|State of the Art 50s Technology|
Changing Pre Amp and Power Amp Tubes is never going to make a Fender amp sound like a Marshall or visa versa but they can make your amp sound and play more to your liking....just remember that 90% of how your amp sounds is in its design, not it's tubes.
|12AX7 - ECC83|
There are lots of big names in the tube world, Sovtek, Electro-Harmonix, JJ Electronic, Tung-Sol, but not all manufacture tubes. GT and Ruby don't make their own tubes, they buy in and re-brand tubes with their own logo. GT have recently been bought by Fender who only use GT tubes in their amps, a good way of keeping your amp sounding it's best is to use nothing but GT tubes....But talk to a lot of Fender amp owners and Tung-Sol tubes seem to be the preferred choice.
|The GT Guess Who Hall of Shame|
Tung-Sol have masses of musicality, I'd call them tight and airy. Electro Harmonix are very similar to Tung-Sol but break up sooner for better blues and rock tones. JJ's on the other hand are huge in the bass department with hard mids and clean highs, great for Marshalls and Humbuckers. I have a pair of GT 7025 that were the best tubes I had ever played but they don’t sell them any more. They still sell a 7025 but it's not the same long plate version and they don’t sound the same.
|Tube Names - Gain Factors|
From the above chart you can see the gain values of each tube and that a 12AX7 “US Name” is the same tube as a ECC83 “European Name”. I have always thought the euro names were misleading in that the ECC81 has more gain than a ECC82, so where does the ECC83 get it's name, it should be a ECC80?. I have put the 5751 in the 12AX7 line as its very closely related to a AX7, it's more closely related to a AX7 than it is to a 12AT7 or a 12AU7.
Pre Amp Tubes
JJ ECC803 - Slovakian - a very high powered 12AX7 tube, extra bite and shimmer in the high frequencies.
Tung-Sol 12AX7 - Russian - very powerful, ultra low noise. tight, punchy, articulate, a very musical tube.
Electro Harmonix - 12AX7 - Russian - easy break up, aggressive, very low noise. probably the best tube in the world and one of the cheapest.
JJ 5751 – Slovakian – low powered 12AX7, very low noise. has bite and shimmer with a good low end.
Tung-Sol 12AU7 - Russian - smooth and balanced - low noise - musical tube.
JJ ECC82 - Slovakian - the lowest output tube you can get. In the pre amp it will reduce gain and give a warm, smooth and balanced EQ out put.
Sovtek 12AX7-LPS - Russian - surprisingly smooth across the EQ response - great for gain but prone to micro-phonics in combo amps.
|Glass Tubes of Power Perfection|
Power Amp Tubes
6V6 Power Tubes have a vintage tone giving an even mix of lows, mids and highs. they have a lower power out put compared to 6L6's
6L6 Power Tubes have a very nice mix of tone. they sound tighter and warmer than 6V6's. a 5881 is basically a low power 6L6....20watt rather than 30watt. A KT66 has a smoother tone with tight lows.
EL34 Power Tubes have a harsher tone with more bass response than 6L6 or 6V6 tubes, more like a classic Marshall sound. a KT77 tight mids with more open highs than a EL34
KT88 Power Tubes similar to a smaller EL84 in the mids, but with more lows and highs for a modern Marshall sound.
Yellow Jackets tube converters allow EL84 power tubes to be used in place of 6L6, EL34, 6V6. EL84's have a lower power out put compared to EL34's but use a small 9 pin design rather than the 8 pin design of 6V6, 6L6, EL34 and KT tubes.
Changing Power Tubes....all 8 pin power tubes can be changed for any other 8 pin tube, "some tubes missing pins" but will involve re-baising of most guitar amps and should only be done by qualified technician.
My Egnater Renegade has a very modern sounding lead channel that I have lowered the gain on with the aid of a 12AU7 for a vintage Marshall, AC-DC tone. My clean channel, I have emphasized the US Fender tone with a JJ ECC803s for some extra grit in the top end.
The tubes that I have in the Renegade at the moment for home use are......
