EHX 6CA7, very interesting

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bandit2013

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I had thought the Mesa STR440 6L6 tubes were great when I first installed them into the TC-100. I did explore all of the channels and voices (normal/drive or the normal/tight). Not bad at all. However I did return to the EL34 to compare and then I went back to the 6L6 and my impression sort of changed. Purpose for this short back story was to provide some feedback on the 6L6 and how they compared to the EH 6CA7 tubes. I had the 6CA7 tubes for a while but first ran them in the RA100 combo just to get an idea how they would respond in that amp. I have had better tubes in the RA so I figured I would hold onto them for the TC series for a rainy day. Yeah, it has been raining here on the east coast in NC for several days now. So before I went back to the EL34 tubes from running the 6L6 tubes a second time I wanted to find out how the EH 6CA7 would perform in the TC-100. Considering how impressive the EL34s sound on the clean channel why not have an EL34 biased variant that is close to a 6L6. Just a note: the 6L6 was nice in its composure of tones but I was not convinced that the clean channel improved at all. The drive voice was similar to the tweed setting on the Roadster or the Mark V, probably closer to the Roadster character as it lacked the ice pick tone of the Mark V on tweed. What is it with that amp anyway? I think it has a vendetta on wanting to drill a hole in my head. Cured the ice on CH3 but not CH1 in tweed but that is ok, I do not use that mode on the Mark V and just for that reason. Anyways, when I installed the EH 6CA7 tubes into the TC-100 and set the bias switch to EL34 I was rewarded with something quite interesting. Clean channel had more of a Fender characteristic than the 6L6 tubes could provide. Bold and piano like bottom end and plenty of crystal chime on the top end. I did not hear the same undertones that I was getting with the EL34 or the 6L6 tubes. What is an undertone? it is a subdued or muted tone that resonates with both the EL34 and the 6L6 tubes. Perhaps it is the resonant frequency of both tubes as the Mesa STR440 does have a unique tone for a 6L6 tube that is similar to the EL34 in some respects. The 6CA7 was a bit different as I did not notice the same chewy midrange peeking out to degrade any note definition under compression or high gain settings. I would say that both the TC-100 and the TC-50 have a dry characteristic, tight character or something that would relate the two words to denote the sound effect of muted strings being drum like with no bottom end drone. This is one character the JP-2C has over the Mark V as the Mark V seems to drone out or get mush from palm muting but not to the degree as the Roadster on CH4 in modern voice. CH2 on the TC with the influence of the 6CA7 retained some of that crystalline chime I was getting on the clean channel and the bottom end was similar but with more gain and attack. CH3 was just as awesome as you would get with any tube but with a hint of brown sound from the late 70's. Too bad I swapped out the SD'78 model humbucker out of my guitar in lieu of the Pearly Gates I had in there before. I may have gotten stuck on the EVH mode.... Unfortunately I did not explore the potential of the 6CA7 for very long. I was impressed but this time I did not become esthetic over the response I got with the 6L6 tubes on the first try (I was expecting a similar character with the 6L6 tube in the TC-100 as I got in the TC-50 and that did not happen, instead I did not notice any volume drop at all.) I can say this though, the 6CA7 was more interesting than what I got with the KT77 pair in the TC-50. May have to try a pair of the 6CA7 in that amp and see what happens. Note that Mesa does have a tube they classify as a 6CA7 in their on line store, sorry that is not a 6CA7 but an EL34 =C= tube and it will sound just like the EL34 with some differences as it lacks the beam forming plates that the 6CA7, KT77 or 6L6 tubes have in common.
 
The EH 6CA7s are some of my favorite tubes, but they really are amp-specific. My Carvin Legacy 1 sounds like it was made for those tubes, but not so much in my Electra Dyne. When I first got my Mark V, I put a quad of 6CA7s in that amp just for a quick test and was really blown away by the change in tone in that amp. I haven't played with different brands in my TC50 yet as I don't want to void the warranty. But, when I ordered my last batch of 6CA7s, I deliberately purchased a matched sextet. That way, I will always have a spare tube in case one or two happen to fail. Now that I am starting to use my V, I may just have to put either a quad of the EHs in it, or mix up a pair of those with a pair of the =C= I just got from Mesa.

