Presonus TubePRE distorts

[v6v6v6]

Sorry for the newb question...

The quality of my TubePRE had been deteriorating for a while so I finally replaced the tube. I didn't use it immediately after the I replaced it and waited a couple months. Now it distorts no matter what--even when the Drive is all the way down. Presonus says they'll repair it for a flat rate of $50, but I'm wondering if it's probably just a defective tube. Is this a common occurrence?

[jonnyc]

Mine started distorting a little bit but only when well overdriven, I'd say maybe the tube is bad or you didn't use the right part or something. I'm not sure though payin 50 bucks to get a 100 preamp fixed is worth it.

[v6v6v6]

Originally Posted by jonnyc

I'm not sure though payin 50 bucks to get a 100 preamp fixed is worth it.

Yup and that's why I wondering if I should just try another tube or just chuck the whole thing or start thinking about getting a new one.

[SonicAlbert]

I'd try a different tube. It doesn't ahve to be a really expensive one, jus ta new one that you are sure is working properly. If there is a problem with that too, then perhaps somethings a bit off with the TubePRE. I'm not sure I'd spend $50 to repair a $99 preamp either. But I would buy another tube.

[bbbodie]

What tube is in this unit? I have the Presonus Bluetube and it comes stock with the 12AX7 which is a fairly hot tube.

I've exchanged it out with great success for the 12AT7 and the 12AU7. The 12AU7 is a much richer tube that I can run full out and it doesnt distort at all. The key is to look at the Gain rating in the attached chart as I understand it it's how hot it can be driven (so the lower rating of the AU7 is why I get warmth with no distortion). Hope that helps.

Here's an article on the substitution possibilities (and bear in mind these all fit the same socket. (in my experience).


Bodie

[v6v6v6]

bbbodie, thanks for the helpful tip. I've tried 2 tubes and both are from the 12AX7 family: Sovtek and Groove Tubes. But why would this distort the sound if the TubePRE originally came with a 12AX7 tube? Shouldn't it have distorted from the start?

[v6v6v6]

Update: Well, I tried the 12AT7 which has the lower gain factor than the 12AX7. The distortion is still there so I'm positive the TubePRE is just defective. I was thinking about purchasing the M-Audio DMP3 for $150, but I've decided to pay the $50 bench fee to Presonus and get the TubePRE fixed. It simply comes down to how much I can spend and I can't justify paying $100 more for a preamp that is pretty much the same quality-wise.

[treymonfauntre]

isn't the dmp3 2 channels?

[snatchman]

Originally Posted by v6v6v6

Update: Well, I tried the 12AT7 which has the lower gain factor than the 12AX7. The distortion is still there so I'm positive the TubePRE is just defective. I was thinking about purchasing the M-Audio DMP3 for $150, but I've decided to pay the $50 bench fee to Presonus and get the TubePRE fixed. It simply comes down to how much I can spend and I can't justify paying $100 more for a preamp that is pretty much the same quality-wise.

I'll say get the VTB-1 (Studio Projects) for about $99.00 and be done with it! The DI on the VTB-1 is worth the $99.00 IMHO.! This is what I use it mostly for. Plenty of people like/use the pre on the VTB-1 though!....