CC-CCS-X-BZLS: It's alive!

[eLarson]

cascoded ZVN3310: How low can you go?

How low a Vds can you get by with when using a ZVN3310 in a cascode? 5V? 10V?

Before I order some (and I suppose I could just order a bunch and back off if I burn them up) I was curious if anyone actually tried it.

 

[metalman]

Rough rule of thumb:

V(DS)min > V(GS) + V(signal)max

i.e. take the signal output voltage at no attenuation, and add the gain device Vgs, and take that as the minimum value.

Cheers, Terry

 

[coloradosound]

Found it! It would be similar to the Unity Gain Buffer
stage in the Denon DAP-5500. But maybe also
paralled sets on input as well?

 

[coloradosound]

The unity gain buffers are the 4 paralled 2SK170BL/J74BL
sets.

 

[coloradosound]

or a little closer.

 

[coloradosound]

Even closer on just the single ended unity gain interface
which is meant to drive the RCA pre-outs.

 

[coloradosound]

I'm assuming that the 2SC2238/2SA968, 2SK184'ss and HZ5C's
are for coscoding.

 

[Nevod]

Have a question.. Is it suitable for use as a headphone amp(for balancified cans of course)? Also, I'm especially interested in getting rid of output capacitors - if they were out of FB path, it would seem easy, but here, they're within..

 

[metalman]

With this particular topology the capacitors are necessary, and as such I decided to enclose them within the feedback path to ensure any distortion they produced is compensated.

One could add a current mirror arrangement to place the circuit output near ground, thus eliminating the need for the ouput caps (see the UGS threads), but since a preamp is outputting to a (supposedly) relatively high intput impedance of a power amplifier, the relative impedance of a 10uF film cap is negligible compared to the input impedance of a decently designed power amp.

Hope this make sense to you. I've been enjoying a Jackson Triggs Pinto Noir this eveining, and it may be affecting my clarity!.

Cheers, Terry!

 

[metalman]

Forgot to address the headphone question. The answer depends on the impedance of your headphones. For relatively high impedance headphones, you should be ok driving them from the preamp. In my case, where my Grado Labs are 32 ohm impedance, I benefit greatly from having a dedicated headphone amp which makes the dynamics really pop. Personally, I'd advise having a proper headphone amp. Not very difficult to build, and it makes a real difference.

My two cents!

Terry

 

[Nevod]

metalman
It's just that I like the "CC-CCS-X" conception in general. Though I'm also curious of current drive, and may try a F1 for headphones.. Even though it's not probably a best match.