Reducing Hum Noise on the Epiphone Valve Junior

This is a follow up to the last video I made on the modding of the little 5W Epiphone Valve Junior tube guitar practice amp. The amp sounded pretty good by the end of my wrenching, but still was a bit noisier than I would have liked. In this video, we'll try to solve some of the noise issues inherent in this version of the Valve Junior, which I believe is Version 1. I've also made a mod video on Version 2 of the amp, which I will link below.
Previous Mod Video: • Secrets of the Epiphon...
Version 2 Mod Video: • Epiphone Valve Junior ...
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[@MrHeliosoul]

Brad, I always wonder what the mind of somebody capable of repairing electronics like tube amps and such is like. I'm really grateful for you and your Channel. Until I saw how you systematically comb through everything meticulously and deliberately gives me hope that maybe one day I'll might just get to a basic understanding and capacity to repair electronics. You rock brother! Thank you for your candor.

[@TheGuitologist]

That was a super nice comment. Thanks for taking the time to leave it. I don't know everything there is to know either, man. The minute someone calls himself an "expert" at something is the minute he cuts himself off from learning. My message to you is, do not stop learning something because you're afraid or because someone questions your expertise. It's a badge of honor NOT to be an expert. It means you're open to learning. This is why I can't stand Fauci and these other "experts" leading us down the road to ruin IRL.

[@RHR-221b]

@@TheGuitologist A pearl or two of Wisdom, B. Thank you. Stay free. R 💚 😎

[@hestheMaster]

I also recommend D-Lab Electronics and Uncle Doug. Both do very much the same thing with "problems" such as this video shows when it comes to the transient noise problems in amps. You can learn a lot from all three YTers.

[@mikek464]

You should have narrated with a Carl Sagan impersonation. With that background music I was dying to hear you say "Bill-Yuns and Bill-Yuns"

[@rayhogan785]

First of all: you DON'T check the noise of your amplifier with something plugged in. Notice that after your "fix" it seemed quieter. Nothing was plugged in. A better comparison would have been a voltage reading with a meter or a scope before and after.

[@pharmerdavid1432]

Having an amp be quiet at idle is very important to me, being a lowish volume home player. My Fender PR amps were noisy, obviously needed servicing by a qualified tech, but I traded them both (ouch). Then there was a Kalamazoo Bass 50 amp, with two C10N speakers, which sounded awesome, but was VERY noisy, so I sold it (sigh). If only I had had it serviced by someone like Brad, it would still be mine (woulda, coulda, shoulda). Came here from the Dave Simpson video at Andertons, where Brad made a polite comment, and was attacked by a viewer who apparently had their feewings hurt. Glad he reminded me of this channel, because I hadn't been here in awhile. Always excellent technical information here, interlaced with humor, and sometimes Brad will state his honest opinions, which I may not agree with, but it's HIS channel. I love the song quote he used one time after somebody complained about something here (paraphrase): "You can't please everyone, so you better please yourself". One of my favorite parts of the videos here, are when Brad plugs into the newly serviced amps, and squeezes some sweet tones out of them!

[@sophiemilton5939]

Removing the 220 Ohm resistor in series with the HT line destroyed the intended hum filtering. The 220k from HT to ground was a bleed to take the voltage off the caps at power off. The 100n cap in parallel with the electrolytic was there to short any RF or hf oscillations to earth. It is common to add a small cap in parallel like this because a large electrolytic performs very poorly at hf

[@joenovak6393]

Audio gear head on Stereo equipment and my goto cap for High volt is Nichicon PW, PM (Low Impedance). Thanks for the video.

[@ericmdk]

YES! Finally something I own(head variant)!! I modded my input resistors to taste. Had a friend borrow it so long I thought I might not get it back. . Its been a wonderful amp for the money, great to see your thoughts and ideas improving it!

[@JustFred1564]

Are you ambidextrous? I've never seen anybody solder with either hand holding the gun. Love your channel!

[@TheGuitologist]

I can solder with both hands, and I used to switch hit in baseball. That's about the extent of it.

