Hi All,

A year ago I replaced my Krell SS amp with a Primaluna 400i tube amplifier. There's a pic of my old setup on another thread somewhere.

Over the course of a year I've had to replace two 12au7 driver tubes. One went noisy and was replaced under warranty and the other popped just yesterday.

I'm told all tubes only have a 3-month warranty. While I love the sound of this amp when it's running I'm disappointed with the reliability of these tubes.

I believe all Primaluna-branded tubes are of Chinese origin and wonder if anyone has had similar experience with these devices. Is this just my rotten luck?

I can get a replacement Primaluna tube easily enough from the importer who is not far from me.

Are better tubes readily available?

I could potentially replace the two original preamp tubes with alternative devices and use an original to replace the blown driver tube (and have one spare) but I'm not sure how this will affect the sound.

Would appreciate your thoughts.

Regards,

Derek.

Hi Derek..

While I can't comment on how flash or unflash your current glass vials are I would suggest a decent quality is all you need. How or who determines "decent" is purely subjective obviously..

About 8 or 10 seasons back I purchased an Absolarè Intergrated amp for the cost of a small island and not long after it arrived the bloke I had purchased it from said he had some uber rare and very flash tubes that would improve things a tonne..Now with full transparency I'm fairly gullible so jumped at the chance for such rare and fabulous jewels for my new and smart amp. About two weeks later they arrived in a very securely wrapped box from a land far far away..(ok..Perth) for the princely sum of $600. (Please still laughing)
And WOW...what a difference!!!
Ok..thats a small fib.. No matter how much I tried to tell myself the noise was better it just wasn't..
So.. Be very mindful of tube rolling with an improvement in sound. Better to put the speaker cables up on loo rolls to get them off the floor.
All the best.

I always have spare tubes...

My Audio Note preamp developed a rustling tendency, replacing the 6SN7GT output tube solved the issue. I ordered two more as I've run out. The blown one has lasted for 4 years.

And as you know, PrimaLuna have installed own-branded tubes which implies modern tube production. At which point you probably have Golden Lion (Russia), PSVANE (China), or Mullard re-issues (Russia). As with all the modern tubes that is no indicator of reliability or quality. I see you mention Chinese origin, then that would be the PSVANE tubes. These are considered good quality and I suspect you have been unlucky.

If you're going to do tube rolling, then the two input tubes are the ones to play with, and any of the following can be swapped in: ECC82, US Military 5814A, and the E182CC. However whilst they will change the sound, they won't be anymore reliable than the modern ones.

I see (from Tubedepot) that the modern Mullards can be picked up for US$30 plus shipping, so whilst not cheap, they are not insanely expensive. I kind of object when it's US$599 for a tube... as you will see if you go there and check.

Hopefully your replacements will last a little longer than 3 months.

As Jon says probably bad luck and it may depend on which Chinese manufacturer. I have a Line Magnetic which came with their own branded tubes (undoubtedly made by someone else) which didn't fail but I replaced them with NOS Mullards which definitely sounded better. I run Mullards in my preamps and have never had a failure. Jon's advice to try thetubestore is sound and US$30 each for remade Mullards (these are not NOS) are affordable. I wouldn't like to guess where they are made however - certainly not Blackburn UK - but you definitely need some new ones and these might made an audible improvement. True NOS Mullard, Telefunken, RCA and Seimans turn up from time to time on Trade Me. Look out for TWL and Harrison112 who sell such stuff. Harrison112's moniker is Paul Burgess from St Johns Wood Auckland so you should be able to find and ring him. Paul and TWL test their valves so you are assured of quality - at a price. Beware of unboxed NOS which might have high mileages on them. If you are stuck send a PM to me as I have some spares.

Thanks all, have picked up a PL-branded 12au7 replacement from the importer today. Will install tomorrow if I get a chance. Will do some research and have a look around for another pair at some stage. Seems prudent to have a spare valve or two laying around for events like this. Having never had a valve amp before I never considered the maintenance aspect. Never too old to learn!
Regards,
Derek.