Ok... here are the new files... Same basic setup, just easier for you to read and solder to.... I tried out a new piece of software and like it so far....

Cabinet Simultor Layout and Parts List



New PCB (PCB size 3" x 1.5")

Ok guys!

Being a Vet, there are certain holidays like Memorial Day, 4th Of July, and Veteran's Day that mean a WHOLE lot to me. What does this have to do with guitars, amps, and music in general? Well, outside of the fact that music is what got me in a zone whenever my unit was in a "Hot Zone", absolutely fooking nuthin'.

I know you've seen the Marshall Cabinet Emulator... Some may have even tried it... An amplifier is only 1 part of an overall sound. The cabinet is the other part. Speakers and cabinets work together to give you an overall tone.

In Short... Here's the Boogie...


Triaxis Cabinet Simulator Schematic



Cabinet Simulator Parts Layout



PCB



PLEASE... Double check the schematic to make sure I have everything right. I need an extra set of eyes.... If there's anything I need to adjust, let me know and I will do what I can.... I'm not the greatest PCB designer as this is only my 2nd or 3rd from scratch, so it is a bit large for the component count.... Comments, criticisms, bitches, etc... shoot me a PM or leave me a post....

1 thing I do plan on this weekend is putting in bigger pads to solder to.... When I printed it out, they were thin... That will be updated on the final PCB....

I'm glad you posted steve. Normally I would have mentioned the precautions of working with tubes but I'm still finishing my first cup 'o coffee. Tube voltages are VERY dangerous as they utilize anywhere from ~100v (in starved tube mode) to 300 - 400 volts. These voltages WILL kill if not worked with very carefully.

I'd take Steve's advice on the McTube as I never finished the one I was working on before gutting it for my Firefly tube amp. It was mainly put there as an illustration that tubes CAN be used in the form of a stompbox.

I've done a number of the Tube Emulation circuits and have them up and operational as we speak. I LOVE these little circuits because they flat out rock! They can be a bit of a B*t*h to dial in, but are a lot more forgiving if you make a mistake and touch one of the hot leads. They won't kill you.

So you're looking for another gain stage. In order for me to REALLY help out the way you're looking for, I'm going to need the schematics, BUT, there are a bunch of possible solutions in the form of footpedals which don't require you hacking apart your amp.

1. Real McTube - You asked for a Tube Gain Stage.... This is exactly that. A tube preamp built into a stompbox

http://www.dogstar.dantimax.dk/tubestuf/mctube.htm

2. Tube Amp Emulations - These actually sound VERY good and you can build them off of ANY established tube amp design. They're not perfect, but definately give you the character you'd expect from that amplifier.

Example: Marshall Super Lead 100 http://www.runoffgroove.com/thunderchief.html

3. Build a tube amp from scratch with exactly what you are looking for, tone-wise: Sounds crazy? No way.... I've done it and it sounds incredible. There are many people out there on the net that do exactly that and are willing to help you get through it. 2 years ago, I never would have dreamed that I could do ANY of this. Now, I know I can do it and do it regularly. Hi, my name is Bob and I'm a tone junkie.

I'm with Joe on this.... Anything can be modded, understanding however, all mods have a cost associated with it and space is always at a premium, but we need to know what we're dealing with in order to help out. I have just about every Vox "AC" model schematic under the sun, but have no "AD" models at all. We'd need to see that in order to help out.

My question REALLY is: What do you feel you are lacking? is is just power? or is it tone as well? Based upon Vox's previous numbering scheme, and I may be mistaken, but the AD50VT would be a 50 watt amp, yes? If so, that's not enough power? What would you like to see?

Another question is "Do you ever plan on using it live with a PA?" Reason I ask is simple. Adding more power can actually do the opposite of what you are trying to accomplish. If it's a bigger guitar sound that you are looking for, smaller amps actually have a bigger sound when miked. I know it sounds weird, but it's pretty simple when you factor in many rigs are close miked when going into a PA. The sound only needs to be loud enough for the mike to pick it up and then will be amplified through the console rather than from the amp. If the sound is too loud, the mic and the mic preamp itself will distort and give you crappier sound....

Well, I've rambled enough, but look forward to what your response is.... I'll help out whatever way I can, but hope that you understand what I've laid out....

I'm interested.... PayPal is on the way.... Forgot about my VA check....

Modified***********************************

Ok... payment made.... Be sure to check the email directly from my email account. I had my old shipping address in paypal and didn't see it until after i clicked the submit button. The second email has the right shipping addy. I've since fixed it and deleted my old address...

My PayPal is coming Sat morning....

a 9v circuit is plenty big enough depending on it's design.... my DR Boogie and JCM800 emulators are more than enough to push my solid state DuKane 60 watt amp that I use from time to time, with no other preamp circuits at all... Matter of fact, I have to turn 'em down because they get to be almost too much of an input for the amp...

If you're going to pop these into a foot pedal, I will make 1 suggestion... If possible, use the 16mm pots over the 24mm that you have linked to. There's a total of 6 potentiometers that have to go in the box and the 24mm's are a tight fit in smaller boxes and require pretty precise drilling. The 16's give you some wiggle room on the sides and perform very well. I learned this one on my first build and remembered it for the second and it worked out a million percent better as I don't have a drill press....

If you have more room than say 3 inches across, the 24mm's will be just fine.

The values you chose are right on the mark though. I used 250k and 25k as well.

The trimmers that you mentioned will work, though they are not the "multi-turn" type and will be a bit of a pain to dial in.

These are the type that I was referring to.

http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=267703&e_categoryid=318&e_pcodeid=59403

These will be quite a bit easier to dial in the jfet's bias. With short turn trimmers, the voltage fluctuates wildly with the slightest movement of the dial...

I'm glad to hear ya got it under control and it's working the way it should. I used the original Bucksears / Electritabs design and made my circuit board. I think in my case, I just had my 9v power wire too close to some of the pots wiring, which I didn't follow very good practices with as my leads were pretty long. Once I spread mine out in the 1U case, all my squealing disappeared. I love this box and wouldn't trade it for anything, but also love the JCM800 every bit as much.

Ya know what... Mine did exactly the same thing.... I reboxed mine into a 1U rack, spread it out a bit and it went away.... Mine are biased to 4.51v

#3

I actually fit Sprague orange drops and silver micas into the circuit. It's a tight fit for the orange drops, but they will fit. You can probably get away pretty well with mylar caps in place of the orange drops if you need to keep the cost down though.

Absolutely interested! Just let me know when they're ready and how to pay for it....

Damn! I wish I would have found this board earlier. I'm working on a guitar amp using The ROG Eighteen, Thundercheif, JCM800, and DR Boogey using sequential switching and wanted to mate them to an LM3886 based amplifier in a combo type install. I've already got the DR Boogey and the JCM800 built, tested, and tweaked the best I can and working on the Thunderchief this coming weekend.... oh well.... Everything is designed... Just got to pony up the cash for the parts.....