Fender Blues Deluxe Reissue 2015 Guitar Amplifier Service and Demo

本站添加: 2026-05-23

[00:00:01]Hello, and welcome to the channel. So, we've got Fender Blues Deluxe Tweed, nice tweed deluxe Blues Deluxe there. So, this is in from the symptoms that the customer uh was telling me, it sounds very much like uh one of the uh electrolytics has gone open.

[00:00:24]So, I'm sure I'm sure you've all seen these before, but for those that haven't, we'll just have a look. So, we've got volume drive, treble, bass, middle a master volume, reverb, and presence.

[00:00:38]We've got a channel select there. We've got a bright and normal switch.

[00:00:42]Foot switch socket power amp and preamp hat.

[00:00:47]Right, we're looking inside there.

[00:00:51]And uh my money's on him.

[00:00:55]So, we're going to test him with the with the peak.

[00:01:00]With the purple peril.

[00:01:05]So, let's pop that on there.

[00:01:07]Give him a open circuit or low capacitance. So, yeah, that's blown.

[00:01:15]So, uh no need to switch on. That That's confirmed that for us. Let's check it Just check the others.

[00:01:29]So, that These All these need to come out. These 1 2 3 and this one in the corner there.

[00:01:36]But, we'll see what to Yeah, 23 at 3.8.

[00:01:44]Yeah.

[00:01:45]>> [snorts] >> 3.9 ohms, so that's not great.

[00:01:50]Let's see what else we've got.

[00:01:53]Now, this amp I think it's a 2015 model, if I remember the customer saying he'd had it 10 years.

[00:02:01]4.4 ohms, so yeah.

[00:02:04]I think we can say that they're all over and then there's another one. Oops, sorry. And then there's Oh, you can just see that other one there.

[00:02:14]Let's attach onto him.

[00:02:19]Yeah.

[00:02:21]So, yes, they're those three aren't particularly healthy and obviously that one's open.

[00:02:29]But, I've ordered some capacitors for this and they've arrived cuz I guessed that I'd need those, so I ordered them in.

[00:02:37]Um we'll check around for dry joints on this board, usual deal. We'll also check to see if it's wired for 240 V. I'm guessing it isn't cuz all of this is looks like it's factory, so it'll it'll be wired for 230.

[00:02:53]Of course, that's only applies in the UK.

[00:02:57]So, we need to get the board out and swap those. While we've got the board out, we'll just check the other capacitors, make sure they're okay.

[00:03:06]These um some of these caps here, they don't get as much hammer where these have had quite a bit of hammer.

[00:03:18]And obviously uh he said good night. This has been out of the cabinet before cuz all the screen, you can see there, all the aluminum screen is trapped there. I don't think I need to take this board this whole chassis out there. I'll just need to take the board out.

[00:03:37]Right, we'll make a start.

[00:03:41]Right, I've got all the knobs off and normally we've got those plastic inserts that go in and no uh no nuts, but on the but these are proper got proper nuts on.

[00:03:54]Much better quality pots in this amp.

[00:03:59]That's refreshing to see.

[00:04:15]You can hear that meowing. It's Pink.

[00:04:23]It's uh a mere 20 minutes since she had something to eat, but she's back for more.

[00:04:31]The bottomless pit.

[00:04:34]Eating me out of house and home.

[00:04:39]That's Pink's specialized subject. For anyone who's uh a recent watcher of the channel, Pink is my cat.

[00:04:46]And you will see her in some of the videos.

[00:04:49]She appears.

[00:04:53]As somebody uh once left a comment on the channel, and I think it was Mark, said that Pink's a troublemaker, and she is indeed.

[00:05:05]So, I've just uh I've just released the uh part two of the Mighty MoFo amp.

[00:05:14]And uh I don't know if any of you have watched it yet, but if you've not, go and give it a watch, and you can see my latest superior plank moment. I'm not going to tell you what it is, that would be a spoiler, but uh yes.

[00:05:28]A bit of a plank moment, but it turned out all right in the end.

[00:05:39]Mhm, he's slightly bigger, so I'll have to go and get some sockets out of the workshop because uh that's the biggest I've got in those.

[00:05:51]Right, so you can see I've got the the board out. And the best way of getting these out uh obviously you take all the the bolts off the top.

