2. amps-preamps
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12ax7 vs 5751

hi all,
i need some advice. i`m very new to tube amplifiers and i`ve been doing some tube rolling.

i currently have a pair of grant fidelity matched psvane 12ax7t`s in my amp which sound fantastic.

what i`d like to know is which are the better tubes, 12ax7`s or 5751 tubes. i`ve been looking at forums and there are folk out there that say 5751 tubes are better than 12ax7 tubes.

can i have your thoughts on this please and also which are the good 5751`s to go for.

i really like the psvanes but if they can be bettered i`d go for it as my next line up of replacement tubes.

my amp is a yaqin mc100b. the tubes i have installed at the moment are.....
2 x psvane 12ax7t`s
2 x brimar 6sn7gty/cv1988`s
2 x sylvania 6sn7gtb`s
4 x electro harmonix kt88eh`s

many thanks in advance guys.
grayf
mechans
3,048 posts
 
There is an acid etched code on the tube that will tell you where the tubes were really made. Phillips owned both Amperex and Mullard brands and cross labled many of their tubes. If they were made by Phillips they will flash upon start up and have typical cross molding marks in the glass on top of the tube. In any event if made in Great Britain it should sound rich and mellow like the Mullard tubes do. The Amperex Holland tubes have a cleaner and 3d imaging with better detail in the top end. All the comments on sonics are IMHO of course.
mcpherson
174 posts
 
Mechans
Rich and mellow compared to the Golden Dragons is a good description. For my set up rich and mellow is a good thing. Once I compare side by side, I will share my thoughts.
Thanks
mcpherson
174 posts
 
The Amperex are working out very well for me. They have taken the edge off of the cd's I really had trouble tolerating before.
This is the first set of tubes I have bought so I dont know what to expect with break in etc. They seem to have opened up a bit in the right places and stayed smooth on the top end which is exactly what I needed.
Lets just say they restored some order in my set up. Looking forward to adding the GE 5751 next.
miketuason
337 posts
 
Hi guys! been following this forum and learned a lot from you guys. I just bought the McIntosh C220 tube preamp that also uses the 12AX7 tubes, as soon as the warranty expires I might try and change it to the 5751, we will see. Thanks.
Ag insider logo xs@2x
jazzerdave
163 posts
 
Miketuason - If you don't feel like replacing all the tubes, the most important place for the 5751's would be to replace the 2 12AX7's in the phono stage. Theoretically, they'd make the biggest difference there as the decrease in noise would be most helpful there.

If you've got the amp still under warranty, it might be a good idea to just watch out for good buys on some of the 5751 or 12AX7's that have been discussed here. If you go out hunting for specific tubes (and want them now), you'll pay a lot. But just keep an eye out for all of the good ones and try to snipe them at great bargains.
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