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Great info, as usual Chris. Hope to see more of your excellent videos soon!

Subbed! You're a great teacher.

What about the shock of the 440V A+, B,C,&D plus voltages hitting the tube plates almost instantly before their filaments heat up? The original tube rectifier ramped the high voltage up very slowly as it warmed up, but now it goes up instantly with the solid state rectifier before the tubes warm up. This is known to reduce tube life by 30%. A good argument for installing a standby switch, like the Deluxe Reverb, or just using the original 5AR4 Rectifier. The Weber looks suspiciously like a 10" Jensen frame and cone with a Jensen C12K Ceramic magnet.

HOWDY FROM MISSISSIPPI!! MY MIND WAS BLOWN THE OTHER NIGHT WHEN I DECIDED TO CHECK THE BIAS ON MY '65 DELUXE. BACK IN 2001 MY FOOTNOTES DESIGNATED MY RECTIFIED CURRENT WAS 452 VOLTS. THE SCHEMATIC SAYS BALLPARK IS SUPPOSED TO BE AROUND 325 VOLTS WITH 117 LINE VOLTS FOR AN AB763 CIRCUIT OF THIS DELUXE....SO I CHECKED AGAIN TO SEE IF I HAD 452, AND INSTEAD I GOT 488/485 VOLTS FROM THE AMPEREX GZ34 RECTIFIER TUBE! I DON'T KNOW WHY IT IS SO HIGH WITH 124 LINE VOLTS. HAVE YOU EVER SEEN AND OR KNOW WHY THE VOLTAGE COULD BE SO INCREDIBLY HIGH? THE AMP WORKS FINE, AND I BIASED IT FOR 15 MILLIAMPS AT 485 VOLTS.... ACCORDING TO SOME CHARTS I HAVE FROM A WORN OUT TUBE BOOK OF MINE. THANKS, I ENJOY YOUR AMP VIDEOS!

I didn't see anyone mention this, so I guess I will. The third harmonic sounds at about the 7th fret. It's actually the fourth harmonic which is at the fifth fret, and then the rest said about it is true.

2:25am local Detroit time Mi. US hi Chris. Can't sleep as usual saw your vid. On tube fabulous guitar work jazzy bluesy. Nice work on the Chinese vox AC ten amp gooday mate. Dwight.

ive tried both ways of dropping the voltage- your way is much better than the usual 1k Cathode Bias resistor that you always hear about. I ended up withe the same setup as this- 3.9k Dropper and 560k cathode bias resistor. Sounds awesome!! Great video!!

Hi, very interesting work! Here are a few thoughts. Are you sure your schematic is for the Champ you have? The CBS Champ version around 1979-80 had 420V B+, while older ones had closer to 350V. Regarding your tests, that EL34 was not running at 24 watts, because you based the finding on cathode current, which includes screen current. Tube dissipation ratings are based on plate current. An EL34 in a cathode biased Class A design is probably sending 10ma out the screen. That means the plate has more like .057 ma, and is sitting around 86%, not 100%. Also, EL34s use twice the heater current of a 6V6. Your heater voltage will be lower, which may partly explain the lower power. Low heater voltage can also shorten the tube life and possibly overheat the little transformer. As far as plate voltages, I wouldn't worry. Fender regularly exceeded maximum voltages and dissipation ratings of power tubes. The 6V6s in particular can really take a beating; great tube. Consider using a JJ6V6S. Unlike an older 6V6 that has a 350v stated limit, the JJ can take 500V.

... not nearly as much as a speaker with 101 SPL. Save your money, your PT and your OT. Get the speaker. If you double the output power from 5 watts rms to 10 watts rms, you will only get a 3db of gain. But going from the speaker with SPL of 91 to 101 you get the equivalent of going from 5 watts rms to 40 watts rms. That is an 18db gain. The EL34 requires twice the heater current. Very hard on the tiny power transformer of the Champ. --- Thank you very much for the excellent presentation. I enjoyed it very much.

In my prior comment, I fixed the reverb/tremolo issue. A wire came loose from it's solder point and that's all it was. Looking at that Jensen speaker, which I had in my similar amp 1965, I played with it for awhile and I thought it sounded kind of neat because it would break up so much, but it was too much and lessened the gain significantly. Jamming with a drummer, I had to put it up full to barely be heard. Turn the page, I bought a Jensen Neo 10/100 speaker many years ago and stowed the original away and between the clarity and gain improvent, times double sound output, it is a way, way better amp now.

