Report from a tube-change

[GoranS]

At last!
My new tubes for my Express 5:50 arrived this afternoon. I've been discussing this in at least two threads
but this requires a new thread.

The story so far
I bought the amp used earlier this year. When firing it up for the first time in my kitchen my emidiate reaction was that it
was very bright. Since it was used I ordered new power tubes and two SPAX7 that I put in the V1 and V2 positions
since that's where low noise tubes makes the most sense.
Fought the brightness by learning the tone controls and posting/reading on this forum, but it still had some ice-pickiness.
Soon the power tubes begun to rattle and I got a new set cheaper without returning the old ones. Picked a set of Mesa
6L6GC Red's thinking they might be less bright, as some info stated that, but they where not.

Suggestions from the forum
On this forum there was info on all sorts of tube combinations that users found working well, but the solution didn't
appeal to me. Mainly because of how I know I work, with a slight Alzheimer Lite I sure would have forgot where to put
which tube. The one suggestion that made sense to me was putting SPAX7's in all positions. Clean and simple.
But I also wanted to tame the IMO a bit over the top reverb, and found a thread about putting in a 12AT7 tune in V5.

The present
So today the tubes arrived. I had ordered two Mesa SPAX7 and a Groove Tube 12AT7. Plugged them in and without
changing any control settings I fired it up. The first thing I noticed was the the small barely noticeable crackle some
seconds after taking it off the standby position was gone.

Rolled up the guitar volume and played a chord. WOW! A a smooth, soft, full, very nice tone filled the room!!
The amp was in the clean mode and I continued to play some solo and really provoked it with hard picking. No ice-pick!

And the reverb is so full, and I am able to tune in just the right amount for my taste; barely noticeable at 9 o'clock.
This was impossible before the 12AT7.

The configuration
My Express 5:50 now has Mesa SPAX7 in all positions except V5 where a 12AT7 sits. And Mesa 6L6GC Red's.

Conclusion
The last tube change really made a difference, I'm so very happy it turned out so well. Now I must start to explore the
other modes as well, I have mainly used the clean mode because I didn't really liked the others. I believe one of the last
changed tubes (V3 or V4) must have been faulty. The SPAX7's might also been good for my amp!

/G

 

[Don]

Great results! Thanks for the review!

 

[vbf]

This is a very timely report...thank you! My biggest gripe with my 5:50 is it's too dang bright. Would you say it reduced the brightness a little or a lot. Is the amp quiet? Also, I looked on Mesa's site and didn't see the 6L6's your mentioned. Could you be more specific about those please? Thanks again!!!

 

[EtherealWidow]

Always nice to hear a tube swap review. I'm thinking about going with an RFT 12AT7 for V2, then JAN-Philips 12AT7's in all the rest around Christmas time. It'll darken it up a bit and I can get some NOS tubes for cheap! I don't care so much about the lower gain. The circuit in the amp has plenty of gain anyway. I never turn it past 2 o'clock with a 12AX7 in it, and if it's not enough gain you could always go oldschool and just turn it up louder.

 

[GoranS]

About the Mesa 6L6GC Red's..
The coding system is Mesa's way of matching the tubes, they have Red, Yellow and Green which means that they have
different current ratios. At Thomann.de it's possible to order the different color coded Mesa tubes, and that's where I
read about the Red's being "softer". But that's not true, they break up a little earlier that's all. They all sound the same.
The stock amp is equipped with yellow-coded power tubes.


To my ears my amp got a little less bright with the SPAX7. Combined with a "fuller" tone with more bottom
and a less ice-picky mid. I played at home an hour after posting here, and I had to relearn the tone controls again.
There was definitely a difference in tone compared to before.

 

[vbf]

That is music to my ears...no pun intended. I love the tube cocktail form Doug's and am happy with it. But the amp need what you're describing, to my ears anyway, and I may just have to give those preamp tubes a try. Thanks again...very, very helpful.

 

[GoranS]

The crucial change was when changing V3 and V4 to SPAX7 in my case. That's when the tone changed for me.
Already when the amp was new (to me) I changed the V1 and V2 tubes trying to get a lower noise floor.
But that did not really alter the tone.

So if you want to try it get one or two SPAX7 and give it a try. I suspect that the V4 has a lot to do with it?


Edited to add:
About the noise. **** if it isn't a bit lower... Or have I just got used to it? I don't know, it just don't annoys
me that much anymore. The thing is that I've got used to the noise level using Line6 Flextone III for a couple
of years... That is; lack of noise, as in zilch, zero, none... :wink:

 

[vbf]

Thanks again for all the great info. I ordered of few of them this afternoon and will report back next week after I've had a chance to put em' in.

