Vox AC-30cc2 "Tune Up"

[paologregorio]

I hate to be contrary, but I have been quite happy with Chinese tubes. I think a lot of things get a bum rap when they are piled on in internet fora.

Since Ei tubes have become terribly hard to get, I use the Chinese EL84s in my DC30, so I can save my Ei's and NOS tubes for lower voltage amps. They are less "velvety" than JJ's, but frankly, sound much more like EL84s to me than JJ's do (JJ's EL84s sound a lot more like a 6V6 than an EL84 to me). For preamp tubes, I feel generally the same way, but haven't tried the JJ long plates. The 12ax7LPS tubes from Russia are supposed to be good. I'm pretty happy with the Tung Sol 12ax7 reissues (but am glad I have some Ei's in stock.)

The more observations the better! ASpen Pittman of GT fame has said nice things about Chinese tubes, and he knows his tubes. Certain tubes work better with certain amps as well. In my own experience, the Chinese tubes were fine when I first had them, but they degraded rather quickly, and were more prone to going microphonic than some of the other brands with different countries of orgin. I think the problem was that Vox wasn't all that particular about thre tubes they put in the amps, hence the issues. I should also add that the EL84s in both of our amps were Sovteks, rather than Chinese. the preamp tubes in our amps were the Chinese tubes.

[kennyhowes]

I tried to take some step-by-step photos that might assist others looking to change their tubes and by-pass the Neanderthal Vox method of having to unsolder your speakers in order to pull out the chassis, in order to change the tubes.

For anyone contemplating the new or future AC-30 cc2 purchase, the new models on display at NAMM have averted this "problem" with the new AC-30s having the tubes finally mounted towards the back of the amp ...so you can access them easier.... See the photo's at the end of this series.

waitaminutewaitaminutewaitaminutewaitaminute

On the AC30CC series, you have to un-solder the speakers to change the tubes???

On the TBX series from the '90s, the speakers were attached with clips (at the terminal) and, on the other end, to a 1/4" plug which is detachable from the chassis. So even though there's a bit of yoga involved with getting ot the tubes, there's never any soldering involved.

Not cool.

[8mileshigher]

waitaminutewaitaminutewaitaminutewaitaminute

On the AC30CC series, you have to un-solder the speakers to change the tubes???

On the TBX series from the '90s, the speakers were attached with clips (at the terminal) and, on the other end, to a 1/4" plug which is detachable from the chassis. So even though there's a bit of yoga involved with getting ot the tubes, there's never any soldering involved.

Not cool.

Yep Kenny ---- that's what the first step in this "tune up" was -- to re-route and replace the short speaker wires and add a 1/4 plug, (just like on the earlier versions). Which enables future tube replacements to be accomplished by unplugging the speakers, then slide out the chassis, to change the tubes like on the earlier models. (See the pics I posted preceeding of Paulie's other Vox AC30s... the Top Boost and the Heritage Handwired).

Imagine how much money Vox saved over the entire production life of Custom Classic series, by having just a short few inches of speaker wire and no 1/4 plug (as in the TBX and Heritage Handwired series)..... Their cost accountants probably had it down to micro-cents per millimeter of copper .....

Looks like Vox engineers finally listened to some of these complaints and redesigned the new AC-30 chassis and PCB placement overall, with the tubes section facing the back panel, so now a Vox owner doesn't have to touch the speakers wiring at all. We complimented the Vox R&D guy at NAMM about the new tube positioning !!!

Paulie may set up a little side-business (while he's in school) doing Custom Classic rewire jobs like this....

[8mileshigher]

I hate to be contrary, but I have been quite happy with Chinese tubes. I think a lot of things get a bum rap when they are piled on in internet fora.

Since Ei tubes have become terribly hard to get, I use the Chinese EL84s in my DC30, so I can save my Ei's and NOS tubes for lower voltage amps. They are less "velvety" than JJ's, but frankly, sound much more like EL84s to me than JJ's do (JJ's EL84s sound a lot more like a 6V6 than an EL84 to me). For preamp tubes, I feel generally the same way, but haven't tried the JJ long plates. The 12ax7LPS tubes from Russia are supposed to be good. I'm pretty happy with the Tung Sol 12ax7 reissues (but am glad I have some Ei's in stock.)

The more observations the better! Aspen Pittman of GT fame has said nice things about Chinese tubes, and he knows his tubes. Certain tubes work better with certain amps as well. In my own experience, the Chinese tubes were fine when I first had them, but they degraded rather quickly, and were more prone to going microphonic than some of the other brands with different countries of orgin. I think the problem was that Vox wasn't all that particular about thre tubes they put in the amps, hence the issues. I should also add that the EL84s in both of our amps were Sovteks, rather than Chinese. the preamp tubes in our amps were the Chinese tubes.

With this discussion on the types/brands of tubes and the quality of same -- I thought I might add a chuckle to the proceedings, by sharing this insight that some philosophical Amp-Guru had posted on the Vintage Amps forum, several months back, regarding getting the "best" NOS vintage tubes :


"I generally use my old American tubes, because life is short. Heaven will have it's own forms of amplification. "

[johnallg]

Go ahead and be contrary, but know I do not listen to internet fora..... I use my ears. Besides, I have a lot of NOS tubes to keep me going and prefer the sound of them over the harsh-to-my-ears Chinese tubes I have received in equipment I've bought. And my NOS tube supplies were free to me, so it is not a "protect my investment" opinion. IMHO YMMV, etc.

[paologregorio]

waitaminutewaitaminutewaitaminutewaitaminute

On the AC30CC series, you have to un-solder the speakers to change the tubes???

On the TBX series from the '90s, the speakers were attached with clips (at the terminal) and, on the other end, to a 1/4" plug which is detachable from the chassis. So even though there's a bit of yoga involved with getting ot the tubes, there's never any soldering involved.

Not cool.

Yep. Neither my `73, nor my CC2X, came with speaker jacks (both have them now! ). On the CC series, the length of hard wired speaker wire is so short that one cannot completely slide the chassis out of the cabinet to change the tubes.

The `73 had an only slightly more generous length of wire, which allowed one to slide the chassis completely out, but not much more than that.

The 90s Korg Voxes with a speaker jack were a good improvement wrt speakers that pluggedc into the chassis via a jack.