One mistake I made with the Carvin was running it on half power for an extended period of time. In that amp, half power is just turning off 2 tubes. After about a year of running on half power, I flipped the switch on the back to go to full power, and 2 tubes smoked almost immediately. I didn't expect that, but I learned a valuable lesson: either never switch back to full power and just rotate the tubes, or never use half power. But, since I don't use that amp anymore, I don't have to worry about it.
 
I think that is the reason why I run the Mark V at 90W. I had issues in the past at 45W burning up the center pair. Since then I cringe when I use the 45W mode but no fear to worry as I had adjusted the bias point with a resistor change. So far I have yet to kill any tubes in it. That is a good thing too as tubes are expensive (that being obvious). I only ran the 6CA7 for about 20 minutes as I was changing tubes from 6L6 to EL34. I will not use JJ power tubes as I had issues with those I do not want to repeat. One of these days I should get a tube tester.
 
Hey bandit if you could only pick one, TC-100 or JP-2c? Only asking because I can’t decide myself which one to get. I literally live thousands of miles away from the closest store to try them out.
 
barryswanson said:
Hey bandit if you could only pick one, TC-100 or JP-2c? Only asking because I can’t decide myself which one to get. I literally live thousands of miles away from the closest store to try them out.

That is a very tough decision. It really boils down to your desires or mainstream use of the amp. My choice would be both, but if I had to only keep one, I would keep the JP-2C. (it is more of an amp than it appears despite the versatility of the other amps). I find it more suitable for the style of music I play on my own which is a modern form of expressionism that can get on the heavy side but yet slide into a more classic tone all without having to change channels. I never really used my volume control on the guitar all that much but with the JP-2C that is where the magic of its dynamic character is. I only wish the amp had an FX button on the Footswitch controller.

If you need that dark tone and sinister attack of the Roadster but yet want to hammer out some pinch off harmonics as well as get into nose bleed rhythm riffs and beyond...not to mention a nice warm clean channel that works well with any guitar. I have several guitars in my collection ranging from set necks with humbuckers, neck though with humbuckers and active tone controls, to bolt on necks in SSS, HSS, and the single coil HHH arrangement, JP-2C all the way. This amp delivers the goods in spades. The gain range of both CH2 and CH3 are usable. Full dynamic character and control of the amp using just the guitar volume cleans up nicely for more of a vintage crunch to even clean and down wright wicked when you max the volume control. I normally play classic rock and dive into a more modern heavy tone and the JP-2C just works for me. I wish I can afford a second one as I would love to daisy chain the two with the midi. However, the TC-100 serves up the goods in a different format. It does not really need any GEQ but you can add that in the loop if you so desire. The TC has a different tone to it even with 6L6 tubes and just does not get to that magic the JP-2C can dish out. However, the TC does have three formats of gain and distortion since the clean channel has a drive mode and that just rings out some plexi tone especially when using EL34. It does have a modern twist on CH3 which is similar to the Rectifier amp. I would assume that the preamp is tuned in a similar format but does not have the cold cathode circuit like the Rectifier amps have. Classic rock all the way with this amp from early heavy metal and then some. The TC seems to work well with the P90 pickup if you can figure out how to dial it in. Sounds just as good with most other pickup formats too. The only channel that seems to have similar dynamics as the JP-2C would be the clean channel on drive mode with the gain near max. That I can clean up with volume control. Awesome for blues too. CH2 is close to the RA vintage lo or the blue channel of the Electra dyne. I a bit thin but yet had plenty of low end if you push the bass a bit. The bottom line, if you need more classic rock and some heavy metal with a different tone than a Mark Series amp the TC-100 would be for you. You can use either amp for most music styles. They are both worthwhile investments. If you have a Mark V and are going to keep it, I would probably venture onto the TC side and then pick up the JP-2C later on. I would also look at more video's and dig into what other's have posted on youtube to get a better feel for the amps in a non-professional studio. When I heard the JP on the "sessions" video, I had to have that amp. Other video's were not convincing enough. So far the JP-2C works so well with Stratocasters I am hooked. Then again the TC-100 is good too. JP-2C compared to the Mark V, Similar but not. Mark V has a thinner voice and a bit loose or sloppy in the bass region, at least mine was before I did a few mods. Then there is the versatility of either amp. JP can only use 6L6 tubes. TC can operate with 6V6, 6L6 and EL34 (including variants). First try of the 6L6 tubes and though this was as good as the JP, not quite. The 6CA7 was quite interesting as that had more Fender charm to the clean channel, and it retained the bell like chime on CH2. Quite an interesting characteristic. Nothing sounds as good as the blend of the TC and the JP, that in itself is quite a unique experience. The only problem is that the footswitch midi commands are not compatible with each other so you cannot daisy chain them and expect to use one footswitch. Sure you can use midi to control both if you have that gear. Just note that the CH2 on the TC will be out of phase to the JP. You ask a person who has both? I could not decide either. I did get the JP before I got the TC-50. Now the TC-100. They all have their use depending on style of music.
 
