I own Magnepans.. as I count them, only two pairs of my speakers exceed 90 db/watt.
So, it's a matter of habit... The First One Hundred Watts Matter. Not to play loud, mind you, just to play well.
So, it's a matter of habit... The First One Hundred Watts Matter. Not to play loud, mind you, just to play well.
^ I just want to see how much power I can get out of it without Chernobyling itself. It's as simple as that.
I already got other amps...
Will there be a full kit on the DIY store? I think I'l like to keep the ones I built "normal" and then try for power in a new build.
I already got other amps...
Will there be a full kit on the DIY store? I think I'l like to keep the ones I built "normal" and then try for power in a new build.
Have breadboarded the Zenductor.
Congratulations to Nelson and Michel. This amp is a major achievement: Sounds good. Is as simple as possible, but not more simple. Einstein would approve.
Have also tried various transistors. So far the IRFP048 beats them all. IRLB3813 comes close but is more difficult to drive.
Next on the list is a cascoded LU1014d (once i get some coming in)
In Spice it seems to work. But the proof shall be in the pudding.
Below a Spice simulation based on models found in a different thread. My apologies and thanks to the author for using his intellectual property.
Looking forward to comments
Congratulations to Nelson and Michel. This amp is a major achievement: Sounds good. Is as simple as possible, but not more simple. Einstein would approve.
Have also tried various transistors. So far the IRFP048 beats them all. IRLB3813 comes close but is more difficult to drive.
Next on the list is a cascoded LU1014d (once i get some coming in)
In Spice it seems to work. But the proof shall be in the pudding.
Below a Spice simulation based on models found in a different thread. My apologies and thanks to the author for using his intellectual property.
Looking forward to comments
A 50 watt Zenductor amp should be doable based on some ideas from Nelson Pass previous BAF projects. It does take a much beefier Mosfet, inductor and heatsink though.
50 watts into 8 Ohms, 1.07 percent simulated THD at first onset of clipping (see the lower part of the waveform). It takes a huge inductor that can take a steady 4 amps of current (at least) and 36 volts powersupply. Each Mosfet dissipates about 30 watts of heat, so the heatsink should be up to the task.
And either the preamp must be powerful enough to drive this load or the amp needs an input buffer of some kind.
The same "single end triode" respons curve as the original Zenductor. I would go for an input buffer to get a little better top end respons and increase the input impedance of the amp.
I own pair of Vandersteen 3A Signatures. Perhaps not as challenging to drive as the Maggies, but certainly more demanding than my older 2Cs. The 2Cs needed special builds of the ACA to sound good. That was what inspired me to build some of the DIY First Watt amps as well as higher power versions of some of those amps.
It can be enlightening to hear what relatively simple component changes can do to the sound of an amplifier. Even when basic listening levels remain the same, an amp running at different voltages and bias current can open up the sound of a good recording.
Amps with simple circuits such as the Zenductor and dare I say, the F6 respond well to careful modifications. This is the fun of DIY. I have a couple builds currently in progress. When I am done with those, the Zenductor looks like a fun way to experiment with reuse of ACA and MoFo components.
It can be enlightening to hear what relatively simple component changes can do to the sound of an amplifier. Even when basic listening levels remain the same, an amp running at different voltages and bias current can open up the sound of a good recording.
Amps with simple circuits such as the Zenductor and dare I say, the F6 respond well to careful modifications. This is the fun of DIY. I have a couple builds currently in progress. When I am done with those, the Zenductor looks like a fun way to experiment with reuse of ACA and MoFo components.
I got A5 and A2. The latter are awesome on hard to drive speakers.
Even the Conrad Johnson MF2100 does a solid job...
So, I'm set, I just want... more. And I wanted it sort of exotic. I think the most mainline I'd go for now is a Nakamichi PA7 Mk I or maybe a Sony VFET ( TA-8650 )... or even an F5 Turbo V3.
BTW, the SissySIT does an outstanding job with the Maggies. It doesn't play loud but the noise level of my system is now pretty low... so the dynamic range between the soft and loud is pretty good even at low levels.
So, I'm not in need of more power. I just.. want to try things at this point.
But, I'm still waiting to see what the BigBaddaBing (Boom?) looks like. I got the Tokin's ready to go..
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With my speakers, 90db/w at most, it's really hard to compare the SissySIT with the Zenductor because of volume levels and the effect of power reserves, even at low levels, on the frequency response.
The SissysSIT is simply better because it offers full range sound.
The Zenductor sounds extremely good too but it lacks the dynamics and bottom drive. It lacks the sense of deep bass... that lessens the "impact" of kick drum/bass. I figure those extra 30 watts make a huge difference in the dynamics of the music.
In the midrange... hmm... I still prefer the SIT. There's something about how it sounds that I really, REALLY like. The sound staging is outstanding and the music sounds like music. Detail, macro/micro dynamics, the attack of the drum kit, the metallic sound of the cymbals, the wetness of the trumpet/sax.. it's all there. It takes what makes tubes good and removes everything that makes tubes not sound so good.
I can not underestimate the impact that having that extra power on tap to drive the bass has on the sound staging. It makes the music sound real. The instruments sound full (*)... the Zenductor mimics the SissySIT but it presents a 7/8ths miniature. It's there, for sure, but it just sounds... smaller.
The only upgrade, IMHO, would be a pair of vintage Tannoys, or AN J/LX or even, gulp (Pandora's Box)? Harbeth 30.1?
Anyhow, the Zenductor sounds more "forward" as the deep end is missing. I got the Zenductor turned 1/4 of the way on the gain pot.