[@TheLonesometoad]

I would loop all active power wires individually thru ferrite cores to eliminate 60hz and all other RFI being induced by other sources.

[@deepwater2652]

Brad, sounds pretty good after you laid hands on it!

[@kxmrock]

Glad to see this. I think the same way, Lets Lose any extra fields of AC & Dress it up a bit Just did something like this to a Jet city 5wt

[@matthewf1979]

That choke looks like it’s double the size needed. Probably raised the noise floor. I’d just leave the screen resistor in and physically rotate the output transformer 90* to see if that helps. When I install power transformers with export taps, I pop open the bells and unsolder unnecessary taps. It just looks better inside and out. Same goes for output transformer taps that aren’t needed. I try my damnedest to get a direct replacement, since Classictone shut down its getting hard to do.

[@TheGuitologist]

I considered the orientation, but it is turned 90 degrees already. Still, it's sitting virtually on top of the PT, so I think removal is the way to go with that choke. I'll replace with a dropping resistor and see where that gets us. I also want to go back and see what a Zobel Network on the output will do. That should smooth any spikiness these are kind of infamous for.

[@matthewf1979]

@@TheGuitologist I remember when you did that Zobel network. I liked the results. Sometimes things need to be done when an amp is modded or just has a bad design/parts.

[@cgavin1]

Can we do more hypnotic ambient music sped up sections? Like 1-2 hrs of them? Most relaxed I've been in months..

[@baylockthewarlock5729]

I was hoping you might just chuck the board and go point to point and use real tube sockets. That along with the wiring you did this time would be the hat trick master upgrades. The output transformer and choke seems a little flakey. Let me know if you get back to this project though, it's a good chassis to possibly dial-in a signature.

[@paulcargo4233]

Brad, on a side note I recently was directed to the GuitarStruggles channel by one of your viewers commenting on Rick Beato, his work is excellent and many of Bill's ideas and viewpoints are right in line with yours. Please try to give him some props so as to compel him to continue providing quality entertainment along with you. Thanks in advance, Paul

[@JohnLee-mq4hk]

It sounds good for such a simple design.

[@wayshot]

Time to do the same wire cleanup on my own Valve Jr v2 head. It isn't really that noisy, but it'll certainly look prettier on the inside.

[@brian50g]

One time I reached up into an amp and touched a bare wire...shocked the hell out of me....it was a great day

[@Robster-Craw]

I used to play gigs with this old Guild Thunderbass amp and my bandmate thought it would be funny to switch the polarity switch on my amp so id receive a shock. I don't know if you ever been hit in the face with a sledgehammer but that's how it felt to get zapped by the mic when my lip touched it with the polarity switched the wrong way from the mic. After that day until the day that amp burned up in a house fire I would tap the mic with my hand while holding my strings, Still hurt but nothing like taking the shock to the face.

[@Chinaguitarsceptic]

Such an improvement. Excuse my ignorance but is this a similar effect to changing capacitor values on your tone pot? Great video mate!

[@jon759]

Brad, been meaning to tell you that I find your amp repair videos very relaxing, especially this vid with that back ground music. Maybe worth considering putting AMSR in your repair vids title. Just a thought and thank you for the vids, I do enjoy them.

[@bertrandmajorik6589]

I'm already on the net for BASS tube amp schematics, i'm GASSIN for one, thank you for the wonderfull info, Brad.

[@jeanlawson9133]

Mighty fine.... thanks 😎 that little fella not only sounds better....but looks so much better...

[@roncarter2188]

The music that played when you installed the new filter cap made me feel that everything was gonna be ok😅

[@TheGuitologist]

Yes, but it isn't.

[@roncarter2188]

@@TheGuitologist yes you're right reality has bit me in the ass once again

[@bigyin.7710]

I found it soothing too, what was the music, Brad?