Barry,
If you like your Mark V and it does everything for you, keep it, get the TC-100 for that British flavor the V struggles to deliver. CH2 crunch is similar, probably closer to the lo gain channel 2 of the TC. That circuit is tuned for a bit more depth than the TC since it is derived from the Mark I voice. What makes it similar is the TC places two gain stages in front of the tone stack which is all. Definitely a different tone though. CH3 or vintage HI gain or what ever Mesa is calling it now is similar to the CH3 of the V but with many exceptions. CH3 of the TC is based on the CH2 circuit but adds another gain stage before the tone stack and makes adjustments to the gain stages just like the MK V does. CH3 is the ticket to getting more authentic AC/DC or Led Zeppelin tone. Sure you can do this with the Mark V but the TC-100 gets you much closer to the tone. However, I much prefer Led Zeppelin though the JP-2C as I can use the dynamic gain structure to get the sound I want (just with the guitar volume).

If you do not like your Mark V and want something better or at least something that is closer to a Mark series then the V has become, get the JP-2C. I have run both in parallel and the end result was rewarding. I still much prefer the blend of the JP and TC amps though. In comparison, the Mark V is a bit wet on the bass, even with mods so it is a bit loose and has more power sag than the JP or TC. JP and TC has a dryer bass response so it remains tight. There is some sag in the power section but not as much as the Mark V. Hit a power chord hard and you will notice the difference. Think about what it is you want out of the amp. Not sure when the next best thing will be from Mesa and when it will come out. If it looks good and sounds great, I will just add it to my collection as I would have difficulty parting with my current amps, even the Mark V (I may consider selling it as I have done so often).
 
Thank you so much for the detailed response and sorry to high jack your thread. Yeah I love my Mark V could never part with it and I also have a multi watt dual recto. I love my Metallica and thrash metal so part of me wants a 2c and the other tells me to go something different. I guess I’m worried that channel three in the TC will sound too much like my rectifier? Then there is the fact that I live in Australia and a JP-2c is $5,500 the same price as a new Diezel VH4 which is something else I’ve always wanted. I guess I just need to weigh it all up. I was even considering an Axe Fx 3 but then I thought why have a computer that pretends to be all my favourite amps when I can just own all my favourite amps and play the real deal. Instead of spending the rest of my life turning knobs on a computer convincing myself how convincingly real it is.
 
barryswanson said:
Thank you so much for the detailed response and sorry to high jack your thread. Yeah I love my Mark V could never part with it and I also have a multi watt dual recto. I love my Metallica and thrash metal so part of me wants a 2c and the other tells me to go something different. I guess I’m worried that channel three in the TC will sound too much like my rectifier? Then there is the fact that I live in Australia and a JP-2c is $5,500 the same price as a new Diezel VH4 which is something else I’ve always wanted. I guess I just need to weigh it all up. I was even considering an Axe Fx 3 but then I thought why have a computer that pretends to be all my favourite amps when I can just own all my favourite amps and play the real deal. Instead of spending the rest of my life turning knobs on a computer convincing myself how convincingly real it is.

