I think this is the section I intended to share from Rod. Indicating we don't need to overly stress about inductance of large caps.
impedance of a simulated 1,000µF capacitor with 20nH series inductance and 10mΩ series resistance. The 'self resonance' frequency is 35kHz, with a minimum impedance equal to the series resistance (ESR). Even at well above the resonant frequency, the cap still provides capacitive energy storage - it is not an inductor, despite appearances. This is commonly claimed, but is generally untrue. The impedance is increasing, but until such time as the inductive reactance becomes significant (with respect to the circuit impedance) the composite circuit is still a capacitor. Even at 1MHz, the total impedance is only 125 milliohms. Although the 125mΩ is almost all inductive reactance, it cannot be considered 'significant' (a somewhat vague term that is usually taken as around an order of magnitude compared to the load). In this case, the load is 10 ohms, so 1 ohm is 'significant'. This occurs at 8MHz. It is very important to understand the difference between a supply bypass application and a tuned circuit or other electronic function. Note that self resonance in electrolytic caps is very broad because both internal (large) capacitance and (small) inductance are low Q.
At least one person has declared that the above is garbage, but only after taking the material out of context and deciding that I also include RF transmitters as part of 'audio' (strangely, no, I don't). The simulations are accurate, and if the silly claims of self-resonance were true, no-one would be able to use 100,000µF filter caps (for example) because the self resonant frequency would be well within the audio range. Strangely, most amps work perfectly well at all frequencies with very large filter caps, even where the theoretical self resonant frequency of the power supply is within the audio band because of very large capacitance.
In a normal circuit (such as a series tuned circuit for example), when the applied frequency is the same as the resonant frequency of a capacitor and inductor (including leads, PCB tracks, etc.) the tuned circuit is no longer reactive - it is resistive! The resistance is equal to the sum of all component and lead resistances (including ESR). Below resonance, the circuit is capacitive - above resonance, inductive.
impedance of a simulated 1,000µF capacitor with 20nH series inductance and 10mΩ series resistance. The 'self resonance' frequency is 35kHz, with a minimum impedance equal to the series resistance (ESR). Even at well above the resonant frequency, the cap still provides capacitive energy storage - it is not an inductor, despite appearances. This is commonly claimed, but is generally untrue. The impedance is increasing, but until such time as the inductive reactance becomes significant (with respect to the circuit impedance) the composite circuit is still a capacitor. Even at 1MHz, the total impedance is only 125 milliohms. Although the 125mΩ is almost all inductive reactance, it cannot be considered 'significant' (a somewhat vague term that is usually taken as around an order of magnitude compared to the load). In this case, the load is 10 ohms, so 1 ohm is 'significant'. This occurs at 8MHz. It is very important to understand the difference between a supply bypass application and a tuned circuit or other electronic function. Note that self resonance in electrolytic caps is very broad because both internal (large) capacitance and (small) inductance are low Q.
At least one person has declared that the above is garbage, but only after taking the material out of context and deciding that I also include RF transmitters as part of 'audio' (strangely, no, I don't). The simulations are accurate, and if the silly claims of self-resonance were true, no-one would be able to use 100,000µF filter caps (for example) because the self resonant frequency would be well within the audio range. Strangely, most amps work perfectly well at all frequencies with very large filter caps, even where the theoretical self resonant frequency of the power supply is within the audio band because of very large capacitance.
In a normal circuit (such as a series tuned circuit for example), when the applied frequency is the same as the resonant frequency of a capacitor and inductor (including leads, PCB tracks, etc.) the tuned circuit is no longer reactive - it is resistive! The resistance is equal to the sum of all component and lead resistances (including ESR). Below resonance, the circuit is capacitive - above resonance, inductive.
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well, nothing beats good motor-run cap, with few green LEDs on top
Now you got me intrigued, please explain.
The power supply has to provide the lowest possible impedance at the widest possible bandwidth.
There are a few things that are equally important to achieve the above:
1. Capacitors' values
2. The impedance of the tracks, between the equivalent capacitance (created by the combination of various capacitances) and the device that is being supplied by current from the rail. Note: the placement of the capacitor is tightly related to tracks impedance...
Now, everyone thinks about the capacitors'values (and the combination thereof, to produce that low impedance at wide bandwidth), but not many people take the tracks' impedance into consideration.
In digital electronics, this is a bit of a science, not many manufacturers get it right.
In analog electronics, what Tungsten suggested a few pages back is spot-on... (caps combos)
But... the wiring between the power supply PCB and the AMP PCB's is in fact - the tracks I referred above... so they need to be as short and as thick (the wires!) as possible, and in particular -> because there is no real local decoupling of DC rails on the AMP PCB... apart from 9.1 V Zener voltage being decoupled bu that 10uF cap to its corresponding return (which is + DC rail in this case)
Rod has been one of my go to guys for things audio for several years now.
I haven't checked in on him for a year or so, thanks for the reminder.
The capacitor paper you referenced is a good read, not only does the guy know his stuff, he's articulate enough to get some of it across to even me.
This is a total noob question, so fair warning. I'm getting parts together for an aleph j build (my first amp build) and I'm having a little trouble with the non electronic parts needed. Mostly just don't know what to search for. In particular, I don't know what to call the bolt-array things by the power supply, where the thermistors are wired. Any other little bits not listed in the bom that I may be missing would be very helpful.
Thanks!
Thanks!
I use this one, workout the number terminals you need and you're good to go.
