I almost laughed out loud when you said you're red green color blind. I am too. Funny story, in 1969 when I went to an electrical engineer college, my first week's quiz was resistor color codes. I was handed a bunch of resistors and the quiz was to write down the value. I told the professor I was colorblind and could give the value if someone told me the colors. The prof said I'd fail. A veteran in the class had just returned from Vietnam with his right hand missing, a hook in place while waiting for his prosthetic chimed in, "if i can't pick up the resistors will you fail me too". I aced the quiz and made a new friend all at the same time.
I've heard you talk about the insulation of cloth covered wire becoming conductive. Seeing you demonstrate it was well worth the long video! No need to apologize for long videos, Lyle. Thanks for the excellent content!
Like alot of people talking about the RU-vid revolution making long form podcasts possible and people wanting to watch people talk for 2 or 3 hours, there are many of us who love to see these hour long amp videos. Thank you ❤️
I gotta say I've seen some techs use offset bending pliers on resister and cap leads but you are the only one I've seen use a micrometer to measure component gap spans...Your work and commentary are hypnotizing
Wow I really enjoy these longer indepth videos. I love tube amps. Its never boring. You're really a fantastic amp tech and its fine that you toot your own horn. Another good tech to watch is Brad from down under. I really enjoy your videos Lyle keep up the great content 👍
Sorry I haven't liked on or commented on your videos for a while, I've been watching them on TV. As ever I find your work both fascinating and really educational. Keep up the good work. I'm learning so much.
Not enough repair videos show soldering, IMO. I learned how to solder in high school (a long time ago in a galaxy far, far away), a vocational class in electricity and electronics. I remember being struck at the unique odor of hot solder and the tip of the iron. Now whenever I see soldering on video, I can smell it. Cool.
WOW, some curvature on that fiber board.....electrons probably had problems going 'uphill' ;-)) Another great job and enjoyed viewing the work you do on these amps.
@21:15 The machines I'm familiar with that use component reels don't pull the part out of the paper, they cut the leads before placing the component on a PCB. These are automated pick and place machines in an electronics manufacturing environment.
Lot's of poetic and profound moments in this video: 27:23: "Part of me likes the meticulousness of all this. Just really, really taking the time to get this stuff just right. . . . in a world of non-repairable things where nothing is of lasting value or consequence; like doing this kind of stuff is kind of an act of rebellion in my own quiet way." 37:20: "It was a bad solder joint in 1963/64; it's a bad solder joint now --- or it was until 3 minutes ago. Now it's a good solder joint" 42:25: Disquisition on the evolutionary significance of non-linear distortion and why the human nervous system responds to it with special attention.
Lyle, for removing the paper and tape strips from those caps and other parts that were similary designed for automatic, mechanized pick-and-place machinery, see my other post. You might still have to use steel wool on the parts leads afterward, but unless the manufacturers have changed adhesive, an alcohol soak should soften the tape and the paper to the point where they separate. I've done an entire role of 100 caps or other parts at a time this way, in one fell swoop.
Well, I for one, do care a lot about this stuff. So, thank you very much for going to the trouble for those of us who do care. I'm not an amp tech, just an old guitar player that still uses the pre CBS Fender amps I bought used back in the 70's. And I used the hell out of them, 5 to 6 nights a week for decades. I've made a few minor repairs recently, and electronics does not confuse me, I get it. I'm watching and re-watching, and I'm sure I'll watch again. I want to be able to restore my old amps, the repairs that have been made over the years by good, and maybe not so good, techs have made them sound less and less like I remember they 'used to sound'. If I'm crazy, then I'm crazy, I don't care what they say, but I say, if it's different, then it's different. So, I completely agree with what you're saying about using the right/original type parts. By the way, what brand/make are those ceramic disc caps? Where can we get some? And, if you had, say, NOS A.B, Sprague, etc. that measured and ESR to spec., would you use them? Don't worry about answering, I know you're a busy guy. I'll just keep watching. I'm up to being able to pull the Filter cap board and bias board and rebuilding them (as soon as the bus wire arrives my '63 S.R. will get the treatment), the main board still kind of scares me, but you're giving me the confidence, it really needs it there's gobs of solder between the boards. I've already measured DC on my '64 D.R's board then cleaned it like you do and saw the DC drop. So, I do care, and your videos and techniques are great. My goal is just to restore and maintain my own stuff, (I live in a rural area now, no techs around here that I would trust the old stuff to, besides I want to do it myself). I don't want to do this for a living. I probably wouldn't get any customers anyway. Okay, enough from me. Thanks again.