[00:06:01]And uh you take the screws out, but you need I've taken off a lot of these wires here because when you're pushing down on the board, these are causing some tension.

[00:06:14]And uh it would put extra strain on the board. So, I've removed those to make it just come out easier.

[00:06:20]And the only other thing you need to do, the wires from the output transformer here, there is a they are bunched together and they will stop you pushing it down to get the get the pots to clear the chassis here.

[00:06:35]So, what you have to do is cut the tie wrap off and flatten all the leads down cuz they're all bunched up.

[00:06:40]Um and that gives you just enough room to push it down and get it out. So, there we go.

[00:06:47]So, we can see now.

[00:06:54]There you go. You see we've got a bit more bit more light and you can you can see the the light coming through the holes.

[00:07:03]That's not something with the board.

[00:07:05]It's just the light shining through the pot holes.

[00:07:09]Just doing a little round. All looks in good order.

[00:07:12]At a glance.

[00:07:14]Looks like there are no dry joints anywhere.

[00:07:19]Or do I?

[00:07:21]Let me just check that.

[00:07:23]Of course, I've just realized we need to change these resistors on this board.

[00:07:27]Just suddenly as as I looked at the solder spotted that dark patch.

[00:07:31]Yeah, you can see here. Look at the See if we can go in on that.

[00:07:41]There.

[00:07:43]So, you can see the uh uh discoloration on the board and this looks like it's uh given this solder a bit of a melting.

[00:07:52]That looks uh a little bit rough.

[00:07:57]Right.

[00:07:58]So, I've got a couple of these. These are 470 at 10 W.

[00:08:03]And uh we're going to put those in in place of those 5 W ones because I can't use these again cuz obviously the legs aren't long enough on them.

[00:08:15]And uh I'm not into extending the legs on them.

[00:08:18]And given the fact that it's melted that solder on there, extending the legs is not a good idea.

[00:08:24]So, uh we'll have those out.

[00:08:27]And uh yeah.

[00:08:34]So, they they they definitely have to go. So, that's uh that that needs sorting.

[00:08:41]And I think there might be a dry joint on this.

[00:08:44]Must be an op amp. Yes, that must be on the reverb or something that. Yeah. Um so, we'll just touch that up as well, reflow that.

[00:08:55]Get the uh unleaded solder off and and whatnot.

[00:09:01]So, yeah.

[00:09:04]Let's Let's snip out that uh Oh, dear.

[00:09:07]I've got the wrong glasses on.

[00:09:22]Wow.

[00:09:29]That's some uh That's some serious glue they've stuck that on there with. My word.

[00:09:35]Actually, we've we've tested it while it's Now we've cut the leads. Should have done that before.

[00:09:41]But I think that's blown.

[00:09:45]It's always best to test them out of circuit, but that that tester does test in circuit as well.

[00:09:57]But I think he's blown, madam.

[00:10:00]Like Mrs. Blankensop's TV, blown.

[00:10:10]We'll just confirm, but it's coming out anyway, so it doesn't matter, but Yes, thinking about it.

[00:10:28]Ooh.

[00:10:32]Can't even find a component, can it?

[00:10:45]Yes, I think that's definitely open circuit, yeah. So, that is definitely, yeah. No question, that's gone now. Now it's out of circuit. New question.

[00:11:02]Thought it was, but uh that confirms it 100%.

[00:11:08]So, I've taken out those resistors, which were here, but we've got a diode here that's also sat on the board baking the board. And uh I've just put a bit of solder on those, cuz I'm going to take that out in a minute, and then I suddenly realized, oh, I haven't got one of those in stock. So, I went off to check, and I have. I've got some of those, I thought I had. And you can see that the board's discolored around that as well. And they do get quite hot. And that is 1N 53 5 1N 5353B.

[00:11:44]And that's those there. And I have got some of those. So, I'm going to change that and raise that off the board. So, a bit of luck there because we've got got some resistors in stock, but we've also got the diode in stock.

[00:11:57]So, that's a a bit of good luck there.

[00:12:01]So, we can change that as well. And basically, what we're doing is as well as recapping this amp, we're making this amp more reliable.

[00:12:08]The last thing you need is that just you know, those coming loose and then you've got intermittent problems because it's literally unsoldering them. And obviously, if if we put some longer leads on them as well, then it's got a little more heat dissipation. There's more metal there.

