Tube Amps 101 repairs, maintenance and more

[cast390]

Were those sprag bumblebees?

[pghg022]

WW II engineering lol

[wybo2]

Wow, wait, wait wait, is there a deference in the sound production of a amplifier if the rectifier is solid or tube-based?

I know very, very litle aboud music, but if thats the case then my entire worldview on what sound is, is basicly wrong.

[glprecycledsound]

@wybo2 Not sure if youre being serious or not but YES, there is a difference. Solid state rectifiers tend to have a more defined low end that holds together better and adds a little punch too! While a tube recitifier introduces "sag", sometimes softening initial attack but blossoming into sustain as the note is held. Both useful.... just a matter of choice, taste and tone!

[TheEPROM9]

I also find caps are best seconds to chips and transistors when trying to date old electrical equipment.

[Rocknrollthor]

Changed filter caps and changed all 6 valves + bias adjustment for the el34's in my video:

Sound City L-B 50 Plus (1973 mod) - maintenance and repairs.

[Rocknrollthor]

Great video. Thanks!

[glprecycledsound]

So the pedal board actually got WET? The best thing to do is run the amp straight, no board and see what happens. Moisture can be a bad thing, circuit boards don't like it, capacitors don't like it, resistors don't like it.

If you suspect or find trouble with your amp... try leaving it on for several hours, to cook some of that moisture out, assuming it isn't blowing fuses.

[12Rockstarlivin]

@glprecycledsound leave it off to dry you will fuck it up with it on my dad salvaged computer that were under water for days during hurricane katrina and thats all he did

[glprecycledsound]

@12Rockstarlivin if you read the original post.... the AMP did not get WET! Sure you can let it try to dehumidify by lettting it air dry...but you will need to cook the moisture absorbed by the pcb or wait for a good long dry winter. In any case you HAVE TO test the amp at some point........ test it with a current limiter and you can determine if it is or was part of the problem......

[AceOfHeart2012]

I played an outdoor gig last weekend and it was humid and rained off and on to the point where we had to shut things down several times. In the course of the evening I noticed my sound cutting in and out. I suspect something on my pedal board got too wet. I don't suspect the amp (Marshall 1987X Plexi) was the issue, but some rain, coupled with the high humidity got into the circuitry of one of my pedals. Am I correct in assuming it wasn't the amp as it was not exposed directly to the rain?

[BayouBluesMan]

this guy knows his trade

[jetmicbev2006]

hi..just what to ask a question about my tube amp..my problem is i accidentally plugged the footswitch to the output speaker of the amp.,still got power but the thing is a cant get any sound on both channel..not sure if it is the tubes or the output transformer is the problem or something else..thanks alot..

[panter7722]

good day. I have a problem with a marshall jcm 2000 dsl head. latch on properly, the tubes light up fine, but nothing is heard it all, I opened it and everything looks good does not look that burned inside, the fuses are good, you could help me

[glprecycledsound]

@panter7722 If it all "appears" normal you could have an INPUT problem or an OUTPUT problem. DO you get ANY sound at all (noise or ??) when you crank up the volume? If no noise or other sound, I would say it is an OUTPUT problem and you need to test your speaker, speaker cable, etc to be SURE they are good. If it is an INPUT problem, start with your guitar, then check your guitar cable. Readvise after doing all that.

[glprecycledsound]

If you like the series of previews we post here, you would LOVE our DVDs. All 3 volumes totaling over 6 hours of troubleshooting, repairs and now MODS!

You HEAR the symptoms and WATCH the repair!

This IS the way to learn tube amp repair, if you don't want to go to school for electronics.

I'd like to the results of your transformer idea when you get it done! Thanks for your post!

[MAGNETGRUNT]

This is a great video series. Someday soon I will put one together on how to make your own Pi-Unity wound audio output transformers , based on a design tutorial I got from Robert Bross of Peerless about forty years ago.

[Oceanbreezestudio]

great help, I enjoy tech talk.

[MAGNETGRUNT]

There is no way that Orange Drops and Mica Disc Caps can be an improvement - lol



[madamerotten]

@MAGNETGRUNT What is your technical basis for making that statement?

