Substitute 5V4G tube for 5AR4 tube

Brad, if the manufacturer says it compatible, then go for it! 5V4Gs are cheap. 5Y3s cheaper yet. You might also want to consider the Mullard 5AR4 which is the best example of a 5AR4.

The reason that I like the instrumentation or ruggedized grade of the 12AU7 is that they tend to be much less microphonic, which seems to be a great problem in this tube type. Many of the ruggedized versions are built to be much more stout for use in hostile environments or left on 24/7, the 5814 is another good example that is a direct sub for 12AU7. There are some more such as 6189, which I have not had good luck with, as well as 7730, 7318, and 6067, which I have no experience with. Sometimes these instrumentation grade 12AU7s sell for peanuts, so it is fun to try things out, as you will be doing with the 5V4. Good luck, and most of all, enjoy yourself.

While the 5V4 and 5AR4 can be interchanged in your circuit; you'll find the 5V4 less dynamic. A NOS Mullard(Blackburn Plant) 5AR4 will provide long life, dynamics, and a clean/smooth presentation(no sacrifices). ie: (http://cgi.ebay.com/MULLARD-GZ34-5AR4-CV1377-rectifier-tube-NOSNIB-/270598619300?cmd=ViewItem&pt=Vintage_Electronics_R2&hash=item3f00ef40a4) Many others on eBay as well.

Rodman99999

Thank You for your advice. I will need four, 2 ea for the preamp and 2 each for the cd player.The tubes are somewhat spendy, but it seems the sonic upgrade in replacing the Chinese tubes should be a pretty good value. All the tubes I have replaced have made a significant difference, except for the RCA 12AU7 clear tops. They just didnt seem to make that much difference. They have since been replaced with some Tungsgram 12AU7's which I like alot.

Thnx again Mr Rodman99999
Brad

One of the good things about the Mullards is their longevity. They will most likely be the last rectifiers you'll have to buy for your amps/pres(unless you keep them for the rest of your life). My experience has been that power supply mods make some of the best sonic improvements, and the better the rectifier: the faster, smoother and cleaner the overall presentation. Let us know how you like them. Happy listening and you're welcome.

Hi, I am resurrected this old thread because of similar reason - the 5ar4 is too expensive. Can u share your experience using 5v4g on the prologue 3? Is it worth the money or should I bite the bullet to buy the 5ar4?