[00:12:25]So, hopefully, and these are 10 W those resistors we're putting in a 10 W instead of five. So, hopefully, uh they should uh suffice better.

[00:12:37]We shouldn't have as many problems with that.

[00:12:41]But yeah, you can see I've got the caps out now. So, I've got to clean off this uh silicon.

[00:12:46]And uh I've desoldered the pins that I've cut them out. Desoldered the pins.

[00:12:51]So, always cut the pins either side and then you can just twist the the caps off it off the silicon. These came off really easy, the 22s. Not done the one up there yet.

[00:13:03]And it that they came off really easy.

[00:13:05]And then just unsoldered the pins. It's an easier way of doing it.

[00:13:10]Right, cleaned uh I've got all the pins out, cleaned all the traces up, got the unleaded uh solder off there. You can see just just there that board was just beginning to uh suffer a bit of damage there with heat.

[00:13:27]We just got here in time with those, I think.

[00:13:32]That'd have been left much longer.

[00:13:34]So, if you you know, if you've got one of these, I I recommend you raise these resistors and raise that diode.

[00:13:40]Obviously, you're going to have to buy new ones cuz the legs won't be long enough as I said earlier.

[00:13:45]But, yeah.

[00:13:47]It's discolored that board, but there's a tiny bit of damage there just beginning to appear, but luckily, I've caught that.

[00:13:55]But, we we're ready to start putting the parts back in now that we've took out. Might just give those a little bit of a re- clean up and reflow. They They look like they cracked around the edges there.

[00:14:08]Not sure if they are, but I can see. So, I'll just give them a go anyway.

[00:14:12]We'll get that uh unleaded solder off. They vile this solder that they use at It's absolutely awful.

[00:14:19]And it just clogs up the um the solder sucker.

[00:14:24]And you you have to get all of this off or you just don't get a decent joints.

[00:14:29]It It It's you know, you see people where they've just added the leaded solder with the unleaded that you know, they get They They try to pull the components out from the bottom. They don't clean it off. They just uh hold the iron over the joints, push the the caps in, whatever, and then just solder them and you just end up with that like bullet-looking, you know, like bird poop look. So, it's You've got to get it all off. Do it right. That's how I do them anyway. You don't have to, but that's just how I do them. It just looks neat.

[00:15:02]And the idea is when you finished it and cleaned the board, it looks like factory.

[00:15:08]That way you know it's bang on. And you And the thing is using leaded solder, it's it's just not going to crack like this stuff does.

[00:15:17]It's rubbish.

[00:15:20]So, we'll start getting some components back in.

[00:15:25]And uh get this pulled back together. Then we'll have a a good ins- a good inspection.

[00:15:34]Speaking of inspecting, where's my my pink is? She's the uh ultimate inspector of my work.

[00:15:41]Well, that's besides Gordon and Jeff.

[00:15:46]Who frequently inspect my work and keep me on my toes, but I don't mind.

[00:15:54]Right, got these caps in and I've got the resistors in and I've got the diode in.

[00:16:02]You can see I've got the diode lifted off the board there. There's the got these 10 W resistors in and they're obviously lifted off the board.

[00:16:11]Got 47 22 22 and the 22 in there.

[00:16:15]So, that's all done.

[00:16:18]And all looking good. Now uh we're to move on to this board. I've still got some flux and stuff to clean off there from soldering those components in.

[00:16:27]But noticed uh just the odd crack on these uh That one doesn't look very good. So, what I'm going to do for sake of reliability and longevity, I'm going to suck off all the solder on these and reflow them.

[00:16:45]Uh one pin on that uh IC that looks a bit dodgy and then there's a couple here.

[00:16:55]And everything else looks perfectly fine. I can't see uh see anything else.

[00:17:03]So, not that much really.

[00:17:06]But yeah, we just got to go through those.

[00:17:10]That'll take a bit of time, but it's worth doing because obviously um so, the board's a bit skew if it it's going to, you know, it's going to make this amp reliable. We don't want to 6 months down the line we don't want these all cracking if they're starting to go.

[00:17:29]And that one that one is cracked around the edges so we'll do the lot.

