Little Walter 22W - Part 2

[@thatampguy]

It’s amazing how some of the simplest amps can present the most complex rehab work.

[@BradsGuitarGarage]

And it can be hard to explain to the customer and fans of that brand, but the electrons don't care who's name is on the badge. They will do what they do with the circuit they are presented with.

[@davesimonis1476]

That's an exceptional sounding amp!

[@MikeM-Colorado]

Hours worth of content packed into 26 minutes. Great job!

[@Splattle101]

Some Monster may have been harmed in the making of this video.

[@IAmChrisR]

Great playing at the end Brad! Don't think I'd heard that side to your playing before.

[@goodun2974]

For non-technician players: as a general rule of thumb, push-pulll tube amplifiers are at best 20% efficient, so if you take the wall-socket AC wattage power consumption (your measured wattage perhaps being more accurate than the manudacturer's rating) and divide by 5 it'll give you a rough approximation of what the audio output power should be. In other words, if the chassis is stamped to indicate a 100 W draw from the wall socket then the audio power output is likely to be no more than 20 Watts, probably a little less. Fixed bias push- pull amps are generally the most efficient, cathode-biased push-pull amps (like the Little Walter) a little less so; and a single-ended cathode-biased amp is extremely inefficient, so you might want to divide the wall current wattage by 6 or 7 to arive at an approximation of audio output power. And then, you've got the highly dangerous, transformerless, "AC-DC" circuit,"widowmaker" amplifiers (such as a Kay 703) which don't even have a power transformer and operate directly off of the wall current voltages; those things are so inefficient that the chassis might be stamped "25 watts" but the audio output power is about 2 Watts! Not to mention that those things represent an extreme shock hazard and really should be run with an isolation transformer to protect yourself from electrocution......

[@MikeM-Colorado]

Extremely in-depth comments here, goodun. Thanks for the time and effort to spread the knowledge. Amazing.

[@socallars3748]

Wow, Brad. I admire how you kept your cool each time you found a flaw. If anything maybe you were too kind! I can understand the frustration of having to do so much just to make an amp safe and reliable and then sending it out into the world with someone else's name on it. I just checked and these sell for $2400, you'd think they could afford a few star washers and a tube of silicone.

[@jasonwooler801]

Great vid. Loved the spot of playing at the end.

[@MoeWatts1957]

Excellent video Brad. Very thorough reveal of circuit design issues and I appreciate the way you went through the circuit and wiring issues in depth as a "buyer beware" video. Personally, I think that repairing the electrical shock hazard on the fuse wiring was a necessary safety correction for the customer but correcting the circuit design is something I would not repair unless there is a shock hazard. Thank you for the great videos!

[@gringopig]

It does sound pretty good though in the end. Nice amp now! ❤

[@oldasrocks9121]

I know this wasn't one of your favorites but it was one of mine. Spoken as a total hack btw. I think if a tech encountered one of my "modified" VHT Special 6's he'd throw it in the road rather instantaneously. Without even asking!! You make me want to be a better "modifier" B, and I thank you! (The VHTs are mine btw, I have yet to inflict them upon others. 2 of them actually sound really good lol!)

[@Byron_Blue]

It is a nice little amp.

[@BenState]

great work again man! nice playing too

[@taijazvidfish]

I’m a long time gigging and recording musician. The Little Walter 44 I have is by far the best sounding and most responsive amp I have owned or played, and my list of previous played covers pretty much all the big players from boutique to vintage. I haven’t played a real Dumble but have owned or played most all of the big names here. 50 years of playing. I really love my LW. Mr Ford, Mr Gill… seem to agree. No reservations taking it to all my gigs.

[@bambule5268]

Once again, such great work!

[@butchlauer]

Howse about an, "AS FIXED BY BRAD'S GUITAR GARAGE" stickers for truly offensive amps. 😅😂

[@BradsGuitarGarage]

Not a bad idea. Or "design un-fucked by..." etc for the more egregious cash grab amps.

[@brucehayes7251]

You may want to get on to that sticker Brad, maybe even a nice aluminium plate, I can think of a few products it would be suitable for

[@fearnpol4938]

Didn’t Psionic talk about this very thing?

[@butchlauer]

@@fearnpol4938 I watch Lyle, but I can't remember his politics on such a touchy issue, lolol.

[@tedmich]

Good fix Brad!

[@Andy_Yates]

Just curious about the diodes on the rectifier. Would the stand-by switch be recommended with them? Are they wired across the plate and cathode such that the plates of the preamp/output tubes are seeing B+ before the heaters have done their job? Maybe it isn't enough voltage or voltage for long enough to worry too. Just to be clear, I like the addition of the diodes and when you do the flyback diodes too, but this occurred to me as I watched today

[@BradsGuitarGarage]

No, they are in series with the rectifier tube plates. not parallel.

