Hello,I would like to know about parts inside the amp. For an example i would like to know wha ta transformer and all that stuff is any info you can spit out at me is apreciated. Remember try to make things simple. thanx

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otay! heres how teh puppay works. Take note, this example is for a tube amp.

Power transformer! This large box inside of your amp converts that lovely 120VAC wall power into whatever power your amp desires. Its basically the powerplant for EVERYTHING. Funny thing is, most power transformers are 117 VAC (volts...something..soemthing) which gives you a power sag which makes your amp sound "vintage" or in otherwords, muddy saggy and shitty. Poweramps should be matched to wall power so that they can effectively HANDLE wall power. Fucking amp companies cutting corners. /rant Mako amps website has more info. Anyways, a having enough current is KEY because if your current is lacking, so will be your tone.

Now, with your power transformer supplying power to your amp, the signal from your guitar goes through your amp like this:

input --> preamp --> phase inverter --> poweramp --> output transformer (OT) --> speaker out

Input is the plug.

preamp is where your initial sound and tone comes from. If you mod a preamp, you're modding your overall tone and gain. This is also where distortion comes from. Most preamps are DIFFERENT, and are what makes amps different from eachother. Basically, the preamp takes your weak ass guitar signal and gives it character before sending it to the phase inverter to be readied for the poweramp.

Phase inverter is this lovely object that takes your signal and inverts half of it so that it can swing between your A/B power section. Its fucking hard to describe, i need graphs to help me, dont worry about it. Basically, it takes the preamp signal and gets it ready for the poweramp.

Poweramp! this is where your volume comes from. I dont really know much of what goes on here, except that the design of poweramps is essentially THE SAME between most amps. The only differences really being tube type, and transformer type (need certain transformer to have enough power to drive certain tubes). Most poweramps have even number of tubes (2, 4, rare cases 6), which are separated into PAIRS. With a 4 tube power amp, there are 2 pairs (a and b), which is why you need the phase inverter, so that you drive pair A and pair B inverse to eachother. Again, would make more sense with a graph. Only minor tonal changes are made here depending on tube type and contruction of the OT because this is the part which lets your preamp tone through. Different power tubes/OT's also give you different types of attack, saturation and compression.
Output transformer! Is part of the poweramp and is what actually adds the volume by dumping a load of current into the signal path, thus making it powerful enough to drive speakers. Again, its the last wall between your guitar and the speakers and differently designed OT's will let different sounds through. Best results are had when an OT is appropriately supplied with enough power, without enough power it will cut holes in your tone.

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GOOD STUFF! Thanx. What do u mean when "drive A and B inverse with eachother"?

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ummm k. Hopefully you have some idea of physics.

Class A amps have positive current in the tubes ALLLL the time. So theyre always hot, and they're always in use.

Class A/B use whats called a push/pull system. Now, theres 2 pairs of tubes, or 1 pair of tubes. Either way, imagine that there are partners. The added current of the partners is ALWAYS 0. Therefore one partner is positive, and one is negative. So the current swings in the tubes, so a tube never has constant current within the tube. This not only extends tube life, but is also FAR more efficient. (2 el34's in class A is about 30 watts, 2 el34's in a/b is 50 watts). I dont exactly know why, as far as im concerned, it just is that way.

http://www.mesaboogie.com/US/Smith/...-WebVersion.htm

read that, it shows the graphs and gives a professional explanation

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Good posts bleeding! Just FYI, the "AC" in "VAC" is Alternating Current.

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Haha, wonderful seeing class room lectures take life in music.

Bleeding, you mentioned that there are many different kinds of pre-amps; care to give examples of a few really good, as well as really bad, and give some explanation about the technical and practical differences?

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Yea i would also like to know.

preamps! (this will encompass tube, SS and digital)

Good preamps? bad preamps? no such thing. Its all a matter of preference (and money... and quality). Your preamp is your tone shaping machine. But the general unanimous agreement is that tube sounds better than SS, and SS sounds better than digital in most cases.

Example of a PURE TUBE preamp. The preamp in a marshall jcm800. (its where the 12ax7's are). On the inside of the amp, theres wires, resistors, capacitors and tubes. What you usually see on the outside is your EQ, (treb, mid, bass), your gain, and your channel volume. PRESENCE AND RESONANCE ARE NOT PART OF THE PREAMP, they are dampeners for the poweramp.

A marshall jcm800's preamp is different from a jcm900 dual reverb's preamp in that the jcm 900 has more tubes (and therefore more gain), and also has diodes in it. Most amp preamps are different, with the exception of copy amps. Examples of this: the original marshall bluesbreaker has an almost identical preamp to a fender bassman. Or laney protubes and sovtek mig 60's have identical preamps to jcm800's.

Now i've just been talking about tube preamps, you can also have Solid state (SS) preamps. An SS preamp is almost IDENTICAL to a tube preamp except it uses transistors instead of tubes. Gives it a more harsh, tight, grainy sound. And incase you didn't know, tubes and transistors are idealogically the same thing, just in different packages.

