F6 Amplifier

[Zen Mod]

I expect one or few more tricks from Pa , but it's not mine to reveal them

[lhquam]

Originally Posted by Zen Mod

I expect one or few more tricks from Pa , but it's not mine to reveal them

I am eagerly waiting for them and trying to figure out what they might be. Perhaps I should tweak the circuit and its parameters some more.

[lhquam]

How does this relate to the F6?

Originally Posted by Zen Mod

just for your amusement

pics of next (semi public) Bfish Ikebana



(we must keep this silly thread alive , or Pa will forget to publish bloody article , to stop this agony )

[Zen Mod]

we were talking about Ikebana style prototyping

[Melon Head]

Originally Posted by Zen Mod

I expect one or few more tricks from Pa , but it's not mine to reveal them

All will be revealed on April 1st, 2013

[Antoinel]

Originally Posted by lhquam

I suspect the "boomy" sound on the bass is due to a low damping factor of about 4.6. I estimate the output impedance is around 1.7 ohms. The closed-loop gain is 4.7.

Your loudspeakers were optimized by its manufacturer to work with an ideal voltage source amp [Zo <0.1 Ohms]. Now you drive the same loudspeakers with TEASER 6 of higher Zo = 1.7 Ohms. TEASER 6 gave you [and us] the correct and expected answers. Your build is A+. Its got power, low %THD, is stable with no hum and buzz. Unfortunately, its loudspeaker mate is suboptimal. What is Zo for your F5 build?

• Do know the impedance versus frequency curve of your loudspeaker especially in the midrange; to explain the mud and listener fatigue?
• The classic designs used a voltage gain stage on the primary side of the transformer. kasey197 used a step up transformer to harness more open loopl gain than available as depicted by Conceptual F6. You also have indicated other options to lower Zo!

[buzzforb]

That was the point i was mqking earlier.

[lhquam]

Here is Stereophile Mag's impedance measurement of my B&W CDM1 speakers. Yup, my next tweak will be to lower the output JFET source resistors to somewhere near ZERO ohms, which will increase open-loop gain to around 100 or so. I could also reduce the closed-loop gain below 4.7, requiring an input source capable of higher voltage drive.

Originally Posted by Antoinel

Your loudspeakers were optimized by its manufacturer to work with an ideal voltage source amp [Zo <0.1 Ohms]. Now you drive the same loudspeakers with TEASER 6 of higher Zo = 1.7 Ohms. TEASER 6 gave you [and us] the correct and expected answers. Your build is A+. Its got power, low %THD, is stable with no hum and buzz. Unfortunately, its loudspeaker mate is suboptimal. What is Zo for your F5 build?

• Do know the impedance versus frequency curve of your loudspeaker especially in the midrange; to explain the mud and listener fatigue?
• The classic designs used a voltage gain stage on the primary side of the transformer. kasey197 used a step up transformer to harness more open loopl gain than available as depicted by Conceptual F6. You also have indicated other options to lower Zo!

[buzzforb]

Listener fatigue does not fit what i would expect. I would expect smooth and transparent.

[Antoinel]

Originally Posted by buzzforb

That was the point i was mqking earlier.

buzzforb. I second you opinion and first point you made earlier. You also build and know loudspeakers very well.