Zenquito Variants - SK170 SJ74 ...drive 2SK1058 - Page 2

MiiB · 3rd April 2011, 08:49 AM

Here a model with current mirrors and cascode...a fully scalable design. Just add output sets the needed SOA. It SIM's with rather low distortion and also a good distortion distribution..!!

But must still say that I have a little problem with the split and having complimentary parts handling the signal.

The one J-fet amplifier you previously pulled out of the hat....I fancy that...

Bonsai · 3rd April 2011, 09:00 AM

Quote:

Originally Posted by lineup

This configuration shows very little distortion.
1 Watt 8 Ohm, THD 0.00044%

Max output at +21/-21 Volt is more than 16 Watt.

I really like the simplicity of this circuit Lineup! And the results look very good as well.

WuYit · 3rd April 2011, 09:09 AM

MiiB,
most of the nice features of the original design are gone. The input cascode is OK, but there`s no need for another VAS.

fotios · 3rd April 2011, 09:59 AM

Very nice circuit Lineup! I know that you like very much symmetrical input stages and you are right on this.
We could use the channel bridging mode to increase the output power, keeping thus the supply voltage in low level instead cascading transistors. In such a case, we need 4 channels (instead the ordinary two) for making a fully symmetrical (balanced) from input to output stereo amplifier.
Just an idea, because i have a 2 X 21V / 200VA toroid surplus which can provide an output power (according to bridge mode) of 2 X 70 Wrms / 8 Ohms.

MiiB · 3rd April 2011, 11:07 AM

What do you mean.. The VAS is already there...Here I am just setting the current in The VAS by using current mirrors...this lowers the higher order harmonics...

The Cascodes are there so it can be scaled to higher voltages

WuYit · 3rd April 2011, 12:45 PM

I see that, nevertheless, the cascoding transistor is a voltage amplifier. By adding another voltage amplifying stage and altering the common source stage into source follower the design is made more mediocre compared to the original Zenquito. This amp will behave very differently.

lineup · 3rd April 2011, 12:59 PM

I like the MiiB 60/50 Volt variant.

The original Zenquito can be made in different flavours.
Lower voltage, higher voltage, Class AB, Class A.
See here: 2A & DIY

Personally I like amplifiers with lower power.
It is enough for most cases.

It is striking how simple amplifiers can be designed
with Lateral MOSFET, 2SK1058/2SJ162.
If I was to build a power amplifier I would go this way.

WuYit · 3rd April 2011, 01:23 PM

OK, now I understand, the topology I had in mind obviously has many names, Zenotron, zenItron, Amperotron...I`m very sorry.

3rd April 2011, 09:59 AM	#14
fotios diyAudio Member Join Date: Feb 2007 Location: ΔΡΑΜΑ - North Greece	Very nice circuit Lineup! I know that you like very much symmetrical input stages and you are right on this. We could use the channel bridging mode to increase the output power, keeping thus the supply voltage in low level instead cascading transistors. In such a case, we need 4 channels (instead the ordinary two) for making a fully symmetrical (balanced) from input to output stereo amplifier. Just an idea, because i have a 2 X 21V / 200VA toroid surplus which can provide an output power (according to bridge mode) of 2 X 70 Wrms / 8 Ohms. __________________ Best Regards FOTIS ANAGNOSTOU Direct Contact: eal@dra.forthnet.gr

3rd April 2011, 12:59 PM	#17
lineup diyAudio Member Join Date: Dec 2005 Location: the north	I like the MiiB 60/50 Volt variant. The original Zenquito can be made in different flavours. Lower voltage, higher voltage, Class AB, Class A. See here: 2A & DIY Personally I like amplifiers with lower power. It is enough for most cases. It is striking how simple amplifiers can be designed with Lateral MOSFET, 2SK1058/2SJ162. If I was to build a power amplifier I would go this way. __________________ lineup

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3rd April 2011, 09:09 AM	#13
WuYit Banned Join Date: Oct 2010	MiiB, most of the nice features of the original design are gone. The input cascode is OK, but there`s no need for another VAS.

3rd April 2011, 11:07 AM	#15
MiiB diyAudio Member Join Date: May 2005 Location: Denmark	What do you mean.. The VAS is already there...Here I am just setting the current in The VAS by using current mirrors...this lowers the higher order harmonics... The Cascodes are there so it can be scaled to higher voltages

3rd April 2011, 12:45 PM	#16
WuYit Banned Join Date: Oct 2010	I see that, nevertheless, the cascoding transistor is a voltage amplifier. By adding another voltage amplifying stage and altering the common source stage into source follower the design is made more mediocre compared to the original Zenquito. This amp will behave very differently.

3rd April 2011, 01:23 PM	#18
WuYit Banned Join Date: Oct 2010	OK, now I understand, the topology I had in mind obviously has many names, Zenotron, zenItron, Amperotron...I`m very sorry.

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