[@Andy_Yates]

@@BradsGuitarGarage oh sweet, thanks Brad!

[@JagStar]

17 watts!!! 😮

[@BradsGuitarGarage]

Yeah, they all often rely on the marketing wattage point, as opposed to reality! Whatever, makes no difference, really. The difference between 22W and 44W is noticeable, but not very.

[@henrikreiersen837]

Greetings! Love your channel! Rookie question: If you parallel the diodes of the rectifier valve with solid state diodes, don't you eliminate the voltage drop that the valve would have if operating on its own?

[@BradsGuitarGarage]

Yes, but we never install them in a paralleled configuration. We install them in series with the rectifier valve.

[@usualthings-mq1cb]

Fairly impressed how much soldering iron damage they did to that belton.

[@goodun2974]

It'd be one thing if the tube sockets were mounted into a narrow bottom lip of the chassis, as they would be if it was a tweed type clone where it can be tricky to get in around the back side of the tube socket to reach some of the terminals; but everything is easily accessible inside this chassis and there's just no excuse for soldering technique this bad. Maybe they should manually solder-tin all the tube socket and tag strip terminals prior to mechanical installation, or perhaps even dip them into a solder pot first. Or use ceramic sockets which can withstand the heat of a soldering iron being wielded by a primate that doesn't have opposable thumbs....

[@usualthings-mq1cb]

@@goodun2974 they'll always create a better idiot

[@watkinscopicat]

Who do you think makes the best modern tweed type amps? the Fuchs and Tungsten 5E3 clones are tempting me, Rift ones look awesome too but hard to find many of them.

[@Splattle101]

My (very limited) experience of 6SC7s is that they're nice sounding but I went through a big bag of 'em trying to find 4 that weren't microphonic. A 5751 would be a good replacement and objectively better, if you're willing to make an adapter or replace the valve base.

[@MikeM-Colorado]

I had the same experience with 6SL7 tubes. I have 40, most are microphonic. I was excited to try octal preamp tubes, but the excitement has worn off. I do like their sound, but too much trouble.

[@Splattle101]

@@MikeM-Colorado I built a V-front Super clone using 6SC7s, and that's when I discovered they were very inconistent. I ended up rebuilding it with 6SL7s as a kind of 5E9A / 5C4 cross. So an all octal V-front with tremolo. I'm still not convinced about the sound of the 6SL7s. And I've also decided the trem in 5E9A is arse. But hey, it's all a learning experience. 🤣

[@johnwilliamson467]

Screen grids can handle about 7 to 10 ma the plates are in the 50 to 70 range explains how fragile they are. Pins can be replaced if you have some of those pin done that for years. Power supply dropping resistor is an other place to drop the high voltage rail .

[@TheSizzlingBadger]

Should have been called Little W*nker instead of Walter, what a mess that amp was.

[@alexdeleon7135]

Well done, Brad! Your breathing sounds a bit labored. I hope this was filmed before your current bout with that chest cold. Nevertheless, that amp has a very tweed character; clean and mean. Stay well, legend.

[@jamesprice6381]

Built for Cesar. Duaz after he passed. While earlier ones were def DECENT builds. Later when he was sick n VERY busy. Amps suffered. When u build for ROBBEN FORD. as this guy did . U might become VERY VEFY BUSY n some amps might suffer. Technically this proves. U may be able to BUILD a amp. But def not KNOW crucial details. (. Dumble amp craze in 2008!). After 33. Years building modding tweaking. I sure dont know it all. But have picked up every.Thing possible learning from others. Even. Phase on AC input has an effect. on tone n hum. Heck EVERYTHING DOES. Few builders MAKE IT. I applaud the guy for what hes sonically achieved. But nuthn wrong with going bk to basics!

[@fearnpol4938]

Christ that was difficult to read, and the irony in that..

[@Mr_Bio_Hazard]

Nice mushroom.

[@paulwatson8809]

This amp is now a little Walter, a lot of Brad. You should write 'BradAssed' in 18 guage brad nails under the logo...

[@Mark70609]

I’m wondering if you have come across amps that sound buzzy (in the preamp) when distorted? What did you tried to overcome that?

[@BradsGuitarGarage]

Not sure what you mean. You got an example video?

[@Mark70609]

@@BradsGuitarGarage I did try recording it and putting on You Tube but YT seems to compress the signal so it sounds okay. This is the clip but imagine there is much less bass and a lot more treble. kzbin.info/www/bejne/aHndgJ9qltOEkJYsi=gwY034j6twOHmBtI

[@markspurgin8225]

What more 😳

[@fletches4084]

Talk about dedication to your craft. Result shows it was worth the effort though. Think of it as doing a service to the planet; not throwing away something that was already built and wasting the resources that went into it. That's the excuse I use for sticking with my 25 year old V8 beemer at any rate.