[00:17:35]Right, so I've sucked all the solder off these and obviously I go over them with leaded solder first.

[00:17:42]Go over them with leaded solder and then suck the solder off these.

[00:17:47]Um, some of these are grounds on here either side and I I go back and do those after cuz if you suck them all out you'll end up with a pot dropping out.

[00:17:58]Right.

[00:17:59]Sorted out all the board.

[00:18:02]Cleaned all the flux off. I've checked the two board. There's no dry joints on there. So we're ready to put this back together now.

[00:18:12]Right, got everything sorted. Now So we're all back together. I've changed it from 230 to 240. Just swap P10 and P4 round.

[00:18:27]Black and white black. So you just swap those. You can see how to do that on the schematic. It's quite easy.

[00:18:34]And uh, I was on the other diode I just remembered just before I put the board in diode I got the other diode as well to do there. Almost forgot that with focusing on this lot. So yeah, I've got to heat them in.

[00:18:46]And he's all good to go. So we're going to fire this up on the variac now.

[00:18:50]Variac, I don't use a variac anymore.

[00:18:53]We're going to fire it up on the current limiter on the bulbs and just bring it up steady on the bulbs so we don't shock these new caps to life.

[00:19:03]And uh, yeah, see how we go on.

[00:19:07]But that's all good now. So yeah, resistors replaced.

[00:19:11]Diodes replaced. They're lifted off the board and we've just put those four caps in there.

[00:19:17]Everything else is fine in the amp, so Right, we're on the current limiter.

[00:19:24]Just going to switch on.

[00:19:29]There we go. We've just got a 40 W bulb in there to start off with.

[00:19:35]And if we go up we can see the voltage there on the meter.

[00:19:48]200 430 V. That's dropping now because the tubes are beginning to conduct.

[00:19:56]Drawing 100 mA, so nothing sinister going on.

[00:20:06]Oh, look at that.

[00:20:07]Wow, that's so quiet.

[00:20:12]We'll just let it sit for a few minutes at 213 V.

[00:20:16]Hmm.

[00:20:24]40 W bulb is lit, but it's not at max brightness.

[00:20:36]Drawing 110 mA now as the tubes have just obviously they're conducting a bit more.

[00:20:46]We'll put another 60 W bulb in with the 40.

[00:20:49]That should take us up to 100.

[00:20:52]You can hear the volume come up straight away on there.

[00:21:05]That's all good. See, we're up to 330 V now drawing 180 mA.

[00:21:11]Oh, it's the reflection of the the amp on that meter. I was trying to see what's causing that line across it there.

[00:21:23]It's the reflection of the amp.

[00:21:25]Let's try and tip that. Oh, I've tipped it down too much now. Let's have a look.

[00:21:31]Yeah, that's okay. Just keep that off it. You can see it better now.

[00:21:35]So, yeah, I think we'll we'll lose the signal now. We know we've got signal through it.

[00:21:42]Yeah, that's quiet.

[00:21:47]Pretty good.

[00:21:52]So, what we'll do now, we'll put a 100 in with the uh 40 W. That's 140, and that's going up again. You're bringing this up nice and steady. And now, we're at 200 milliamps.

[00:22:12]So, we're drawing. Okay, the problem is the milliamp meter's behind the amp, so you I can't get the camera on it.

[00:22:20]So, up to three 370 now.

[00:22:26]Just check the channel switching. Yep.

[00:22:29]Um Yep.

[00:22:34]Drive.

[00:22:37]Yeah.

[00:22:38]Channel switching's okay. You can tell the reverb's working.

[00:22:44]So, that's all looking very good.

[00:22:48]Very good.

[00:22:51]Just go up a little more on the knobs.

[00:22:58]There we go. 380.

[00:23:04]Okay. the next two bolts we will have to bias the amp again as well because because we've moved it from 230 to 240 um the there'll be less plate bolts on there now.

[00:23:18]So we'll which uh means we'll have less uh less bias. We'll drop the bias a little bit.

[00:23:28]But that's no big deal. We're drawing 210 milliamps at 381 volts and things are looking uh very good.

[00:23:38]So we've got 160 watts of current limiting.

[00:23:45]So we'll stick a 150 in with that 60 and that should Yeah, we see we're flying up now. We've got 233 volts going into the amp.

