Elrog 300B vs Takatsuki 300B tubes

Ecx123, thanks for the additional info. I see what you are referring to in EML’s note 4, which states in part:

Replacing 5U4G with 5U4GB may result in higher rectified voltage, so should never be done. Replacing 5U4GB with 5U4G may result in lower rectified voltage, and may result in damage of the 5U4G rectifier.

However, here are vintage datasheets for the 5U4G and the 5U4GB. Note the statement in the first paragraph of the 5U4GB datasheet that:

The 5U4-GB ... may be used as a replacement for either the 5U4-G or 5U4-GA.

Also, while the detailed parameters indicated in the datasheets do suggest that substituting a 5U4GB for a 5U4G will result in higher rectified voltage, the difference does not appear likely to be major.

Finally, my older Sam’s Tube Substitution Handbook lists the 5U4GB as a direct substitute for the 5U4G (while of course not listing the reverse). I have never known its listings to be inaccurate, and I have often found them to be overly conservative (i.e., to err on the side of caution) if anything.

In any event, all of this is of course superseded by the indication from Israel and in the manual that the 5U4GB should be used in the Franks. He should update the website description of the Franks, though, which indicates 5U4G as I mentioned.

Enjoy!  Regards,
-- Al

Well I have EML 300B XLS in my Ruby amps for several years and the sound is superb. These are more rugged and reliable and you can get more power from them if you design an amp around it.
- IMO they are among the best 300B's that can be had at any price and run around $750/pair

I have both the Elroy 300b and Tatsuki 300b along with XLS, mid eighties WE 300b, Psvane WE300b 1:1 and Shunyang WE300B, as well as EH300b, Shunyang Treasure, Genelex Gold Lion reissue 300b.

I have bought the Elrog 300b tubes from the new Elrog owner and let’s say after comparing them to the Tatasuki and the WE 300b’s I bought another pair as these are my new standard. I use the tubes in my Manley Neo Classic 300b Preamplifier. They are a modern 300b and not even based on the original WE design at all. Transient response and slam are beautiful and yes they even maintain just the right amount of euphonics across most genres. I can not say the same about the orig WE 300b’s for sure. I have ~500 hours on the Elrog 300b’s. It was hard to best the Tatasuki 300b. Until the Elrogs they were by far my favorite. They did take a while to finally break in. Not so with the Elrogs they were pretty much perfect from the first power up. h and they look amazing very tall and not at all like a standard 300b bottle.

Oh and they were nearly half the price of the Tatasuki's.  I love me a "bargain"


My System: Manley Neo Classic 300b Preamplifier, TT’s #1 modded Clearaudio Performance Turntable with Champion Motor and speed control, Panzer Platter, Soundsmith Strain Gauge Cartridge System, TT #2 VPI Signature Soundsmith Hyperion Cart, Manley Steelhead Phono Pre, Mytek Manhattan DAC Revox B77, Manley mono block 120’s and Martin Logan Summit X with ML Descent i Sub, Kimber KCAG interconnects, Kimber 8AG speaker cables with WBT connectors.