Sound of Zenquito

[JFG67]

To JFG67 : It was joke , nothing serious.

Hello,

Unfortunately French I.T. sunken house it is not a plansantery.
Greece France


@ + JF

 

[Mindaugas]

I have just finished Zenquito amp. It sounds right for my taste, but lacks some transparency and bass could be more controled.

ABO, as I know, you made some useful mods for your zenquito amplifier. With these mods amp could sound a lot better .
Would you be so kind and give me some advices about zenquito modding.
my e-mail: audiofan@takas.lt
Thanks in Advance

 

[UltimateX86]

there is nothing to modify ....

"but lacks some transparency " Zenquito is the transparency even !!!

if you does not have bass, you badly dimensioned it...

Miss a pushpull .... power supply too weak...

which Loudspeaker have you?

 

[ABO]

Mindaugas,

I will send you a private e-mail

 

[gaborbela]

Zenquito

Hello ABO

I built several weeks a go the Zenquito amp , it does not sound bad but I would be interested on your mod. especially if these give a bust to the amp .
Please send any information mathelaszlo@hotmail.com
Thanks
The best regards

 

[gaborbela]

Bump.....

 

[Uunderhill]

I'm planning on building a Zenquito amp, so hopefully those who have experience building one
could share their experiences on how to improve its sonics.

IMO the first issue that stands out is the use of 2n3440 and 2n5416 bipolar transistors.
Looking at the Microsemi datasheet for these , it seems they are just basic switching transistors.
I'm wondering if anyone has tried MJE 182 and MJE 172 , which are designed for low power audio amplifier applications ?

Also, I'm wondering if there is a consensus on what value to use for the gate resistors ?
68 R or 100 R ???

I was thinking of lowering the voltage rails to + / - 24 Vdc , but pushing up the bias current up .
Is there a consensus on how much to increase the total output bias to ?
350 mA ? 400 mA ? more ?

I've bought some Exicon ECX10n20 and ECX10p20 lateral MOSFET's
as a substitute for 2sk1058 and 2sj162 .

Very importantly , has anyone build a power supply they think matches well with the Zenquito ?
As one very knowledgeable designer explained to me, the power supply is 1/2 the amp.
When calculating the output impedance of the total amp, the power supply's output impedance must be calculated in.

.

 

[JFG67]

Hello,

Of course, you can use the MJEs ... You are on low voltage ... so there is no problem
2A & DIY

The trans drivers take all the total power supply voltage
The 2n3440 and 2n5416 allow to make an amp from 50 to 300W without asking any questions (perso 285W Mosquito)

With + / - 24 Vdc there is therefore no problem (48V) ... but ...

You lose + -10V to polarize the output Mos (20V). So you have to think about it

What's left on the way out? ... the dynamics flew, the bass too

The polarization current affects the output class A power
This brings the quality, but not the dynamics (Rise time. Voltage) nor the output power (Voltage)

Review the calculations on Jean-Marc's seat
2A & DIY

15 months and it's retirement ... I should resume my Audio activities
@ soon

 

[N101N]

This brings the quality

Power, not quality.

 

[JFG67]

lol


we will have to work eh

2A & DIY

 

[Uunderhill]

Hello,

Of course, you can use the MJEs ... You are on low voltage ... so there is no problem
2A & DIY

The trans drivers take all the total power supply voltage
The 2n3440 and 2n5416 allow to make an amp from 50 to 300W without asking any questions (perso 285W Mosquito)

With + / - 24 Vdc there is therefore no problem (48V) ... but ...

You lose + -10V to polarize the output Mos (20V). So you have to think about it

What's left on the way out? ... the dynamics flew, the bass too

The polarization current affects the output class A power
This brings the quality, but not the dynamics (Rise time. Voltage) nor the output power (Voltage)

Review the calculations on Jean-Marc's seat
2A & DIY

15 months and it's retirement ... I should resume my Audio activities
@ soon

JFG67,

Thanks for the useful tips on building a Zenquito.

Your comment explains why Jean-Marc used 2n3440 and 2n5416 's,
because they have a Vce (max) = 250Vdc and so are set for other amp's with higher voltage rails.
Where as the MJE 182 and MJE 172 have a Vce (max) = 80 Vdc.
But again, in an amplifier, there is a world of difference between a transistor designed for switching
and one designed for audio.

Good point about loosing about 10 Vdc off the voltage rails because of the pair of MOSFETs.

Also, as I am beginning to realize, the output impedance of the power supply is very important.

Retirement is good - I highly recommend it.
Haguenau seems to have quite a long history - You know its in the series Band of Brothers.

.

 

[JFG67]

>>>>
But again, in an amplifier, there is a world of difference between a transistor designed for switching
and one designed for audio.


Hello,

Bah, for your fight. And given the low tension. You can try the MJE or the 2N (or other transistor) and see what it gives.

Personally, the strong quiescent currents make a significant difference (Jean-Marc witnessed this on Mosquito)
I am a follower of class A. Or Class AB (Mosquito) with high rate of class A.

And personally ... on Zenquito Mosquito GrandMos (Crescendo / Balaise) the difference is undeniable ...

greetings

 

[JFG67]

Power, not quality.

Do you have any other conneries to tell?

I ate my carrots and I'm in a good mood ... lol

Hi

 

[N101N]

Where is the actual electronic schematic, please?

 

[Uunderhill]

The schematic of the Zenquito Amp can be found here.

2A & DIY

2sk1058 and 2sj162 lateral MOSFET's may be difficult to source.
Exicon manufactures ECX10n20 and ECX10p20 's as a direct replacement.

.

 

[N101N]

Thank you, Uunderhill. I am not fond of high rail voltages and paralleling. It should not be impossible to find Hitachi FETs, what is important is to use lateral FETs.

 

[EUVL]

2Sk1058 / 2SJ162 are still quite widely available.
For example :
RENESAS 2SK1058 2SJ162 Power MOSFET


Patrick

 

[EUVL]

And they are not obsolete, only NRND,
2SK1058 - N Channel MOSFET | Renesas
2SJ162 - Silicin P Channel Mosfet | Renesas


Patrick

 

[fab]

Thank you, Uunderhill. I am not fond of high rail voltages and paralleling. It should not be impossible to find Hitachi FETs, what is important is to use lateral FETs.

This referenced website from Uunderhill also includes the Zenotron which is a more simple design and suitable for class A operation and lower rail voltage.. Just a note for those who do not know. Pass F5 is the same topology as the Zenotron topology (also kit sold from Solectron) but with vertical mosfet at output to improve the too low damping factor of the Zenotron. F5 is also using an jfet ID closer to IDSS and a “double” return feedback path.

To benefit from Lateral mosfet audio character with such a simple topology but with a higher damping factor I have created the USSA-3 amplifier - which also uses an higher jfet ID and same feedback return as the F5. The USSA-3 also has more drive capabilities with a driver and double die lateral mosfet. Later Pass created the F7 amplifier using Lateral mosfet but with the positive feedback approach to increase damping factor but no driver nor double die output.

Fab

 

[N101N]

Just go for the Hitachi MOSFETs to get a much nicer sound and ignore the damping factor mumbo jumbo.