Tube amp question

[Jazzer2020]

I'd like to find out if pushing tubes (breakup) has any impact on the ability to get a clean sound?

 

Specifically, if someone plays clean 95% of the time (me) and then pushes the tubes for a few sessions or more (breakup)

will this have any impact at all on the nature of the clean sound?

 

Or another example. Someone plays dirty 70% of the time, clean 30%.

Will their clean be the same as my clean playing 95% of the time clean?

Assuming same amp settings etc.

 

And finally does playing 'dirty' have any effect on the tube life compared to playing clean?

TIA!

 

 

 

[Mikeo]

There a couple kinds of break up, preamp tube break up and power amp tube break up.

 

Preamp tubes, for the most part, tend to work or not work. Powermap tubes tend to get dull over time.

 

If you are using an old-school non-master volume Marshall or a Fender amp without a master volume. or something along that line)You will notice a difference if you replace your power amp tubes. These tubes were really not designed to do what we guitarist do to them to make our amps sound amazingly lovely. The more you push the power amps section of an amp, the less longevity you'll probably get out of them.

 

It wouldn't hurt to replace those tubes every few years, to see what I mean. That is if you a gigging out at least a few times a week.

 

It's like putting on a fresh set of strings on your guitar.

 

 

[daddymack]

To answer the question, no, it will not make the amp play 'dirtier' all the time after playing 'dirty'.

As Mikeo noted, you can eventually have a degrading effect on the power tubes if you push them hard for long periods of time, but in general the answer to the question asked is 'no'. No different than using a dirtbox in front of the amp [although some older ones, like the Big Muff pi from the mid 70s, may have a negative effect on the speaker voice coils if used all the time at full throttle].

[Jazzer2020]

Thanks Mikeo and daddymack for the tips!

[1001gear]

I stay off the big tubes except for the rare thrill of it. I guess stage life OTOH; you gotta have your awesomeness ready to go.

[WRGKMC]

Drive is caused by a flattening of a sine wave into a square wave. There's more involved then just the tubes which causes it. In the preamp section its typically caused by several gain stages passing signals stronger then the next gain stage can handle. In the power section, the power transformer and speaker play just as big a role as the tubes do.

 

In order to understand what drive is you first need to understand, amplifiers weren't originally designed to distort a signal. Most manufacturers tried to design amplifiers which did just the opposite, reproduce the frequency response of an instrument faithfully without any added distortion. Today we accept Bad fidelity as being Good fidelity and quest for "better" bad fidelity can become confusing to those who seek it.

 

Is it the cheap components or the circuit design responsible for the kinds of drive tones we like. Amp manufacturers were mass producing amps for a profit. The distortion they produced when pushed past their limits was caused by the technology limitations, component quality, and the failure of the designer to include high fidelity in the amp design. in short they built the amps to be loud, not necessarily sound good. Once a manufacturer dominated the market, anyone building electric guitars targeted the instrument builds to sound good through the most popular amps.

 

Guitar amps began in earnest during the 40's when guitarists needed amps to keep up with the Horn and sax players.

After the war, big bands were too expensive for most clubs so 50's pop bands started using vocals for the horn sections instead of hiring horn players.

That was what all the Du Whop was about. The singers mimicking horn parts to make the band sound bigger then it was. At the most they might have a single sax player and the buzz tone a sax created was copied by guitarists. Some time during the 50's the first amp pushed past its limits to intentionally overdrive was recorded. After that, fuzz pedals became the main device for driven sound.

 

Pushing amps into saturation really wasn't popular recording till the 60's when bands began to out rule recording engineers desires to keep the signals as clean as possible. As in many things money talks, and if an album sells better recording 100W Marshall stacks cranked to their limits, then the engineers had to jump through hoops keeping the gear running right.

 

Can amps blow up by pushing them too hard? They sure as hell can. There are several important factors involved. Type, Quality, Design, Maintenance, Wear, type of abuse, skill of the performer pushing the gear limits.

 

Example, you buy a vintage amp, plug in, crank it to 10 and start wailing on it. How long do you think it will last if you didn't give it a thorough checkout first. You'd want to know certain things, like do the tubes rattle, are the power tubes a matched par and are they biased properly, is the speaker in good condition and can it handle the wattage safely. Are the caps leaking electrolyte or are they passing high levels of hum. Does the amp design itself lend itself for being pushed hard or is it one of the many that are noted for catching on fire when pushed hard when needing maintenance.

 

Your question about pushing tubes past their limit take on a whole different meaning when you factor in the amps design and condition. Its not unique to the amateur players either. Hendrix, Winter, Buchannan were artists who often had their amps biased hot and would blow amps at live shows on a regular basis.