Hijacking? really? :lol: I think the Fourums have been slowing down for some time. At least this is a discussion worthy of merit on any page here, and it is somewhat related.... I am not sure how much the Multi-Watt Recto compares to the Roadster, I have all the same bells and whistles and CH3 should be as close to the Multi-Watt. I first compared the Roadster to the TC-50, sure it is similar in its organic tone but yet not the same. If the Multi-Watt is similar to the Roadster, it too would have some dynamic response to guitar volume. Just like the Mark V but different. In my experience with the Roadster, Mark V and JP-2C, they all seem to be on the same tone farm range. The JP-2C (tone wise) fits in the middle between the Roadster and the Mark V. Some would say that the Mark V on CH3 has a broader distortion (gain) or drive range than the JP-2C. Perhaps they are right but yet I often felt that the Roadster had more meat in the distortion range than the Mark V. It all depends on how you percieve the characteristic. Mark V will give you the most harmonic response especially with pinch off harmonics where as the Roadster is tuned against you in that regard and works hard to cancell out your efforts. I can pinch off some harmonic tones but the decay rate is excessive even with a sustain pedal. The JP-2C has characteristics of both Roadster and Mark V. Pinch off harmonics do not ring out as effortlessly as they do with the Mark V but I can get some really cool effect with the JP-2C. My issue with the Mark V is I have had a 20 minute run time before the fundamental tone starts to annoy me. I know you have seen the saturation mod, well the 12AT7 helps but there is a false sense of treble response and filtered upper midrange as that gets removed because of C39. It is the high frequency non-linear gain that re-inserts the upper frequency due to harmonic doubling, quadrupling, etc..... There is no boundary or roll off on V4B circuit which in many cases can result in ice pick. 12AT7 seems to cure that issue but it also becomes apparent that there is some musical content missing (C39 again). That and a few other mods I have done improved my amp in particular. Not everyone needs to do this so I envy those that have the ideal amp as mine was not but it is much better now. The 12AT7 does help you get that JP-2C tone but only so far. Even the IIC+ mods help but thats all it can do. Add a grid slammer to the front end will bring you much closer to the JP. So in that respect, do you need it? If you love the Mark V, you can always get a grid slammer or even the flux drive and you will be in JP-2C territory. Just the fundamental characteristics mind you as it is difficult to replicate the power supply of the JP or to get that dry tight bass response which is the side effect of the massive transformer. Even the OT is not the same as the Mark V. At this moment, the JP-2C is by far the loudest and most powerful amp I own (100WRMS, on paper yes, in reality it will peak at 140WRMS as I have seen with the Rivera Rock Crusher, Roadster and RA never get beyond 100WRMS. Mark V may peak around 110WRMS. Not too long ago I restored the bias circuit to its original state and the amp was pegging the RMS meter at 150W, no wonder why I kept red plating tubes in stock form, typically it should get to 110Wrms which is what I have seen before I made any circuit mods to the Mark V).