Those old amps are pretty bullet proof. Aside from filter caps needing changed, not a difficult job, and setting bias, not difficult with a good meter and a little knowledge, these things will run forever if taken care of. Oh yeah and coupling capacitors! They can get leaky. If you have scratchy controls even after cleaning then chances are your coupling caps are leaking. Many good videos on that subject. Basically there exists two schools of thought on coupling caps and applies to amps in general. One is to change all the caps if you find one bad one. The reasoning is that they are all the same age and even if the others are good it won't be long before they too are problematic so change them while your in there. The other folks contend that you can alter the sound of the amp by "shotguning" all the caps and will just change the one bad component. I try to do what the customer wants, within reason, and always observe the Hippocratic oath. I live out in sticks myself, West Virginia boy. If you're wondering about the name this is my wife's RU-vid account lol. Pretty handy with electronics, RU-vid accounts....not so much 😆
Looking over your shoulder amp after amp is the perfect apprenticeship. You could probably charge for this. The only point to point amp I'll ever get inside would be a kit build. However it would be great to de-bug any modern amp I buy. (surface mount not included)
Lyle, I love the attention to detail! What you think is boring I seem to find therapeutically relaxing. Sorta like ASMR. 😌As far as being opinionated, someone once told me, "If you gotta clean up enough of other peoples' s×%#, you figure out which shovel works the best!"
Where do you think the carbon comp resistors make the MOST difference in a black panel Fender style circuit? All plate load resistors and the slope resistor in the tone stack? Just the plate loads downstream where there are bigger DC and AC voltages present? I've heard lots of conflicting information on this. Would the 3.3M reverb mix resistor and the 1M grid leaks be places to AVOID carbon comps to lower noise floor?
The bright switch tends to make a sufficient "pop" that it could be obnoxious to the audience when it goes out over the PA. It occurs to me that perhaps it would be possible to install a 3-position SPDT or DPDT slide or toggle switch with a middle "off" position (on-off-on), or perhaps an on-on-on switch, which could be wired to mute the signal or ground it out when the switch is in the middle setting, so that it doesn't pop when changed from "normal" to "bright". I don't know offhand if it's possible to find a slide switch that will give you 3 mechanical positions within the relatively small space of the slot provided in the face plate of the amplifier; but you certainly *can* find miniature toggle switches that would allow you to do this. You'd need some suitable fender washers, and perhaps a rectangular washer or cosmetic overlay of some kind, to fill the rectangular cutout in the amplifier faceplate when mounting a toggle switch through it.. (For non techs, SPDT and DPDT refer to single pole double throw and double pole double throw switches).
Your obsession with minutiae is exactly the reason I watch your videos. I have ultimate respect for that perspective. I realize that it is necessary to continue the legitimacy of tube amps as most modern ones descend into unreliability and throwaway junk that won't be around in another 50 years. Techs who are as hypercritical of their own work like you are our salvation. We tube amp people need more of those who will chase hum to ends of earth. You do pat yourself on the back a bit too much though. Not necessary, but I do understand the whining you hear. It isn't boring, it just helps me to better understand the inards of my 64 Super Reverb. Keep up the boring minutiae!
There must be something wrong with me, because I am absolutely fascinated by these videos. Especially the ones on vintage amps. Especially Fenders. As good as my '67 Deluxe sounds (and it is REALLY good), when I watch these videos I wonder if it could be better?
Yeah man, me too. I have 5 pre CBS amps that need this kind of work. I'm going to try to do it myself, but, I better study these videos and re-study them.
Those capacitors on the paper strip have more lead length stuck down under the tape than they have above it! Which is okay if you're using the caps for PCB mounting or on an eyelet board with closely spaced eyelets, as is being done here; but it would suck if using those caps for a point-to-point design, or on a turret or eyelet board where the connection points are widely spaced, because the glue left behind on the leads tends to resist solder. You can stand up the caps in a glass with a half inch of alcohol, and the paper and tape will soften and fall away, but there will often still be adhesive residue left behind on the component leads.
