Is it a bad tube?

[Flod]

Or is it just the way it should be?

 

I have a EBS Fafner amp. There is a tube in the signal chain, and when I overdrive the tube, I get this really farty sounding distortion.

 

The tube sounds absolutley amazing as long as I don't overdrive it, and this seem a bit odd to me. Shouldn't a bad tube be bad all the time?

[fretless]

Originally posted by Flod Or is it just the way it should be? I have a EBS Fafner amp. There is a tube in the signal chain, and when I overdrive the tube, I get this really farty sounding distortion. The tube sounds absolutley amazing as long as I don't overdrive it, and this seem a bit odd to me. Shouldn't a bad tube be bad all the time?

 

 

could be , I would pop another one in to check sometimes a preamp tube can sound harsh or crappy but farty , maybe .

[phatster]

what preamp tube ya useing? You may need to decrease the gain by useing cooler{lower gain} tube!

[Flod]

It isn't really a pre-amp tube. It sits between the pre-amp and the power amp. As I understand it is:

 

EQ->gain(ss)->gain(valve)->power-amp

 

edit: Have no idea what tube it is.

[Jamacuco]

It's a 12AX7 if I am not mistaken. Try changing it for a GrooveTubes ECC83S and you'll notice a pleasant difference. The GT ECC83S is the preamp valve on the Anniversary Ed. Fafners.

 

**Edited to add the final S on the ECC83 model**

[fretless]

you would need to test them on a tube tester , most electronic supply stores have them you can test for free , but a test won't tell you if it sounds good to you or not , so if you don't like it change it or them . I recommend getting a few different brand tubes till you find that "color" you are looking for , some are 5 bucks some are 150 . Look in the manual to see what all the different tubes are .

[Flod]

Thanks man! I should have asked you, my fafner-buddy

 

These tubes are intechangeable?

Changing tubes, is it more difficult than changing a light-bulb?

[Jamacuco]

Originally posted by Flod Thanks man! I should have asked you, my fafner-buddy These tubes are intechangeable? Changing tubes, is it more difficult than changing a light-bulb?

 

I haven't done it myself as it already came installed on mine's. But some Fafner owners from Spain have and they haven't had a single problem. AFAIK it's a simple operation (umplug old valve - plug in new one).

 

Now if we were speaking of power and rectifier valves that would be another story.

[Flod]

Allright... so "pre-amp" tubes are easy to change? no need to do aditional seting up?

 

How do I know what tubes fit?

 

These are the ones I have available:

 

GMF

[Flod]

Jamacuco: You don't mean ECC803S (added a zero), cant find any other?

 

Are all 12A-tubes compadible?

[Jamacuco]

 

Originally posted by Flod Allright... so "pre-amp" tubes are easy to change? no need to do aditional seting up? How do I know what tubes fit? These are the ones I have available: GMF

 

 

Basically any 12AX7 tube will fit if I am not mistaken but the gain and harmonic response vary depending on the model.

 

I posted about the GT ECC83S because that's the one being recommended by the Spanish EBS dealers but I will leave other option to the tube gurus which I am not one of them.

[der oxenrig]

The Groove Tubes ECC803S is EXACTLY the same as the JJ ECC803S. Go with the JJ and save a few bucks.

 

 

Also, remember that preamp distortion is still preamp distortion, and can get farty. Really good distortion comes from overdriving power tubes, which the Fafner doesn't have.

[Markee]

All 12A's are nine pin. The tube you discribed is the phase inverter tube and does the most work of all your pre-amp tubes. It causes the speaker to be pushed and pulled. The tube in question should be changed whenever you change the power tubes. The other pre-amp tubes can last way longer as they only idle along at about 4-7 volts. You can check the tubes in your amp safely if you pull your chassis out, keep a load on the amp by keeping your speaker plugged in and volume up about a quarter, and tapping the tubes individually with a chop stick. Sick tubes will make an audibly scratchy sound or may cut out all together.

 

 

You can also visually inspect the tubes by looking at them in a darkened room. The heater plates and or glow of the tubes should be consistant. Usually, when a tube is at the end of it's life it gets either noticably brighter or duller than the rest.

[the_big_geez]

I'm curious to know if you have the manual for the amp. If not, you can get it in PDF from the EBS website.

 

The manual has a number of charts for various sounds you may want. NONE of these charts seems to show any of the controls 'maxed out'.

 

Pretty much ANY peice of audio equipment can be turned up to a point at which it no longer sounds good. (Car stereos are a prime example). It's the nature of the beast. So what I'm saying is the problem can be solved by merely turning the thing down.

 

It's kind of like the old joke about the guy going to the doctor and saying, 'Doctor it hurts when I do this _____ .' To which the Doc replies, 'So, don't DO that!!!'

 

You are correct that a tube is pretty much either good or bad. But since the tube itself IS an amplifier, and all it can do is make MORE of what is put into it... If the signal the tube is getting is 'bad', what you get at the output is LOUDER bad. Similarlly, if the tube is getting MORE signal than it can handle, it can't help but distort. This is solved as I said above, by simply turning down.

 

Hope this helps.

