Mini Guitar Amp

[ironskilit]

that was Kutless @ 1:22! Nice project by the way! good job!

[Boxcarcrzy12]

Im not that good with tubes, but could i get instructions or diagrams anywhere? Nice vid by the way love the sound.

[CameramanLink]

Thanks. Go to my website for a diagram.

[FugginNorb]

I have a question for you: Do you think it would be possible to create an amp with essentially two amplifiers? IE, a main switch controlling which amp is powered on/connected to the speaker/connected to the EQ? You could also possibly have individual EQ for each amp and switch between two sounds (would probably have to be solid state to switch between two amps and to have two amps next to each other and not overheat).

I know, you can just add channels to an amp, but my idea is crazier.

[CameramanLink]

Yes, I think this could be done without over heating as long as the enclosure is made properly. It wouldn't have to be transistorized either. Your idea could be done with several relays connected to the main switch. There would be one relay for the speaker, one for which amp gets power, and one for the EQ output. This could be connected to a single foot-switch. Essentially what you're talking about IS adding 2 channels to the amp. Don't use solid state, because it sounds like crap.

[FugginNorb]

Very cool, and some not-half bad playing (having a nice amp really helps =P).

I'm just trying to get into electronics, and I really don't know hardly anything, and I'm curious on how hard it would be to make an Oscilloscope like that for guitar (and musical instruments) with a larger display (short of modifying a TV into one).

[CameramanLink]

Modifying a TV into a scope is very easy. There are lots of descriptions out there that tell you how to do it. What you do is disconnect the horizontal deflection coils and attach them to an audio power amp. This will make a wave go vertically. If you want it horizontal, just loosen the yoke and turn it 1/4 turn to the right (looking at the TV from the back). This is the simplest way to make an oscilloscope.

[LeviMan2001]

how come i dont see any filaments glowing? lol niice amp though.

[CameramanLink]

You can see them, you just didn't look hard enough. Observe the middle tube; at the top and bottom is an orange glow. The filament glow is viewable on all the tubes if you take the time to look...

[reckonman]

i cant believe how high the price for these amps , hell , i make my own and its quite easy to do .

[solerso68]

which model jensen 25 35 or 50 watt?

[CameramanLink]

As I recall, I used the 25W.

[GoogleEqualsEvil]

Very cool. I love learning about unique tube designs. The more I can learn the better. I've never even thought of doing anything with either the 6AB4 or the 6EH5 (probably because I didn't know they could be used in a guitar amp!) I'm surprised at how much low end you get with that much clarity with just a 3w O.T.

[GoogleEqualsEvil]

By the way, despite what one commenter said, your mini-amp sounds excellent, including the distortion. Sounds very much like your Hi-Octane build, which sounds a helluva lot like the Mesa Dual Rec I just sold. Oh, again, very cool 'scope. Very kind offer...how do I send my email without displaying it to the world of freaks and nuts out there...lol?

[CameramanLink]

On my channel you can click on "Send Message" under the "Contact" box. That way I'm the only person who can read what you write. I've drawn all the schems of my amps on paint so let me know if you'd like to see any.

[GoogleEqualsEvil]

So now I'm back to a single 12AX7 pre-amp (modified AA764), and a single ended 12AT7 output. I still have some tweaking to do, but so far it is really awesome. Has as much rich, awesome distortion as my Superlead and my JCM800 (both of which I modified). But still has great cleans (but at really low volume, but loud enough enough to drive the speaker to where it sounds good miced up.

[GoogleEqualsEvil]

So I tried a 6N1P in the output and that was better, but still not right. I figured out what I didn't like was the self-split driver, so I rebuilt it with a long tail pair P.I. driving the output. That was much better. But I keep coming back to trying to make the circuit as simple as possible with the least amount of components because that always seem to sound better.

[GoogleEqualsEvil]

No, it's actually a Fender AA764 Champ pre-amp with much different voicing (I use cathode resistors and cathode bypass caps that are totally different) to make it sound like my favorite amp (Hot Rodded Marshall SuperLead). The Firefly uses a 12AU7 for the output tube, self-split. I built one and didn't like it very much. I'm not a fan of the cascode boost, and the 12AU7 doesn't have enough gain on it's own without the cascode.

[GoogleEqualsEvil]

I'm prototyping a "mini-amp" with a 12AT7 for the power stage, so this amp is definitely interesting. 2-3 watts is ideal for studio use in my opinion. Loud enough to fill out the speaker and make it sound "right", but low enough volume that you can stay on speaking terms with the neighbors! Oh yeah, sweet 'scope! You ought to copyright the schematic, write up some instructions and a bill of materials, and sell them.

[CameramanLink]

Are you making the ax84 FireFly? I think that one uses a 12AT7 also. The scope is actually a very old kit from Devry Technical Institute. All the boxes were falling apart, the case was rusting, the caps were old, and many parts were missing. I really had to do quite a bit more work than was originally intended.

[GoogleEqualsEvil]

Another very cool build CameramanLink. Are you using the 6EH5 as a single ended output or the 6AB4's in push-pull? If you're using the 6EH5, are you running the power to the pre-amp nodes first to lower the B+ on the 6EH5? If I remember correctly those don't like much plate voltage.

[CameramanLink]

The 6AB4's are for the preamp and driver. The 6EH5 is connected as single ended in pentode connection. The output transformer is a really cheap, small 3W from Antique Electronic Supply. The power supply is designed so the B+ on the 6EH5 doesn't get too high, and decoupling circuits provide anode voltage to the 6AB4's. If you'd like to see any schems or photos of my amps or scopes or anything else I've made, you can provide your email and I'll be glad to send them to you.

[CameramanLink]

The 6EH5 is single ended with a tiny 3W transformer, and the plate supply is fairly low. The 6AB4's are for the preamp and driver and get B+ from decoupling circuits. If you'd like to see schematics or pics of anything I've made, you can message me your email and I'd be glad to provide them.

[METALmaniac123454321]

whhhhat

the distortion is horribleee lol

[CameramanLink]

what's wrong with the speaker? the overdrive is from the tube and it wouldn't matter what size the speaker is. the impedance match is all that matters.

[DOSphantom]

Three watts driving a 12"?... might need to step down a size on the speaker.