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Substitute 5V4G tube for 5AR4 tube

I have mostly PrimaLuna equipment, I.E. Prologue 3, 5, and 8
The diode tubes in the Prologue 3 and 8 are 5AR4 tubes (Chinese). I would like to know what sonic changes others may have found by substituting either 5V4G or 5Y3 in place of the 5AR4 diode tube. The 5V4G tubes I am considering are NOS RCA's. All signal tubes, 12AU7 and 12AX7 are Tungsram.
I have rotated RCA cleartops and BB's and still go back to the Tungsgram tubes, although I recently aquired some 12AU7 Slyvaina Gold Brand triple mica, extra rod, that I am experimenting with. I need more time to see which unit they may sound best in, but I did get as far as pluging them into the cd player and noticed right away a focused, stronger base.
bradf
bradf's avatar
bradf OP
288 posts
 
Thank You very much Viridian. You have been very informative. I will probably look further into the 5963 and 6680 tubes.
The owners manual of the referenced components states that the 5V4G tube can be used in place of the 5AR4 tube but to expect sonic differences. If your interested you can review said owners manuals by going to www.upscaleaudio.com. You will find a special section on there web site for PrimaLuna components, including the manuals.
Thanks again for your help.
Brad
viridian's avatar
viridian
4,184 posts
 
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.
rodman99999
3,557 posts
 
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.
bradf's avatar
bradf OP
288 posts
 
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
rodman99999
3,557 posts
 
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.
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