New SPAX7 in V1 - sputtering

[theredmenace]

Recently was playing with Tungsol vs original Mesa tubes in V1 and broke my original factory tube (snapped the tip off, doh!). I ran with the Tungsol for a while but decided to try a new SPAX7 Mesa tube. Fine for a while but now have fairly regular sputtering and random hiss on all channels (not all the time and sometimes improves as amp heats up). I put back Tungsol for now but was wondering if this is common (a new 'double tested' 12AX7 that is noisy)? I wonder if I should try and return (Sweetwater) or just avoid Mesa preamp tubes. Kind of wish I'd left the factory tube alone as it sounded slightly better than the Tungsol I have in there now. I'll keep experimenting but thought I'd see if anyone had similar experience with 'fresh' tubes...

 

[bandit2013]

I have not used SPAX7 since the mid 90's. They always went microphonic on me. Things have changed since then (primarily the source). I also had poor performance from Penta Lab tubes (have long plate design). Actually they are the closest to the old Mesa tubes. The best long plate I have used is the Sovtek LPS in V7. The new SPAX7 are the same tube as the standard 12ax7a, just has different sorting criteria.

I have rolled tubes so many times I forgot what I had at one point. The stock Mesa tubes are not all that bad.
At first I did not care much for the TS in V1, sounded okay at first, seemed a bit muddy in the clean channel. Now I am pleased with TS. I had 8 tubes to choose from, guess the one I put in was just right.

An option, if you still have all stock preamp tubes, swap the TS for the V4, V5 or V7. If you had the triodes matched, put it into V7. That way you will get back the mesa 12ax7a tube for V1. Note: V4, V5 and V7 are essentially driver circuits, however you will notice a deeper tone with TS in V7 but not as much as an effect as it would be while in V1.

 

[jmontgomery]

I'm guessing you broke it putting the cover back on?

 

[bandit2013]

I would not go that far to avoid Mesa tubes. If you like the tone and gain character from the Mesa 12ax7a, there is nothing wrong with sticking with them.

I can see how easy it would be to damage the tube if you had the head version. For ease of install, and tube rolling, I normally would pull the amp out of the shell and place it on top of the cab (inverted, tubes facing up). Recently, I wanted to experiment with a different tube in V1, I had a Ruby HG tube but wanted something that does not distort early (clean channel was sounding like the edge mode in channel 2). I opted to put in a TS but did not feel like pulling the amp. It actually took me longer to change V1. Had difficulty getting the shield back on. If the shield was only a bit shorter (by an inch or so) would improve tube replacement effort.

 

[pivot]

I hit the same problem replacing v1 the first time 3 weeks ago! Replacing the cover is a royal pain its very tight and you have to push hard to get it seated. The spring grabbed the tip of the tube and popped it off. Changing tubes was easy its replacing the caps(covers) that is a pain in the ass!! Really good info here I ended up buying a spax ax7 for v1 but it came in late so its my spare now and I used a stock ax7 from mesa for v1. Allot of people responded to my last post saying I should try tungsol. I think im going to give that a shot next time a pre-amp goes in the mean time the mesa tube to me sound perfect for what I do. This board Rocks! Really helpful not to mention mesa support has been really good too. Love the V

 

[crane]

The best long plate I have used is the Sovtek LPS in V7

Give a try to Mullard reissue 12AX7. V1. It really open up the tone to me, but for sure have their own character so you may or may not like'em.

 

[theredmenace]

Thanks to all for the speedy replies. Yep broke the tube putting the cover back on (in a combo no less...).

I'll try these suggestions. Didn't like the Tungsol in V1 (hard to explain, just didn't click). I've heard good things about it in other positions tho. Will try that out.

 

[bandit2013]

I did not care much for TS the first time out, It took several tube rolls to dial in the tone I was pleased with. My problem is trying to find a combination of tubes that sound great with all of my guitars. Plus I was breaking in a set of SED or GT6L6R-2 (same thing). Now that I had noticed the amp was a bit too crisp for my taste. The TS made its way back into V1 and now I am happy with all channels and with all guitars. I had seven TS tubes to choose from. Perhaps the one I put in had the desired characteristics. Not all tubes will sound exactly the same even if they are identical. I do not get any noise at all when the guitar is unplugged. Once in a while I will pick up a bit of a hum from the power line (all depends on what is running at the time.