How to repair and refurbish vintage tube amps?
- Clean the amp chassis of accumulated dust, cobwebs, dead insects etc.
- Clean all pots, switches, valve sockets, RCA terminals and speaker terminals with electronic grade contact cleaner...
- Connect speakers and slowly power up through the bulb variac.
- If the high wattage bulb does not light up, or is dim, then...
Full Answer
What should I do if my amp won't turn on?
FIRST, UNPLUG THE AMP! (But that doesn't make it safe....) --Take a screwdriver or a jumper and short the capacitors leads. --OR jumper the power amp tube plate pin to GND for a minute or so (Class A, single power tube only.) --OR jumper the positive (+) lead of each large cap to GND for several seconds.
How do I replace the tubes on my amp?
If you have a non-adjustable bias amp, you can either replace your tubes like-for-like (relatively easily done if the existing set have a rating label attached to them), or talk to a reputable tube retailer who will be able to sell you a set that fall within the ideal range.
How do I know if my amp needs a rebuild?
Step 1: Symptoms: How Do I Know My Amp Needs a Rebuild? -- Hum: Usually a sign of bad filter caps. Poor routing is often a cause. Adding a three-prong cord will help. -- Weak signal: Bad tubes, failing output transformer. -- No highs/loss of tone: Bad tubes, coupling or bypass caps.
Do I need to recap my tube amp?
ALL tube amps need a recapping job at some point. Old power supply 'filter' capacitors are the primary cause of hum. And used or not, the capacitors fail over time. Electrolytic (tubular) capacitors have an optimum life of 10 years.
What causes hum in tube amps?
Why is the old can in the amp?
Can a tube amp handle current?
Do guitar amps have capacitors?
Can an amp kill you?
Do all digital amps have a special sound?
Do small caps block frequencies?
See more
About this website
How do you troubleshoot a tube amp?
0:376:19Troubleshooting Your Tube Amplifier - YouTubeYouTubeStart of suggested clipEnd of suggested clipTry turning the volume up and. Down. If it changes the volume of the noise you're hearing then theMoreTry turning the volume up and. Down. If it changes the volume of the noise you're hearing then the problem lies in the preamp tubes. If not it's a power tube.
How do I know if my tube amp is blown?
Symptoms of Bad Pre and Power TubesUnusual sounds coming from the amp..('popping' 'hissing' 'crackling' 'humming')The amps overall volume lower than usual.Individual tubes glowing brighter or dimmer than others.The amp's tone has degraded (loss of tonal dynamics)The amp will not power on.
Do tube amps need maintenance?
These heavy lifters degrade over time, usually losing some of their sparkle, at which point you'll need to replace them in matching sets. Even if just one of your tubes is causing problems, you'll have to check your amp's manual to find out which other tube it's matched with and change that one as well.
Are tube amps hard to maintain?
> Yes, tubes are generally more fragile than solid-state amps. They require more attention, so you can't be clumsy around tubes. > Tubes have a life span of about 3,000 to 5,000 hours before needing replacement, depending on usage.
How long does a tube amp last?
Power tubes like EL34's and KT88's are good for about 2500 hours or more. But may go longer in an amplifier with a conservative design. Small signal tubes with numbers like 12AX7, 12AU7, and 6922, and rectifier tubes like 5AR4 may go 10,000 hours.
How often do amp tubes need to be replaced?
You can expect a conventional amplifier tube to have a service life ranging up to 10,000 hours. Tubes with military specifications are built to last up to 100,000 hours.
Can I replace amp tubes myself?
To change preamp tubes, all you'll need is a screwdriver and a little know-how. On a lot of amps, you will need to remove the back panel; but don't worry, this will not void your warranty. Nearly all manufacturers expect you to change your own preamp tubes, but check your manual to be sure.
How long do amp valves last?
between 1,000 and 5,000 hours“In theory, a valve should have a working lifespan of anywhere between 1,000 and 5,000 hours for common types, and up to 8,000 or so for the more rugged industrial/mil-spec variants.
How do you clean a tube amp?
