StradiTube.. review incoming (any requests?)

[GroovySauce]

I have two Stradi 5u4g and they are fantastic and no issues.

 

[John(Stradi)]

So all of you have had failures?

2 cases so far(12 June 2025).

Of these, Khashmi(ID) is the only case where the second 5U4G failed again with the same problem.

 

[aLLeARS]

2 cases so far(12 June 2025).

Of these, Khashmi(ID) is the only case where the second 5U4G failed again with the same problem.

I have around 400 hours on my new pair of Stradi 5U4G's. So far they have performed flawlessly and they sound fantastic! They have the look and feel of NOS tubes made in the golden age. I'm verry impressed with this tube!

 

[khashmi]

I’m saying a little prayer and hoping third time’s a charm! The approx. 250 hrs between the first two tubes were hands down, glorious! John has been very communicative and fair about all of this.

 

[Mr P]

Still waiting for that 274B………………….

 

[Golum]

Still waiting for that 274B………………….

I'm pushing John for this one as well....

 

[John(Stradi)]

I'm pushing John for this one as well....

The 274B is currently delayed due to other(unexpected) development schedules.
I will keep you updated on its progress.

 

[mariovalvola]

Good morning everyone. Also thanks to this discussion, I would like to try the 300B or S300B Stradi.
I ask those who have been using them for some time (I am not considering rectifier tubes): have you noticed a drop in parameters, a worsening of vacuum, or an increase in noise? Are there any special precautions to be taken? In my amplifiers, I use an anode delay, a gradual rise in voltage and current to the filaments (it is complicated in AC to have a variation of only 2.5%, so I stabilize it; Rod Coleman's old DHT regs in cold weather make the supply voltage vary a lot, so I shelved them) and I make the 300Bs dissipate no more than 24 W.
I own the new WE, Elrog, and EML mesh: what do you recommend? The regular one or the S300B?
Thank you very much and sorry for the trouble.

 

[Treehaus Audiolab]

Good morning everyone. Also thanks to this discussion, I would like to try the 300B or S300B Stradi.
I ask those who have been using them for some time (I am not considering rectifier tubes): have you noticed a drop in parameters, a worsening of vacuum, or an increase in noise? Are there any special precautions to be taken? In my amplifiers, I use an anode delay, a gradual rise in voltage and current to the filaments (it is complicated in AC to have a variation of only 2.5%, so I stabilize it; Rod Coleman's old DHT regs in cold weather make the supply voltage vary a lot, so I shelved them) and I make the 300Bs dissipate no more than 24 W.
I own the new WE, Elrog, and EML mesh: what do you recommend? The regular one or the S300B?
Thank you very much and sorry for the trouble.

I have been running their 300Bs for a while now, and I haven't noticed any degration in performance. It also sounds like your amplifier is being very kind of whatever 300B is in it, which is always a benefit.

Between the S300 and 300B; The S is probably closer to the experience of the Elrog, perhaps even more clean/ lean. If I had to chose one, Id probably lean to the regular 300B. Its quite special. If I had a very syrupy 300B amp (like the earliest classic circuits, with a 2.7 output tap) and wanted it like a 45ish sound then Id lean to the S300B.

 

[mariovalvola]

I have been running their 300Bs for a while now, and I haven't noticed any degration in performance. It also sounds like your amplifier is being very kind of whatever 300B is in it, which is always a benefit.

Between the S300 and 300B; The S is probably closer to the experience of the Elrog, perhaps even more clean/ lean. If I had to chose one, Id probably lean to the regular 300B. Its quite special. If I had a very syrupy 300B amp (like the earliest classic circuits, with a 2.7 output tap) and wanted it like a 45ish sound then Id lean to the S300B.

Thank you very much.
In fact, to the 45 in single ended I always preferred the RE604 in its Globe version precisely because, the latter, it sounds more magical but also more full-bodied. The circuits are always different. I go from a basic Zaika to circuits with interstage transfo ( Tango NC-20).and barium driver tube ( RE134).

 

[Treehaus Audiolab]

Thank you very much.
In fact, to the 45 in single ended I always preferred the RE604 in its Globe version precisely because, the latter, it sounds more magical but also more full-bodied. The circuits are always different. I go from a basic Zaika to circuits with interstage transfo ( Tango NC-20).and barium driver tube ( RE134).

I’ve had an RE604 amp… pure magic.

.. I also have a zaika 300B monoblock on a mono bedroom speaker!

 

[mariovalvola]

I’ve had an RE604 amp… pure magic.

.. I also have a zaika 300B monoblock on a mono bedroom speaker!

The RE604, is a truly magical tube. Its construction is amazing. The hypnotic harp filament. Huge is the stated dissipation plate. It should be pointed out, however, that the real RE604, that is only the Globe one ( built in three different versions ) which has a completely different filament structure and activation process. thee newer versions( 1943/44/45 ), the ones with the bulb of the AD1 TFKs, is much more similar, constructively to a 45, it has nothing in common with the older ones. The filaments are conventional and the harp structure is no longer present. Good tubes too but far inferior to their progenitor.
The amazing thing is that the old globes, despite their years, have perfect vacuum as opposed to the 45 globes that are often very precarious ( not to mention the 10's that if you dare to make them go A2, you see fireworks from loss of vacuum ).
Sonically, the Globe RE604s, are the only members of the “barium tubes” family to be timbrally balanced. The AD1 TFKs, beautiful and incredible, do not exhibit the same balance being slightly dry in body and a little unbalanced in the mid-range.
In summary, it is a pity that Stradi could not replicate the true, unique and inimitable RE604 globe. With the AD1, the argument could be similar, but the AD1 was born in Philips. Telefunken's interpretation is just one of many. The Philips version, it is not a barium tube.