 

[THE TUBENATOR]

GoranS, thank you for posting and letting us know your reaction to the SPAX7's. I swear by them! As I have writing on several other posts, shortly after I purchased my 5:50 (new) I called my Mesa dealer and explained the tone issues I was experiencing and he immediately told me that perhaps I should change out ALL of my pre-amp tubes to the Mesa low-noise tested SPAX7 (12AX7) tubes. I drove over there purchased five of them little jewels and instant happiness! I have the highest gain pre-amp tubes but each one is tested for low noise and proper operating parameters by a reputable dealer - Mesa.

I look forward to reading your future posts when you start experimenting with very high settings on your amp. You will even be able to enjoy that amp with maxed out settings and you will have much more use out of the Burn mode too! And on the Clean mode I like to use fairly very high settings on the amp and clean up the sound with the guitars volume control. The SPAX7's will make it very easy to go from squeaky clean to mud pit dirty by simply turning the volume control on the guitar!

 

[jsabo]

hm... what does this tube change do to the gain of the amp? ive been trying to use burn to get as close as i can to a recto, but have found that the tone i get is rather harsh and ice picky, as you say.

changing the tubes to SPAX7's mellows the ice pickyness, but does it reduce the gain a lot? if it does, is there some combination of 12AX7 and SPAX7 that is ideal? any other good/bad effects to be aware of ?

 

[jsabo]

I look forward to reading your future posts when you start experimenting with very high settings on your amp. You will even be able to enjoy that amp with maxed out settings and you will have much more use out of the Burn mode too! And on the Clean mode I like to use fairly very high settings on the amp and clean up the sound with the guitars volume control. The SPAX7's will make it very easy to go from squeaky clean to mud pit dirty by simply turning the volume control on the guitar!

hah, oh, i see this now. you posted your burn settings (everything "maxed") in one of my threads about burn settings...

i tried those settings and liked them, but had to roll off the tone knob on my guitar to mellow the icepickyness.
if i change the preamp tubes, i wont have to do this??

 

[THE TUBENATOR]

hm... what does this tube change do to the gain of the amp? ive been trying to use burn to get as close as i can to a recto, but have found that the tone i get is rather harsh and ice picky, as you say.

changing the tubes to SPAX7's mellows the ice pickyness, but does it reduce the gain a lot? if it does, is there some combination of 12AX7 and SPAX7 that is ideal? any other good/bad effects to be aware of ?

The 12AX7 pre-amp tube is the highest gain Dual Triode tube available. The Mesa SPAX7 is a 12AX7. What makes it a Mesa SPAX7 is nothing more than the result of testing by Mesa…. When they encounter a very low noise, high output 12AX7 tube in their testing procedure it is pulled aside and given a dense rubber coating (sleeve) to further quiet the tube and re-branded as Mesa SPAX Special Requirement Pre-Amp Tube. I prefer the 12AX7 (SPAX7) over all the other Dual Triode tubes because of its high gain potential, gain factor or 100. I believe the next in line is the 12AT7 which has a gain factor of only 60. I like to use the SPAX7 in all five pre-amp positions because every tube handles the signal therefore every tube contributes to the overall sound quality and second I just don’t want to give up any gain!

 

[THE TUBENATOR]

I look forward to reading your future posts when you start experimenting with very high settings on your amp. You will even be able to enjoy that amp with maxed out settings and you will have much more use out of the Burn mode too! And on the Clean mode I like to use fairly very high settings on the amp and clean up the sound with the guitars volume control. The SPAX7's will make it very easy to go from squeaky clean to mud pit dirty by simply turning the volume control on the guitar!

hah, oh, i see this now. you posted your burn settings (everything "maxed") in one of my threads about burn settings...

i tried those settings and liked them, but had to roll off the tone knob on my guitar to mellow the icepickyness.
if i change the preamp tubes, i wont have to do this??

jsabo, this is a copy of the reply I sent to your PM.