[00:23:58]Four Sorry, 470 volts going into the amp. Now they're 418.

[00:24:03]Just um Go Yeah. There we go. 300 watts current limiting, 426 volts. 240 milliamps we're drawing.

[00:24:15]And we've got 237 going into it off the wall. I would say that's uh pretty cool.

[00:24:26]That's good.

[00:24:30]You can tell the bias is a bit low cuz the voltage the plate voltage is a bit high.

[00:24:36]So if we come down here drop down to there. There we go.

[00:24:47]So you can see Let me just get something to point with cuz there's a lot of voltage in there.

[00:24:54]See the bias pot is there.

[00:24:58]Um That's the same one on the one we did before. I don't know if that was a Hot Rod Deluxe or we did do one of these a while ago and this wire again here pressed up against this PC board getting rather close to getting trapped in here. The last one had got trapped from the factory. So, we we have just re-routed that cable around there.

[00:25:23]That's just a camera effect in there. Um And this this one again here really should be on the outside of it. But I can't get underneath to unplug it. I don't really want to start soldering on these traces, so I'm going to leave it.

[00:25:36]Obviously, that's done from the factory.

[00:25:39]But it's always better to have it's a bit difficult though it to it you can get that around the outside of that.

[00:25:45]It's just but just induces a bit of noise sometimes, but it's okay.

[00:25:52]So, let's just uh see what is happening with those resistors.

[00:26:15]Yeah, they're okay. Let's just see if we can get on the diode.

[00:26:21]That's a lot bit That's a bit hotter.

[00:26:24]Not much hotter than the other diode.

[00:26:31]That one's not bad.

[00:26:35]Just uh what I'm going to do now is I'm just going to switch the amp off.

[00:26:41]And I'm going to watch that voltage drain out of it and the minute it does I'm going to drop my finger on those resistors and just see how hot they are.

[00:26:53]And they're hot they are hot in this, but they're supposed to be 10 W resistors, but they are hot.

[00:27:01]Just looking at that, it's not close to that. Let's move it across a little bit.

[00:27:06]But yeah, they're um But at least they're not on the board thrashing the living daylights out of it.

[00:27:16]So now we need to check the bias and then it's done. I've I've got the knobs to put on as well. I didn't put the knobs on in case something was wrong and I'd got to take it out again.

[00:27:26]But that's all looking good to me.

[00:27:30]Right, I'm just going to go off and have a bit of a good leg at the schematic uh on the computer and just see uh just see what information there is about biasing. I think most of these I I seem to remember biasing around 16 W.

[00:27:47]I don't think we wind them up to 21.

[00:27:50]I can't remember what we biased the last one. I've probably got it in me notes, but anyway, I'm going to have a bit of a good leg at the schematic and then we'll come back, we'll bias this amp, get the knobs on it, get the back on it, and it's done.

[00:28:03]Right, so I've just done the bias how I normally do it using the Ohm's law method and uh I've got uh 18.5 mA on one side and uh 18.6 mA on the other, and they're only biased to take W.

[00:28:23]And they are pretty cool.

[00:28:29]So the the transformer is 80 ohms on one side and 106 on the other. So uh to uh it's a Friday afternoon wind, I think, that one. But we've got a bias test point here, apparently.

[00:28:45]And you have to set this to 60 millivolts, and it's set at 42 millivolts.

[00:28:52]Which doesn't I would imagine that 60 millivolts is 60 milliamps divided by two tubes is 30 milliamps, but uh that's doesn't quite add up to what I've got here. So, there's a bit of a So, what I'm going to do is I'm going to set this to 60 milliamps, and then I'm going to go back and re-bias it the way I normally do them.

[00:29:17]And uh we'll see.

[00:29:21]We'll see what the bias is.

[00:29:25]It's always handy to know what the bias in these are, and it's for most people when you see you know you do this. That's what I'm assuming 60 millivolts is 60 milliamps divided by two for each tube. There's no way one of those is biased at 60 milliamps in this amp. So, I'm guessing they're biasing them at 30 milliamps.

[00:29:44]So, we'll get a screwdriver, and we'll uh turn the preset pot. Let's have a look what we've got. It's just a slot.

[00:29:51]And uh we'll adjust it.

[00:30:01]Here are we?

