Article - Sony VFETs part 1

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#841
wengtech said:
can everyone give an explanation:
which one correct, is it IT or OT used at the CSX1 or CSX2
because JT112L and JT123FLPCH are the Output Transformer

thanks.
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They are transformers, where you put them determines if they are input, output or interstage. 🙂

So I would call them input or possibly interstage if you run the buffer on the input.
 
#843
wengtech said:
so you mean it is no problem where to put the transformer right? (in/out)

and also the JT112L and JT123FLPCH are sold as the Output Transformer, correct?

thanks.
Click to expand...

Transformers like all electric components have charictoristics that make them better for some applications than others and that doesn't preclude you from using them in other positions.

So it's not a problem to put a line transformer in the front because it can be a input or output. In the case of the Jensen transformers they are pretty generic and can be used for many applications.

Or I could just say yup, no problem 🙂
 
#845
Dear Wengtech, I recomend, probably many members will agree with me, there are an incredible book made for Morgan Jones, Vacuum tube amplifiers 4th edition, you can read from no knowledge, like me to be a smart «intrepreteur» in electronic applied to audio.
 
#847
Oh yes this book.
That book does not bring a single page or detail to spare. I have the third edition and now with the IVth to bring it up to the third but modernized with new topics. That book if you have a little patience, you not only learn basic concepts, digestible mathematics is one hundred percent clear examples and even a dose of English ironism.
 
#851
2SK82 have low MU , so no much trouble here , i have tried a LM337 regulator too can't say if it 's less noisy cause there is no noise with this kind of amp 🙂

for information , i have changed my CSX1 in Ironamp SIT as michael 's one with minor changes in the power supply . very similar animal , the CSX1 was perhaps the more transparent and the ironamp seems more tubey to me but it's only because i want it too .. the major change i have found is with input
transformer , i have one pair jensen 1:1 to test with a pair of Cinemag and a pair lundahl 1592 to come , funny time!
 
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#853
Nelson Pass said:
I have not played with the Lundahl, but Cinemag makes a transformer which
duplicates my result with Jensens. It has a little different pin-out, although I
have someone looking into getting them with the same pins.

😎
Click to expand...

i have also mesure my new built ironamp with a CAP resistor input and the
Cinemag 1:1 input transformer i get 1,3% distorsion with the transfo and 0,3% with a 10uf cap input coupling 😕

i still prefer the sound of the transformer input .. but perhaps i love good distorsions 🙂
 
#854
MY CSX1 build is progressing nicely but I have one quick question about adjusting the reference voltage prior to startup. Do I just leave the SITs out and adjust the initial reference from pins installed on the pads marked below? After that I install the SITs and I'm good for the next step?

Regards,
Dan

CSX1Bias_zpsa126ddcf.jpg
 
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#858
I plan on a separate power supply chassis with both power, and bias transformers in it. I will have the 2 chassis stacked for testing, and would like to be able to turn off the big ones, and do the bias correction from the top of the amp chassis. I suppose one could just unplug the 32v positive lead at the amp board, which probably would be the easiest. Would just need to protect it from ground during the procedure.

I do like the terminal blocks too, it make it easier to take a look and be certain of what is hooked to what.
 
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