[MAGNETGRUNT]

@madamerotten - I think you may be referring to my comment about the Sprague Orange Drop Mylar Caps and ceramic disc caps. (?) I'm just trying to help but I know that nobody likes a smart ass. Orange Drops are a TV repair man's nightmare in relation to reliabiltly, though certainly better than the bumble bee and black beauties which you have to change about as often as tubes. Since 1949, my customers worldwide, such as Capitol, RCA, Warner Bros, Sheffield, London etc say Disc Caps suck - LOL

[madamerotten]

@MAGNETGRUNT I was referring to your comment about "Orange Drop" capacitors and "Mica Disc Caps." I concur with glprecycledsound that in both cases, these represent reliability improvements over the stock capacitors used in this amp. "Mica Disc," however, may be a misnomer, because the common variety of micas are not discs but more rectangular in dimension, e.g., the excellent Cornell Dubilier CD15 types. I have used many of the 715P Orange Drops in high-voltage circuits without a failure.

[MAGNETGRUNT]

@madamerotten - Oh My, what in the world did Fender use originally. I forgot. CD15's are good if that's what they are using. They're Silver Mica's which oddly operate quite differently from ceramic discs. 715P's are Polypropylene as oppose to say the 712' s which are Polyester (Mylar) Besides being lower leakage and having a lower porosity film, the end weld construction is different on the 715P's and thus opens due to mechaniclly and thermally induced lead separation was less likely.

[MAGNETGRUNT]

@madamerotten - There is a 'technical basis for my statement but it is beyond the scope of a YouTube discussion

[MAGNETGRUNT]

@madamerotten246 AM - However, while I am here I will say that ' what is acoustically correct does not always sound good and vice versa

and

Most audio products seem to be made of 10% parts and 90% BULLSHIT.

It is always good to run your own tests, using only the ears of others as the judge

[glprecycledsound]

@MAGNETGRUNT I have to say I really enjoy the exchange between you and madamerotten! This is the kind of discussion I would like to get going over at our new Discussion Page on TUBE AMPS!

tubeamps.ning.com

Check it out and Lets get something started!

[thehornypuppy]

What is the difference in the rectifiers mister?

[glprecycledsound]

@thehornypuppy I'm not sure I understand your specific question BUT, generally there are two types of rectifiers. Tube Rectifiers and "Solid State" rectifiers. Tube rectifiers will generally give you a little "sag" when worked really hard and this sag can extend your sustain or clip off the front end of your notes - depends on your attack. A solid state rectifier is a bit "punchier" and helps hold your bottom end together. They each have their place and one is not better than the other.

[thehornypuppy]

@glprecycledsound So what about the Mesa's that have multiple rectifiers? Wich i frankly find idiotic...or not so only that it kinda sickens me the "hype" about this kind of thing. Or the "tube purist" attitude. I LOVE hybrid amps. My intention is to get a Deluxe VM Fender. Like this amp it has a tube and power for the reverb...it makes amps too expensive.

[glprecycledsound]

@thehornypuppy I can't say I am necessarily a "tube purist" but it IS the tone you hear on most all classic rock records. I am more bugged about the "hand wired - point-to-point" guys. Most don't even know what point-to-point really means. AND everybody is using PC boards these days, yet some think this detracts from tone....Crazy! The difference between hand wired and circuit board only makes maintenance and repair easier.

[thehornypuppy]

@glprecycledsound So what would your opinion be on the Vintage Modified Fender has been doing? I got myself a Vibro Champ XD and i find it to be a great amp for the price. And then i wanted to get a 40 watt all tube fender but they are so expensive and i certainly don't see why. It feels more like i'm paying the fact that the amp is a fender rather than it is a good amp.

[bilbomarks]

@glprecycledsound Which one is easier?

[glprecycledsound]

@bilbomarks If you're asking which rectifier is "easier", theres really no difference from an install perspective. But I tend to lean toward the solid state. My hand wired Revenge Classic uses a bridge rectifier.... 4 wires.... done.

[bilbomarks]

@glprecycledsound So circuit board is solid state and point to point is tube?

