ZEN Again....Class eh

FTGV
FTGV Posts: 3,649
edited April 2011 in DIY, Mods & Tweaks
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.
Z1.JPG 256.2K
Z2.JPG 272.5K
Z3.JPG 363.9K
Z4.JPG 372.3K
Post edited by FTGV on
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Comments

  • thsmith
    thsmith Posts: 6,082
    edited April 2011
    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
  • Tony M
    Tony M Posts: 11,009
    edited April 2011
    That's great.:wink:

    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.
  • zingo
    zingo Posts: 11,256
    edited April 2011
    It's always nice to have an old friend back again. :smile:
  • jinjuku
    jinjuku Posts: 1,523
    edited April 2011
    Nothing like getting back to your roots. Love the muffin fan in the top.
  • Face
    Face Posts: 14,340
    edited April 2011
    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
  • megasat16
    megasat16 Posts: 3,521
    edited April 2011
    It's got a fan to extract fumes? :tongue: 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:
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    jinjuku wrote: »
    . Love the muffin fan in the top.
    It's just an orament now as it didn't improve air flow over the heatsinks which is what would be needed for it to be effective.
    megasat16 wrote: »

    And What's Class eh? :biggrin:
    Thats what we call Class A north of the 49th parallel.:wink:
  • megasat16
    megasat16 Posts: 3,521
    edited April 2011
    FTGV wrote: »
    Thats what we call Class A north of the 49th parallel.:wink:

    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:
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    megasat16 wrote: »
    It must make your igloo extra warm in the summer? :biggrin:
    You bet,I can almost boil water on it.
  • strider
    strider Posts: 2,568
    edited April 2011
    I've heard that the really cool guys on the diy audio scene build a Pass clone as their first project. :wink:

    Did I tell you I just got done building and F5, my first amp? :smile:
    Wristwatch--->Crisco
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    strider wrote: »

    Did I tell you I just got done building and F5, my first amp? :smile:
    Congrats but as they say Pics or it didn't happen.


    btw.did you ever get that BurrBrown dac eval board working?
  • TECHNOKID
    TECHNOKID Posts: 4,298
    edited April 2011
    megasat16 wrote: »
    It must make your igloo extra warm in the summer? :biggrin:
    Actually, if he could invert the fan it would generate air conditioning. :eek::confused: That all is you need to keep the ice box at the desired temperature. :wink:

    Very classy DIY vintage GV! :cool:
    DARE TO SOAR:
    “Your attitude, almost always determine your altitude in life” ;)
  • george daniel
    george daniel Posts: 12,096
    edited April 2011
    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)
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    So,, whats the power output--I'm assuming it's class a--nice work indeed sir.
    Thanks George, if your AC line can give you 120volts it will output about ten watts of single ended Class A goodness.
  • Face
    Face Posts: 14,340
    edited April 2011
    megasat16 wrote: »
    And What's Class eh? :biggrin:
    A is not a word in the Canadian dictionary. Have you ever spoken to eh Canadian in person before? :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
  • strider
    strider Posts: 2,568
    edited April 2011
    FTGV wrote: »
    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
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    strider wrote: »
    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.
    Awesome Ben!I assume your liking the results?
    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.
  • TECHNOKID
    TECHNOKID Posts: 4,298
    edited April 2011
    Face wrote: »
    A is not a word in the Canadian dictionary. Have you ever spoken to eh Canadian in person before? :biggrin:
    Hum, you are right A is not a word for a Canuck but rather a vowel but eh is both a vowel and a word, eh?:wink:

    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” ;)
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    TECHNOKID wrote: »
    I pray this is the last one for eh-while, eh-men!
    Then be sure to put the X beside Steven on your ballot and maybe there won't be.:wink:
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    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.:tongue:
  • megasat16
    megasat16 Posts: 3,521
    edited April 2011
    I think you can make Class AD hybrids out of marrying Zen and Hypex.

    You still wearing that same socks from a week ago? :tongue:
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    megasat16 wrote: »
    I think you can make Class AD hybrids out of marrying Zen and Hypex.
    Would that make it a ZenPex or HyZen?Anyway good thinking but it might be a challenge to get a smooth transition from Class A -D.:smile:
    You still wearing that same socks from a week ago? :tongue:
    No smarta$$ thats my other pair.:tongue::biggrin:
  • TECHNOKID
    TECHNOKID Posts: 4,298
    edited April 2011
    FTGV wrote: »
    Then be sure to put the X beside Steven on your ballot and maybe there won't be.:wink:
    Just depend if he gets eh m-eh-joe-rity this time eh-round, eh? :wink:
    DARE TO SOAR:
    “Your attitude, almost always determine your altitude in life” ;)
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    TECHNOKID wrote: »
    Just depend if he gets eh m-eh-joe-rity this time eh-round, eh? :wink:
    He He thats why we all have to do our part and vote for uncle Steve eh.:wink:
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    .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.
  • megasat16
    megasat16 Posts: 3,521
    edited April 2011
    FTGV wrote: »
    .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:
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    megasat16 wrote: »
    Watcha talking about all of a sudden? :biggrin:
    Just some demented ramblings after hearing it for the first time(today) in years.:tongue:
    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:
    True enough,but there are ojectivists that might suggest .5% must sound inferior to .005%.

    I think high sensitivity speakers does not bode well with 0.5%THD though.
    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.
  • megasat16
    megasat16 Posts: 3,521
    edited April 2011
    FTGV wrote: »
    Just some demented ramblings after hearing it for the first time(today) in years.:tongue:

    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. :tongue:
    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:
  • Face
    Face Posts: 14,340
    edited April 2011
    Your average speaker has more than .5% distortion, I wouldn't worry about it Fred. :D
    "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
  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    Face wrote: »
    Your average speaker has more than .5% distortion, I wouldn't worry about it Fred. :D
    Yes agreed Mike I know distortion in loudspeakers is usually many times that.My point being that low harmonic distortion is a poor indicator of SQ in amplifiers.