[@retrobrw919]

I had to do a similar thing with my 20W epiphone valve amp I bought. It's the Galaxie 25. The wire dress on everything was sloppy and it hummed like a sum bich. I had to redo all the filament wiring, and replaced the power tubes and rebiased it correctly. It was running a pair of el84's super hot and one of them red plated as a result. Been meaning to dive back in and fool around with the circuit to make it sound a bit better too. Already replaced the stock Celestion 70/80 with an Eminence Cannabis Rex speaker, which improved the tone quite a bit already. I think it's a trend for all of these Epiphone amps to have sloppy wiring, likely due to the low price point and the factory rushing production.

[@stevehead365]

I think the choke was probably wired in the wrong place, thinking that the hum was coming from the preamp section when it was the output stage causing the problem. Just a guess.

[@robertcalkjr.8325]

Good job, Brad. I heat the glue up with my heat gun to help removing it. Sometimes it makes it easier.

[@mr.keebler7927]

I noticed that you put your signature on the chassis

[@blennyvisions8279]

yup, had the same prob. replaced the first cap with a 47, did help. later on i just did the whole thing wire by wire so that the filaments are not on the pc board, helped also. there is still a little buz but ok now.

[@decomputerleraarable]

You should write a note and included it in the amp with your modifications, so the next tech knows what is done. This methode should be obligated for every amptech. Rob

[@HiHello-ku1fl]

Those little Weber signatures sound great to me. I had one in a blackface vibrochamp and it sounded so good.

[@jebboceefus553]

Going the extra mile with that amp 👍.

[@russellhltn1396]

Since the hum is controlled by the volume knob, it appears that the hum is from the first stage. I wonder if it would be more effective to upsize the third cap in the power supply, since that's probably the one filtering the power for the first stage. It also might be worth checking the diodes to make sure one hasn't opened up and gone half-wave rectification on you. Although the buzz did sound more 120Hz than 60Hz.

[@TheGuitologist]

Yes, but there’s background hum also, and it’s being induced into the signal.

[@bingskiddd]

Hey Brad, just wanted to let you know that I didn't get a notification for your video. you might want to look into that.......... Love the channel brother, be safe.

[@TheGuitologist]

You won’t get my notifications. I’ve offended Susan.

[@niptodstan]

These amps were rebranded as Grainger amps. I've got a 50 head and cab. It has attenuation built in to drop it to 25w. It's a good amp really.

[@niptodstan]

@@electrofrying1685 . I know. Epiphone did these little junior amps and the big head and cab.

[@gw2031]

Hum = AC ripple on DC lines ,, expired mains smoothing caps main culprit ! You can see it on a scope ! Great playing btw brad,

[@allansmith6140]

If the hum is 60Hz it is pre-rectification, if it's 120Hz it is post. Sometimes you may have both, but even then one will usually be prevalent. The first thing to determine when trying to correct such issues is to know which of the two it is, as otherwise you may end up chasing your tail or otherwise wasting time. You should know what it is just from the tone.

[@DavidA-uk9bm]

Hey Brad, thanks for all the great restoration videos. I was actually watching one of your old videos on a Magnavox console restoration and wondered what you use to clean the components with? I'm afraid to use something that might etch the plastic pieces or damage them somehow. Thanks!

[@yosemitesam4549]

Feeding the algorithm

[@TheGuitologist]

in my case, I'm not sure if it'll work. Susan is onto me. I'm guilty of multi-level wrongthink.

[@cognizantretard]

Would this make me dessert?

[@TheMentalblockrock]

@@TheGuitologist you are a "wrongun!"

[@BockwinkleB]

@@TheGuitologist deffinately. I get comments removed all the time, no cursing or anything. HAL has been optimized.

[@russellhltn1396]

@@TheGuitologist "Right think" is dictatorship. Thoughtful, respectful dissent is the mark of democracy.

[@wjewell63]

you should do more playing man your a great guitarist.,is that a tele I hear ?awesome bud....

[@stuartcleary8621]

I had one of those but it had granger instead of epiphone on it????

[@TheMentalblockrock]

Please? how would I fit a master volume to my 1992 Marshall JTM-45 Bluesbreaker re-issue combo?? It's part point to point and part printed circuit. thanks John.

[@CoNfUzLeDaNdLoSt]

I’ve got a ‘65 Skylark and it has a moderately loud hum, tried swapping the tubes but I think it might need more work... Hoping once COVID is over I can bring it to someone.