I think amplifiers are fascinating, and when i rebuild one and it works well , I'm extremely satisfied. GOD BLESS YOU! GOD BLESS AMERICA!! GLORY BE TO GOD!!! IN JESUS NAME WE PRAY!!!!!!!
Ever try soaking the sticky part of new components in a little ISO? Just do it before hand. Might help to remove the tape. I’m going to try that. Lighter fluid might work well too.
I was unable to find the AA763 Twin schematic also. I looked for hours after your first video on this amp, using every search engine and different search terms. I find it acceptable to use the Showman and Super schematics, considering the situation.
They very much can... and that is one of the beautiful things about carbon comp resistors that you lose when you replace them with "perfect value" components.
So I notice you don't put a heat sink or alligator clip on the lead of small components before soldering them. I trust that you definitely know that excess heat is not traveling into the caps and cooking them. I know as long as you get in and get out quick you heat them up but not to death and I guess touching the ceramic disc or whatever it is will give you an idea of how hot it's getting too. I learn so much from these videos I love this stuff!
Whatever your meter leads read up in the air is acceptable. Leads often read up to 20mV when not touching anything. Anything more than that on something which is supposed to be an insulator is a problem. You definitely don't want more than 50mV on any insulator.
@@PsionicAudio thats whats weird with my fluke 117. he reads 0.0001V on most places on wires and on the board but when set to mV he reads 350mV and even if I'm not touching anything it stays in the 70-400mV range. so which range should I work with:(
DC on the volume pot often makes an awful noise and a cleaning doesn't help for long. That noise using the bright switch often also indicates DC on the pot which the switch is across. Unfortunately there is no "coupling cap" and the 3 caps of the tone stack serve that purpose. So when the bright switch is noisy the volume may also be soon, and you have to test all the caps in the stack...and then it might be DC leakage in the board LOL. But that noisy bright switch usually has nothing to do with the switch itself. I didn't go back to see how noisy the volume was when you started. How far to go? Only you can say...
THen again all the tone pots were quiet. Go figure....LOL. Maybe the noisy bright switch is worth living with? Maybe it's cumulative leakage of all 3 caps in the stack?
Can you share some tips on how to prevent the “rushing water” when using the volume pot on the vibrato channel? I’ve used the alcohol method along with the heat gun and now the dc voltage is very close to 0 on wires and on the board. I have 40-50mV on the ground side in one of the coupling caps. Tried different cap but I still get very small voltage to ground. Is that normal?
Below 50mV is normal. Once DC is eliminated, the next suspect is the wire from wiper to grid. If that isn't the culprit, pots wear out (I'm assuming you've already cleaned the pot with Deoxit).
Thx Lyle. I have 100pf on my Deluxe clone. Was told it could filter ice pick highs. I have turned my tone pot into a mid cut so I’m running the highs unfiltered and use my guitar to tone to control highs.
@@jbolt247, Well, most technicians, if they are not colorblind, will do a quick perusal of the amplifier and look at the color bands to spot any resistors that are not original and perhaps changed by someone else to a different value from what you would expect to see in that position. It's not possible to do that by sight when you're color blind, and so you end up having to measure every single resistor. Which isn't necessarily a bad thing, since many or all of them should be checked for drift, but it's good for the tech to be able to know at a glance if the resistors conform to the values printed on the original schematic; or even if it appears to have been factory-built with the "wrong" parts values (which might actually turn out to sound good, or different in a usefull or pleasing way). Otherwise, you need to start with a paper copy of the schematic and write in the values of the parts that you find in each location, as you go along with the ohmmeter, because you can't simply verify them at a glance as you work on the amp. At least, I myself would likely find that necessary, if I couldn't trust my eyes; mostly, however, it's my *memory* that can't always be trusted!
I find it ironic that in every video where you mention how boring this must be, tend to be my favorites. So yes, I am really into amps, and really into learning about them. All of the things you assume are monotonous and boring are little bits of knowledge that you give away for free and save me hours of trouble shooting. So more talk and less 10x please.
