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In the Forum: Melquiades Amplifier
In the Thread: Super Melquiades Amplifier.
Post Subject: Super Melquiades vs Melquiades treble channelPosted by cv on: 7/17/2005

domperidone sirop

domperidone eureka
Romy,
Now you mention the issues here, I am thinking about what the differences in quality might be due to. I notice that you haven't explicitly said which is better, super or regular... so think of this just as brainstorming as to why things are... different.

The single section 6C33 should theoretically be purer sounding than both halves in use.

Now, as regards the small coupling/high pass capacitor, the filter will have a high output impedance at the x/o frequency.

If you are crossing over at 1kHz, then your RC filter will look something like 1.6nF/100k grid resistor(correct me here if I'm way off the mark).

I make that a driving impedance of around 70k into the 6C33 at the x/o frequency.
This is fine relative to the load presented by a 6C33 grid in engineering terms, but as the input capacitance of the 6c33 varies with signal, it may be that the high Zout of the coupling circuit is not dealing with it as well as before, where the Zout was lower.

You might investigate this by trying a 10nF/16k filter but that would start to load down the driver stage.

Anyway, this post was probably very premature, given that you haven't gotten to the bottom of the differences. I merely suggest these points for experimentation should you end up disatisfied with the new treble channels.

cheers
cv

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