[DaveC113]

I was poking around ebay after my Sylvania 5ar4 didn't survive the move. Everything else was ok, but I guess this tube was getting old. I found these Richardson 5ar4s, does anyone recognize them?

http://cgi.ebay.com/RICHARDSON-5AR4-6106-TUBE_W0QQitemZ400059089213QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item5d2561413d&_trksid=p3286.c0.m14#ht_500wt_1182

[S Clark]

One thing for sure, it's not a Sylvania- most likely a GE....  just looked at a pair of GE's and they don't match either.

[Les Lammers]

That is not a 5AR4 it is a Bendix 6106/5y3. It is an excellent tube though.

https://www.tubeworld.com/5y3gt.htm

[lcrim]

If you need a 5AR4 I would highly recommend the Mullard GZ34 if it can be found at a reasonable ($60 or less) price.  They last forever and sound terrific.  They can be pricey so shop carefully.

[FullRangeMan]

Sorry my complete ignorance about Tubes.
I Wonder how this tube could be a Bendix 6106/5y3, if it have a label of National Electronics/Richardson 5AR4 on the glass and in the paper box ?
Do you think it was washed and re-labeled to National/Richardson 5AR4 ?

[DaveC113]

Sorry my complete ignorance about Tubes.
I Wonder how this tube could be a Bendix 6106/5y3, if it have a label of National Electronics/Richardson 5AR4 on the glass and in the paper box ?
Do you think it was washed and re-labeled to National/Richardson 5AR4 ?

Richardson re-labeled quite a few tubes, like many companies did (and still do). I posted on diyaudio and got confirmation it is a Bendix tube.

Les wins the prize (if there was one  ). The Bendix 6106 is an inderectly heated 5y3, and is rated lower than a 5ar4 for DC output current from what I can tell. It might make a good substitute for lower power requirements, but I'll pass at that price.

I had my eye on a couple of tubes on ebay... I won both. Got a NOS Matsushita for $25 and a OS Mullard fat base that measured at 95% for $40. Both my amp and preamp use 5ar4s, and I currently have a Mullard in the preamp, so I have one extra old stock and a couple of Sovteks that I will hopefully never use again. 

[Les Lammers]

Sorry my complete ignorance about Tubes.
I Wonder how this tube could be a Bendix 6106/5y3, if it have a label of National Electronics/Richardson 5AR4 on the glass and in the paper box ?
Do you think it was washed and re-labeled to National/Richardson 5AR4 ?

Richardson probably bought them un-labled in bulk. I have one or two just like them. Bite the bullet and get a Mullard and live happily ever after...or till you go deaf. What piece of gear is it going in?

[DaveC113]

I use one 5ar4 in my Simple SE amp (kt88 SE, triode or UL, no feedback...in avatar) and another in my Anthem Pre 1 w/ remote ps. I already have one Mullard, a mid 60's w/ serrated plates... I think I'll keep that in the preamp and use the fat base in the amp. I'll have the Matsushita (and 2 Sovteks) for backup...

[Syrah]

I bought a stack of 6106 tubes a few years ago.  All of them were mislabelled Richardson 5AR4 and the tube vendor told me as much.  Great tube on my Supratek Syrah, horrible on my Modwright Sony 9100.

[his047]

I bought some Bendix 6106 for my two Radford STA 15s in December last Year. They are wonderful tubes developed for missile guidance systems (radiation apparently destroys solid state equipment) and specified to very high standards. they have three layers of Mica supports, very solid glass and should be astonishing when they work.
Unfortunately they did not work in my Radfords: Sparks and blown fuses within a few minutes. The supplier (Walden-Puddle tubes) were very helpful to me and even supplied a new set of valves  before we agreed that the 6106 did not work in Radfords. I was fully re-imbursed for the valves (Thank you, Jessica).

What surprises me is that these tubes are clearly stamped 5AR4 which should mean that they are replacements for GZ34s and should work in the higher-current applications.