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Stradi tubes, anyone tried these?

Gordon and Gang,

Take a look at the Stradi 3A 110B.
1. There is a grid wire Above the top of the plate.
2. There is a grid wire Below the bottom of the plate.

Note: All of my National 45 tubes have grid wires above and below, versus their plate's tops and bottoms.
Therefore, the 'diode action' of a 'filament and plate' Without the grid wire between them, is eliminated!
Just saying that this extra grid wire 'factor' might be one of the characteristics that makes the 45 such a good sounding tube.

Your opinions, please . . .

Thanks!
 
They go on about the frame grid, but really having it above and below the plate structure wouldn't really have any effect I think.
They do go on and on about their frame grid being less microphonic.
My question is that I have never heard of these guys and my user base is large and usually some tube nerd is proding me about new tubes.
I did get on them for the RS241/242 not being true Tele types. I said just rename them because I sold a couple of amps that are Class A/A2 with RS241 and I am pretty sure these would arc over or lock up when hitting A2.
The 2A3 looks interesting, but it's not my fav tube unless you have TungSol single plates. Otherwise most of the new ones are just 300B with the filament folded in half. This one is just a Eb with a different filament which would probably sound great with AC heaters. Problem is most of my users will want an amp that has NOS tube capabilities. Which fine you could work up a 15W 2A3 bias and have it work. But sonically it would be very different.
BTW the 45 is the best sounding tube ever made. The NOS ones are just the best. Actually the amp I am making now.
Thanks,
Gordon
 
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It's interesting to see Stradi talking about optimising for DHT preamps. If it means that they have successfully reduced the microphony in this range of DHTs, it's good for the sound in all applications.

It's a pleasant surprise to see their version of the STC 3A/109 too. Splendid tweeter driver or preamp valve.
 
Your opinions, please . . .
The classic 3/2 power triode model is based on infinite parallel planes, and smaller, finite, surfaces add impurities. Maybe a decent analogy to "overhung" grids might be overhung voice coils, in the sense that they minimize edge fringing effects, but not in the sense that they sacrifice conversion efficiency (because the grid doesn't consume power, and is unipotential anyway).

Very cool to see these craft valve businesses keep appearing. Coming from Korea, expectations should be high.

All good fortune,
Chris
 
Build an underhung voice coil, and the good and bad tradeoffs are well known.

Build an underhung triode grid, and I suspect that part of the tube acts more like a diode, than a triode.
You essentially get a triode in parallel with a diode.
The degree of the effect depends on the area that the underhung grid covers, versus the area the grid does not cover . . . that is the diode area.

The 45 tubes I have seen all have overhung grids.
 
What irks me most with these tube companies is when they say they optimized the original design and then when you look at the specs they have optimized out some of the most elegant things the original had.
Like grid to plate spacing... the closer the higher the gain, lower Rp but then they do mesh and on power up with a directly heated rectifier which heats quickly the damn thing arcs over. Then they change the design to fix that with gold grid and increase the cost 3x.
When the 300B was redone by Charlie the vacuum equipment on the circular workstations were crap so he had to have some re-engineer that. That increased (decreased???) the vacuum by 30%. This dropped the Rp and gave the tube better range.
In the end lets hope they sound and work better than some of the NOS tubes I have.
Thanks,
Gordon
 
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Gordon,

I am so glad that you and countless others in the commercial tube business, let so many magazines publish your schematics, etc.

Your "Baby Ongaku" built and written about by Frank Reps in Sound Practices is one example.
I am quite sure that many diy'ers built it, or were at least inspired to design and build their own.
The Bugle was one of the other examples.

You can put a number on commercial business success.
But it is impossible to measure the impact of your and other's actions that lead to so much fun, and listening joy to others.

Thanks to all of you!


"It is a Mean thing to say that Karl Friedrich Gauss was an Average man, who was Centered on his Gaussian Curve."

 
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