 

Here's an article which covers allot of what I'm talking about. https://www.analogbros.com/tech/articles/goodgobad.html

 

I will add if the amp is designed to overdrive, you're typically OK doing so. I don't want to make you fearful about pushing your amp. Many newer designs have an extra gain stage added to the lead channel and you wont damage anything cranking that lead drive to max. In other situations using classic amps designed to run clean, pushing them into saturation should be done safely. The amp needs to be in good order pushing a proper load to avoid damaging it. When you blow an amp and/or its speakers you'll learn quick enough, it doesn't pay to do stupid things unless you can afford to take the loss when it fails.

[Jazzer2020]

I will add if the amp is designed to overdrive, you're typically OK doing so. I don't want to make you fearful about pushing your amp. Many newer designs have an extra gain stage added to the lead channel and you wont damage anything cranking that lead drive to max. In other situations using classic amps designed to run clean, pushing them into saturation should be done safely. The amp needs to be in good order pushing a proper load to avoid damaging it. When you blow an amp and/or its speakers you'll learn quick enough, it doesn't pay to do stupid things unless you can afford to take the loss when it fails.

 

Thanks for the history on this. It was quite interesting.

 

In my case, yes the amp was designed to overdrive.

It's a new Fender Blues Junior LTD.

15 W with a 12" speaker.

It has a pre-amp Vol. and a Master Vol so it's easy to set it for overdrive.

Plus is has a FAT button to add additional gain.

 

But ironically my preference is to get as much clean headroom from the amp as possible.

So far in my biggest room at home with settings of:

Rev 3, Master 6.5, Mid 8, Bass 8, Treble 1.5, Vol 2.5

I'm getting very nice clean headroom.

 

I really haven't done much experimenting past that so far,

I'm usually a "set it and forget it" type of guy with music equipment.

If I get a good sound, I make note of the settings for the room.

 

Interesting thing too about this Mexican amp is that it's a hybrid (tube + solid state).

So I wonder how that might affect things down the road (good or bad)?

 

 

 

 

[daddymack]

I am unaware of a hybrid version of a Blues Junior...and I have both a USA and a MiM.

If I were looking for a clean jazz amp, the BJ would not have been on my list.

Your clean settings seem reasonable, if 'dark', but you could change your preamp tube to a 'cooler running' tube and get more headroom without pushing the Master as hard.

[Jazzer2020]

I am unaware of a hybrid version of a Blues Junior...and I have both a USA and a MiM.

If I were looking for a clean jazz amp, the BJ would not have been on my list.

Your clean settings seem reasonable, if 'dark', but you could change your preamp tube to a 'cooler running' tube and get more headroom without pushing the Master as hard.

 

Sorry maybe I used the wrong terminology?

I'm sure it's not Point-to-Point wiring, so they must be using a printed circuit board/chips right for the connections?

I call the circuit board/chips 'solid state'.

 

To round out the picture...

I have two great sounding tube 'jazz amps'. My Fender Princeton II and my Headstrong Lil' King-S.

They are both gig-ready.

 

I just wanted to buy a small tube amp for home practice so I could preserve the tubes of the other two amps.

I will still practice with them, but not as much.

 

The Blues Junior has a personality all its own. The way it's sounding now is mighty fine to me

although it can't compete with the other two of course.

 

"but you could change your preamp tube to a 'cooler running' tube and get more headroom without pushing the Master as hard."

 

I'd like to experiment later with some other pre-amp tubes to see if there would be any color/tonal changes and also to

get more headroom.

 

If you could make some recommendations I'd really appreciate it!

Maybe tell me what you have tried and what the results were?

 

TIA

 

 

 

 

[WRGKMC]

 

In my case, yes the amp was designed to overdrive.

It's a new Fender Blues Junior LTD.

15 W with a 12" speaker.

It has a pre-amp Vol. and a Master Vol so it's easy to set it for overdrive.

Plus is has a FAT button to add additional gain.

 

But ironically my preference is to get as much clean headroom from the amp as possible.

 

Interesting thing too about this Mexican amp is that it's a hybrid (tube + solid state).

So I wonder how that might affect things down the road (good or bad)?

 

I looked at the schematic. The Blues JR is NOT a hybrid. It does have an op amp for the reverb send and return. That may actually be a benefit given the fact tube driven reverbs make the amp more expensive and typically tend to be less reliable in a small combo that sees allot of speaker vibration.

