ZEN Again....Class eh
FTGV
Posts: 3,649
This little beast was my first foray into DIY amplification some 15 +years ago .After reading Nelson Pass's ZEN article in Audio Amatuer I knew I had to build it.However about a year later I ended up trading it for some speaker parts, but I recently reaquired it as the person with whom I traded it has had it in storage for many years and had no need of it.(It's limited ouput makes it only practical for use with high sensitivity speakers like Klipsch Horns etc.)
Unlike today back then I did'nt have many options for the chassis so I opted for a pair of Sescom units and built it in two pieces, with the amp circuit and power supply each having their own chassis.It's not pretty but it worked.
The circuit itself is as simples it gets,a single MOSFET that delivers about 10watts of single ended Class A into 8 ohms.The power supply is monterous for such a small amp consisting of a 300VA Plitron toroidal transformer,80,000uf of filter capacitance and a pair of Solen air core inductors provide some additional noise filtration.
Since it had not been fired up in some years I first bench tested it to make sure it was still operational.Thankfully it worked just fine,only needeing some minor tweaking to insure that clipping would be symetrical.
As expected distortion measured on the high side(.5%THD) but since it is mainly of the second harmonic variety will be less audibly offensive whilst adding some extra "warmth" and "character".
For nostalgic reasons It's nice to have one of my old projects back in house to see how I did things in the early days of my DIY journey.
Unlike today back then I did'nt have many options for the chassis so I opted for a pair of Sescom units and built it in two pieces, with the amp circuit and power supply each having their own chassis.It's not pretty but it worked.
The circuit itself is as simples it gets,a single MOSFET that delivers about 10watts of single ended Class A into 8 ohms.The power supply is monterous for such a small amp consisting of a 300VA Plitron toroidal transformer,80,000uf of filter capacitance and a pair of Solen air core inductors provide some additional noise filtration.
Since it had not been fired up in some years I first bench tested it to make sure it was still operational.Thankfully it worked just fine,only needeing some minor tweaking to insure that clipping would be symetrical.
As expected distortion measured on the high side(.5%THD) but since it is mainly of the second harmonic variety will be less audibly offensive whilst adding some extra "warmth" and "character".
For nostalgic reasons It's nice to have one of my old projects back in house to see how I did things in the early days of my DIY journey.
Post edited by FTGV on
Comments
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Kewl, congrats !Speakers: SDA-1C (most all the goodies)
Preamp: Joule Electra LA-150 MKII SE
Amp: Wright WPA 50-50 EAT KT88s
Analog: Marantz TT-15S1 MBS Glider SL| Wright WPP100C Amperex BB 6er5 and 7316 & WPM-100 SUT
Digital: Mac mini 2.3GHz dual-core i5 8g RAM 1.5 TB HDD Music Server Amarra (memory play) - USB - W4S DAC 2
Cables: Mits S3 IC and Spk cables| PS Audio PCs -
That's great.
The prodigal son returns....:biggrin:
Not many guys can say what you just did. It's like getting an old favorite car back. Just like Papa John getting his old car back. There's something special about these kinds of reunions...:cool:Most people just listen to music and watch movies. I EXPERIENCE them. -
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Nothing like getting back to your roots. Love the muffin fan in the top.
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Nice slippers."He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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It's got a fan to extract fumes? I say you are covered for the smoky situation.
And What's Class eh? :biggrin:Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin: -
. Love the muffin fan in the top.
And What's Class eh? :biggrin: -
Thats what we call Class A north of the 49th parallel.
It must make your igloo extra warm in the summer? :biggrin:Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin: -
It must make your igloo extra warm in the summer? :biggrin:
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I've heard that the really cool guys on the diy audio scene build a Pass clone as their first project.
Did I tell you I just got done building and F5, my first amp?Wristwatch--->Crisco -
Did I tell you I just got done building and F5, my first amp?
btw.did you ever get that BurrBrown dac eval board working? -
It must make your igloo extra warm in the summer? :biggrin:
Very classy DIY vintage GV! :cool:DARE TO SOAR:
Your attitude, almost always determine your altitude in life -
So,, whats the power output--I'm assuming it's class a--nice work indeed sir.JC approves....he told me so. (F-1 nut)
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george daniel wrote: »So,, whats the power output--I'm assuming it's class a--nice work indeed sir.
