**** ANNOUNCING ****
A contest. There two prizes. A first place prize and another first place prize. The idea of the contest was approved by Mr. Pass before I made this post.
Each prize is a matched quad of LU1014D from the Pass stash. There are exactly two of these quads in my hands from the 500 piece stash that I matched.
The rules are simple. You design a SUSY LU1014D amplifier and post a working LT SPICE model of the amp you designed including all files to run the sim. If you do not know what SUSY is, if you are not versed in LT SPICE, you have to go figure it out. Hopefully your design will be one to three stages max just like the Firstwatt and Pass Labs amps that are discussed and cloned (with the blessing of Mr. Pass) on this forum.
I will likely confer with one or more DIY members to pick the winners. If there are more than two great submissions, I may award matched quads from my personal stash at my discretion. The picking of the winners could be totally capricious which would make the contest more of a lottery and not the first lottery of Pass stash parts.
Ground rules. No arguing or complaining. Just submit your design and be patient. This contest is intended to generate interest and discussion and bring out some new designs of the LU1014D. There are lots of these parts in the surplus market. I have purchased hundreds of them and they are genuine triode curve parts.
The contest will be open for one calendar month ending July 12th.
Let the submissions begin.
A contest. There two prizes. A first place prize and another first place prize. The idea of the contest was approved by Mr. Pass before I made this post.
Each prize is a matched quad of LU1014D from the Pass stash. There are exactly two of these quads in my hands from the 500 piece stash that I matched.
The rules are simple. You design a SUSY LU1014D amplifier and post a working LT SPICE model of the amp you designed including all files to run the sim. If you do not know what SUSY is, if you are not versed in LT SPICE, you have to go figure it out. Hopefully your design will be one to three stages max just like the Firstwatt and Pass Labs amps that are discussed and cloned (with the blessing of Mr. Pass) on this forum.
I will likely confer with one or more DIY members to pick the winners. If there are more than two great submissions, I may award matched quads from my personal stash at my discretion. The picking of the winners could be totally capricious which would make the contest more of a lottery and not the first lottery of Pass stash parts.
Ground rules. No arguing or complaining. Just submit your design and be patient. This contest is intended to generate interest and discussion and bring out some new designs of the LU1014D. There are lots of these parts in the surplus market. I have purchased hundreds of them and they are genuine triode curve parts.
The contest will be open for one calendar month ending July 12th.
Let the submissions begin.
I'll refrain, few reasons:
- have plate(s) full, and involvement couldn't stop at posting sim schm
- don't need a Prize (well, that's trivial reason)
- as I said few days ago somewhere, after all these years in Papaland, playing with Passlegos is, if not easy, at least second nature ....... so Prize Task is easy; maybe I even already have something simmed in my PC.........if not, will think about at least 6 possible scenarios, and - if ever - post after Contest end
Lets Roll ....... I like idea !
- have plate(s) full, and involvement couldn't stop at posting sim schm
- don't need a Prize (well, that's trivial reason)
- as I said few days ago somewhere, after all these years in Papaland, playing with Passlegos is, if not easy, at least second nature ....... so Prize Task is easy; maybe I even already have something simmed in my PC.........if not, will think about at least 6 possible scenarios, and - if ever - post after Contest end
Lets Roll ....... I like idea !
can I write some fluffy ideas, without Contesting ? 
- take BA3 Bal FE, put on right and on left LuDEF OS cells, increase OLG, apply overall NFB to make it SUSY
-take recent Stasis FE, mirror it (tossing Vbe multiplier out, no need for), put on right and on left LuDEF OS cells, apply overall NFB to make it SUSY
- implement Lynn's ideas about increasing Iq trough tiny bugger, cascoding it either with few T0247 mosfets or with one puck mos
just few thoughts after full day
🙂
- maybe I did post this in Stasis thread, can't remember ....
- take BA3 Bal FE, put on right and on left LuDEF OS cells, increase OLG, apply overall NFB to make it SUSY
-take recent Stasis FE, mirror it (tossing Vbe multiplier out, no need for), put on right and on left LuDEF OS cells, apply overall NFB to make it SUSY
- implement Lynn's ideas about increasing Iq trough tiny bugger, cascoding it either with few T0247 mosfets or with one puck mos
just few thoughts after full day
🙂
- maybe I did post this in Stasis thread, can't remember ....
Attachments
can I write some fluffy ideas, without Contesting ?
- take BA3 Bal FE, put on right and on left LuDEF OS cells, increase OLG, apply overall NFB to make it SUSY
-take recent Stasis FE, mirror it (tossing Vbe multiplier out, no need for), put on right and on left LuDEF OS cells, apply overall NFB to make it SUSY
- implement Lynn's ideas about increasing Iq trough tiny bugger, cascoding it either with few T0247 mosfets or with one puck mos
just few thoughts after full day
🙂
- maybe I did post this in Stasis thread, can't remember ....