[@YeatzeeGuitar]

Members first 👌😎

[@BradsGuitarGarage]

I clicked that by accident. It is now public. I needed to get them out over the weekend as I've been so lacking in content. But hopefully I can get a constant stream of videos happening later this month and yes they will feature member's only previews, usually on the weekends, then get drip-fed to the public throughout the week.

[@goodun2974]

​Drip-fed? Am I a "drip" to you? 😉 (Not to mention that I can't be a proper werewolf or loup-garou without a glowing pentagram on my palm that only witches, warlocks and other pentagram bearers can see!).

[@goodun2974]

At 2:24, you used bent up, pent up, went up in smoke Pentode language to describe the catastrophic vented failure of a creamed, unseamed, Beamed Power Tube: 6V6's dont have suppressor grids! Now take 20 lashes with a wet, lent ramen noodle! 😁

[@BradsGuitarGarage]

What potential is the beam former at?

[@goodun2974]

​@@BradsGuitarGarage, the beam forming plates are internally tied to the cathode, as the suppressor grids would be in a pentode (internal connection on an EL84, but external connection for EL34); anyway, I'm guessing that the beam formers aren't as physically close to the screen grid as a suppressor grid would be, and therefore if an overheated screen grid starts to come undone it's probably more likely to contact the grid, or the plate, than the beam formers. Just a semi-edjumicated guess on my part, but anyway......it's also interesting that most USA tube manuals diagram 6V6, 6L6, 5881 and the like as if they were pentodes and not beam tetrodes, though I've seen a few tube-manual diagrams that include the wing-like beam formers. Its definitely harder to draw the tube that way! If I draw a schematic by hand, I do them as tetrodes.

[@BradsGuitarGarage]

Exactydactyl! It's an educated guess on what likely happens inside the valve to cause a grid-cathode short. I'd imagine the molybdenum wire would be under tension that was set up during the winding process, and would spring outward. However if it made it to the temperature that it could break, perhaps it would have annealed by then and be under no tension, and just sag under gravity. Not sure, that kind of metallurgy and failure analysis is likely within grasp of those with a much higher paygrade than I!

[@goodun2974]

​​@@BradsGuitarGarage, It's interesting to note that some tube manuals will specifically mention that if the tube will be operated in a horizontal position, you must orient it a certain way ---- it'll say something like "pins 1 and 5 must be in line vertically", so there must be a certain amount of elemental sagging that takes place even under normal operation. (At this point, my own elemental sagging is both internal and external and takes place in any orientation!)😉

[@goodun2974]

​@@BradsGuitarGarage , The vertical and horizontal expansion of the elements of a tube and perhaps even the mica spacers is likely to be a factor when the tube is overheated; and if the glass gets so hot as to be sucked in by the vacuum (pushed inward by the outer air pressure is the physics-teacher-approved description), this too could have an effect on alignment of the elements.

[@goodun2974]

At 3:15, now I I know for certain that you're still tuckered out from your bout with pneumonia, because 5Y3's don't have independently heated cathodes and therefore it doesnt matter whether you take the B+ from pin 2 or pin 8 of a 5Y3 ---- until somebody substitutes a 5AR4/GZ34 or 5V4. I always move that connection to pin 8 "just in case", but technically it doesnt matter here.... although, I've seen a few old amps that were originally designed around 5AR4 or 5V4 where the B plus was indeed taken from pin 2, which is just plain stupid on the part of the designer. Regardless, whoever builds these Little Walter amps should have known better. Anyway, in theory they should have built a clone of the Danelectro Commander which was supposedly Little Walter's favorite amp ---- but that would be much more complex and so I expect that they'd mess it up even worse!

[@BradsGuitarGarage]

I swear I took footage talking about the differences with directly and indirectly heated rectifier cathodes, but the footage just wasn't there. At any rate, you don't know if someone's going to sub in another recto, so it's good practice to always draw the HT from pin #8, but maybe I'm splitting hairs here, I don't know. It wouldn't cost anything.

[@goodun2974]

@@BradsGuitarGarage , I'm with you 100%, if I find the B+ at pin 2 I automatically move it to pin 8, just in case!

[@Echo_III]

5:00 That's why I would NOT repair someone's job. Send it back to this crappy designer. Let him learn about the lock washers and safety. Someone will open this amp and see all well done but all the other amps from this guy will be shait anyway.

[@BradsGuitarGarage]

Yes, I struggle with this on every "boutique" amp that comes in. Generally, doing the job right and documenting it all gives me a customer for life, though. Sometimes you get a butt-hurt fan-boi that decides to start a fight due to buyers remorse, though. You can scroll through the comments on such amp videos to find these weirdos.