Changing Tubes In Microphones

[brandondrury]

Hey people,

My Soundelux U99 has become noisy recently. VERY noisy! As in too noisy to use on anything serious. This a bad thing. I expect it to be the tube, but that is just a guess. Regardless, I want to try out a new tube in it to see if it sounds cool. I've read that switching tubes in the Soundelux U99 can reduce the noise floor.

My pair of V69s are suffering the same fate (although I can't get any audio out of them at all). So I'm thinking of trying new tubes in those as well. Maybe the problem is something else, but again, I think a tube swap could be a good thing. If I could get the V69 to be more reliable, I could recommend it as one of my favorite microphones. (When it works, it gets used much more than my AKG 414 or AT4050) but not all the time.

Anyway, the only problem with swapping tubes in my microphones is I don't know anything about the process. I don't know what tubes work and what don't. I don't know if I'm going to blow something up because a different tube has different electrical characteristics, etc.

I expect the physical process of pulling out a tube and putting a new one in is quite easy (just like a guitar amp). However, I'm more concerned about choosing the right replacement tube.

Any thoughts?

Brandon

[lolzgreg]

I would recommend calling the manufacturer of the microphone or look up some reliable audio techs in your area. I know of a great place out in New York, but you're a thousand-and-then-some miles from there, so that wouldn't make much sense.

-Greg

[brandondrury]

I just read that a dude put a EF86 in his Soundelux. So as long as I know what family of tube I'm dealing with, it shouldn't be an issue. While rusty, I have a background in electronics. These preamp type tubes (as in preamp tubes for guitar amps) are self-biasing so that takes care of that worry.

Brandon

[brandondrury]

Round #1

I ordered a NOS Mullard EF86 for my Soundelux U99. I paid $10 extra to get one that didn't suck. It cost me about $80 give or take. The noise I was hearing is completely gone. In fact, I'm not hearing any noticeable hiss at all, which is strange for a tube mic. I just held the mic and talked in it listening with headphones and now I'm reminded why I paid $2500 for this mic. Holy hell! It has that incredible voiceover type of sound!

It turns out that changing the tube in the Soundelux U99 took just seconds. I just unscrewed the base of the microphone, pulled the tube out, and put the new one in. Done. ANYONE can do this!

I've been in an SM7 only mode for a while now and I think I may be going back to condensers for a while! The sound of the Soundelux U99 was EXCITING!

Now I've got to figure out how to get the damn tube out of my MXL V69s.

Brandon

[lolzgreg]

I've never used a tube mic before. I'm just starting to really get serious with recording music. I've only been at this seriously for about a year now and I'm enjoying it beyond belief. Just about every free second of my time that isn't devoted to my religion, school or work goes into reading, learning and testing out methods. I'm going to make some bass traps with Roxul and build a "guitar fort" like isolation system for my 5150 4x12. I'm thinking of building a strong plywood box with a door that can open that's floated with roxul and lined with roxul and acoustic foam. I'm also floating it off the floor with roxul underneath. I did some research and plan on leaving a tad bit of air room in there. I hear if it gets too tight it sounds unnatural. I'll use my ears to judge that one.

Good luck with your re-tubing. Talking about tubes, when's the last time you put new tubes in any of your valve amps?

-Greg

[brandondrury]

Talking about tubes, when's the last time you put new tubes in any of your valve amps?

Honestly, I don't remember. Because I don't use my own amps that often, they still sound good with whatever they have in them. My 5150 could probably use some help, but it doesn't get used that often anyway.

Brandon

[lolzgreg]

Originally Posted by brandondrury

Honestly, I don't remember. Because I don't use my own amps that often, they still sound good with whatever they have in them. My 5150 could probably use some help, but it doesn't get used that often anyway.

Brandon

Sorry if this is getting too off topic...

A lot of people buy tube amps (or microphones) never change the tubes or keep the stock tubes (which generally aren't that great in MOST cases). It's a real shame, because few people know what a good tube amp is REALLY supposed to sound like. My friend has a Marshall DSL 100 and the thing sounded like absolute horse shit before I retubed and biased the sucker. I also heard some EXCELLENT Rivera K-Tre sound clips on youtube (yeah YOUTUBE). If the thing sounds good on youtube, it's gotta be awesome. There's a good possibility the one I played was a dud. I saw one on e-bay for $1400.00 buy it now. I almost peed myself but then realized I'm a poor 19 year old who needs to pay off my car repairs and acoustically treat my room. I'm actually building an 8'x3'x4' dual cabinet isolation box (one side for my bass cab, the other for my 4x12) out of MDF, roxul, and wedge acoustic foam. I plan on putting the acoustic foam on top of the 2' 4.5pcf Roxul Safing. I'm giving the cabs plenty of breathing room. Hopefully I'll really knock the dB's down and get a great sound. That way I can stop procrastinating and get clips of my amps up here and maybe give some other people advice on building one of those things (not to mention improve my tone a thousand fold or two).

-Greg

[brandondrury]

then realized I'm a poor 19 year old who needs to pay off my car repairs and acoustically treat my room

Yeah! Reality sets in. These days I'm a poor 27 year old (not for long!).

I also heard some EXCELLENT Rivera K-Tre sound clips on youtube

Sounds pretty bad ass. Sounds like my Rivera Knucklehead on a good day with the right Les Paul.