3:4610:25Guitar amps - How to clean and tighten tube sockets - YouTubeYouTubeStart of suggested clipEnd of suggested clipThis is a brush it's plastic handle with nylon. Bristles. Let's take a delve into the first tube.MoreThis is a brush it's plastic handle with nylon. Bristles. Let's take a delve into the first tube. Socket. When you're working on your amplifier.
Do tube amps get better with age?
YES! A tube amp always sounds better over time.
How can I prolong my tube life?
So with so much resting on your tone, here are 7 ways to prolong your tube's lifespan.Power Up Properly. ... Avoid Cold Temperatures Right After Playing. ... ''Don't Store Your Amp Anywhere You Wouldn't Want To Sleep''. ... Regularly Service Your Amp. ... Bias Your Amp. ... Match Your Impedance. ... Handle With Care.
Do tube amps sound better?
Just like our ears, musical instruments and just about everything else natural, tube amplifiers have the least distortion at the lowest levels. This is why a tube amplifier can sound great played softly, while with transistor amplifiers people are usually needing to turn it up to have it sound best.
Do tube amps break?
Tube amps do not need to be broken in. Their technology is ancient but not that quirky. However, if there's something wrong with any tube it will likely fail within the first 50 hours of usage. Keep in mind, also, that tube amps sound better after about 15 to 30 minutes, when the valves get hot.
How do you take care of an amp?
Basic Guitar Amp Care And MaintenanceExtreme Temperatures Are Costly. Like all electronic equipment, an amplifier doesn't like things too hot or too cold. ... Keep It Dry. ... Handle With Care - (Isn't that a song title?) ... Don't Turn to 11. ... Avoid Dust. ... Replace Your Tubes. ... Firmware Updates. ... In Brief.
How do you care for a tube amp Reddit?
What should i do and not do?...Never power the amp on without speakers connected. You will likely blow your power transformer.Use the standby switch (as others have described) when powering on your amp. ... Change the tubes periodically. ... Always use the recommended ratings for fuses and speaker load.
8 Guitar-Amp Mods for Newbies - Premier Guitar
Another way to increase your amp’s headroom is to adjust the size of the negativefeedback resistor. Because the earliest tube guitar amps from the 1950s weren’t intended to overdrive (though it wouldn’t be long before rock ’n’ roll pioneers harnessed the glorious sound), the negativefeedback circuit was implemented as a way to reduce distortion.
How To Tweak Bright Caps in Your Guitar Amplifier – 300Guitars.com
What does that little capacitor soldered to the volume pot in my amp do? And why are some of those little caps hooked up to a switch? Let’s get started by looking at what these little caps do, why they are there and how you can swap them with different values to help tweak your amp the way you like it.
Guitar Amp Schematics - www.thetubestore.com
Guitar Amp Schematics. Here we've listed our collection of guitar amplifier schematics. All are available for free download. If you need a guitar amp schematic for your amp repair that is not listed here, contact us and we'll try to locate it.
What causes hum in tube amps?
ALL tube amps need a recapping job at some point. Old power supply 'filter' capacitors are the primary cause of hum. And used or not, the capacitors fail over time. Electrolytic (tubular) capacitors have an optimum life of 10 years. Of course, they may last much longer. They will often operate sub-optimally for much longer.#N#But tube gear is sensitive to cap failure. Tubes circuits operate at higher voltages, and many amps are quite simple. Older caps with outmoded technology ('paper electrolytic') are almost certain to fail over time. In one sense, tubes are less susceptible to cap failure--unlike solid-state amps, many will continue to operate, although poorly.#N#Cap types#N#Most common replacement caps are:#N#Non-polarized (polypropylene, or mylar)#N#Rating: 500V minimum#N#Most builders (and rebuilders) use high quality polypropylene ('orange drop') caps. But a quality mylar cap exceeds the characteristics of the original capacitors. I wanted to retain the vintage sound, so I choose mylar. It's amateur builders, not pros, that insist a certain type of cap is a must. In any event, the difference is subtle, and the qualitative differences are a matter of personal taste.#N#Is the difference between cap types real? Probably.#N#Here's an interesting cap bench test.#N#Polarized (electrolytic)#N#Rating: depends on the amp. I used 350V caps where the originals were 150V.#N#Regular 'computer' type electrolytic capacitors work fine. Especially for the power supply filter caps.#N#They come in two packages: radial, with the leads on the same end, and axial, with the leads on inline on both ends.#N#Oh, Yeah...as the name implies, polarized caps must be installed with the correct....polarity. Inserting one backwards--fireworks!