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And What's Class eh? :biggrin:"He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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Congrats but as they say Pics or it didn't happen.
btw.did you ever get that BurrBrown dac eval board working?
Yessir, had it up and running within a couple months of receiving it. Still haven't built a faceplate for the chassis it's in, but that doesn't impair function....
Was actually thinking about what I could do to take it up a notch or so, I may drop you a line at some point if that's ok.Wristwatch--->Crisco -
Yessir, had it up and running within a couple months of receiving it. Still haven't built a faceplate for the chassis it's in, but that doesn't impair function....
Was actually thinking about what I could do to take it up a notch or so, I may drop you a line at some point if that's ok.
Yes there are a couple of things that can be done to squeeze a bit more performance out of it.Feel free to drop me a line any time. -
A is not a word in the Canadian dictionary. Have you ever spoken to eh Canadian in person before? :biggrin:
BTW; this is stepping away from the OP (sorry GV) but did you know that we are about to have an eh-lection eh-gain? I pray this is the last one for eh-while, eh-men!DARE TO SOAR:
Your attitude, almost always determine your altitude in life -
I pray this is the last one for eh-while, eh-men!
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In complete contrast to the Zen here is my current amp build using the Hypex Class D modules.These compact 2.75" x 2.75" modules are capable of 90 ish watts into 8 ohm's and 180 w into 4 ohms with the power supply I'm using.Other than the use of Mosfet's and large toroidal transformer (650va) there is little similarity between the two.With efficiency approaching 9x that of the Zen means very little excess heat is generated thus only minimal heatsinking is required.
btw.they are socks not slippers. -
I think you can make Class AD hybrids out of marrying Zen and Hypex.
You still wearing that same socks from a week ago?Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin: -
I think you can make Class AD hybrids out of marrying Zen and Hypex.You still wearing that same socks from a week ago?
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Then be sure to put the X beside Steven on your ballot and maybe there won't be.DARE TO SOAR:
Your attitude, almost always determine your altitude in life -
Just depend if he gets eh m-eh-joe-rity this time eh-round, eh?
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.5 % THD should'nt sound any good right? Not true from what I'm hearing with it hooked up to a pair of low sensitivity mini monitors (approx 86db).While the obtainable levels where lower than I would ideally want it sounded very good indeed with a smooth sweet top end and articulate midband.Definately a strong indicator to me that measurements of electronics atleast ,don't necessarily corelate with what we hear.Now I guess I need to be on the lookout for a higher sensitivity DIY speaker to mate with it plus a nice single chassis and better heatsinking.
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.5 % THD should'nt sound any good right? Not true from what I'm hearing with it hooked up to a pair of low sensitivity mini monitors (approx 86db).
Watcha talking about all of a sudden? :biggrin:
I suppose depends on the SPL and frequency but 0.5% can't be heard mostly. If 0.5%THD can be heard, I am pretty sure the Tube guys will never say "Tube Rulz" in the first place. :biggrin:Now I guess I need to be on the lookout for a higher sensitivity DIY speaker to mate with it plus a nice single chassis and better heatsinking.
I think high sensitivity speakers does not bode well with 0.5%THD though.Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin: -
Watcha talking about all of a sudden? :biggrin:I suppose depends on the SPL and frequency but 0.5% can't be heard mostly. If 0.5%THD can be heard, I am pretty sure the Tube guys will never say "Tube Rulz" in the first place. :biggrin:I think high sensitivity speakers does not bode well with 0.5%THD though.
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Just some demented ramblings after hearing it for the first time(today) in years.
I think the high THD makes people think it's more life like. After all, we are used to noise all around us. Without noise, humans must feel lonely and lifeless.True enough,but there are ojectivists that might suggest .5% must sound inferior to .005%.
All I can say is that something with low THD makes me more electronics purists though.
Leaving the world of audio, noise is a lot more concern in the other applications.
But audiophiles makes more noise about the higher THD than any other one on the planet. Coz we humans fear sound that we can't hear and things we can't see; etc. :biggrin:Certainly having lower signal to noise ratio's will be benificial with higher sensitivity speakers I don't see the higher THD being any more of an issue with them.
No issue but speakers with high enough sensitivity will make you hear some noisy sounds?Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin: -
Your average speaker has more than .5% distortion, I wouldn't worry about it Fred."He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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Your average speaker has more than .5% distortion, I wouldn't worry about it Fred.