Yes your ideas are most welcome. Maybe someone else will sim one of your ideas and post it.
there is Magura Choke Beast amp, which he/we made eons ago
it was full SUSY
though, I can't even remember how thread was titled
it was full SUSY
though, I can't even remember how thread was titled
Hi Woofertester,
Here is my SuSyLu amp for your consideration:
ZM confirmed that it is a SuSy given the coupling and feedback via the transformer load.
Here is my SuSyLu amp for your consideration:
ZM confirmed that it is a SuSy given the coupling and feedback via the transformer load.
found what I mentioned , amps made in 2009
Magura's amps (monoblocks)
one of a kind, his extreme skill, my back of napkin schematic
pet name was Donut a' la overkill
gargantuan thread on Baby DiyA : Donut a' la overkill - Solid State - diyAudio.rs
some pics (hotlinks from Baby DiyA thread and taken from some threads here)
I would do dome details in schm differently nowadays, but that's normal
I'm not tying even my shoelaces same each time
Magura's amps (monoblocks)
one of a kind, his extreme skill, my back of napkin schematic
pet name was Donut a' la overkill
gargantuan thread on Baby DiyA : Donut a' la overkill - Solid State - diyAudio.rs
some pics (hotlinks from Baby DiyA thread and taken from some threads here)
I would do dome details in schm differently nowadays, but that's normal
I'm not tying even my shoelaces same each time
.....
I would do dome details in schm differently nowadays, but that's normal
I'm not tying even my shoelaces same each time
same applies for this sim ...... probably halfway to hypothetical nowadays amp
as I see it now, it's bloody over-complicated
.......... and - it's not hving LU at all
.......... but imagine thempic also taken from Baby DiyA , sorry for blur
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This thread came up a bit early for me, I've just discovered the little buggers. I take it the competition fizzled out.
Only two submissions and one was Zen Mod. I think that my ask was probably a bit too advanced. We shall see how XRK's version turns out. I am looking forward to when he has it finished.
I have all the parts. Just waiting for the time to tackle the SuSyLu build. Serious drill and tap operations and planning where everything goes to fit inside a rather small monoblock chassis. I might run it as an open plank amp first to debug.
Looks promising, and aligns with the way I was considering using them. I also look forward to the real world results.
![2021-08-26 00_24_23-LTspice XVII - [LuFet_LU1014DSUSY.asc].jpg](/community/data/attachments/903/903958-4b0e0a39d40f4c68c2c72f38783029dc.jpg?hash=Sw4KOdQPTG)
A Pass Triode Cell with the LU1014 has an equivalent Rs of 1~1.5R.
Used as balanced source follower, the total Zout is double that, i.e. 2~3R.
Even if you then modulate the current source (e.g. White Follower or TCS), it can only half that.
As a power buffer, this only has a damping factor of 3 with a 8R load !!!
On top of that, your preamp / signal source has a high capacitance / gate leakage current to drive.
So it has to be very low impedance.
Cheers,
Patrick
Used as balanced source follower, the total Zout is double that, i.e. 2~3R.
Even if you then modulate the current source (e.g. White Follower or TCS), it can only half that.
As a power buffer, this only has a damping factor of 3 with a 8R load !!!
On top of that, your preamp / signal source has a high capacitance / gate leakage current to drive.
So it has to be very low impedance.
Cheers,
Patrick
Whoa! Nice one. Any chance of doing a simulation of distortion and power into 16 ohms? I have an immediate use for such an amplifier to drive a pair of Stentorians.
Thanks Patrick.
Being a computer engineer and programmer, I generally do my thinking after doing the simulations. The trouble is I haven't used LTSpice for a few years, and at my age I need to be retrained after going to lunch, everything goes in one side and out the other. 🙂
I'll draw it up and give it a shot anyhow. If I don't get distracted this could be the start of a really nice project.
Rob
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The "official" Spice model for the LU1014 is only useful for switching and not for linear applications.
You need to find the right model here in the forum before any simulations give sensible results.
Patrick
You need to find the right model here in the forum before any simulations give sensible results.
Patrick
Yeah. already found it. Here is my result for a single-ended circuit into 15 ohms at 1 kHz. This shows a certain amount of promise. 🙂
Now investigating the effect of inserting an inductor in series with the load, since I want to run an electrostatic tweeter with it and that will represent the primary of the transformer. It does look as if the rail voltages could go much higher as well, so a tube voltage gain stage isn't entirely out of the question.
Now investigating the effect of inserting an inductor in series with the load, since I want to run an electrostatic tweeter with it and that will represent the primary of the transformer. It does look as if the rail voltages could go much higher as well, so a tube voltage gain stage isn't entirely out of the question.
Attachments
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