that you liked??

I'm currently reading through the Metro Amp forum and learned A LOT! Already read the Ceriatone forum which had a few things but didn't have a lot... but it seems that Nik responds within 24 hours anyway so :idk:

Last question until I have the kit in my hands: What resistor should I use to make a cable to drain voltage out of an amp? I have read about a bunch of different values and wattage ratings that work. I read that anywhere from 10k to 500k. Also read from one place that 1w is ok and another that said it NEEDS to be 10w... So I'm a little up in the air on that one :idk:


Thu Sep 09, 2010 3:40 pm
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Loves Behringer
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Post Re: I am currently 200% sure my next amp is going to be...
knope wrote:
Image

Ceriatone's Bad Cat Hot Cat clone :love: :love: :love:

http://www.ceriatone.com/productSubPage ... ricing.htm

:love: :love: :love:

I should stop being a fanboi :facepalm:



HAWT!!! :eekass:

How much?! NVM... $650?! WANT. :love:


Fri Sep 10, 2010 10:14 pm
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