Wickedly good sound. The Gretsch sounds epic through that Champ, great job! BTW I even check the phasing in the wall sockets..surprising how many are the wrong way round!

Hiya. I'm struggling a with my 65 Princeton Reverb AA764. I just did a capacitor kit replacement that includes the can cap and 7 of the original caps that were still in it, one 50 uf and six 25 uf. I verified that it was all done correctly before I reassembled. Now I'm not getting any reverb or tremelo. The tubes are all glowing. I'm pretty sure prior to the replacement everything was working. I know my soldering was done properly. I'm very frustrated. I almost feel like, since I have all the old caps, putting everything back the way it was and seeing if it works. If I slightly rock the amp, I can hear the reverb spring sound out of the speaker. But no reverb when I play a guitar and adjust the knob. Very frustrated.

At about 23:35, I thought he said 'building up hate.' Second time through, I figured out it was 'building up heat.' Well that makes more sense. 😁

cool

I wouldn't call Nyquist's Theorem a 'rule of thumb' really. But I shan't complain about someone spreading real knowledge 🙂

Slightly higher screen voltage can sound better in certain amps. If all the other readings are acceptable and the screens are a couple/few volts higher, I don’t worry about it. I’ve had amps sound less pleasing after lower the screens below plate voltage. It’s quite common to find this in single ended cathode biased amps. Yes,WGS sound fantastic in Blackpanel amps. The 10” Fat Jimmy ceramics work well in a Aa764. Adds a bit more lower mids to my ears. Punchier too.

A very good video. Champs and clones of them are nice simple little amps especially for a beginner to learn and compare and test many things. For example to try tone circuits or tone stack component values, putting EL84 instead of 6V6 using adapter, tweaking or removing NFB, adding a master volume, lowering B+, connecting output tube as a triode, trying different speakers etc.

A very interesting guided tour around the innards of The Champ. Thank you 👍

hi i drive my champ with a 6l6 ,i have 384v plate ,345 v on g2 and 470 ohm on cathode for 53ma dissipation 18watts ,i can pull 6.8 watts before clipping ,i could go up the plate to 450v maybe i could have a little more watts .No problem with a output transformer 100 ma but not less .It takes 35v voltage swing to drive 6l6 ;the same with el 34,you can use kt88 ,807 and many tubes in se ,but dont forget it modify negative feedback when you change tube

You decided to put a 470 ohm screen resistor in for the 6v6? Should I do that for my home built tweed Princeton 5F2A?

Having listened to bother the WGS and the Weber, which one do you prefer on a Champ?

I've built several champs out of a Webster 205 reel to reel. They have a 5Y3 and a 6V6 but use 2 6AV6 and a 5879. Ijust use the 6AV6s as theyy are single triodes equivalent to half of a 12AX7 so 2 of them work as 1 12AX7. I use the cabinet and cut an 8 inch speaker in. The cabinet is made out o 3/8 ply. They sound great.

Excellent job. Thanks😊

Good vid again, and the right outcome with that 5U4 and EL34. Save the poor little power transformer!

What is flat white with coffee, is it just a different term for milk?

Great vlog

That was very educational. Thank you for the work you put into making these videos. It would have been interesting to hear that Champ compared to your personal Champ, Chris. But right now I am going to put into practice that simple and practical test to check my ground and fuses have been wired correctly.

Great vid with huge amounts of useful info!

Another great video Chris. Really like your approach, very well explained and easy to understand. Bravo sir 👏👏👏

I agree on the double shot, my friend. But I'll take it black with a sugar.

Lovely work Chris! It would have been interesting to listen to that little beast with the el34 as well though.

Hee-hee; not "Fazed", ay?! Minha, mon cherie☝️. Sounds freakin' awesome! Luv ur work, Chris😉

Breaks up nicely! Modified the proper way. Excellent Chris!🎉

Thanks Chris! Love to Harley!

Really looking forward to part 2. Chris, I love your videos and humor. Which LCR bench meter do you use for 4 wire ESR measurements? I am also curious which frequencies you typically test at. Cheers and thanks for the great videos Chris!