 

The rest of the circuit is a typical Fender Tube amp. Your drive comes from one tube gain stage overdriving another. There are no SS amplifying devices besides the reverb loop. The power supply uses SS rectifiers instead of a rectifier tube, and again that's common in most newer tube amps since the 60's

 

If you're looking for clean headroom, you likely bought the wrong amp. 15W with a drive channel likely has between 30 to 50% clean tones max. you might get the clean tone percentage and actual clean decibel level higher using a more efficient speaker with a higher SPL and maybe using the EH tubes. I saw a big jump in headroom switching from Groove tubes to Electro Harmonix. (Fender owns Groove tubes now and uses them in all their amps) it wasn't a small jump either it was actually much larger then all the other major tube manufacturers I've tried.

 

A Higher SPL speaker can make a significant difference in how loud the amp is. Most Fender Ceramic Magnet speakers have SPL levels in the mid 90dB level. you can get something made by Eminance or Celestion with a +100dB SPL can double or triple the amps actual loudness. For ever +3dB of SPL efficiency improvement, the volume doubles.

 

Switching a speaker from one with a 95dB SPL to a 101dB SPL is the same as switching from a 15W to a 60W amp. You'll get triple the volume with a 6dB increase, all other factors being equal.

 

You'll still get the amp to overdrive at the same notches on your volume knobs but the volume is much greater so you can actually turn the volume down and have more headroom available. Different preamp tubes can help as can modifying the circuit but again, you want more clean tones, you probably want an amp with less gain stages or cooler stages designed to run clean, not overdriven.

[daddymack]

 

Sorry maybe I used the wrong terminology?

I'm sure it's not Point-to-Point wiring, so they must be using a printed circuit board/chips right for the connections?

I call the circuit board/chips 'solid state'.

 

To round out the picture...

I have two great sounding tube 'jazz amps'. My Fender Princeton II and my Headstrong Lil' King-S.

They are both gig-ready.

 

I just wanted to buy a small tube amp for home practice so I could preserve the tubes of the other two amps.

I will still practice with them, but not as much.

 

The Blues Junior has a personality all its own. The way it's sounding now is mighty fine to me

although it can't compete with the other two of course.

 

"but you could change your preamp tube to a 'cooler running' tube and get more headroom without pushing the Master as hard."

 

I'd like to experiment later with some other pre-amp tubes to see if there would be any color/tonal changes and also to

get more headroom.

 

If you could make some recommendations I'd really appreciate it!

Maybe tell me what you have tried and what the results were?

 

TIA

 

 

 

 

Hybrid, to clarify, typically refers to a combination of a tube pre-amp/solid state power amp or a solid state pre-amp/tube power amp. The use of circuit boards in commercially produced amps has been in place for decades, and although, yes, it is a part of what can be referred to as 'solid state', it is not the definitive aspect when discussing guitar amps.

 

Regarding tubes that will alter the V1 gain [V1 is the first tube in the system, and typically the one that will start the overdrive ball rolling]. The 'normal' [or ubiquitous] pre-amp tube is a 12AX7, but I have used the AY7 and AT7 at different times to tame an amps' OD level or to increase headroom. Here is a fairly good layman's level look at possible alternatives to the standard 12AX7. https://reverb.com/news/how-to-impro...amp-tube-swaps

 

I am currently running RetroValves [labeled as Jet City/333 Amps], which are '100% analog tube replacement devices' in several of my amps, particularly my 2 BJS. These have been on the market for a number of years and I bought them on a lark, thinking I could swap them out if I didn't like them..and they are still in there, and out of dozens of people who have played those amps at jams, only one has complained that he thought it sounded 'like crap' [but this is a high gain amp guy who actually rebuilt his BJ to be a 30w firebreathing monster]. The RetroValves come in 3 'levels' one of which is referred to as 'cool', and I use that in my Champion 600 because it is my 'test bench amp' and only 5 watts [i have a couple other low wattage amps that are tweaked for early breakup], so I like it to keep the clean tone. RetroValves also have a very interesting 'glow', the 'cool' one glows blue! http://www.robertsaudiotech.com/designs/retrovalve.php

 

There are other ways to increase the headroom, like more efficient speakers, but the change is less noticeable.

[Jazzer2020]

Thanks WRGKMC.

As I mentioned earlier, lots of clean headroom was not my first priority.

I just wanted a good-sounding, small tube amp for home use mostly.

Later I may experiment with some different speakers, but right now it sounds

really nice.

[Jazzer2020]

Thanks daddymack. I've made a note of your pre-amp replacement tubes and may experiment down the road.

Which speaker came with your BJ amps? Fender has changed them over the years.