[@TheGuitologist]

COVID will never be over. They're going to milk that bullshit until the end of fucking time.

[@Chrispy_tV]

Why wait til covid is “over”? Don’t get it. Amp techs still need to eat during the dark ages.

[@westelaudio943]

A dying filter cap maybe.

[@CoNfUzLeDaNdLoSt]

@@westelaudio943 Thanks for the constructive reply! Where I live, nobody is doing business because the shelter in place is still in effect. I was going to bring it to Skip Simmons and have him work on it (I live about an hour away) but he’s not accepting any new amps until after COVID cools down. His words not mine...

[@BockwinkleB]

My local shop is open for business and has been the whole time. No mask required.

[@l6srob990]

amp sounds great and nice demo why do you twist the wires?

[@miketaylor8510]

I’ve had em all hard to beat a Marshall or a Fender Amp

[@BockwinkleB]

@Busta Speeker I liked my Valvestate 265, wish I hadn't sold it.

[@BockwinkleB]

@Busta Speeker It was better than my Fender Super 60, better than my Vox ACTV4, better than my Vox Pathfinder (awesome SS amp), not better than my Katana. Yeah, nah, sorry man, different strokes and whatnot...

[@leelossi1257]

you are one brilliant man!!!!

[@docamosroxie8686]

Hey Mr. Guitologist, is it more or less harmful to have tube/SS amps plugged into Furman type power conditioner and leave amps power button in the on position full time and just turn all on and off at once with Furman power button? Or does not matter either way?...thank you Sir!

[@h.p.dominocus]

It seems like everytime I watch a live stream nowadays(at least in the passed 2 weeks), I keep seeing The Guitologist making comments in the Live Chat. Every damn time pretty much!!! Not naming names. I have alot of respect for this guy from what I've seen on this channel. I don't have a following like he has so no matter what I say it makes no difference. Love the channel thats all. Biden bedtime.

[@shytweedabone2663]

You might have said already but what does twisting the wires do?

[@peteytwofinger]

a twisted pair reduces electromagnetic radiation from the pair and crosstalk between neighboring pairs and improves rejection of external electromagnetic interference but dont take it from me ...

[@MinimGuitars]

I think it's a basic way of shielding the signal cable; helps to reduce unwanted noise. Not as much as a proper shielded cable but better than none. Also it's tidier!

[@TheGuitologist]

It's supposed to aid in the cancellation of hum. It's been standard EE practice since the dawn of electronics, pretty much. There have been a lot of discussions in recent years questioning its actual efficacy, and it's thought that proper lead dress to get wires away from neighboring components where the electromagnetism can be induced is more effective than any wire twisting.

[@shytweedabone2663]

@@TheGuitologist Thanks, in the context of a video about reducing noise it seems obvious now.

[@jakedyer2674]

Have you ever worked on a fender 75? Mine is making some weird noises and it’s cocos the crap out of me when I go to turn it off. I don’t understand that part considering it has a 3 prong on it. HELP. P.s. love your videos! My buddy Alex tried sending you an old fender PA head a while back, wonder what ever happened with that. Don’t know the whole story but I guess she got destroyed in shipping by the lovely workers in the postal industry 🙄.

[@TheGuitologist]

Not sure on the PA thing. Not sure on your 75 either. If by "cocos" you mean shocks, then discontinue using it until you have a professional look it over. Something has probably come loose, a ground connection and/or other shorted connection. not safe.

[@Nizodizo]

I always use a pedal board with a DS-1 and a Boss RV6.

[@scub761]

please dont shave I LOVE THE BEARD AND ALOT OF US DO TOO!

[@vidanmitkovski7785]

Maybe rectifying the filament supply would help. Thoughts?

[@Nizodizo]

This is fun to watch but not doing that to my perfecly working amp.

[@joshuataft5541]

I realy like the retro look of those. Thanks for the vidio brad. Love your content ...and your opinions there entertaining and full of awsome useteling truth..love it lol

[@Dan.Solo.Chicago]

A guy near me is selling one of these for $150. Is that a good deal? Should I get it?