Why is the old can in the amp?
The old 'can' was left in place for looks, and for a reference to whoever 'recaps' this amp in the future.
Can a tube amp handle current?
A tube power amp can probably handle the current, but if you're messing with a transistor power amp, beware! Even if the amp circuitry survives, there's a good chance you'll blow the output transformer if the speaker isn't close to spec... Ask Question.
Do guitar amps have capacitors?
Many guitar amps have the larger electrolytic caps in sealed "cans." Quite a few, this one included, have multi- capacitor cans--more than one capacitor together in a single package. They usually are the power source filter caps.
Can an amp kill you?
A tube amp, even an unplugged tube amp, stores enough electrical energy in it's capacitors to kill you! YES, KILL YOU. Don't touch it unless you take precautions. See the section on DISCHARGE THOSE CAPS!!!!!
Do all digital amps have a special sound?
Yes, they do have a special sound, one that digital 'modeling' can't quite get right... It's actually the limitations of tubes that impart that special tone--that natural compression and smooth breakup. Sure, they keep improving solid-state amplifiers--but a look at the majority of mid-range to high-quality amps, the current models (mostly all tube, tube/ss hybrids, etc.) should convince you that it's very difficult to capture 'that sound' without tubes.
Do small caps block frequencies?
So in each case, small caps block more lower frequencies. It's just a matter of how they are used. Here's a simple calculator and illustration of high vs. low pass.
What are the tubes on an amp?
They are often—but not always—hidden behind metal sheaths that are there primarily to reduce microphonics. Most modern amps are designed around 12AX7 preamp tubes, which have a very high gain factor, and generally the brands that tend to be fitted at the factory (common ones include JJ, Ruby, Sovtek and Shuguang) are robust and will perform well.
How reliable are preamp tubes?
Preamp tubes—in terms of reliability—can be thought of a bit like lightbulbs. Most will work well for several years, but occasionally one will fail prematurely for no apparent reason. Tubes can be very consistent but arguably are not made as well as they were in their heyday around 50 years ago—and even with the best production techniques in the world, they are simply being asked to do a lot of work. A 12AX7, which sits in one of the early stages of a high gain circuit, will tend to fail quicker. The more gain you supply it (from higher-output pickups or an aggressive attack) or ask of it (by turning up the gain control), the quicker it will generally wear out. As always, though, there are no hard and fast rules. I've owned 15-year-old Peavey 5150 amps that were still running the original tubes; I changed the entire tube complement out of habit, and it yielded no improvement in sound.
How are power tubes biased?
Power tubes are generally biased as a matched set of four (like in most 100W amps), or as a matched pair (like in a 50W amp). Some class AB amps like the Marshall DSL are biased separately on each of their two distinct push and pull "sides," allowing for two matched pairs to be fitted in place of a matched quad—or in a 50W amp, two unmatched tubes to be fitted in place of a matched pair. This, however, is probably your amp tech's territory, so if in doubt you should just carry a matched set of whatever tube complement your amp carries.
What type of tube is used on a Soldano?
They are generally of either EL34 type (taller, "British" style tubes), 6L6 type (fatter, "American" style tubes) or occasionally manufacturers like Soldano will use 5881 (a robust military-grade 6L6 equivalent).
Why is my guitar amp humping?
A systematic check of all your peripheral components—even your guitar—can pinpoint many problems immediately. Hum issues can be caused by pedal power supplies, a bad supply in the venue, or even running signal cables too close to power cables.
What happens if power tubes fail?
If everything else in your chain is good but your amp just seems to lack sparkle or authority, it's a great idea to try a new set of power tubes—you may find the old set were still performing well enough to be kept as an emergency "spare spare" set! It's worth mentioning again at this point that if your amp starts smoking or producing a burning smell, it's likely that the damage is more extensive. Failed power tubes can sometimes take out their protection circuit, occasionally overheat part of the board, or in extreme cases even blow an output transformer. Switch the amp off immediately, grab a backup (you packed one, right?) and call a tech!