Now to the topic at hand, TC-100. It may not be as organic or dynamic in its gain response, it can clean up with volume control but the drive or distortion influences are still quite present so it becomes difficult to get a clean sound with a moderate gain setting using the volume control on the guitar. That character is differnt than the other amps that use a different preamp design. The Clean channel on drive mode will give you that dynamic. Holly crap do I love the clean channel with the gain maxed out with the voice switch set to drive. That is Plexi on steriods. CH2 seems to have less midrange but yet it is also a great channel with the bass boosted. A big trick about the TC series that some did not understand when they read the manual or perhaps they did, but from a viewers perspective they will not understand unless they actually use the amp. The Presence control is not a negative feedback control like it is on the Mark V, Rectifier, or JP-2C. Call it the ice pick control but that may be misleading. the presence on the TC is actually a high pass filter for frequencies above audible range. 20kHz and above (or somewhere in that range). What it does is sharpen up the distorted waveform, gives it more edge (assuming that is where the actual term comes from). If you saw the actual waveform from the amp for a given frequency, it will look square but with the corners grosly rounded off. this is part of the high frequency roll off. The more round the corners the warmer the amp will sound, The sharper the corners of the waveform (higher frequency, more harminic content and not referring to the musical sense of harmonic here) the brighter the tone will be. A tube amp will not generate odd harmonics, it will always be an even order of harmonic so the tendency of shot noise is not as great. What is shot noise? This term is common with solid state amplifiers since they can generate odd order harmonics as well as even order harmonics since the gain is basically linear. Shot noise is the description of the sound of an audio amplifier relative. It was said that too much gain or clipping on a solid state amp sounds like thousands of small steel BB's falling into a large steel bowl. That is a nasty sound. This is caused by influencing the wave form with odd harmonics, may even add a hook to the waveform or a peak like I have seen with the Mark V (result of the GEQ circuit as it is all solid state devices). In short, the presence control on the TC series amps will enhance the high frequency response and it set aggressivly may result in ice pick tone. No fear though. I have yet to find any setting that would annoy me. The amp can get bright but not like the Mark V in stock form. I would highly consider the TC amp but considering the cost, compare other amps in the same price range or what it would cost you. I basically did the same thing befor getting the TC-50 and looked at what else was available in the same price point. PRS Archon 100W head was the other contendor since that was closer to the cost of the TC-50 than the 50W Arcon. Similar amps but I thought the Mesa sounded better. I have to say this. My friends are overly impressed with both the TC-50 and the TC-100. They like it more than the other amps I have including the JP-2C. Have to consider that they are more tuned into the hard rock of the 70's. I do not see it as a Heavy Metal amp as it has much more use in other music styles. JP-2C on the other hand, you need to be creative if you want to get more into classic rock tone as the gain can only go so low. Clean channel can be driven hard but lacks that character needed for classic rock. TC series can do it with ease. I would say the TC is as versatile as the Mark V, it may not have the same number of voices per channel or may not be a novelty amp in the Mark areana, it is a novelty amp in the British format though. Vox, Marshall, Orange characteristics but with a Mesa twist. It should not replace the multi-watt or the Mark V but it will complement each amp if you use it in parallel. Mark V + TC-100 = :shock: :shock: awesome. Roadster + TC-100 = :twisted: :shock: , TC-100 + RA100= :shock: :shock:
 
One more thing to state..... Keep in mind I did not like the TC-50 when I first got it. That may have been due to the honeymoon not being over with the JP-2C. Actually I was not overly impressed with the JP right out of the box but that did not take very long to figure out why... it sounds much better when you use the GEQ on CH2 and CH3. The TC-50 was quite a different story though as I was pitting it against the RA100 and I have that amp dialed in with the right set of preamp tubes that keep the hi gain out of the mud. Stockers just do not suffice since the Hi and lo gain channels share the same tone controls but may have a different gain character as it uses a stacked potentiometer for the control. The Royal Atlantic was a favorite and it still is. TC-100 on the other hand had more of what I wanted tone wise and that easily pushed the Royal back into the pond. Still I love the RA for what it is. TC-100 is just a bit more of a beast when you want it to be that. Also got used to the TC-50 before the TC-100 so I already knew how to dial it in. Both have become favorites. JP-2C was more of a hit for me once I figured out the midrange and Mahogany body guitars with a set neck sound the best with a higher setting on the mids. Just keep in mind that the TC series is a bit different than what you may be used too. It will grow on you. Also some may feel the amp is not the best option for them, just like any other guitar amp, it is all based on how it fits your needs.
 

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