C3g triode-strapped linearity question

[Joshua_G]

Well you need to decide what you want first as a bjt could not be the best choice for MM input or at least it will not be the best for the circuit I told before. The noise figure changes quite a lot because of the different source impedance for sure. It works very well with low impedance sources like MC's.


Because I don't know the MAT03? The actual transistor is not really the point, there are some just as good. It is rather the type and its application.

Thank you.
I'll probably use SUT.
For getting the picture clear, if I'd like to have the first stage SS, cascoded by a tube, to be switchable between MM and MC, is JFET a better choice than BJT?

 

[euro21]

At 30mV output, you're probably measuring the distortion of the source.

30mV was the generator output (after the inverse RIAA), i.e C3g input. C3g output about 1.2V.

 

[SY]

Thanks for clarifying.

 

[45]

Thank you.
I'll probably use SUT.
For getting the picture clear, if I'd like to have the first stage SS, cascoded by a tube, to be switchable between MM and MC, is JFET a better choice than BJT?

Too general question.
I would go for the low noise/low frequency BJT (MC input). Maybe JFet for MM.

 

[euro21]

In this year Hungarian Spring Triode Fest my presentation was the designing and measuring the prototype phono (now still breadboard state 🙂 ): C3g, C3g, D3a.

Both C3g and D3a distortion was very low.

This spectrum is fresh measurement.

 

[SY]

Topology is pretty similar to His Master's Noise. GMTA!😀

What voltage is 0 dB in that plot?

 

[euro21]

Phono 10mV RMS input, 1.75V RMS output.
From the phono output 100k attenuator to EMU0404 soundcard.
0dB is 0dBm in my voltmeter (two channel Kenwood VT176).

 

[Joshua_G]

In this year Hungarian Spring Triode Fest my presentation was the designing and measuring the prototype phono (now still breadboard state 🙂 ): C3g, C3g, D3a.

Both C3g and D3a distortion was very low.

This spectrum is fresh measurement.

Thank you.
Why did you choose C3g and D3a?
The measurements look excellent.
Do you have some initial listening impressions?

 

[euro21]

Why did you choose C3g and D3a?

I bought few dozens of C3g (used tubes, but all working state) at fair price. The matching measurements shows it's potential. Low noise, good linearity, very useful tube for small signals, and excellent driver tube (low THD at very large level).

D3a is the first tube of my amplifier (D3a, CCS, Powerdrive, 300B), very good tube.

Do you have some initial listening impressions?

No, this is the prototype.

 

[Joshua_G]

Thank you.
Please update once you'll have listening impressions.