I generally keep my guitar’s tone control between 0 – 6 on a 0 – 10 scale with 10 being the high or bright setting. I like a darker thicker tone and yes, if I turn the tone up all the way on my guitar it does get way too bright. Overall, the SPAX7's will help considerably with the brightness of the tone because they produce a fuller, thicker tone. In addition, you may also want to turn down your Mid tone control on the amp as well depending on your guitar. I will give you an example; I love guitars with humbuckers and Mahogany bodies – deep dark sounding. On the other hand, my best friend owns single coil guitars Fender Strats and Tele. When he plugs his guitar into my amp he maxs everything on the amp but he has to back the Mid control down to about 9:30 ~ 11:00 or the tone will be so ice pickish it will pierce our ear drums! Those guitars sound great once the Mid control is adjusted. I also have a Stiletto cab which pushes the Mids.

 

[GoranS]

Played around with the amp this weekend, and it still sounds good. It wasn't just a placebo effect.

For some reason this mod allowed me to use the tone controls better. I can get a really mellow sound if I want to but also a crystal clear fender twin type of sound (with a Mesa twist). I use mainly Strats so I have to keep the mid control down under 11:00 (depending on the others) else the ice-pick returns, but not to the same amount as before.

To summarize it all; This was a really good mod, much better than I thought. And thanks The Tubenator for bringing this mod to my attention in the first place!!!

/G

 

[THE TUBENATOR]

Played around with the amp this weekend, and it still sounds good. It wasn't just a placebo effect.

For some reason this mod allowed me to use the tone controls better. I can get a really mellow sound if I want to but also a crystal clear fender twin type of sound (with a Mesa twist). I use mainly Strats so I have to keep the mid control down under 11:00 (depending on the others) else the ice-pick returns, but not to the same amount as before.

To summarize it all; This was a really good mod, much better than I thought. And thanks The Tubenator for bringing this mod to my attention in the first place!!!

/G

I'm very happy to read that you are happy with the tube suggestion. Those tubes really help to tame the hissing issue inherent to the Express amps and they also open up a new range of tone options and high gain ranges.

You will have lots of fun experimenting with all the settings on both your amp and the guitar. You can also get a wonderful tone out of the Clean mode when you max the settings and go for a Eric Clapton "Woman Tone" on your guitar. The ice-pick is not as prevalent on the Clean mode even if you max it out and it really cleans up as you roll off the guitar's volume control.

Albert

 

[vbf]

I replaced V3 and V4 with the 12AX7's and a 12AT7 in V5 (I left both Tungsol's in V1 and V2) and it definitely reduced the ice pick. Thank you for recommending these tubes. I'm definitely going to need to tweak my dirt pedals accordingly....can't wait to let it fly at practice tomorrow night.

 

[vbf]

I am so happy with these tubes it's not even funny. Every dirt peddle on my board was run through the amp at practice tonight and oh man did they sound good. The ice pick is greatly reduced and the amp sounds much better. For once I wasn't twiddling with the tone knob on my guitar trying to get the brightness out without muddying up my tone. I didn't touch the tone knob even once. I can't thank you enough for passing along your experience with the tubes.

 

[GoranS]

I am so happy with these tubes it's not even funny.

:lol:

I can only agree. They're great. Credits to The Tubenator.

 

[THE TUBENATOR]

I am so happy with these tubes it's not even funny.

:lol:

I can only agree. They're great. Credits to The Tubenator.

I am thrilled that those of you who have converted to the Mesa SPAX7 pre-amp tube are happy! About two weeks after I received my 5:50 Express I switched to the SPAX7's in all pre-amp positions. That was almost three years ago! I really don't understand why Mesa doesn't ship these amps with SPAX7's? The SPAX7's make such a big difference it's almost like having a different amp! Please understand; I have no vested interest in what you purchase, I have no connection to Mesa or any Mesa dealer. I am just another Express 5:50 owner who was searching for a lower noise pre-amp tube with depth in tone, rich over-tones, no ice-pickiness, incredible gain, heavenly sounding at max settings and also able to provide good tube life......then I was turned on to the Mesa SPAX7! I hope you all remain satisfied with that tube selection.
Albert

 

[vbf]

I had some time yesterday and A/B'd a bunch of new overdrive pedals, including a fuzz. Taking the ice pick off the top makes a big difference in a lot of my pedals. The Crunch Box (distortion) sounds so much smoother than before. I almost sold it...glad I didn't. Ditto the Boiling Point. I actually had to roll in some high cut on a couple pedals, which is exactly where I wanted to be with respect to controlling the high end. I'd much rather need to add some than fight it all the time because it's to brash. I ordered two more ax7's for V1 and V2. With the at7 in V5 (reverb), however, it seems to have really reduced the amount of reverb available. It's not a bad thing because I don't use a lot of reverb but wondering if others have noticed this too? Again, very happy with these tubes.