Why does my guitar have hum?
Hum issues can be caused by pedal power supplies, a bad supply in the venue, or even running signal cables too close to power cables.
Who wrote the book "Valve Amplifiers"?
Read "Valve Amplifiers" by Morgan Jones. You'll learn how tubes & tube amps actually function. This is a prerequisite, IMO.
How long does it take to get an associates degree in electronics?
It took 2 years for me to get an Associates degree in electronics and there's good reason why it takes that long. IMO, there's no short cut to learning electronics...you need simultaneous theory, math, & lab to learn it the right way.
What is the old American Radio Relay League?
Old American Radio Relay League (ARRL) annuals (circa pre-transistor days - early 1960s and before) are a good source for understanding the basic electronics involved in tube amplification. They were written specifically for the amateur and cover all the basics. Shop around, one can usually be had for a few bucks. M.
Can you find faults by tapping with a chopstick?
I agree with both of these posts, but would add that it's necessary to also learn logical fault finding techniques for those times when swapping tubes, tapping components with a chopstick and looking for dry joints doesn't find the fault.
What causes hum in tube amps?
ALL tube amps need a recapping job at some point. Old power supply 'filter' capacitors are the primary cause of hum. And used or not, the capacitors fail over time. Electrolytic (tubular) capacitors have an optimum life of 10 years. Of course, they may last much longer. They will often operate sub-optimally for much longer.#N#But tube gear is sensitive to cap failure. Tubes circuits operate at higher voltages, and many amps are quite simple. Older caps with outmoded technology ('paper electrolytic') are almost certain to fail over time. In one sense, tubes are less susceptible to cap failure--unlike solid-state amps, many will continue to operate, although poorly.#N#Cap types#N#Most common replacement caps are:#N#Non-polarized (polypropylene, or mylar)#N#Rating: 500V minimum#N#Most builders (and rebuilders) use high quality polypropylene ('orange drop') caps. But a quality mylar cap exceeds the characteristics of the original capacitors. I wanted to retain the vintage sound, so I choose mylar. It's amateur builders, not pros, that insist a certain type of cap is a must. In any event, the difference is subtle, and the qualitative differences are a matter of personal taste.#N#Is the difference between cap types real? Probably.#N#Here's an interesting cap bench test.#N#Polarized (electrolytic)#N#Rating: depends on the amp. I used 350V caps where the originals were 150V.#N#Regular 'computer' type electrolytic capacitors work fine. Especially for the power supply filter caps.#N#They come in two packages: radial, with the leads on the same end, and axial, with the leads on inline on both ends.#N#Oh, Yeah...as the name implies, polarized caps must be installed with the correct....polarity. Inserting one backwards--fireworks!
Why is the old can in the amp?
The old 'can' was left in place for looks, and for a reference to whoever 'recaps' this amp in the future.
Can a tube amp handle current?
A tube power amp can probably handle the current, but if you're messing with a transistor power amp, beware! Even if the amp circuitry survives, there's a good chance you'll blow the output transformer if the speaker isn't close to spec... Ask Question.
Do guitar amps have capacitors?
Many guitar amps have the larger electrolytic caps in sealed "cans." Quite a few, this one included, have multi- capacitor cans--more than one capacitor together in a single package. They usually are the power source filter caps.
Can an amp kill you?
A tube amp, even an unplugged tube amp, stores enough electrical energy in it's capacitors to kill you! YES, KILL YOU. Don't touch it unless you take precautions. See the section on DISCHARGE THOSE CAPS!!!!!
Do all digital amps have a special sound?
Yes, they do have a special sound, one that digital 'modeling' can't quite get right... It's actually the limitations of tubes that impart that special tone--that natural compression and smooth breakup. Sure, they keep improving solid-state amplifiers--but a look at the majority of mid-range to high-quality amps, the current models (mostly all tube, tube/ss hybrids, etc.) should convince you that it's very difficult to capture 'that sound' without tubes.
Do small caps block frequencies?
So in each case, small caps block more lower frequencies. It's just a matter of how they are used. Here's a simple calculator and illustration of high vs. low pass.