New RKII Owner Introduction & Preamp Tube Question

[ubersam]

Hello All,

I just got the RKII head a couple of Fridays ago. Everything was fine until last night, V3 went out. I live about 10 miles from Mesa in Hollywood and was able to get a replacement yesterday. That got me thinking, I have been using NOS tubes in my Triaxis and am pleased with the results. I have Brimar CV4004 and JAN Phillips in the Triaxis. Do any of you RK I/II, or other Rectifier series amp users, use NOS 12AX7s in your amps? What about current production 12AX7s, what are your preferences? Something good sounding and reliable (durable) I heard that the current production Tung Sol 12AX7s are very good; however, I have not tried them. I also heard that the JJs, Chinese 9th, and GT 12AX7M (Mullard clones) are very good; however, they did not impress me in the Triaxis. I actually prefered the Sovtek LPS.

Thanks.

 

[paleamberglow]

cool pics in your signature link

 

[diamondschwin]

I had a real good experience swapping v1 with a tung sol 12ax7a reissue, it left the character of the amp intact but dialed out alot of harshness and the cleans improved dramatically and I had alot more fluid gain on tap, for soloing etc. it would be aggressive rhythm and then single note soloing it immediately sings


this is on a 3 channel dual rec.

 

[ubersam]

Thanks guys.

diamondschwin - Was it just the V1 that you swapped out for a Tung Sol, or did you swap out any other tube?

 

[Dale B.]

I've always loved JAN GE 12ax7wa's in V1 of any Rectifier, with the lone exception being the last 3 channel Dual Rectifier I owned. It sounded better to me with the combination of JJ Ecc83s and JJ EL34's, though that is beside the point. The GE's have a brighter sound, yet they sound very sweet at the same time. They have a beautiful chime on the high end that is detailed. The low end has nice depth as well. It's a very good tube. I have some GE 12ax7wa's that are actually Sylvania 12ax7's, which have the same kind of vibe as the Philips (mentioned below), yet they are have more gain.

I like the brighter NOS "American" sound. The only NOS European preamp tube that I know of that cops the "American" style sound is the Tungsram. RCA's are right up there with the GE's in my book, but they have slightly longer plates and tend to feedback more. The JAN Philips 12ax7wa has a cleaner sound with a tighter low end, even mids and a high-mid kick. Like the RCA's, they're a long plate preamp tube that tends to have a lot of feedback.

The European stuff has more of a relaxed vibe that is neutral, yet the Mullard Ecc83 has a huge 3D sound stage with a high-mid kick. RFT Ecc83's have a ton of gain and they can bulk up the front end, but it depends on how the preamp section is engineered. Telefunkens have more of a compressed vibe that is clean, yet they're still musical. NOS Tesla or Telefunken Ecc803s and E83cc's have a super clean and super compressed type of vibe that works well in audiophile type stuff, but may not be the most desired in an amp like a Rectifier. I have a huge stash of these as well.

As far as current production stuff is concerned, Mesa is only using their "Russian 2" 12ax7a's at this point. That tube is just a relabeled EH from what I little bit I've looked at it. Those have lots of gain and a high-mid kick. The Chinese C9 "9th Generation" 12ax7a is warm and has a tad bit of roundness to it. It's a good choice these days. I've been reading up on the Tung Sol reissue as well. I just ordered a couple. They will be here in the next few days. They are supposed to be great in V1. The GT 12ax7M isn't quite the same as the original Mullard. It sounds good, but there have been huge problems with the QC, which is basically non-existant at Groove Tubes.

I like reading Lord Valve's comments in his catalogs. He pretty much tells you like it is and doesn't sugar coat anything with BS. He stated the reject rate is horrible on the GT 12ax7m and he is having to go back and double screen them. If they pass his double screen process, he sells them. He said the reject rate on the Chinese C9 is fairly high at the moment, yet he mentions it's a good tube. I don't think he has said anything bad about the EH, but I haven't paid too much attention because I'm not all that fond of the EH. He REALLY likes the Tung Sol 12ax7.

