So, according to this:
(from the CMOQ-4 data sheet at https://cinemag.biz/output/PDF/CMOQ-4.pdf), either the 50/50 Nickel-Iron or the 80% high Nickel version should be good enough for an improvement over the Triad transformer? But either are completely pointless upgrades if I anyway want to run at >0.1% 2nd harmonic?
Compared to
from Nelson's Zenductor 2 note at https://www.diyaudio.com/community/attachments/baf-2024-zenductor-2-pdf.1369836/
I got mine today!
Tough to get a nice smear of thermal compound on the odd shape.
@birdbox mentioned that they just friction fit together. Mine set together, but only by the grace of gravity, there's not much friction to it. I think I would want some mechanical stabilization for long term. Could you pinch the aluminum fins on the pins, maybe with pliers or vice grips? I dunno you might break it, maybe don't do that.
Earlier (post #64) I had 182 F / 82 C near the top of the heat sink, at voltage across the inductor of 1.37 v. Near the bottom I could find nearly 200 F.
So I haven't re-done the bias, and they've stabilized (predictably) cooler but also at slightly lower inductor V.
So 137 F / 58 C at 1.30 v. So that's a fair bit cooler, but 0.07 v lower bias. That's up at the top of the heat sink. I was able to find 154 F / 67 C down by the device. There's 6 or 8 F across the join from one sink to the next.
Can we guess at the effectiveness of the stacked option based on this info, or is it necessary to re-bias? I won't get to that part tonight, the bed is calling me.
Oh dear, I hope it doesn't sound like that. It's a very pleasing amp, and I'm thankful for the design and the build camp and the BA event and everyone's effort and expertise.
I’m with MJ. Build it as designed first. See how it performs with one’s speakers/systems. Then tempt fate with FAB experimentations.
I am 100% here for the experimentations tho
I found them... thanks.
I missed it at first because I was looking into the build guide, then the second time I did read it but it was like Thursday night before the trip.
I guess I'm getting old... I forget things. At least I still remember classical mechanics and Ohm's Law. Don't ask me about the plasma equations.
Thanks.
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Finally, after all these years of ZM preaching ........... Greedy Boyz going all Iron
Looking at the schematics... all of those jefts driving the transformer, etc.... I recall seeing that before. Was it one of your amps? Nelson's?
But yes.... using the transformer for voltage amplification followed by a current section....
I had a conversation over at BA24 about using transformers for voltage amplification... the answer was that it can get expensive to manufacture... my reply was: "so what?". I'm not into this to manufacture, and so the cost of the BOM is not that important.
Yes.... iron.
BTW, the Iron Pre Balanced replaced the CJ ET3SE in my system. Using it's balanced outputs driving the BA3 and bridged F4s.... Yowza! It also sounds very nice- hehehe!- driving the A5 via the SE.
MORE EDIT: and the Super Mini.
Maybe what I need is a preamp with built in features for an optional BA3 like section.. and multiple SE and balanced outputs?
A tape monitor would be nice too.
Thanks. To all of you. ;-)
Thanks for the info... I should get my parts by Friday, I hope.
Plan is to use a bit of Loctite Red to hold them together.
You could measure the transistor case temperature difference to room temperature with and without the second heatsink. That would give you the overall improvement factor (assuming same bias current).
Well, most of all i am very, very curious how it sounds. 🙂
More of a weak and distant sound image, or a strong, near and present sound image?
A cold and lean sound_or_ more of a warm, lush, rich and juicy musical presentation?
And the absolutely most important ting of them all for the complete music playback system:
Does the foot start to tap, and the head does the cool moves to the beat???
🎺🙂🎸
More of a weak and distant sound image, or a strong, near and present sound image?
A cold and lean sound_or_ more of a warm, lush, rich and juicy musical presentation?
And the absolutely most important ting of them all for the complete music playback system:
Does the foot start to tap, and the head does the cool moves to the beat???
🎺🙂🎸
Well I have to share now....
I hooked up my Zenductor II monoblocks with some 86db Aerial Acoustics 5b bookshelf speakers. I set bias at around 1.5A (1.41VDC across the choke) and when you crank it up, these amps sound absolutely phenomenal!!!!
I put on the skyscraper heat sinks just to see how "cool" I could get the very hot sinks and I'm able to run at 1.5A bias with below 70°C and no thermal grease at all, just stacking a second heat sink on top skyscraper "style". I also will say that the "friction fit" is not really true as the added heat sinks fit pretty loose, so thermal compound seems necessary. Removing the extra heat sinks bumps up the MOSFET temps from around 70°C to near 80°C, so as one would expect, more mass of heat sinks leads to reduce temps. Bias current doesn't really change any at all by adding the additional heat sinks ("Skyscraper style"), so it seems safe to add on the heat sink stack without fear of affecting the bias.
The bass is what is most impressive of all with these monoblocks. The poor ACA Mini is just blown out of the water here in comparison. These low efficiency speakers I used are just thumpin' like they are hooked up to the F5m Redux 25W amp, but gosh darn it, these are the Zenductor II 10W amps running the show.
