Digitech RP20 Valve Tube Change

Hey Gospel Guitars here again and I got another project, an experiment. Picked up an RP-20 from Digitech. It's a 19... what was this thing? 1998. So anyway they had Pentatubes in their products and I have some leftover Chinese 12AX7s which actually sound very good. I pulled a bunch of these out of an old Karvin Quad X preamp I used to have and loaded it with tongue soles and mullards. Although I don't want to spend the money on this one when I have used these Chinese tubes. It's just an unlabeled factory direct tube I guess from China that Karvin used. And I used to have a Digitech 2101 rack unit and I put two of these suckers in there and woke it up really nice. It's very very comparable to to a tongue sole. Very very comparable. The tone on the tongue sole is a bit richer and fuller but these are not bad. They're not harsh with the distortion. And the Pentas are made in the USA and as much as I hate to say it, I don't like them. I wish I could. I don't like them. I find them very harsh on distortion and they're not very warm. So I'm going to figure out how to get this thing apart and put a new tube right back here. And I know already it's going to involve taking, probably taking apart all of the screws and bolts and nuts holding on all the jacks. Because this metal bottom doesn't just come off. It's actually folded up around the edge. So all of the input and output components are mounted to the actual bottom plate that folds over. So I'm probably gonna have to take apart all of this stuff. Take about a hundred screws out and see if I can't get them cleanly separated. So let's get started. And as much as I know you would enjoy watching me remove these little gizmos and nuts and screws and it'd be so much fun to watch. I'm not gonna put you through that. Okay. Hey, it comes off. That wasn't too bad. Took me about five minutes to get all the screws undone. But there she is. You've got, uh, I don't know, some little hole, little single screws holding on the midi and power inputs and just your normal stuff. Nothing major here. Then this thing just comes right off. But let me pan this down. When it's on the machine, it's on the, actually on the unit. When you're upside down, you just push it forward a little bit and it'll clear your volume controls for your input and output. Because, and the jacks that protrude out. So you want to slide it. Don't pull it straight up. So that takes care of getting the cover off. Okay. Right here is your tube. There is a retainer right here. It's held on by one screw. Well, not actually. Um, you can loosen that or you can just pull back on this bar, which is what I'm going to do. Because I'll probably lose the screw inside or something. Who knows? Yeah. I don't feel it on the top of the unit. So then you have a little socket right here and you just wiggle a little bit. Don't wiggle a whole lot. Pop it right out. It's printed in yellow, bright yellow, 12AX7A made USA Penta Laboratories. Now the other unit I had had gray print on them and I don't really like this tube any better. So out that tube comes and in this tube goes. You want to line up the pins. Um, I can get it here. There's an opening and just look in your unit and make sure you line up the opening. Push the new pin in place. Give it a little support. You don't want to damage anything. Don't push, don't take too much energy. Bend that top part back into place. And there we go. New Chinese tube. It's going to produce a lot smoother, richer distortion out of this thing. And these units can sound really nice. And so almost everything you buy is going to have an okay tube in it. So experiment with your tubes because you'd never know. Mullards have a real good kick in the mids that I like. More of a British type sound and the tongue saws are more of an American type sound. And I've blended the two together in other units which have more than one tube. And using mullards in the distortion and so the valves are used, getting used for distortion channels on amps and tongue saws for clean. And it will wake up a Fender amp in a real hurry. The tongue saws will. They'll wake up just about anything. Tongue saw is a really good tube. To each his own. But so now I need to plug it in and make sure it works. I'm pretty sure the tube is good though. But I don't want to go through all that screwing around again. Something else I want to mention real quick is if your unit starts acting and freaking out and doing weird things and not coming on or not remembering your settings and you're losing stuff. There is a battery in these and it is a CR2032. A flat disk located right there. So you can do the same thing to replace your battery. Just pull the back off and pop on a new one of those. And I've got three or four of these that I've kept in storage from different things over the last decades. But I haven't had a battery die yet. But I'm ready if they do. So that's where you can locate those. That's what they look like. Just a flat, almost a quarter sized battery. Very thin. So that goes for just about any digital device that stores stuff in it. Okay, well the old gal sounds better. It's noticeable difference just by going from the pentatube to an old unmarked Chinese tube. That Chinese tube is old. They came out about while the unit I pulled it from was in 1993. So still kicking. Still sounds a lot richer over the pentatube. Sounds great. I'm happy with the upgrade. Get some use out of this thing now. Got to put the back back on. But I think before I do that. While I have it apart. I'm going to get some contact cleaner and get all these old joints cleaned up. I'm not getting any crackling or anything. But I have it. So why not use it. Get it cleaned up. Prevent any further issues that might come up later. So I hope you found the video helpful on swapping the tube out of a Digitech RP-20. So thanks for watching. Please subscribe and support the channel. Pass it along. Peace.