[00:30:05]And there we go. I don't have to turn that very far.

[00:30:09]There we go, 60 milli Let's just see if it settles.

[00:30:13]59.996 that'll do me.

[00:30:16]So, that's now set at 70 milliamps. The plate volts Sorry, at 60 milliamps. The plate volts is about 420 It's 428 now, and it was 432.

[00:30:31]But, the the bias will have dropped because of course when I changed it to 240, that would have dropped the plate volts. It's also dropped the filament volts to the correct voltage as well, which is important.

[00:30:42]Which is why we changed that over. And there's I've done loads of videos on that. If you look through the Fender, a lot of these Fender videos that I've done, there's it shows you how I've biased them, and we've tested the voltages. Why I'm changing the mains from 230 to 240, and it also shows you how to do it.

[00:31:06]So, basically, it for anybody And this only applies to the UK, for anybody who doesn't know.

[00:31:12]When these amps come into the UK, they're bound by EU rules. And EU rules state that these must be set to 230 volts.

[00:31:21]Which, of course, in this country, our voltage goes up to 200 We're at 241.7 now on the wall.

[00:31:28]So, of course, that winds up the filament voltage.

[00:31:32]Because it's set at 230, you've got 11 volts more going in on the wall now, which equates to probably another 20 volts of plate voltage, and it shoves the filament voltages up. And if they get up to about 7 volts, then it's shortening the life of the tubes.

[00:31:51]So, that's why we set them to 240.

[00:31:56]So, what we're going to do now is we are going to test and see what voltage drop we've got across each side. So, center tap is here.

[00:32:09]And that's on millivolts, so I need [snorts] to change it.

[00:32:14]That's the camera again.

[00:32:19]There we go, DC volts.

[00:32:22]So, you can see that down there.

[00:32:25]So, that's center tap, and that is brown.

[00:32:31]And now we've got 2.1 volts on there.

[00:32:35]And 2.1 volts on brown.

[00:32:39]2.1 volts. Before we had 1.48 when I tested that before.

[00:32:46]And let's So, let's just see what's on blue.

[00:32:51]So, this is just monitoring the voltage.

[00:32:53]I've just not took that off from when we fired it up. So, I and I'm also using that because when I tested the plate volts, it's 2 volts lower than the meter that we originally was looking at. So, it just saves me having to measure it again. It's just a couple of volts less.

[00:33:09]So, we go there this time. And let me just go the other side of this. So, this time we go center tap and we go blue, which is there.

[00:33:21]And that is 2.8.

[00:33:26]volts Now, those two voltages are slightly apart, but then so are the windings on the transformer.

[00:33:35]So, blue. So, if we do the maths on that now, it'll tell us what that what that test point at 60 millivolts has uh has set this bias to. So, we start with brown. So, 2.1 and brown's got a resistance or winding of on the output transformer of 80 ohms. So, we divide that by 80 ohms, that's 2.1. Now, we've got 26.25 milliamps for brown.

[00:34:11]And if we times that by 427 cuz we've got 429 on the meter.

[00:34:21]That's 11.2. Seems a bit low that, but that's what that's what they're saying.

[00:34:26]I presume that you measure that from the I've never used these test points. so never bothered. I've just biased these uh and I usually bias these round about 15, 16 W, but that's really low, 11 W.

[00:34:41]11.2 So, let's try blue. Blue is two 2.8 and uh divide that by 106 because that's the resistance on the winding of the other side on blue, and that gives us 26 mA.

[00:34:59]Again, 26.4 mA.

[00:35:04]And if we times that by 427, that gives us 11.27. By gum, those two, they're matched.

[00:35:13]They really are. That's a a perfect match.

[00:35:17]Almost. 11.11.2.

[00:35:20]It is 11.27, so that is um yeah, it's bang on.

[00:35:27]So, bit low for the bias, but that's what it recommends, so So, 26 26.5 mA a tube. They are 6L6GCs, aren't they? They should be and yeah, they are. I'm going to say they are in these.

[00:35:44]Right, so I've just had a bit of a read at the schematic and it it says uh the bias should be 30 mA a tube and we've only got 26 mA a tube.

[00:35:55]So, Let me just say as I say, I never use these test points. So, let me measure across this resistor instead of measuring it from ground. So, now I've got That looks like Let me just go on to millivolts.

