5AR4 rectifier tube question

I am sort of shopping for one or more 5AR4s for a Cary SLP05 power supply because I’d like to have at least one spare and because I’d maybe like to roll two or three ad see if I can hear an improvement or vice versa. I make no claims of knowing much about the vacuum tube game; occasionally I get lucky & stumble on something that really works for me. As far as the 5AR4, I did a hit at Uncle Kevin’s site, and there were some that looked interesting (I am thinking of one in particular, it had a Japanese sounding name that started with a ’M’) but when I click on it, all I get is a picture of Uncle Kevin’s screaming face telling me "not to buy tubes" (later, when I finally took time to read, apparently his tube tester is down).

So I started doing hits on Ebay, and oh my gosh! I was inundated with choices and the variation in prices! Which do I stay away from and which should I be interested in? Would a 5AR4 from Bugera also be suitable for what I’d want to use it for? Could a rectifier tube provide a big sonic upgrade if I spent enough money on it? Can I make a sonic upgrade from what I believe (I haven’t opened up the power supply yet) is the stock EH 5AR4 without breaking the bank? I would be totally good with the $50.00 range and picking up 2 or 3 different ones to play with if those with experience thought I could improve the power supply in that range. If I had to I guess I could go more (the $100.00 range) but I probably wouldn’t be buying too many of them, and I was kind of HOPING not to go much over that.

Anyway, thanks in advance for the input; I always consider it part of my education.


I really appreciate all the input and there are replies I want to write, but I just spent the evening in my listening room with a bottle of wine and (get this!) some more RCA Black Glass VT231s I just got!

(I type 'more' as I had had a pair of the Black Glass 231s in my balanced input sockets, and I liked them so much, I went on a search and filled all six sockets with them!  It was amazing tonight!)

Anyway, given the events of the evening, I am in no condition to attempt typing or any truly coherent thinking, but I shall return.

Thanks again for all the input!  Matt


ya know, with enough vino, even crappy russkie rectifiers will sound just fine... 

The adage that "you are listening to your equipment's power supply" applies. Rectifiers make differences that are easily heard. Which means you have no objective idea which is real. Like lots of other things in hifi, especially tube gear, tube rolling is an exercise in finding the right "fixed-parametric equalizer" for you. It goes beyond EQ because dynamics and dynamic elasticity are also clearly affected.

For all the reverence for NOS Mullard GZ34, 4 or 7 notch according to one's theology on the matter, in many of today's circuits they can make an amp sound "tight-sphincter-ed and unengaging." They are great (and durable) rectifiers but in many circuits can lack musical elasticity. Among new production GZ34, the JJ is the most elastic, but you just have to change them out on a schedule. For daily use stuff, I change them on schedule every 9 months. Some of my amps that were supplied with GZ34 don't use the full capacity of the tube, and I can instead use NOS 5v4 or 5u4 rectifiers. When that works, the vintage 5v4 usually sounds sublime.

One inexpensive modern production rectifier that I love in some of my preamps, power amps and guitar amps is the STR (Special Tube Request) version of the Shuguang 274B that thetubestore.com sells as part of their Preferred Series. In this case, the STR is ultra-hard vacuum, thicker glass and a higher grade plate plating. It's not a true 274B, having the lower filament current draw of a GZ34/5ar4, but a voltage drop about halfway between a true 274B and a true GZ34. It sounds disciplined yet elastic at the same time, with excellent, hard-hitting base and quick, crisp transients and highs. It's proven long-lasting for me. Really nice $35 rectifier. Beats all the Russian rectifiers I've tried in the past, and betters a surprising number of NOS variants.

The real point here is that rectifiers can have a more profound effect on amp sound than rolling the output or input/driver tubes. So it's a good idea to start there, and it tends to be less expensive that beginning with tube-rolling quads of triode, tetrode and pentode power quads.


"stick with mullard amperex or matsushita old stock 5ar4’s"....bingo

Holland amperex is a great tube...just looked through my globe series 5ar4’s...one bugle boy left.They are all mullard made,All bought on ebay.Never have had problems.Bought from europe as well.