IPhone to babe sag I wanted all kind of new guitar synthesizer send my futuristic metal rock you know etherical kind of stuffand I just when I'm from listening to Debbie metal to us just lots of classic rock and a hard rock and stuff that my parents did said that it was on a class rock radio when I was working all the time really going back more into class rock and hard rock more than metal and I found That tube amplifiers and analog pedals are the best sound you can get and when I see a 2 band I don't mean all these new tube they're almost all garbage even some of the ones that say Marshall, Fender, Vox . . I went out and I found an old 1960 tube amplifier that got better reviews than some of the more expensive amps including 2 that I owned at the time which were fairly popular cheap tube amplifiers the Fender super 60 with 6l6 power tubes one of the famous red knob amps. I also had a peavey tube king 50w. This harmony h303a. One power one pre amp. One rectifier tube. . I never had sag before with those other amplifiers but this was a null1962 the parts in it were not Chinese circuit boards this was old school stuffum I've never seen anything like that the stuff that was in it very old components and a Jensen speaker made in Chicago. . I discovered that when I cranked up the amp but mainly more importantly when I cranked up all of my volume knobs on my instruments and then I had an analog overdrive pedal it was an old boss turbo overdrive totally analog ways like 20 pounds you've knows just a little boss pedal. I discovered that when I cranked up the amp but mainly more importantly when I cranked up all of my volume knobs on my instruments and then I had an analog overdrive pedal it was an old boss Turbo overdrive totally analog ways like 20 pounds even though it's just a little boss pedal . So once everything was cranked up the sag when completely f****** crazy it was like a crazy ethical sound you you don't get out of guitars anymore right go and check out the AT&T minute version of indigotta-devita by Iron butterfly. Same trick. But w a mosrite fuzz tone. . You can make all sorts of crazy sounds out of these amps creating weird landscapes if you listen to that 18 Minute version from Iron Butterfly you're Here you hear 2 Different types of guitar solos 1's got a wap puddle it's Clean it's A Little More distorted The Other does even sound like a guitar sounds like a brooding demonand it is Insane is creepy sounded and it is so Different. As there's a lot of regular parts of the song I mean it's like a bus saw not a guitar that you hear going through most of those parts I Mean It's Insane Some Of It is a technique most of it is guitar equipment you cannot Find any More Push to the maximum where it starts to Really CHANGE and Make Yourself sound Crazy and I have found that this is the song I've been looking for. Not just the sag but the many different versions of twist and turns over it and the organic weird different sounds and things you can get out of the old amplifiers that you k and not absolutely not get out of the nuclear amplifiers I know that for a long time I used to buy some Motorola harmonics pedals when I had a transistor amp I set them back as I didn't like the way they sounded come to find out those are analog puddles and owners are the best if you have a real analog tube amplifier. At the same time all those boss pedals almost all of them are digital garbage don't go with digital goal with analog anytime you can and this also includes with synthesizers I found that there's some pedals out there like that like the old EHX Microsoft that just can give you crazy psychedelic scream sounds out of those old amplifiers unfucking believable sounds come from the old amplifiers. And for my first few years of playing I avoided them because I thought I would sound like old and s***** like some of the needles really old stuff where it sounds like they're playing Plastic guitars you know. And now I know for sure without a doubt the best amps I have ever played were more tubed than anything else in all of them Have tube rectifiers other than some marshals and a few other amplifiers somehow they were able to maintain some of their tube sound but I have played all sorts of different brands over the last couple of years of all These newer tube amplifiers even ones from big name brands Sound like garbage. If people want to because they think that transistor sucks then why aren't they recognizing that you should get a 2 abrupt fire as well I mean you'll get a little bit more stability are you sure that's what you want because I found less stability and morqueos was exactly what I was needing exactly what I wanted to go for I didn't want to sound the same all the time and when you play through this kind of equipment the actual sound of your guitar your instrument comes through you can hear the real tone in your guitar if you're playing just crazy transistor amplifiers with digital boss puddles or any of these digital amplifiers it's just s***** samples I used to have 2 keyboards 1 is full of copied sounds that are basically just s***** samples and the other one is analog synthesizer and all the analog said the seizers at the first keyboard copy. It's all like absolute trash from a crossroom or over a phone you might think that it's the same sound that I would be using if I was playing keyboard part I've been playing. The song jumpgo to learn benhill and jumptry it on a digital keyboard with the synthesizer and then try on an analog synthesizer if you have eardrums and a brain you are gonna go for the analog sound every time some people get tired and bored of the old sounds they want to look into new sounds I've heard a lot of the digital cookie keyboards and the hybrid keyboards and I don't hear anything good we bought my exold lady a $1000 Roland Juno synthesizer and it said they could do all these things it sounded great when we watched the videos but when she got it she was I'm not happy with it she did not feel that the sounds were that great and I had a little tiny corg analog and she said that sounds so much better. We sent that roll and Juno back and then we looked around and we found out there was a cheaper rolling synthesize your that was like 700 bucks at they just come out. You can tell just by looking on top of the thing that it was what you're looking for as a real synthesizer even though it was only a couple 100 bucks and we got one that somebody boughtnew put not even barely a scratch on it because they only had it for a couple of weeks like 2 weeks or 3 weeks before they turned around and sold it for $400. Etc. Plus a better warranty. A must when buying electronics. Extended warranty, do it . Please be wise. . I was actually p***** because it was like $400 for a new one and let's go buy new 1 I asked several different people If they came with an adapter one guy said yeah it does next guy said no it doesn't I said yeah I think so so I sent enough money in for the synthesizer plus tax plus a few extra bucks and then just to find out that I did have to buy the adapter and so Then I didn't have enoughso Then I look around and look around and end up having to bite a used 1 from another state which I did not Want To Do I do not Want To buy a synthesizer keyboard that people have been beating on and touching on I Want To buy a new 14 a reason okay this 1's like new okay Then there's no Real great warranty because Somebody Else's own for a couple of months so I paid for an extended warranty but what p***** me off is once I got my keyboardthere was no instruction books I meanit's a Good Thing I had 1 from a previous model that keyboard I bought before my ex took it split up so I already had a book to thank God for that partbecause it's extremely complex even for a little KORG synthesizer I Mean. Synthesis true truly can be Difficult.

