StradiTube.. review incoming (any requests?)

Treehaus Audiolab

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Apr 24, 2023
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Hi Everyone,

I was having a deep late night dive into rare Telefunkens a few months back and came across Stradi Tube from Korea. I was super curious about what they offered, given they make modern replicas of a lot of classic German DHT tubes which no-one else does. They also have some rather unique DHTs that are specifically re-engineered for very low noise and thus can be considered for preamplifier/ phono stage duties. (DHTs are inherently noisy so at low signal levels they can be more challenging to implement). I spoke to John there, and now I am in possession of three of their tube varieties. One is a Telefunken variant that I want to possibly develop some future things around and the other two are 300B variants:

300B - Basically a WE300B clone with its intent to possess that classic 300B sound.
S300B - This one is more unique. It has a different shaped bottle, and it basically a Siemens tube developed to run at 300B specs to be drop-in on 300B amps.

I am still getting hours on them before I deep dive on all their nuances and how they compare to new production WE300Bs. That said, the initial sound is VERY nice. They are definitely top-tier 300Bs and its probably one of those things that will be a matter of listening preference and system setup. In particular, the S300B sounds VERY much like a VT-52; cleaner and more exacting than the usual 300B sound, but still possessing the liquidity I find 801A lacking when used as a power tube.

I know there has been some talk around these tubes, so if anyone has something in particular you want me to listen when I get a bit deeper into to the listening, please let me know.

COMMERCIAL DISCLAIMER: Stradi provided the telefunken 242 clones as a sample for product development. I purchased the 2 pairs of 300Bs. Considering there is so little info out there on these tubes, I figure its for the "greater good" of the audiophile community to post up my listening impressions.
 

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Thanks Rich… very much looking forward to what you discover with these as they settle in and also importantly how reliable they proved to be in the long run.

It’s great to have some new options aiming at the top end of DHT especially with the S 300B in what sounds potentially a slightly more neutral variant of 300b… is the tonal balance on that still somewhere in the ballpark of the current production WE 300B… also keen to hear more about the Telefunken 242 variant.

Just checked out their site… wow fantastic options there. Thanks for the share on these.

Stradi Tubes
 
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Fantastic topic! So far, there was only short feedback from Lukasz (LampizatOr) who loved their tubes but not going into any specific details SQ wise.

Thanks for the effort!
 
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Thanks Rich… very much looking forward to what you discover with these as they settle in and also importantly how reliable they proved to be in the long run.

It’s great to have some new options aiming at the top end of DHT especially with the S 300B in what sounds potentially a slightly more neutral variant of 300b… is the tonal balance on that still somewhere in the ballpark of the current production WE 300B… also keen to hear more about the Telefunken 242 variant.

Just checked out their site… wow fantastic options there. Thanks for the share on these.

Stradi Tubes

It won't be until sometime next year where I can get deeper on the 242 as I dont have a piece of equipment that runs them yet. The 300Bs, of course, are pretty easy.

Long term reliability I will keep an eye on; they do seem generally well made. Thick glass, nice base, etc.
 
Hi Everyone,

I was having a deep late night dive into rare Telefunkens a few months back and came across Stradi Tube from Korea. I was super curious about what they offered, given they make modern replicas of a lot of classic German DHT tubes which no-one else does. They also have some rather unique DHTs that are specifically re-engineered for very low noise and thus can be considered for preamplifier/ phono stage duties. (DHTs are inherently noisy so at low signal levels they can be more challenging to implement). I spoke to John there, and now I am in possession of three of their tube varieties. One is a Telefunken variant that I want to possibly develop some future things around and the other two are 300B variants:

300B - Basically a WE300B clone with its intent to possess that classic 300B sound.
S300B - This one is more unique. It has a different shaped bottle, and it basically a Siemens tube developed to run at 300B specs to be drop-in on 300B amps.

I am still getting hours on them before I deep dive on all their nuances and how they compare to new production WE300Bs. That said, the initial sound is VERY nice. They are definitely top-tier 300Bs and its probably one of those things that will be a matter of listening preference and system setup. In particular, the S300B sounds VERY much like a VT-52; cleaner and more exacting than the usual 300B sound, but still possessing the liquidity I find 801A lacking when used as a power tube.

I know there has been some talk around these tubes, so if anyone has something in particular you want me to listen when I get a bit deeper into to the listening, please let me know.

COMMERCIAL DISCLAIMER: Stradi provided the telefunken 242 clones as a sample for product development. I purchased the 2 pairs of 300Bs. Considering there is so little info out there on these tubes, I figure its for the "greater good" of the audiophile community to post up my listening impressions.
Awesome! Thanks for doing this and I can't wait to hear what you think about them.
 
You're not testing their 5u4g by any chance?
 
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I bought one today so lets see...
 
I see Stradi has a 2A3 based on Siemens Eb.
 
OK, so far so super good. I still did not receive the tube but communication with Stradi team (John Kim) is exceptionally pleasant with the info on the shipment provided in timely manner with all the details. This "human interaction" part is really important to me.
On top they've sent me some details how they've been testing this tube model which is nice to know.
"We have been stress testing the Stradi 5U4G since May 23rd - it was manufactured around Feb this year. We tested using a mechanical timer and the test device was turned ON/OFF every 15 minutes (i.e. Repeat 15 min On -> 15 min Off -> ..).
It passed 1000 hours in Sep and is still working well(Nov 19)"
Tube arrives next week and then further info will follow. Stradi 1.jpgStradi 2.jpg
 
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