5ar4 rectifier tube

I sort of remember Uncle Kevin saying (on his site) that Prima Luna had some special 5AR4s that they liked for the Prima Luna Prologue 8 CDP.  Are those the only rectifier tubes that they are saying to use with that preamp?  If I remember correctly (and it is quite possible that I don't) aren't those 5AR4s for the Prima Luna a bit taller than the average 5AR$?

Info on this is half way down the page in the following link.

You might look at Japanese production 5ar4 (Brent Jesse has them for $130/each).

https://www.primaluna-usa.com/tube-rolling

DeKay

george53,

First thing you need to do is realize that Uncle Kevin is a salesman, and a business owner. That doesnt mean that he is dishonest, which I dont beleive that he is, but he does steer his customers to what he has on hand. And that isn’t always your best option.

Personally, you couldnt pay me to put a Chinese or Russian 5AR4 in anything I own. They are literally a last resort choice. Spend a little more and buy yourself a genuine Mullard GZ-34. It is equivalent to and a direct replacement for 5AR4, for your Prima Luna. They are both 5 Volts, 1.9 Ampere, Half indirect rectifiers. Then your good to go for the next ten years. 

My Allnic phono stage uses this rectifier and I’ve rolled a bunch, including the GEC U52 (both brown and black base) and the Mullard metal base (really a Philips-Miniwatt, Holland), as well as various bakelite Mullards and a bunch of others. 

There’s a great resource if you look up Dubstep Girl’s Massive 5AR4 Rectifier Shoot-Out. She compares a huge number of different rectifiers (some equipment may not allow for the use of a non-direct "equivalent"). To me, it’s almost like a tone control and the choice I make may not be yours, depending not only on subjective preference, but circuit and system. 

Old stock rectifiers used to be cheap, not anymore. 

First thing you need to do is realize that Uncle Kevin is a salesman, and a business owner. That doesnt mean that he is dishonest, which I dont beleive that he is, but he does steer his customers to what he has on hand. And that isn’t always your best option.

Since Uncle Kevin sells GL 5AR4s I kind of doubt that's why he is advising not to use it in that preamp.

https://upscaleaudio.com/products/gold-lion-u77-5ar4-new-production-rectifier?_pos=1&_psq=5ar4&_ss=e&_v=1.0

@OP - if the tube is a genuine 5AR4 there is no reason why any brand should not work. However there is a huge spread of opinion on whether the entire family of 5--4 and 247 rectifiers are cross compatible, even though they are pin compatible.

That Phillips 5AR4GYS that’s in the Upscale link was a tube that Kevin promoted as the best rectifier tube since sliced bread. He’s definitely sales minded and promotes what HE SELLS. About 6-7 years ago I bought one of those from him that was cryo treated. I think it was about $140 delivered. I have the little Had Inspire Hot Rod 12wpc amp. I purchased some  nos  tubes to try. Mullard GZ 32, Mullard Coke Bottle GZ 34, RCA , RCA Coke Bottle black plate, Tung Sol and Sylvania Coke Bottle. My amp easily tolerates them all. My favorite is the Tung Sol. As mentioned Dub Girls post is great. Never got to try the exotic 274b’s however. Back then they were already too expensive for me. I don’t know squat about what your Prima Luna’s limits are but my amp responds like a guitar amp and a lower voltage rectifier tube really mellowed it out. I guess it’s the equivalent of the guitar term “ Sag “. 

I also recommend Brent Jesse

https://www.audiotubes.com/audtube.htm

just scroll down to the 5ar4 section

I would let him know I was going to buy two pairs of 5ar4’s

1 pair psvane’s at $49.99 and one more expensive pair (you pick or he recommends for your equipment?), simply return one pair after comparing them.

break them in for 60 hours (no signal needed, just leave them on), then compare, pick.

///////////////////////////////////////

now, Brent does not have many low cost in stock, perhaps Tube Depot this time, tell them same thing, ordering 2 pair, will keep only 1

https://www.tubedepot.com/products

My experience, I hated the sound of the expensive ones, loved the sound of the inexpensive ones as much as my Cayin OEM tubes

You might look at Japanese production 5ar4 (Brent Jesse has them for $130/each).

Looks like he's out of them right now, @dekay .  I saw one on ebay for $100 not all that long ago, I think the seller was calling it a "Japanese Mullard," but after my last bad experience, I am personally not buying anymore tubes on ebay. 

Unless I am missing something, the only 5AR4s Uncle Kevin is showing in stock are the reissued GLs and Tung-Sols, which makes me think he is not saying to run the Prima Luna 5AR4 just so he can sell them.  I remember when he had "special" rectifier tubes (I think that they were 5AR4s) for that Prima Luna CDP he used to sell, he had those 5AR4s listed that were theoretically real good in that CDP, but his site was saying he would only sell him to people who had bought that CDP from him.

I use the tubestore "preferred" (Shuguang) 274b tubes in my Had Firebottle because they look so cool. They seem to work very well but mostly...hey...it's the look.

NOS Mullard GZ34

Like most others I normally stick to the  Mullards in my 5ar4/Gz34 positions. They are reliable. I have bought a couple modern tube preamps that use 5ar4's for rectifiers. They both came with modern China made tubes. I would leave them in while "breaking-in" the device & both died within a month. I'm not exaggerating. The last one didn't make it a week & when I pulled it out pieces of the pins were gone. No sign of any remnants..it's like they just disintegrated to nothing. 

Even though mullards are tried & true I have experimented with a few modern 5ar4 rectifiers. One that has worked well for me is the Mesa Boogie low sag tube. When I pop them in my preamp the sound becomes lighter, airy, nice sound. Makes my mullards sound darker in comparison. I even ran one for a few months in a ST-70 power amp with no issues. My Dynaco will chew up lesser quality rectifiers. Killed a brand new JJ instantly. 

I've bought & used 2 Mesa's  over the last two years. They are both still strong.  That doesn't exactly prove they have great quality control on all their rectifiers but so far they have worked for me. 

I love the mullard big base on my Allnic phono stage.  Surprised me what a difference it made verses stock.  Great sound and reliability.  

Here's another tube vendor that I have not checked out yet (recently discovered them).

http://www.vacuumtubes.com/5ar4.html

DeKay

@dekay , I like that he specifies that some of the tubes he sells are used. . . .

I've had no problems with Gold Lion 5AR4s, but I would use what the manufacturer recommends.  A friend of mine continually rolls tubes and has managed to trash a number of expensive amps.  The manufacturer of one amp specifically advised against using a certain brand of 300B.  He did anyway and blew the amp--twice!!