[@circuitsandcigars1278]

When I chase down hum I ask myself is it 60hz or 120hz then go from there. I had hum in a 1950's Bell and Howell 300M reel to reel recorder I resolved with new tubes

[@harryconover289]

It hums because it forgot the words very old but still works one I used was is that a mike in your pocket or are you just glad to see me ?

[@mark64tanner]

Very nice work Brad. Really appreciate your attention to detail and doing thing right. All the best 👍✌😎

[@ilovemonkays]

Just missed the premiere, ah well, good vid brad

[@TheGuitologist]

Next time!

[@TVsGringoStarr]

Where did you get that Stop Resisting sticker? That's amazing.

[@TheGuitologist]

It’s in my channel store. Link in video description.

[@TVsGringoStarr]

@@TheGuitologist Thanks! Just ordered one.

[@scotthutchens1203]

I use an 1800 watt hair dryer. Works good.

[@generalleigh7387]

What year is the amp? Love those little combos.

[@wayshot]

2005-2006, I suppose.

[@Mstrknk]

thumb's up, i dont know how to do it but you know.

[@RHR-221b]

👍 (The first one's free, M.) Oh, what the hell ... 👍

[@comajoebuck999]

Dynamo hum.

[@thedogefather]

well i couldn't say where she's comin from

[@retainium]

and I ain't got a crumb

[@RHR-221b]

To F Z. 😎

[@johnstitt2615]

Funniest video title ever. 🤣🤣🤣🤣

[@danielsaturnino5715]

Is it of any good to rectify the filament feed?

[@RozsaAmplificationLLC]

Just add balancing resistors of of the heaters to ground and call it a day!!

[@johnq5307]

Are you really an ologist?

[@j_morco]

My favorite fix for a problematic Valve Jr is the garbage can...after I steal the components, of course.

[@j_morco]

@@electrofrying1685 lol there are a few. I was being kind of facetious when I said that, to be honest. I just get sick of these Valve Jr. mods, although I am always excited to watch it all go down. I always learn something even if it’s a circuit I’ve been through many many times. I actually use the front end of these for the basis of my clean and mid/treble boosts.

[@j_morco]

@@electrofrying1685 I don’t throw components away. I always keep them. I’ve got some weird 10v vacuum tubes I want to make into a preamp, probably a pedal version, after I finish the rackmounted version. It’s a 2-channel mic/line tube preamp with 48v+ phantom power.

[@NoName-et6wk]

Holy .... Rick Beocryo is crying about copyright strike again.Announced 2 times that he testified in congress.Did he expect congress to call utube and the copywrite claiment for him?Now he's asking his subscribers to help him.You were right about him.If you don't stand up for your own rights who should?

[@TheGuitologist]

Rick gets millions of views from BS videos misinforming his audience on this subject. As long as that continues, he’ll probably keep doing it.

[@HiHello-ku1fl]

Oh BTW I was looking for Brad The Proctologist and I stumbled up the Brad The Guitologist. HaHa! My stupid humor....maybe you can work that into a comedy part of a video.Ha!

[@Chrispy_tV]

2+2=5

[@TheMentalblockrock]

GO WOKE MATHS!!!!

[@cdonovan2511]

Dude they are doing something to your videos it's hard to find them and I never see an update or new videos wtf

[@TheGuitologist]

I know. I don't even care anymore.

[@cdonovan2511]

@@TheGuitologist well everyone who reads this comment do your part, watch brads videos and set a playlist with his current videos he's a good dude and needs a hand lets do him a solid so he can keep making videos...

[@griffengallant5736]

Your videos are funny as fuck

[@lrmars]

Great video as always! I just watched your video with the Blackface Bandmaster kzbin.info/www/bejne/eIiziWCdZ5iYn6M. where did you get those test leads? Thanks.

[@rstuvwxy7020]

Stop making these Valve Jr videos. Mine got jacked and it’s making me sad

[@rstuvwxy7020]

Ironically the first video I ever watched of you involved valve jr, many years ago