Now digital preamps. This is when your tone comes from a computer. Buttons on your amp will change the computer's voice to give you different tones. Tends to sound really... bad. They jsut sound fake, not alot of people liek them. The reason is that it takes ALOT of fuckin work to make a good digital guitar tone, because you have to create it out of nothingness. With tubes and transistors, the tone is all there, you just have to solder it together; with digital, people have to fuckin MAKE the tone and the dynamics and shit themselves... its a bitch

Practical differences? Uhhh... SS and tube, impractical in comparison to digital. SS and tube can only really be shaped by the resistors and capacitors and shit you add into it, but depending on the tube/transistor types, your tone can only go so far. Thus marshalls have a "marshall" sound and fenders have that "fender" sound. With digital, you can get absolutely anything a computer programmer has made, but then again, the tone isnt exactly magical. Thus all line6 stuff can get pretty much any sound... but without that oomph and soul that tubes have. if you dont know what im talking about, go play a tube and a digital amp next to eachother at gigging volume, thats the only way to really know. Now, i did just call tube impractical by versatility standards, but people who buy them LOVE the tone and dont give a flying fuck how versatile it is because the sound makes them cream their pants, i am one of them with mah marshall 6100lm; it is my sex monster.

Now these are all internal preamps built into full amps, you can also buy rackmounted preamps, which are preamps without the poweramp. Some are solid state, some are tube, some are digital, and some are a mix of these. I dont know much about rackmounted preamps because well... i use a marshall stack, not a rack setup :P. Theyre exactly the same as the ones in amps in respect that they are a preamp, except you can combine it with different poweramps and shit. Kinda like a make your own amp thinger. Yeha..... thats about all i got. anymore questions?

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Hahaha Bleeding your like a teacher hat using non stop hahaha.

What would you have to teach us about cabs?
What makes certain cabs better than others (besides speakers)?
What are some parts to cab and how do they work?

I think there should be alot of educatoional threads like this that should be stikys here. Maybe its own fourum topic.

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souli knows more about cabs than i do, but its basic speaker housing principles.

You want a material that wont resonate much, unless you want your cab to fall apart. Thus heavy ass birch, or thick ass particle board is used. You want COMPLETELY air tight, or well ported. You want nice thick wires in it. You want your baffle (the part the speakers attach to) to be COMPLETELY immobile. Cheaper cabs arent air tight, tend to have plastic handles that break (instead of metal ones), and shitty gauge wires.

Another thing to pay attention to is where your cab touches the ground. If your cab is on casters (wheels) it will have less resonance and less bass. If you lay it on the ground, you get as much as a +4dB increase and it sounds like your cab is thundering because it makes the ground shake more. Some cabs have special feet that assist in transferring bass into the ground (like orange cabs). Some cabs just use skids made of maple... which i dont know what they sound like, but xdisx does

Bigger cabs = more bass
air tight = punchy tight bass
ported = loud as fuck bass with loose attack
thicker wires = better tonal clarity, more trebel... it sounds like you just lifted a carpet off your cab, its pretty sweet.
wheels = less bass, less volume
on ground = more bass, more volume, more resonance.

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Thats good stuff. My stack has been on casters this whole time, I will take them off thanx. Anyone that can add ANYTHING, I would aprecate it.
Your input is important.

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Nice shit!

I did post a ass load of info on the amp mod thread about cabs, cables, and mods. It a good thread to find out how to mod you cabs and cables at a low effective cost.

I would get into amp mods but I'm scared someone would kill themselves

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i was actually thinking about this... and would the capacitors hold current in them for more than a few days? because if not, couldnt you just unplug your amp and let it sit for a week before you start working?

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Can you do amp mods yourself soulinsane?

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Sorry but what is ported?

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That's true, but I still worry that something might get missed. Without someone inspecting the final work something might not get placed or connected right. The only thing separating someone electrically in a tube amp from the 500V plate voltage is a few millimeters. If one little thing gets shorted or a value grossly misplaced then it could destroy the amp or kill someone.

If there is no bleeder resister designed into a circuit then in theory the perfect capacitor could hold a charge forever. In reality there will always be loses and a cap will eventually neutralize. I repair Plasma/LCD/tube TVs as a job for now and I get some units shipped in that have been unplugged for days and still hold enough charge in their caps to be dangerous. Capacitor designs are getting more efficient. New materials research ( like Aerogel ) is finding its way into practical consumer components. That's good for us because it means less cap failure and degradation, but it also means they can be deadly for much longer periods of time.

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A ported cab has a hole (on guitar and bass cabs it is in the baffle, on the front where the speakers are mounted), that is tuned to a specific frequency to peak at that point. Basically, when you get down to the frequency it is tuned to (probably between 25 and 75hz i'd guess off the top of my head), you'll get a natural 'boost' in volume of said frequency. Tune the port to respond to your bottom string, and you'll get some very nice results

Most hi-fi speakers are ported, as this can help boost the bass of lower-quality drivers, but most hi-fi speakers have their ports on the back.

A ported cabinet needs to be make accurately and obviously you've got some calculations to make to achieve the results you're after- even length of the port will have an effect.

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Yes. All I need is the schematics in most cases for a specific amp and I can do just about anything I like.

Edit: and ported cabs are the most difficult to design and tune.

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bleeding - don't get me wrong, your post was very interesting; however, I still think I'll rephrase my question a bit:
What is your personal favorites for preamps and why? And don't spare me any technical details! Anyone else with this kind of knowledge is welcome to share... blink blink Soul.

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my playing experience with separated preamps is limited to a pod and a mesa v-twin hahaha. I'm not the one to ask when it comes to rack equipment, though i do really like the sound of those engl's. They sound heavy enough to sink a ship

The V-twin can get heavy as FUCK. Like, it sounds mindblowingly good for a pedal, given you match it up with something appropriate. But isnt really good for anything technical, maybe heavy pounding rhythms and liquidy leads... but none of that necrophagist stuff we all love, leave that to engl and peavey heads. Hell, boost it with an 808 pedal of somesort and you could get some sickeningly awesome tones out of it. Mind you, this is with my limited experience with preamps

Other people here (like Jopop) know ALOT more about rack stuff than i do... i'm a straight up head and cab kind of guy.

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