You can't go wrong with some of the NOS stuff. You're pretty much in the same boat with NOS stuff as you are with current production stuff. If you're going to buy NOS stuff, buy them from someone who screens the crap out them. You will get your money's worth.

Dale

 

[daveythomas]

Weird, I had V3 go out on me last week on my RKII. Second time I had a preamp tube go out but the first time I wasnt sure which tube it was because I pulled them all and switched them around.

Mesa sent me 2 new preamp tubes but I had gotten it working before they arrived. This time I switched them out one by one with the new tube from Mesa until I figured out that it was V3.

So is V1 the place to make a swap that yeilds the biggest results?

 

[diamondschwin]

Thanks guys.

diamondschwin - Was it just the V1 that you swapped out for a Tung Sol, or did you swap out any other tube?

it was just the v1, i am still running the stock tubes besides that, swapping the v1 is according to most peoples opinions the biggest different in tone when you swap a pre amp tube, as all the channels at all times are run through that tube first, so it kind of sets up the character of the signal first, but besides that i dont think bright tubes work well in boogies, that being said dark tubes or dull tubes i think isnt the answer either, i noticed when i swapped to the tung sol that my harmonics were way better, my sustain and fluidity were much better, all at lower gain settings, but the rhythm sound stayed chunky, i consider the tung sol to remove resonant peaks from the sound more then anything, giving the amp more upper mid range response, depth and clarity in the low end and removing the 'spikey' top end.. i highly suggest it, although i know JJs get alot of votes around here, i dont personally have experience with them, but i would just experiment, go buy a bunch of different 12ax7s and swap them into v1, seeing which ones you like, that will also give you a good idea of what the tone of the tube manufacturer is.. thats why i think ill eventually retube all the pres with tung sols cuz they sound good, i havent gotten around to thinking about power tubes or rectifiers (although im seriously considering the jj gz rectifiers because of the description and great reviews and tone clips)

 

[ubersam]

Thanks for the detailed responses. I just stuck a JAN Philips in V1 and I swapped out the V2 & V3 with some JJ ECC83s. It was o.k. but I took out the JJ ECC83s and replaced them with some JJ ECC803s which I liked a bit better. Since I was not sure if the stock Mesa phase inverter (PI) was really balanced, I also replaced the PI with a balanced JJ ECC83s. I am putting together a short list of tubes to order from KCA. Anyone have any thoughts on the SED/Winged C 12AX7s?

 

[ubersam]

I forgot to ask this: Does anyone know what each preamp tube positions' specific task is? I asked the guys at Mesa in Hollywood and to the best of their understanding, V1 - V3 are gain stages, V4 is reverb driver, V5 is loop drive (and return?), and V6 is PI. From that, I presume that V1 is the input stage, V2 & V3 are the drive stages. Can anyone confirm that?

 

[diamondschwin]

it should say in the manual, or if you dont have it, go online to their site itll be there as well.

one thing about using the jj ecc803s is that the long plate designs tend to get microphonic almost chronically, and while they sound good its possible that theyll be worthless in a month, if you like the tone i would talk to bob at eurotubes he might be able to hand select ones with the best properties for preventing this.


anywa like dale b. stated, the tung sols are becoming very popular, really gaining strength as being the ultimate pre amp tube, and alot of places are just suggesting to try it once in v1 and youll understand.

anyway i also would like to add i realized i had a mesa spax7, their hand selected high high gain low microphonics 12ax7.. basically just one that is as good as it should be, and i threw that in position 2, and it really did alot for the amp as well, it added more gain, and added more liquidness to single note soloing, so it complented the tung sol nicely, my dual rec. now has all the buzz saw single note stuff removed, and the rhythm tone is still there and improved greatly, i highly suggest the tung sol still

 

[ubersam]

it should say in the manual, or if you dont have it, go online to their site itll be there as well.

I checked the manual that came with the RKII, I have even downloaded the online version; neither one had the tube task chart. The guys at Mesa did mention that one is in the making. So, in the meantime, I'll be ordering a couple of the Tung Sols and a couple of the Svetlanas (SED/Winged C).