I have tried both in the Elac Unify2 UB52 and Audio Note AN K/LX. Sure both of my speakers are somewhat challenged in the deep bass ( normally I use the Entecs ) but even so they go deep enough ( Audio Notes do ) that you can hear full sound.
IMHO, you need at least 90 db/w for the stock Zenductor. Perhaps doubling the power will help a lot here.
I have not tried the Zenductor over Maggies, but do note that the SissySIT actually does a great job of driving the Maggie 1.7. It lacks the dynamic range than the A2 (200w) introduces.
Let me just state this... since I got the SissySIT, all other amps have sat idle. We'll see what the 252SIT does... I reserve the right to change my mind next week. ;-)
For the time being, the Zenductor with the 90db/w AN speakers are something I could live with... iff I didn't want to play music past 7 o'clock.
-Disco being a 10, ZZ Top and the Sex Pistols being an 11.
Bottom line - for the time being... if you got a speaker that is happy with a SET triode amp, the Zenductor will keep you very happy. But for most of us mere mortals, we need more power because, sometimes it's the First Ten Watts that matter. ;-)
I plan to see what happens if I can squeeze a few more watts from it, but I'll wait until I can get a full kit from the DIY store. I don't want to wreck my current set. They sound too good as they are.
Maybe, what I ought to do, is compare the ACA v1.8, with the Mini and the Redux.... yep... got those too. I could use a B1K with them... I know it introduces distortion but that little sucker sounds... GREAT...
(*) I tend to play music at their natural level... or quieter. ( this was defined eons ago by HP over at TAS ). I don't try to play bluegrass or a capella as if it were Ted Nugent on a drunken rampage. Oddly, I play rock softer than most people might do... but my set up has such a low noise floor now that I'm after dynamic range more than volume peaks.
The SissysSIT is simply better because it offers full range sound.
The Zenductor sounds extremely good too but it lacks the dynamics and bottom drive. It lacks the sense of deep bass... that lessens the "impact" of kick drum/bass. I figure those extra 30 watts make a huge difference in the dynamics of the music.
In the midrange... hmm... I still prefer the SIT. There's something about how it sounds that I really, REALLY like. The sound staging is outstanding and the music sounds like music. Detail, macro/micro dynamics, the attack of the drum kit, the metallic sound of the cymbals, the wetness of the trumpet/sax.. it's all there. It takes what makes tubes good and removes everything that makes tubes not sound so good.
I can not underestimate the impact that having that extra power on tap to drive the bass has on the sound staging. It makes the music sound real. The instruments sound full (*)... the Zenductor mimics the SissySIT but it presents a 7/8ths miniature. It's there, for sure, but it just sounds... smaller.
The only upgrade, IMHO, would be a pair of vintage Tannoys, or AN J/LX or even, gulp (Pandora's Box)? Harbeth 30.1?
Anyhow, the Zenductor sounds more "forward" as the deep end is missing. I got the Zenductor turned 1/4 of the way on the gain pot.
I have tried both in the Elac Unify2 UB52 and Audio Note AN K/LX. Sure both of my speakers are somewhat challenged in the deep bass ( normally I use the Entecs ) but even so they go deep enough ( Audio Notes do ) that you can hear full sound.
IMHO, you need at least 90 db/w for the stock Zenductor. Perhaps doubling the power will help a lot here.
I have not tried the Zenductor over Maggies, but do note that the SissySIT actually does a great job of driving the Maggie 1.7. It lacks the dynamic range than the A2 (200w) introduces.
Let me just state this... since I got the SissySIT, all other amps have sat idle. We'll see what the 252SIT does... I reserve the right to change my mind next week. ;-)
For the time being, the Zenductor with the 90db/w AN speakers are something I could live with... iff I didn't want to play music past 7 o'clock.
-Disco being a 10, ZZ Top and the Sex Pistols being an 11.
Bottom line - for the time being... if you got a speaker that is happy with a SET triode amp, the Zenductor will keep you very happy. But for most of us mere mortals, we need more power because, sometimes it's the First Ten Watts that matter. ;-)
I plan to see what happens if I can squeeze a few more watts from it, but I'll wait until I can get a full kit from the DIY store. I don't want to wreck my current set. They sound too good as they are.
Maybe, what I ought to do, is compare the ACA v1.8, with the Mini and the Redux.... yep... got those too. I could use a B1K with them... I know it introduces distortion but that little sucker sounds... GREAT...
(*) I tend to play music at their natural level... or quieter. ( this was defined eons ago by HP over at TAS ). I don't try to play bluegrass or a capella as if it were Ted Nugent on a drunken rampage. Oddly, I play rock softer than most people might do... but my set up has such a low noise floor now that I'm after dynamic range more than volume peaks.
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I would argue that the inductor in the Zenductor is to small. 35 mH makes it roll of below 100 Hz. Use a pair of large Hammond if you want better (and more) bass.
With 10000 uF C2.
With 3300 uF C2.
My bad. I should have used the exact values in the Zenductor schematic in my simulaion. Yes, the inductur is a bit on the small side but Nelson Pass and Mike Rothacher have solved the problem in a very clever way. I used a 10000 uF capacitor (C2) on the output in my sim, but they used 3300 uF. This trades some negative feedback and damping factor for a bit of bottom end boost. Very clever! And I guess this will sound very nice on a lot of fullrange drivers and/or back loaded horns.
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With the parts I have on hand I would be looking at 70 mH inductor and 4700 uF capacitor.
Those are fairly common values for those of us experimenting with MOT transformers and MoFo amps.
Those are fairly common values for those of us experimenting with MOT transformers and MoFo amps.
I have some spare Keratherms laying around. I assume they'll work fine?
After taking six months off to explore other things the Zenductor has inspired me enough to fire up KiCAD and tinker over the winter!
