My RM20 is starting to sound a little dull and lifeless. It is over a year old, and still has the factory tubes in it. How long do you guys go before you change the power tubes? Any recommendations for el84 brands - sovtec, jj, groove tubes.
Power tubes
- Thread starter SDWR
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JKD said:
No offense, but I couldn't disagree more. I think they're complete crap.
The JJ's are very bland and boring sounding. There was a HUGE difference in tone when I switched to ARS 12ax7's - more top and bottom end clarity and far less mids. The JJ's tend to muddy up the mids and lo-mids, big time.
As for the power tubes, if you can find a pair of old Sovtek EL84wxt+'s, you'll be thrilled. If not, the Mullard EL84's are the best I've found.
Yeah,
JJs, like the chinese tubes; it's a love/hate deal. One man's (make that 2 men's now!)mud is another man's gold. If you use the amp pretty regular, a year is normal for "modern" power tubes.
It's my understanding the JJs are the best made, but I too prefer the sound of New Sensor tubes (EHX, Sovtek, Svetlana, Genalex, Mullard reissues).
If you use the amp a lot, it might be worth it to try NOS tubes? They will be pricy, but in IMO the MTS amps respond well to NOS tubes tonally, and the quality will be there for certain. I am finding pairs of US made NOS ones for under $100.
Old man sage advice; I have had decent luck with "Sovtek" tubes, and they have gone into a lot of amps from britain, but making a choice to "save a few bucks" never turned out very well for me (lightly used choice gear and Korean made guitars excepted).
Good luck!
JJs, like the chinese tubes; it's a love/hate deal. One man's (make that 2 men's now!)mud is another man's gold. If you use the amp pretty regular, a year is normal for "modern" power tubes.
It's my understanding the JJs are the best made, but I too prefer the sound of New Sensor tubes (EHX, Sovtek, Svetlana, Genalex, Mullard reissues).
If you use the amp a lot, it might be worth it to try NOS tubes? They will be pricy, but in IMO the MTS amps respond well to NOS tubes tonally, and the quality will be there for certain. I am finding pairs of US made NOS ones for under $100.
Old man sage advice; I have had decent luck with "Sovtek" tubes, and they have gone into a lot of amps from britain, but making a choice to "save a few bucks" never turned out very well for me (lightly used choice gear and Korean made guitars excepted).
Good luck!
Something the OP may be interested in trying are new transformers and a choke from Mercury Magnetics. Both will greatly increase the tone and performance of the RM20, which has a much smaller transformer (hence, far less headroom) than a 100 watt head.
If you decide to go that route, call them and ask for the output transformer based on the "Radio Spares" transformer.
Good luck in your tone search!
If you decide to go that route, call them and ask for the output transformer based on the "Radio Spares" transformer.
Good luck in your tone search!
jdj8282
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i love the jj kt88/e34l qad in my rm100
imagimotion
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The EL84 JJs are pretty nice overall, but there is a ton of variance within the product line. I had a rebel 20 that used Groove Tubes rebranded JJs with a level of 7 printed on them that were the best EL84 I ever played. The 7 means it is a high gain version of the tube. I compared these tubes to a pair of JJs that I have in my 18 watt marshall clone, and I preferred the Groove Tubes ones from my Rebel 20. They were a bit hotter sounding and really sang when the gain was cranked. There was just a little more saturation that the other tubes didn't have at the same amp settings.
I've also used Ruby Tubes, Sovtek and Electro Harmonix. I'd say the EH tubes are more "aggressive" sounding compared to the JJs, and the Sovteks are just a nice all around tube. Very rounded and not harsh sounding at all.
If you're into heavier stuff, you probably want a pair of tubes that have a higher gain characteristic. Doug's Tubes has ratings for some of their tube brands that will let you choose a higher or lower gain version of the same tube. That makes a big difference in the tone.
Also, make sure your tubes are matched pairs. If your amp is running push-pull in Class AB, then you absolutely want these to be as closely matched as possible. If they're not, it can really muck with your tone since one half of the waveform would not be amplified at the same level as the other half, which will generate second and third order harmonics differently as a result. I think this leads to what many players describe as "smearing" in the tone when driven into saturation.
Finally, how you bias the power tubes has a huge effect on the tone as well. Generally amp manufacturer keep their bias points well below the 80% of max generally recommended for amp design. If you bias cold by dropping the bias point in the plate voltage curve where it is say 60-70% of max plate current, it will have a vastly different sound than if you bias it at 70-80% of max plate current. Of course, you could bias hot so that they are 80+% of max plate current, which is something a lot of pro players do to get that "hot" sound, but the downside to this approach is your tubes won't last as long.
As for the transformers suggestion, that, too, has a huge impact on tone. Swapping the output transformer for a bigger piece of iron that has higher wattage handling will add more headroom to the power stage, and could be just the thing that's needed depending on your playing style. In my 18 watt clone changing the output transformer from the stock Magnetic Components one that has a max handling capability of around 25-30 watts to a Weber transformer that is rated between 35-40 made a huge difference. It totally eliminated the high end fizziness I was experiencing when the amp was driven hard into saturation.
I've also used Ruby Tubes, Sovtek and Electro Harmonix. I'd say the EH tubes are more "aggressive" sounding compared to the JJs, and the Sovteks are just a nice all around tube. Very rounded and not harsh sounding at all.
If you're into heavier stuff, you probably want a pair of tubes that have a higher gain characteristic. Doug's Tubes has ratings for some of their tube brands that will let you choose a higher or lower gain version of the same tube. That makes a big difference in the tone.
Also, make sure your tubes are matched pairs. If your amp is running push-pull in Class AB, then you absolutely want these to be as closely matched as possible. If they're not, it can really muck with your tone since one half of the waveform would not be amplified at the same level as the other half, which will generate second and third order harmonics differently as a result. I think this leads to what many players describe as "smearing" in the tone when driven into saturation.
Finally, how you bias the power tubes has a huge effect on the tone as well. Generally amp manufacturer keep their bias points well below the 80% of max generally recommended for amp design. If you bias cold by dropping the bias point in the plate voltage curve where it is say 60-70% of max plate current, it will have a vastly different sound than if you bias it at 70-80% of max plate current. Of course, you could bias hot so that they are 80+% of max plate current, which is something a lot of pro players do to get that "hot" sound, but the downside to this approach is your tubes won't last as long.
As for the transformers suggestion, that, too, has a huge impact on tone. Swapping the output transformer for a bigger piece of iron that has higher wattage handling will add more headroom to the power stage, and could be just the thing that's needed depending on your playing style. In my 18 watt clone changing the output transformer from the stock Magnetic Components one that has a max handling capability of around 25-30 watts to a Weber transformer that is rated between 35-40 made a huge difference. It totally eliminated the high end fizziness I was experiencing when the amp was driven hard into saturation.