[glprecycledsound]

@bilbomarks No. Point to point does not use "boards" whether pc, eyelet or turret boards. PtP attaches all parts directly to each other. Look inside an amp from the 50's or early 60's (excluding Fender) and most of those are PtP. PC board amps can be all tube, but not hand wired. All Solid State amps are PCB. Most amps these days use PCB to minimize cost. Hand wiring takes alot of time.

[bilbomarks]

@glprecycledsound Ah, ok. Would you say PtP vs PCB affect tone in a way.Or do they just affect time/cost?

[andy92811]

i'm guitararded, I wish I could understand. :(

[glprecycledsound]

@andy92811

Thats why we made the DVDs..... so everyone could understand.

Beginners AND GEEtards!

[randomfoo95]

do you know why reverb on an amp would stop working? i have a peavey classic 50 watt tube amp

[glprecycledsound]

@randomfoo95 Sorry if I haven't replied to you sooner. Most often a dead reverb is from a bad tube or bad cables - In the case of the cables you can have adirty or loose connection or the wires could be broken. I usually always start a repair in a tube amp by making sure all tubes are KNOWN good, then go from there.

[bigwrench01]

i wanted to watch videos on how a amp works before i went out and bought a brand name, i liked the vox ac30, but its pretty expensive. i am looking for something i can be just as happy with.

[jhino25]

which is better in electric guitar amps?fender amps or marshall amps?need some suggestions pls? A.S.A.P

[glprecycledsound]

Depends on a lot of things - Tube or Solid State? Hi watt or low watt, etc. Tone is a matter of perception, YOURS! High Gain, lots of distortion - Classic Rock - Marshall. Vintage Fenders do not lose value and are easy to work on - nice bright, scooped mid tone. If you re talking solid state... it really doesn't matter.

[jhino25]

thank you so much. . can you teach me what setting will i make for my amp?can i know if the bass always have the greater usage than the mid and treble?pls i want to know. . btw my type of genre is blues with a little rock hehe

[glprecycledsound]

Usually - when your playing at home, by yourself, you set up so YOU sound great. Plenty of low end, some Reverb, etc. In a band or gig setting, you need LESS Bass, more Mid and Treble so you can cut thru the mix. What works at home doesn't work in a band/gig setting or for recording.

[jhino25]

thank you so much!! ahhmmm can you advise me?what amp should i buy for a place where the capacity is for 500 persons only can you tell me how many watt and model should i buy?. . (hehehehe and does have the quality that every guitarist are looking) I will appreciate your response

[glprecycledsound]

More then how many people is the size of the room..... but if it will hold 500, you will probably have a high power PA system? If so, you could use most anything as you will run your amp mic'd to the board for the venue.

[jhino25]

ah ok thank you so much. .

[gorblimey61]

I never date trannies.

[glprecycledsound]

Original Trannies make up a significant portion of the REAL vintage value. Don't date the trannies and you risk getting ripped off in your vintage amp purchase.

[gorblimey61]

It was a joke!

BTW: I never date she-males either.

[glprecycledsound]

@gorblimey61 It was a good one too!!

[jigibao]

nice small amp...

[tehsalt]

I envy you for having that amp!

[qqstar999]

Note how almost everything on this amp says "Made in USA" ROCK ON!

[jigibao]

why? is "korea "worser to bild something? oor today russian are making new vacum tubes,is therefore tubes not good no more? what is with you like "america the only country in the world who bild something good???i dont onderstend people like you.....grow up kid...

[qqstar999]

jigibao, in the USA we take pride in what we make and build, In no where in the last comment I made say that Korea builds Horrible products, I own a few guitars and basses that were made in Indonesia and many other 3rd world countries. How ever the few Guitars that I have from China there quality control is horrible. My Main onstage bass is made in Japan.

[jigibao]

jess,i know quality of chine products is low,but it is demand from buyers for cheap trow away products,as far as i listen to chines tube amps there are "shitt,small,and poor quality ones" and then you have "expencive and good ones" so the choise is for buyer...i know that good 50watt end transfo who is coild in layers is best of all but it cost much too ,so it is the price of end product and who wants to pay it...regards from europ...

[blasttapes]

Very informative.