Different tubes, different world

[efhjr]

I've had some annoying popping in my system and figured it was time to roll some tubes.

So last night I pulled four signal tubes out of my two McIntosh MC30s -- the 12BH7s and 12AU7s, all Telefunkens -- and replaced them with some RCA 12BH7s and JJ ECC82s.

Well, the popping went away, and so did the magic :realmad:. One or more of those Telefunkens must be on its way out (I figure they're 55 years old or so). The JJs look brand-spanking new, so I hope they mellow as they break in, but I doubt they'll ever make that Telefunken magic.

After I replaced the tubes, it felt like I had replaced the amps. There was much less golden, creamy midrange, a bit of harshness, and it sounded slower, too. The sound felt less "mature," like the taste of a new bottle of wine over an old one.

Tonight's task: figure out exactly which Telefunken is bad, and put back in whichever ones are still good. And start scouring estate sales for more Telefunken tubes.

[Sckott]

You don't have a tube tester? They're VITAL, IMHO.

I've had the same thing happen with a couple of clear-top RCA 12AU7's. When I shut the amps down, it popped on the way out... Not badly, but once I replaced the tubes, the whole thing shuts down quietly.

[efhjr]

Originally posted by Sckott
You don't have a tube tester? They're VITAL, IMHO.

I've had the same thing happen with a couple of clear-top RCA 12AU7's. When I shut the amps down, it popped on the way out... Not badly, but once I replaced the tubes, the whole thing shuts down quietly.

Nope, don't have a tube tester. I'll add that to the list of tube toys to acquire;).

The popping I was getting started after power-up and continued intermittently. It was closer to a scratching/popping noise and was just loud enough to be annoying. At least I've identified the guilty tubes and can sort them out even further tonight.

[Jeffrey]

Hi,

I hear ya! I rolled some Sovtek 12AX7's into a McIntosh C-22 when the Tele's died and the sound went to hell! :( New Tele's were purchased the next day! :)

-Jeffrey

[cwon]

Originally posted by efhjr
Tonight's task: figure out exactly which Telefunken is bad, and put back in whichever ones are still good. And start scouring estate sales for more Telefunken tubes.

While you're at it, look for spares for your other tubes. Get 'em when you don't need 'em so you'll have 'em when you do. Especially since they don't make them anymore.

[Ronflugelguy]

Originally posted by Jeffrey
Hi,

I hear ya! I rolled some Sovtek 12AX7's into a McIntosh C-22 when the Tele's died and the sound went to hell! :( New Tele's were purchased the next day! :)

-Jeffrey I'm going to buy some extra Teles for when I get my preamp!

[sgb]

Originally posted by efhjr


Nope, don't have a tube tester. I'll add that to the list of tube toys to acquire;).

The popping I was getting started after power-up and continued intermittently. It was closer to a scratching/popping noise and was just loud enough to be annoying. At least I've identified the guilty tubes and can sort them out even further tonight.

I've experienced the SAME popping noises on some NOS RCA tubes (they're in my Quicksilver's driver stage). It started AFTER the seller's 30 day warranty period ended, so I was bummed at the prospect of spending another $40/tube to replace the culprits.

About a month after the popping began, it suddenly ended, and the tubes now continue to perform as they should.

Don't know how a Mullard 12AU7 would sound in your equipment, but in mine it beats the pants off the Telefunkens I bought (NOS at a very healthy price). I think SH has also stated some dismay at the sound of this kind of Telefunken. The Mullards aren't dirt cheap either, but the are cheaper than the Tele's.

[Ronflugelguy]

I have a pair of bugleboys 12Au7's coming.:cool:

[Steve Hoffman]

Originally posted by Ronflugelguy
I have a pair of bugleboys 12Au7's coming.:cool:

Ah, that'll be just right!