Need to replace the EF86. My U99 is ser#20 so it's an early model. The orig is an russian tube but has no vendor name. It does have a blue ink stamp OTH 53 and has a silver mesh. Most tube vendors that I've talked to haven't been much help as far a suggestions. Regarding choices, I know Telefunken tubes have a great rep but will they change the sound of my mic too much or is that exactly what I should be going for regardless of the price. Should I stick with with a russian tube? I know tubes have different characteristics. Can anyone explain the difference in perceived sonics between different brands? I'm sure I'm not the first to swap tubes in a U99. I heard stories of engs going thru a box of different brands of the same model looking for the right sound. Also any vendors that you have had great success with would be appreciated. Thanks in advance. Kelly.

I use Amperex tubes in my U-99... they sound great.

Thanks Fletcher. I was considering those. SND site has them for $50 new stock. Still checking other dealers.

I've got a newer U99 Sn #770.Mine has ehat appears to be a generic russian tube(Sovtek?)

Fletcher,
Why do you prefer the Amperex tube?(as opposed to the stock russian tube?)

I would use Telefunken EF806S or EF86 for
best sound.

I had emailed David Bock about this not too long ago and he recommended Mullard or Valvo tubes. I think he's actually using NOS Mullards in the new U99B...don't quote me on that though.

Brad

Amperex are made by Valvo or do you mean only the Valvo brand. Is there a difference. Thanks for all the help guys.

Miniature tube:

EF 732

Something other pin allocation, but sounded greater

That's good to know concerning Valvo and Mullard. So which would you recommend for the U99? A made in Great Britain Mullard?

thanks,
Brad

Mullard and Valvo are not identical.
Mullard has more bottom and finer trebles.

Maybe the old U99 sounds better with the Valvo and the newer U99B is better with Mullards. Perhaps the design change of the B version has something to do with it.
I am curious what finer treble means. Is is a more refined top are more top? Maybe I should buy one of each and experiment. At the moment I'm leaning towards Fletcher's choice since he's using one and likes the reuslts.

Go with the Telefunken ef86 or ef806s for a clean sound. If you want a little more color and musicality - go with the NOS GEC CV4085 from this guy: http://www.kcanostubes.com/index.html#ef
I had all these for a pair of soundelux U95s that used ef86 tubes. I tried virtually all of them. The Mullards and Amperex are good too. Get them from someone who tests for microphonics and noise.

Thanks AB3. Good tube source and info.

From what I understand the only difference between the U99B and the older U99 is that the U99B has a redesigned headgrill and uses an NOS tube.

Brad

Interesting info...

I love the U99 but at times find the High end a bit much.
Any thoughts on which ef86 might tame the top end a hair?

I'd be curious to know any sonic differences B/t the stock tube and other Ef 86s

bump

The current Russian tubes seem to be very brittle and harsh on the high-end and that is probably why saucyjack doesn't like his U99. The tube that would help tame down the high-end would be the 1960's West German made tubes. I don't want to reccomend a brand because in this tube type brand name doesn't mean anything. The design to look for has a very thin mesh around the plates or inside of the tube. The place I ended buying my EF86's gave me the best deal and the tubes were real. Try out www.tubesandmore.com

BEWARE The EF86 is one of the most inconsistent tubes out there. There are so many different constructions it is hard to find even 2 that are similiar internally. I purchased a couple "NOS Amperex" and in the box was tubes labeled Amperex but made in Japan. Also, I purchased a few "NOS Sylvania" and they ended up being Sovteks marked Sylvania on the tube.

To clarify..I really love my U99 but if a tube swap would help tame the high end a bit and enhance the overall musicality of the Mic then I think it's a worthy upgrade.

The stock Russian tube was having a bad day and the Amperex was the first EF-86 I found in the parts room... we have others, but this sounded good so I saw no reason to drive myself nuts changing tubes when I had one that sounded fine.

I found the Amperex a bit deeper sounding than the Russian tube... which might be a reality or could be an imagined event... I have never taken the time to A/B the two.

The early EF86 Amperex tubes do seem a little bottom heavy compared to the Russian, also I found the lower mid range of the Amperex gets quite muddy compared to the Siemens and Telefunken tubes. Of course I haven't tried every version of the older Amperex tubes because they all seem different. Of the ones I auditioned I really did not like the Amperex especially the ones that said made in France.

Bump

classic man... tweak free.

Finally got around to swapping tubes and checking the U99 on a vocal session. A friend who is one of the better amp techs here in Austin had a Telefunken NOS kicking around. The tube makes the mic sound really smooth but I've noticed the highs are a more subtle now compared to what I remember the mic sounding like. Is this what I should expect from Telefunken? I was going to get an Amperex but he had the Telefunken sitting there. Curious what the Telefunken is worth. Haven't paid for it yet. Thanks.

I just bought a NOS GEC CV4085/EF86 (made in Britain) for my U99 from this place:

http://www.kcanostubes.com/index.html#ef

I have yet to really test it out, but my initially impression is that it's a much sweeter sounding tube than the stock Russian one. I'll have to post again when I've had a chance to really listen to itk.

Brad

Let me know how that goes Brad. I have a voc session starting here in a couple of hours. Should be a good test for the Telefunken.

I put a NOS GEC tube in as well.
Only used in one session so far.I think it replaced a sovtek which came with the U99.
I didn't appreciate a night and day difference between the tubes but I didn't really A-B compare the tubes.Just swapped em out and rolled with it.
I'll know more after a few sessions.

Old amperex ef86 tubes from holland are currently in both of my u99 mics. I also tried Mullards. To me, the Amperex sounds slightly less bright than the Mullard which sounds less bright and nicer (technical term) than the russian tubes that were supplied in the early u99.

Chris Rival

bumping this thread - I'm going to need another tube for my U99, and wondered what the skinny is on EF86 replacements now that some time has passed, and users have judged the sound of their replacement tubes.

I'm leaning towards Fletcher's Amperex choice, but if it's really worth the extra, I'll flip for a Mullard or old GE if they're deemed a better choice for fidelity's sake...

BTW - my U99 is an early model - #100 or close...

regards,

Okay I've been able to record some vocals with my new GEC EF86 and in comparison to the stock tube (from what I seem to remember), it seems to be much sweeter in the midrange, tighter and less boomier on the low end, and a little smoother up top. I really like it. The stock tube made the mic totally unuseable on my voice--the mic used to sound very nasally and sibilant on me. Now the sound on my own voice is much improved and rich sounding. I still wouldn't pick it for my vocals, but it seems to be doing very well on everyone else's.

Brad

I'm curious also. Any feedback would appreciated, and helpful.
I too have an early U99, and It's time for a change...

Andrew