[00:36:14]And uh That's just the camera.

[00:36:18]So, if I measure across that, I've got 54 54 millivolts. So, let me just up that a bit more.

[00:36:29]As it looks like it's supposed to measure across that resistor and not to ground then that's why I've got a little bit under as I say I never use those test points. This is the first time I've ever used one. I just never bother with them.

[00:36:40]I always just do it like I've just shown you with the Ohm's law way.

[00:36:46]So that's up to 59 is just a knats Can you see that?

[00:37:06]I've gone a little bit over now. What we on the wall? Yeah, 241 we'll have that down a bit.

[00:37:13]Just a shade.

[00:37:27]There we go. 60 60 millivolts on the nose.

[00:37:32]Yeah, that's come That's okay.

[00:37:36]So what we'll do now is I'm going to now measure across them again and get another reading. I So it's nice to check these test points out and things down again just to see if if they're accurate as well.

[00:37:53]All it says is is is bias test point and there's a line pointing to that uh pin there.

[00:38:00]That trace. With one end of the resistor.

[00:38:04]So I measured that to ground but it looks like you measure that across the resistor by the look of it. That's what I'm guessing but we'll find out in a minute.

[00:38:12]So we're going to center tap again and then we'll go to brown.

[00:38:18]Oh we're on millivolts, aren't we? So we're not going to get a reading.

[00:38:26]There we go, DC volts.

[00:38:29]Not that it's a very big voltage. It'll probably be about 3 volts, maybe. Let's have a look.

[00:38:35]But, it won't measure 30 millivolts.

[00:38:40]Well, as I'm seeing things, that's Oh, no, it has gone up. That's not gone up much, but it's gone up from 2.1 to 2.37. So, let's give that a try.

[00:38:55]2.37 / 80 ohms = 29.6 milliamps. So, yeah, you measure across the resistor then. Doo.

[00:39:08]I'm a plank. But, yeah.

[00:39:12]29.6 and we're at 241 on the wall.

[00:39:18]So, we could have we could snake that up a tiny bit, but that's near enough. So, what's that giving us then? So, we've got 400 and still 400 27. It's not really changed it that much times That's 12.6 watts.

[00:39:35]Yeah.

[00:39:36]12.6 watts. That's what That's what it says. That's That is 30 milliamps per tube because we know those tubes are brilliantly well matched. So, there's no point measuring both sides.

[00:39:48]So, 29.6 So, yeah, anywhere between 12.6 and 13 watts.

[00:39:57]So, yeah, that's what it says on the tin. So, that's what we'll bias it at.

[00:40:02]It's correct. That's it.

[00:40:06]So, if you want if you're looking at biasing one of these you go to the bias test point. If you look underneath, you'll see a resistor.

[00:40:14]I think it's 22K. Measure across that resistor till you get 60 millivolts and you've biased your amp.

[00:40:21]And that will give you 30 millivolts a tube and that will leave your amp biased somewhere between 12.6 and 13 watts.

[00:40:28]So, that's that. That's done. So, all we've got to do is put the knobs on and uh put the back on and uh plug it in and have a bit of a blast on it, which I should be doing in the morning. Now, it's nearly 12:00 at night, but it's as good as finished.

[00:40:44]Right, I've got this Fender Blues Deluxe ready for a demo.

[00:40:51]>> [music] >> I'm on the clean channel.

[00:40:57]>> [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] >> Lovely clean tone.

[00:43:26]Let's add it to the uh play with the drive channel. So, So, this That's maximum drive. These amps don't have a lot of gain.

[00:43:42]>> [music] >> And that's not how they're designed.

[00:43:51]>> [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] >> Here we go. Some rusty blues playing there.

[00:45:11]Along with some rusty clean playing.

[00:45:14]But yeah, you get the general idea.

[00:45:16]That's a very tasty sounding amp. I I really like that. That's that's that sounds great. Lovely tone.

[00:45:24]Celestion speaker in it. Really nice bit of kit.

[00:45:28]And yeah, it's should be good and reliable now. So, that will do it for this one. So, thanks for watching and you all take care and I'll see you all in the next one. Bye for now.

[00:45:42]>> [music] [music] [music] [music] [music] [music] >> Woo!