If you sub a 5ar4 or a SS recto, you’ll give that el34 a bit more power and ease up on that 5v tap

double heat shrink on those two wires off that PT . . maybe 3?

Hello Chris, this is once again a very instructive video. Das ist gut, das ist sehr gut 😁 I would be very happy if I could give my amps to you for service. I can't wait to see part two. Best regards from Germany

hi what voltage you put on the el34 on the champ,if i want to use 6l6 can i use the same voltage plate and g2 ,so what voltage do you suggest to me and can i use the same resistors supply in this shematic .If i look datasheet 6v6 tube, the plate voltage is different that g2 ,why fender put the same voltage on plate and g2 ,thanks

I built a champ circuit with voltage and bias switches that allow you to swap around 8 pin power tubes. 6L6 for punchy headroom. EL34 for creamy compression. KT77 sounds best, imo. It's somewhere in the middle - something like an EL34 with more definition. It was a kit from Trinity Amps.

I work on Robin Trower ‘s gear and his dressing room amp is a Fender Champ with a EL34!

What do you think of the Marshall EL34 dual power amps ??

You must have some "Chic" lps im your collection. Nile Rogers is 2nd to Hendrix for funk. That weber sounds great, almost as good as an Eminence GA12 sc64. To save time with running in a new speaker I plug a cd player into the amp and use it as a juke-box for a month, if you play Mozart( string quartets) and Bethoven (greatest hits) the speaker will know what it's purpose is and it will be ready for work sooner.

I got a similar settup. Champ with 5AU4/ 5881 and ecc83. A 3 way bright switch was added( low/ off/high brght) . It has an upgraded mercury magnetics transformer. The head room is massive. It needs the volume on 8 before it begins to break-up but what a sound it makes ultra clean with a subtle valve sag. The speaker is a 10" Eminence GA10 sc64. It has a very very low hum as an extra 20uf electrolytic cap was added . The one on your channel is the only other I have seen modded with a 5u4 and a bigger power valve. Should sound great with that speaker. It should stay clean up to 7/8 then stand back if the transformer checks out for extra power that is.

I built a single ended tube amp, similar to a champ, but with a 6384, it's about 9 watts.

With hot glues and silicone sealant a drop of Isopropyl alcohol will usually free the bonding without melting it to a gooey mess, than you can just pull the material away. For soldering to steel chassis', I stumbled upon a flux made for soldering to Aluminium which also turned out to be very good for steels and iron. Brand - La-Co though I don't see it for sale these days, only their regular flux. I've had mine some 30 years and I'm not half way through the tub.

Please correct me if I'm wrong, but even if one goes through the trouble of upgrading the power and output transformers, and the power and rectifier tubes to get double the output power, in theory that's only going to be about 3dB louder. A barely perceptible volume boost. A larger and more efficient speaker will probably make a much larger difference.

Don't mind me. Just dropping by to say hi and help with the algo a bit.

Well, good to see someone else is getting the dodgy-hacked-up jobs, too!