[Flod]

Originally posted by The Ox The Groove Tubes ECC803S is EXACTLY the same as the JJ ECC803S. Go with the JJ and save a few bucks. Thanks for the tip! Also, remember that preamp distortion is still preamp distortion, and can get farty. Really good distortion comes from overdriving power tubes, which the Fafner doesn't have. Well d'oh! I did not know that

[the_big_geez]

 

Originally posted by Markee All 12A's are nine pin. The tube you discribed is the phase inverter tube and does the most work of all your pre-amp tubes. It causes the speaker to be pushed and pulled. The tube in question should be changed whenever you change the power tubes. The other pre-amp tubes can last way longer as they only idle along at about 4-7 volts. You can check the tubes in your amp safely if you pull your chassis out, keep a load on the amp by keeping your speaker plugged in and volume up about a quarter, and tapping the tubes individually with a chop stick. Sick tubes will make an audibly scratchy sound or may cut out all together. You can also visually inspect the tubes by looking at them in a darkened room. The heater plates and or glow of the tubes should be consistant. Usually, when a tube is at the end of it's life it gets either noticably brighter or duller than the rest.

 

 

I only want to correct you on the application of the 12AX7 in the Fafner:

 

It is a hybrid amp, and that is the only tube it has. Hence it is not a driver.

[phatster]

You should be aware of a site...plexipalace.com.there is a tube section that is visited many tube experts.they offer good advice and steer you in the right direction.I buy all my tubes from a guy in California...tubetramp.com...he is very helpful but only deals with vintage tubes,new stuff should generally be seen as inferior in amp applicationsIMHO.

[bassplayinguy]

http://www.thetubestore.com/gainfactor.html

 

this site will help if you are looking to put cooler tubes in your amp, and it will also tell you what tube are interchangeable with 12AX7/ECC83 tubes

[Flod]

Thanks for all the replies!

 

Big geez: I have a manual here somewhere, although I can't find it at the moment.

 

I thought the purpouse of the tube was to add warmth (which it does), but also to get som nice distortion/overdrive. If it's only there for warmth, then everythings working perfectly. I just can't get a nice overdriven sound.

 

Markee: Although the Fafner is a hybrid, as mentioned, I found the bit about dim tubes interesting. The tube is way darker than I'm used to seing tubes.

 

I'm guessing this tube (whatever it's function's called) shouldn't glow as much as power amp tubes, correct?

 

Again, thanks for the input!

[phatster]

That is a big 10/4 buddy...preamp tubes last indefinitely because little voltage runs through.

[Rippin' Robin]

 

Originally posted by phatster That is a big 10/4 buddy...preamp tubes last indefinitely because little voltage runs through.

 

Breaker, breaker, that's a solid 400 volts, buddy, unless it's a starved-plate design.

[der oxenrig]

 

Originally posted by Flod Thanks for all the replies! Big geez: I have a manual here somewhere, although I can't find it at the moment. I thought the purpouse of the tube was to add warmth (which it does), but also to get som nice distortion/overdrive. If it's only there for warmth, then everythings working perfectly. I just can't get a nice overdriven sound. Markee: Although the Fafner is a hybrid, as mentioned, I found the bit about dim tubes interesting. The tube is way darker than I'm used to seing tubes. I'm guessing this tube (whatever it's function's called) shouldn't glow as much as power amp tubes, correct? Again, thanks for the input!

 

 

If you want good power tube overdrive, but still have a solid state power section, the only thing I can think of would be a Warwick Pro Tube head, which uses an EL84 for overdrive, but still uses a solid state poweramp. The only other option I can think of is an SWR Interstellar Overdrive preamp, which uses a pair of EL-84s, which can also be used as a 4 watt tube practice amp.

[Rippin' Robin]

 

Originally posted by The Ox SWR Interstellar Overdrive preamp, which uses a pair of EL-84s, which can also be used as a 4 watt tube practice amp.

 

 

Make that into a box with a speaker and a microphone and you have one schweeeet recording utensil.

[der oxenrig]

 

Originally posted by Rippin' Robin Make that into a box with a speaker and a microphone and you have one schweeeet recording utensil.

 

 

Yup, I also hear it works great for guitar as well.

[the_big_geez]

 

Originally posted by Flod Thanks for all the replies! Big geez: I have a manual here somewhere, although I can't find it at the moment. I thought the purpouse of the tube was to add warmth (which it does), but also to get som nice distortion/overdrive. If it's only there for warmth, then everythings working perfectly. I just can't get a nice overdriven sound. Markee: Although the Fafner is a hybrid, as mentioned, I found the bit about dim tubes interesting. The tube is way darker than I'm used to seing tubes. I'm guessing this tube (whatever it's function's called) shouldn't glow as much as power amp tubes, correct? Again, thanks for the input!

 

 

All tubes are not created equal.

 

The 12AX7 is the highest gain tube in the family of compatible tubes. A side effect to this much gain is that they can (and often DO) sound harsh. There is a certain brittle quality that the tone takes on at some point, and many find this to be undesirable.

 

Solving this can be one of two things:

 

Either one must use the controls of the amp to fine-tune the sound to their ear, or the circuit itself needs to be 'tweaked'. It is far easier to twiddle the knobs though! In fact, that is what the knobs are FOR: They allow you to 'redesign' the circuitry through adjustment.

 

If the distortion in this amp is more than you want, but you still want it to crank up, I'd reccommend the 5751. It is a direct replacement for the 12AX7/ECC83, and it was Stevie Ray Vaughn's favorite. It produces less overall gain than a 12AX7 and has a smooth compression when pushed hard.

 

Dan Torres usually has these in stock (http://www.torresengineering.com) at a decent price.

 

At $10-$15 bucks each, you could afford a fair amount of experimentation to find what you like best in this amp, no matter WHO you get them from.

 

But, as before, you can solve the problem just by using the amp's controls...