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tube rolling first-timer

So I bought some NOS tubes to try in my preamp. It is my first piece of tubed equipment, and this is my first time switching out the tubes for something different. The pre is a Nagra PL-L. It comes with some Sovtek tubes. The tube complement is two 12AX7's and one 12AT7.

So, I've done a fair amount of reading about different tubes, and decided to start with some Telefunkens. I found a good deal on a matched pair of Telefunken smooth plate 12AX7's and a Telefunken 12AT7.

Here are my questions:

(1) when you are first learning about tube characteristics and your preferences in your system, is it best to stick with all one kind of tube and swap them all out, or should I first switch out the AX7's (leaving in the Sovtek AT7)... I'm just curious if people think there is a "right" way to go about it.

(2) Does one generally switch to all of the same brand tube, or do people tend to mix and match brands to their preference? Of course I recognize you need to use the same brand (and closely matched) tubes for the L/R channels, so I would stick with the same brand for the AX7's.

(3) Do folks have particular preferences or combinations of tubes that they have like for the Nagra PL-L and would recommend?

Thanks for your advice and recommendations.
dgaylin
tbg
5,263 posts
 
I am sure that Nagra has to live with tubes that are readily available and make their best choice among them. I my opinion, 50s-70s tubes are far superior to what you can buy today.

I know my Reimyo 300B amp came with new production Westrex 300Bs that were made with the same equipment as my 1960s WE 300Bs, but in the amp the60s tubes were quite superior.

All that I can really tell you is to experiment. Telefunken 12AX7s are still sought.
blindjim
3,092 posts
 
Tbg is right about the current tube selection in designs. Be it whomever... amp makers gotta choose which ones are avialable now and in good supply.

otherwise they'd say which NOS ones to use and not supply tubes with their amps, right? Leaving it up to us to feret out them still strong as new, non noisey, non fonic NOS tubes to fill it out with.

But that dog just won't hunt. At all.

Again, the true key in tube substitution is the vendor and the testing equipment they have and the measures with which they test them... and how well they support waht they sell.

I'll not mention names here either in terms of those who don't support well what they sell... but that part is integral IMHO. Knowing who is as good as knowing which.

I found not much difference from the Tele to the RCA. Some for sure, but not lots. RCAs have more lower end definition and weight IMO. tele top ends are super but that's about it IMO. both their mids were similar.
tbg
5,263 posts
 
Blindjim, that still does not rule out the possibility that NOS tubes might be better in the Nagra. Trying them is the only real test.
dgaylin OP
255 posts
 
Yes certainly sseems I'm on the right track to experiment here and will do so with interest. Plenty of agreement on that score. Intersting, Jim that you prefer RCAs to Telefunken. I've got a lot of listening to do....
samhar
1,048 posts
 
How's the tube rolling going?
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