I am seriously impressed by the Zenductor II sound. I played some taxing tunes (Techno) and they are thumpin' like I can't believe. I'm seriously blown away at the capability. Unreal sounds from these bad mamajamas. The bass on Beastie Boys Intergalacit should not exist on these speakers, but sure enough, there's some serious boom boom. Below is my listening tracks to test these bad boys out.....absolutely impressive!
I don't know what I can say beyond....wow!!!
I love these amps. I'm so lucky to have these. They are my precious...this is unreal.......Thank you Papa!
Amazing... I'm in love...................so good.
I hooked up my Zenductor II monoblocks with some 86db Aerial Acoustics 5b bookshelf speakers. I set bias at around 1.5A (1.41VDC across the choke) and when you crank it up, these amps sound absolutely phenomenal!!!!
I put on the skyscraper heat sinks just to see how "cool" I could get the very hot sinks and I'm able to run at 1.5A bias with below 70°C and no thermal grease at all, just stacking a second heat sink on top skyscraper "style". I also will say that the "friction fit" is not really true as the added heat sinks fit pretty loose, so thermal compound seems necessary. Removing the extra heat sinks bumps up the MOSFET temps from around 70°C to near 80°C, so as one would expect, more mass of heat sinks leads to reduce temps. Bias current doesn't really change any at all by adding the additional heat sinks ("Skyscraper style"), so it seems safe to add on the heat sink stack without fear of affecting the bias.
The bass is what is most impressive of all with these monoblocks. The poor ACA Mini is just blown out of the water here in comparison. These low efficiency speakers I used are just thumpin' like they are hooked up to the F5m Redux 25W amp, but gosh darn it, these are the Zenductor II 10W amps running the show.
I am seriously impressed by the Zenductor II sound. I played some taxing tunes (Techno) and they are thumpin' like I can't believe. I'm seriously blown away at the capability. Unreal sounds from these bad mamajamas. The bass on Beastie Boys Intergalacit should not exist on these speakers, but sure enough, there's some serious boom boom. Below is my listening tracks to test these bad boys out.....absolutely impressive!
- Muete - Live in Paris (entire concert) [This band is crazy good!]
- Daft Punk - Around the World
- Beastie Boys - Intergalactic
- Jack White - Ball and a Biscuit
- Dean McGraw - Foxfire
- ZZTop - La Grange (live)
- Greatful Dead - Touch of Grey
- ACDC - Thunderstruck
- The Roots - Bilal
I don't know what I can say beyond....wow!!!
I love these amps. I'm so lucky to have these. They are my precious...this is unreal.......Thank you Papa!
Amazing... I'm in love...................so good.
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With regard to the stacked heatsinks, I would connect the two heatsinks with an aluminum bar on the backside, with screws, to transfer the heat more efficiently from the lower sink to the upper sink.
When @lastnamenelson first introduced the 'skyscraper' stack in the ACA Mini thread, I jumped on it, bought more heatsinks, and wrote up a plan to use aluminum bar to connect them. Both for security and improved heat transfer. We had a hot summer and the loose stacking solved the probem (105F with no ac) despite increased bias settings. I planned to use bar on both sides. That depends on how much vertical surface remains above the mosfets. I'm sure the Z2 is putting out a bunch more heat than the ACA Mini, but with hard clamped, gooped stacked sinks a good bit more heat can be handled.
Well worth trying @pinholer's suggestion above IME.
Skip
complete back of hsink is free for connecting plate
so make plate long as 2 hsnks
you'll just need longer screw for mosfet
Have tried Loctite Red?
It seems to me like the aluminum bar is a complication that can be bypassed by gluing them together with the "rods"....
The flip side might be to just remove the transistors off the small heatsink and attach them to a bigger chassis with larger heat sink using flying leads..
That's a good point, instead of a bar to connect the heat sinks, use a plate to hold and conduct heat as well.
BTW, you don't really need to make the plate that long that it gets in the way of the mosfet. Just make it so it extends about one inch down the lower mosfet. A 3 inch long plate should be enough.
Hmm... I guess it depends on your definition of "rod" and "plate". A 5/8" wide plate will fit... make it 3" long. Ideally on both sides.
Heck, the way we're going, how about this? It will solve both the cooling and the case issues in one shot.
https://www.amazon.com/Frigidaire-P...40&mcid=ad522615205d3e809581f5d2eade1191&th=1
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Hell... why not just build a Tower Of Babel and stack them a foot high? Wrap them with nice LED Christmas lights...
More and more, I think active cooling is the way for these.... with this one you could slip some heat temp sensors and mount them on the window. to monitor the heat action.
Then we can go into another psychotic audio nervosa episode: What is the best temperature to operate these amps?
More and more, I think active cooling is the way for these.... with this one you could slip some heat temp sensors and mount them on the window. to monitor the heat action.
Then we can go into another psychotic audio nervosa episode: What is the best temperature to operate these amps?
bingo
cut to approx. 2 hsnk length, drill 2-4 holes in appropriate positions, few bolt'n'washers'n'nuts, some thermal goop and Voila!