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Swordfishy/ASPEN FETZILLA power amp

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Hallo Hugh.

Thank you for given reply my little DIY Work.
Oh, yes i'm proud that i got the Amp running- but it's real simple to do,
when you read instruction.
So it makes lucky how good the Sound comes out- musically and begins
floating the Room- from simple, but good, DIY Speaker.
My Capacitor choice- Nichicon QXP+ parallel 10n PIO KU40-9 works very well.
The Amp works every long Day now.
I'm a Listener to different Music, like you from sixties to eighties and brass, Bigband- with these Speaker touching you.
That amps is sounding what i was long Time searching.
Now it's time that the Amp moved in a beautiful case.

DIY is the nice possibility to create or rebuild and handcrafted your own.

I've read You was surprised, about success these Amp, you don't should.
It seems that is a Gift for all of us understanding what was written long
Thread here.
My Amp is working on 370mA and all is in good condition touchable.
If we take a side glance to also very successful Nelson F5 Amplifier, so we
could say we have a much more economical One here, this way.

The F5 is an other Chapter, i have assembled a Clone, but he is burning so
many more Heat out with only 500mA max. quiescent and lowered Voltage,
that i swapped without repentance.
But without input Cap........ other Way.

So many Impressions in DIY Audio Forum here.
Many to read, to Test self and learning given Stuff.

Best Regards.
Hagen.
 
Hagen,

Thank you for your comments on the FetZilla, appreciated, and the fine work you did to bring a FetZilla to life! But in fact there were lots of other people in the development of this amp; the 'Father' was Lineout, from Sweden, and the 'Wireman' who did all the work was Greg Peters, from Queensland, in the north of Australia. There was a lot of input from Mikelm, who added a lot to powersupply and input stage, and Paul Bysouth in Melbourne who added the hybrid bootstrap system which magnifies the voice qualities whilst delivering strong bass. I merely did the layout, which was largely based on my present commercial amps.

BTW, if you want EVEN BETTER performance, see my NAKSA and Maya amps. They will cost you money, but they are much, much better than the FetZilla and deliver the 'house sound' that Aspen is famous for.

Meanman,

Did YOU solder a 100k across C5? I am very interested in your results!

Hugh
 
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solder a 100K resistor at C5(PL) ?

Hallo Patrick & Hugh.

No i have not soldered the 100k in PL position in moment, but i have noticed
that and write a note for my remind to do it to find out the Differenz.

Yes i also registered the much work by your named members here by reading
along the thread.
The done work together here i can only say GREAT THANKS! :D
It is amazing clever with only 5 Transistors to get so superb result.
I am only in position to assemble it and enjoy with not so bad ears, i think
the musicality and 3D imaging.
In last days i have also visit your website again, to see what you are actually sell.
Also i have read about how much time it needs, for you, to give a Ampwork
ending OK for the market.
For that reason we can trust that they are very good performer.

I'm in parallel tested the VSSA- Jason, Boards from Patric, that one i would
prefer for movie watching on TV because clearance and 3D Imaging,
but to listen music i prefer FetZilla there is a magically colored tonality with
fuller tones, difficult to describe.
That has to be test out with different Speakers to find the right playing partner.
On VSSA i test yet the FE126En Hybrid Horns- i like that one long time now.
That also is to do with Fetzilla- a overdue yet.
If i also tested a little ACA- Pass amp i have had a bit contact with 2picoDunmbs, who lives in your neighborhood.
DIY Audio is so many inspiring Stuff. :eek:

Next time i will test out the 100k and give a comment.

Regards Hagen.
 
I calculate my Fetzilla has been powered up for about 26,000 hours. I recently upgraded the transformers to some made by Harbuch, 160VA's. The amp still sounds sweet and very balanced, we use it in our home entertainment driven by a NAD M51 and its a really nice combo. It only gets powered down when we shift or when I'm reconfiguring or tweaking. I'm seriously considering replacing the blocking caps with V-cap TFTF as I have a pair I've been holding onto for a couple of years used in various amps and DAC's,not due to any issues with sound but wonder whether it will improve over the Auricap.
The other current main amps in the house are a home built LM3875 with tube buffer and regulated PSU (Teddy Pardo Powerreg), a Parasound A21, and last but definitely not least, a Naksa 80.
I run the Naksa and the Parasound from a Plinius M8 into different pairs of speakers just so I can switch for different music/moods. I'm just finishing up a simplistic phono stage build and then I will be in audio heaven with my happy mid-fi setup.
 
Hi Andrew,

Wow! 26,000 hours! That's a long time, more than the life of a good diesel engine in a large truck..... talk about durability. Maybe this is the good active components, huh?

Question: How does your FetZilla compare with the NAKSA? I am about to replace the NAKSA 80 with a new, super AKSA, which I will call the SAKSA! It will use the same footprint and general appearance - even the same transformer - as the NAKSA 80 and will sell the same price.

Sound quality? A marked step up..... very punchy, very strong bass, more resolution, and a cleaner top end. Same spatial characteristics, and similar power - 85W into 8R. I have upgraded the output stage for about double power so it can easily drive 4R loads, and should be impossible to break.

Living in Sydney or Perth? Congratulations on your good job, difficult market, a strong, hard effort.

Cheers,

Hugh
 
Hi Hugh - I'm in Perth and now occasionally hop over to Melbourne I'll definitely be interested in the new module. the Fet vs Naksa - well Naksa has it in detail and soundstage but the Fet just sounds great in a very non fatiguing way. It's probably the one amp I'll always keep and its sound signature suits its application as our AV 2ch amp. The Naksa will be the one I listen to in my main music rig. Congrats to the design team on the FET and of course the lovely PCB design which made it a cinch - I really look forward now Hugh to having more time to experience your Amps - in time I will be in touch.


Sent from my iPhone using Tapatalk
 
Hi Ben,

Using laterals I cannot achieve the very high transconductance in my new amps to reduce the compressive distortion which permits me to use very little global feedback. Therefore I use VFETS, in fact I generally use Fairchild and IXYS devices. Their gm is far higher than even large bipolar transistors, and they have vanishing low Rdson with huge current, voltage and dissipation parameters. Driven correctly, and this is difficult because the gates have very high Ciss capacitance, they work very, very well.

Andrew,

I expect you to take the Hurstbridge line to Rosanna next time you visit Melbourne. It's 28 minutes from the CBD, and we have good coffee - and a good listen to my next Maya, warmed and ready!

Now that you are a Fat Prophet you will be able to easily buy my technology now!

Cheers to both of you!

Hugh
 
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HI,

A VDMOS version by Ian Hegglun

*VDMOS with subthreshold (c) Ian Hegglun Apr 2019
.model ZVP2110G VDMOS (pchan Rg=65 Vto={-(2.8-6m*(temp-25))} Lambda=6m
+ Rs={2*(1+3.5m*(temp-25))} Kp={0.17/(1+8.8m*(temp-25))}
+ Ksubthres={0.15*(1+4m*(temp-25))} Mtriode=0.5 Rd={2.5*(1+5m*(temp-25))}
+ Cgdmax=20p Cgdmin=3p a=0.5 Cgs=140p Cjo=60p Tnom=Temp
+ m=0.5 Vj=0.75 N=3 Is=5p Rb=1 Vds=-100 Ron=8 Qg=2nC mfg=DioInc1904)


https://www.diyaudio.com/forums/sof...wer-mosfet-models-ltspice-24.html#post5769898
 
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