StradiTube.. review incoming (any requests?)
- Thread starter Treehaus Audiolab
- Start date
2 cases so far(12 June 2025).So all of you have had failures?
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!
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.
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.
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 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.
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!
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.
Likewise, I’d be interested in how the new 45s perform against the regular contenders such as EML 45.
I’m also considering modifying my amps for their 5u4G.
I’m also considering modifying my amps for their 5u4G.
I've posted this elsewhere, but this thread was brought to my attention and so I wanted to share my experience here. I had a Stradi 5U4G for about two months, and last week it arced and burnt the resistor right off the rectifier in a DNA Stellaris, and blew the fuse. The amp maker tested all the tubes in at the time, too, and the Stradi continued to arc in the Amplitrex tube tester, even in standby mode.
I've been in contact with Stradi and they claim the issue must be with the amp, because if it was a manufacturer's defect, it would have shown itself within the first week of use. I admire the bravery of those of you who put in your replacement 5U4Gs but I simply cannot trust using a Stradi rectifier in any amp ever again. Stradi has gone silent since they laid the blame at the foot of the amp maker, and I've repeatedly requested a refund on the tube itself (I don't want a replacement), and I've also asked for additional payment to cover the cost of repair and the parts damaged, but I suspect that's just hopes and dreams on my part.
I've been in contact with Stradi and they claim the issue must be with the amp, because if it was a manufacturer's defect, it would have shown itself within the first week of use. I admire the bravery of those of you who put in your replacement 5U4Gs but I simply cannot trust using a Stradi rectifier in any amp ever again. Stradi has gone silent since they laid the blame at the foot of the amp maker, and I've repeatedly requested a refund on the tube itself (I don't want a replacement), and I've also asked for additional payment to cover the cost of repair and the parts damaged, but I suspect that's just hopes and dreams on my part.
Smartly packed.
EML meshie on left, Stradi on the right.
About the same as an RCA.
To my ears about the same.
Dynamic range, highs, lows, sound same to me. Great presence and air, good separation, etc.
I don't feel like one does something better than the other.
Both cost around the same so I'd call it a coin toss.
Nice! See how those Stradi settle in after about 15-20 hours.
Interesting that Stradi said they wouldn’t recommend using the 5U4G in my amplifier after I told them my LCLC values.
As for the 45, not much point in trying it if it sounds similar to an EML however I’d be interested in how they sound after 400hrs.
A review published by PT Audio of both 300B variants and the 5U4G recti:
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