There are some decent signal generators available for the iPhone, and presumably Android. Older phones are great to keep around for the analog headphone jack. With a simple mini-phono to dual RCA cable, one can feed a simple sine wave into the amplifier, and read the output across the speaker terminals. This confirms that the power supply and channel boards have been hooked up correctly. Some simple math will show that the gain is what was expected,
Hahahahaha
I used spring washers, hex bolts, tin plated brass ring connectors.
I crimped then soldered the ring connectors. OCD.
I used a torque wrench to tighten them to manufacturers specs (found on data sheet)
These bridges are BEASTS.
You will want to take the lid off your amp just to admire them.
HAHAHHAHA
I agree with this 100%, anything less than 400mm is super cramped.
400mm deep bare minimum.
I even think 450mm might be optimum.
I couldn't find that size so built my own chassis and made them 500mm deep.
I too would use 400mm as minimum.
BTW, Modushop has a 500mm chassis, though it's not available through the diyaudio
store.
Dissipante 5U 500mm frontale 10mm NERO coperchi e retro in alluminio 3mm
BTW, Modushop has a 500mm chassis, though it's not available through the diyaudio
store.
Dissipante 5U 500mm frontale 10mm NERO coperchi e retro in alluminio 3mm
Yup, great source for wiring...all gauges, mil spec, teflon insulation (doesn't melt like mom teflon insulation) solid core or stranded, all colors.
Russellc
Hmmm wonder what it's heatsink arrangement is? I always thought an "extended" Deluxe 5U" with 3 sections of heatsink instead of the Deluxe 5 use of 2 would be the bomb.That way, 12 output BBA3 could have 4 mosfets on each heatsink.
Russellc
Some good basic reading
For noobs (hate that term, actually) here is a free, open-source, compendium of excellent knowledge about electronics edited by the incomparable Jim Williams (a true hero of mine in the field of analog electronics):
Electronics: The Art And Science Of Analog Circuit Design (PCB) : Free Download, Borrow, and Streaming : Internet Archive
There are some interesting articles discussing what it is like to be an engineer and designing circuits. Worth a scan.
For noobs (hate that term, actually) here is a free, open-source, compendium of excellent knowledge about electronics edited by the incomparable Jim Williams (a true hero of mine in the field of analog electronics):
Electronics: The Art And Science Of Analog Circuit Design (PCB) : Free Download, Borrow, and Streaming : Internet Archive
There are some interesting articles discussing what it is like to be an engineer and designing circuits. Worth a scan.
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@TungstenAudio, are you sure that the Deluxe 4U won't accommodate horizontal mounting of the transformer (Antec 300VA or 400VA units)? As you correctly surmised, to minimize parts count and complexity we were thinking a single toroid, with the Universal PSU board (rectifier section snapped off, monolythic bridges instead). We've got the Deluxe 4U with drilled front plate, so we could mount the PSU board to the front, if that saves any meaningful space.
The Deluxe 4U chassis may accommodate horizontal mounting of the transformers (one 400VA or two 300VA), if the bulk cap portion of the PSU is mounted vertically on the inside of the face plate. The face plate has predrilled holes that may be used to mount one or two PSU boards side by side, with the rectifiers mounted separately on the base.
Excellent, thanks! We've been planning around the 4U Deluxe, Antec 300VA transformer (I think @alanhuth might have the Antec 400VA), Universal PSU board, and bridge rectifiers. Sounds like it should all fit in a straightforward manner. I wasn't looking forward to adding more parts and complexity for vertical mounting of the toroids.
Get the fully shielded Antec transformer.
If you're going with a single transformer get the 400VA, it will run much cooler for Aleph J. Transformers start radiating quite a bit of heat once you start approaching their rated output.
The less radiated heat in your case the better.
It's already gonna be quite hot.
If you're going with a single transformer get the 400VA, it will run much cooler for Aleph J. Transformers start radiating quite a bit of heat once you start approaching their rated output.
The less radiated heat in your case the better.
It's already gonna be quite hot.
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sign me up
This thread is just what I'm looking for, having finished two ACAs and a keen interest in moving up. Thanks.
This thread is just what I'm looking for, having finished two ACAs and a keen interest in moving up. Thanks.
Just to illustrate my previous point I thought adding this graph might be helpful.
From the graph you can see running a transformer at around 65% of it's rated VA (Power) leads to a rise of 30 degrees above ambient.
If the case temperature is 40C the transformer will be at 70C. That is bloody hot.
This will also affect the cooling efficiency of your heatsinks etc.
Best keeping the transformer operating at 50% or less of it's rated output.
I generally go with a VA rating 3x greater than the amp circuit draws (operating at 1/3 for 10C rise above ambient).
Also get the deepest chassis 400mm or greater (it will run cooler too).
This will help with future proofing for other new amp builds.
From the graph you can see running a transformer at around 65% of it's rated VA (Power) leads to a rise of 30 degrees above ambient.
If the case temperature is 40C the transformer will be at 70C. That is bloody hot.
This will also affect the cooling efficiency of your heatsinks etc.
Best keeping the transformer operating at 50% or less of it's rated output.
I generally go with a VA rating 3x greater than the amp circuit draws (operating at 1/3 for 10C rise above ambient).
Also get the deepest chassis 400mm or greater (it will run cooler too).
This will help with future proofing for other new amp builds.
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For additional peace of mind, I use two Fractal Design Dynamic X2 GP-14 fans. I run them at 10V DC (instead of 12) - they are completely quiet. Most of the airflow goes inside to cool the interior; a portion of the total airflow is "refracted" from the top plate and cools the heatsinks from the outside.
I leave the fans on at all times during the summer period. No need to run them during winter.
I leave the fans on at all times during the summer period. No need to run them during winter.
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Oops, I already ordered the 300VA/20v Antec. Sigh. I believe @alanhuth has the 400VA/18v Antec, so when we two are finished, we will be able to empirically test your advice in the 4U Deluxe. I suppose I could rig a fan if it gets too hot in there, like @Extreme_Boky.
Well, we're already learning a lot!
Welcome, @VineSerf. You can either build along with us, learning as we go, or you can wait a few months and benefit from our mistakes. 🙂 Either way, the more, the merrier.
Just FYI, I've posted the first two entries on the blog:
Introduction: What Is This and Who Is it For?
Introduction: What Makes an Aleph an Aleph?
I don't expect these to be controversial, but comments and corrections welcome!
Introduction: What Is This and Who Is it For?
Introduction: What Makes an Aleph an Aleph?
I don't expect these to be controversial, but comments and corrections welcome!
With a linear psu, we have short high current pulses to charge the capacitors. (Only the top of the sinus). That’s also why we need transformers with a higher power rating than the power rating of the amp.
No, No.
If it proves to be hotter than you like, then later just buy a second 300VA transformer and go dual mono.
Everything will be better, cooler operation, better regulation on dynamic musical loads, better channel separation, etc.
There are many benefits.
Fans should be a last resort. You could certainly use a fan temporarily though.
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