V1 - Tung-Sol 12AU7 "has a gain factor of 20%, this reducers the gain in both channels"
V2 - JJ ECC803S “for some dirt in the top end” (this is now a Tung-Sol 12AX7 - sounds better)
V3 - JJ ECC83S "12AX7" (this is now a JJ ECC82 - sounds better)
V4 - JJ ECC83S "12AX7"
V5 - JJ 5751 "low powered 12AX7, for giving the FX Loop a bit more headroom"
V6 - Tung-Sol 12AX7
"with these tubes Channel 1 is clean with a hint of break up when pushed, Channel 2 is very Vintage Rock sounding"
6V6's in the 6L6 side to reduce the volume a very small amount for a US Tone.
EL34's in the EL34 for the British Tone.
"the Renegade has 2 channel assignable Master Volumes, so I use the 2 MV to give the 6V6 tubes a boost to keep up with the EL34's"
The valves that I have in the Renegade for gig use are......
V1 - JJ ECC83S
V2 - JJ ECC803S “for some dirt in the top end”
V3 - JJ ECC83S "12AX7"
V4 - JJ ECC82 "12AU7" "to reduce the Egnater's Modern Gain Tone...."
V5 - JJ 5751 "low powered 12AX7, for giving the FX Loop a bit more headroom"
V6 - Tung-Sol 12AX7...."I also use a Tung-Sol 12AU7 to drop the power output through the floor for home use"
6L6's in the US Tone Side.
E34L's in the EL34 side for the British Tone.
"These tubes give a very tight powerful tone, Channel 2 has reduced gain to keep it sounding Rock not Metal. The 12AV7 in the PI position will help to get sustain and dynamics at a lower volume for home use."
Power Tube Distortion....the holy grail of tone....actually comes from the Phase Inverter tube breaking up. Fitting an 12AU7 tube will cut a amps rated power to about half....but a 100watt amp is not twice as loud as a 50watt amp, it's more like 100watt and 75watt and it's the same with valves. Fitting a 5751 in a 100watt amp will make it sound like a 90watt amp and fitting a ECC82 will make the 100watt amp sound more like 40watts....what the AU7 does is give you more sustain and playing dynamics at a lower volume. The AU7 will start to break up sooner than a AX7 would....your amp will still be loud....DRUM KIT LOUD.
|GT 7025 - Tung-Sol 12AX7 - JJ ECC803S|
A word of warning....
12AU7 and 12AT7 tubes have Plate Currents of about 1 milliamps where the 12AT7 and 12AU7 both have Plate currents of 10 milliamps and will draw more current. Modern high quality resistors will cope with extra heat but....not all amps are built to the same standard.
I contacted Bruce Egnater about using a AU7 in the PI position and this is what he said....
"You won't harm your amp by trying the 12AU7. The issue is that the AU7 draws more current. The Renegade uses 1 watt MF resistors in the critical locations. The 12AU7 will cause more voltage drop (more heat) on those resistors but should be just fine. The fact that the Renegade does not have a post phase inverter master and does have negative feedback in the poweramp, the audible change with the AU7 will probably be minimal and will not reduce the volume if that is your goal."
|JJ ECC81 - Ruby 12AT7|
The best way to evaluate what tubes will sound best for you is to buy a few and play and swop . Check forums to see what other users of your amp are playing through but remember that how you play will also have an effect, if you play heavy handed you will make a valve break up sooner than a softer player would. I have found that some tubes don't play nice with other tubes, bottom end can simply drop away with some combinations of tubes. 12AT7/ECC81 tubes can be cold and un-musical when compared to the lower powered 12AU7/ECC82 in the same positions.
A good tip when you buy balanced tubes for the FX Loop or Phase Inverter....mark them with a red Sharpie marker pen....because once out of the box you'll never know which ones which.
|Spot the Difference Competition|
I think my amp does sound better for changing it's tubes for my heavy handed style of playing....but it has been a pain in the ass if I'm being honest....
I get my tubes from...."UK"
Again....hope this is of use to someone and yes this is a re-working of a past post....the first one was confusing or so I thought....lol....k.j.