This one has 2 rows of 4 terminals.
http://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/1546670-4/A98516-ND/1277410
This one has 2 rows of 4 terminals.
http://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/1546670-4/A98516-ND/1277410
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A stack of M3 hex socket bolts useful to mount the mosfets and pcbs to standoffs etc
M3 Spring washers
M3 Standard washers
I also use spring washers on the terminal blocks, purchase the appropriate size.
It's likely not complete, but here's a list of things I "forgot" or never knew I needed for my first build along with some web references for suppliers etc.
List of Extra Stuff Not On BOMs
• Chassis and all mounts and I/Os / IEC – Standoffs or Mounts
• Power Transformer(s) and mount(s) and/or cases
• CL-60s or other inrush limiting devices
• Safety Cap for AC Input
• Wire
• Terminal Blocks
• Quick Connect Terminals (if that’s your style). Wire size – Yellow and Blue
• Ring Terminals to fit #6 holes and < width between terminals. Wire size – Blue (If that’s your style)
• Fast-on / blade connectors - male and female. (If that's your style)
Less Common Tools I never knew I might need.
• Dummy Load Resistors – 4 or 8 Ohm 100W or 200W – wire accordingly – Not strictly required.
• Shorting Plugs – Used for checking DC offset
• Dim Bulb Tester – Check for shorts or other critical issues. It may save your amp. Build one. They’re relatively inexpensive. If I had to do it over, I’d do it like @6L6.
• Variac – to check DC offset at slightly higher and lower mains. Bring voltage up slowly for initial checks. Not needed, but can be a stress-lowering device.
• Kill A Watt – Check total current draw of amp. Not needed.
Parts Suppliers –
Mouser - Electronic Components Distributor - Mouser Electronics
Digi-Key - DigiKey Electronics - Electronic Components Distributor
Arrow - https://www.arrow.com/
AVNet - Avnet: Quality Electronic Components & Services
Newark / Element14 (Tied to AVNet) - https://www.newark.com/
RSComponents - RS Components | Industrial, electronic products & solutions
Site to find who has parts – Datasheets, Electronic Parts, Components, Search - Octopart
List of Extra Stuff Not On BOMs
• Chassis and all mounts and I/Os / IEC – Standoffs or Mounts
• Power Transformer(s) and mount(s) and/or cases
• CL-60s or other inrush limiting devices
• Safety Cap for AC Input
• Wire
o Mains to Primary
o DC Power
o Signal
• Fuses – 2.5A Slow Blow (for 120VAC Mains)o DC Power
o Signal
• Terminal Blocks
• Quick Connect Terminals (if that’s your style). Wire size – Yellow and Blue
• Ring Terminals to fit #6 holes and < width between terminals. Wire size – Blue (If that’s your style)
• Fast-on / blade connectors - male and female. (If that's your style)
Less Common Tools I never knew I might need.
• Dummy Load Resistors – 4 or 8 Ohm 100W or 200W – wire accordingly – Not strictly required.
• Shorting Plugs – Used for checking DC offset
• Dim Bulb Tester – Check for shorts or other critical issues. It may save your amp. Build one. They’re relatively inexpensive. If I had to do it over, I’d do it like @6L6.
• Variac – to check DC offset at slightly higher and lower mains. Bring voltage up slowly for initial checks. Not needed, but can be a stress-lowering device.
• Kill A Watt – Check total current draw of amp. Not needed.
Parts Suppliers –
Mouser - Electronic Components Distributor - Mouser Electronics
Digi-Key - DigiKey Electronics - Electronic Components Distributor
Arrow - https://www.arrow.com/
AVNet - Avnet: Quality Electronic Components & Services
Newark / Element14 (Tied to AVNet) - https://www.newark.com/
RSComponents - RS Components | Industrial, electronic products & solutions
Site to find who has parts – Datasheets, Electronic Parts, Components, Search - Octopart
Any time - I just copied and pasted from another set of notes 
Fuse value, yes.
A common cap used is a 0.0033uF X1/Y1 rated.
Many similar to this can be found.
C941U332MVVDBA7317 KEMET | Mouser
Edited to add - follow these guys. The blog they've started is fantastic, IMO.
Aleph J build guide for noobs
Fuse value, yes.
A common cap used is a 0.0033uF X1/Y1 rated.
Many similar to this can be found.
C941U332MVVDBA7317 KEMET | Mouser
Edited to add - follow these guys. The blog they've started is fantastic, IMO.
Aleph J build guide for noobs
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I thought higher wattage Zener diode the better.
But then I saw forum member Christer measurements of BZX55 0.5W 12V Zener diode and BZX85 1.3W 12V Zener diode.
And it appears BZX55 0.5W was less noisy.
Difference was not big, about 0.27 uV max but it was there.
Next time I will stay within 0.5W Zener if there is no necessity of 1W and higher.
So.. I suggest of chosing Vishay BZX55B9V1 model for Alehp J or NXP BZX79-B9V1.
P.S.: Though Vishay BZX55 series have "Low noise" mention in datasheet which other Zeners don't have in their datasheets, whatever that mean.
But then I saw forum member Christer measurements of BZX55 0.5W 12V Zener diode and BZX85 1.3W 12V Zener diode.
And it appears BZX55 0.5W was less noisy.
Difference was not big, about 0.27 uV max but it was there.
Next time I will stay within 0.5W Zener if there is no necessity of 1W and higher.
So.. I suggest of chosing Vishay BZX55B9V1 model for Alehp J or NXP BZX79-B9V1.
P.S.: Though Vishay BZX55 series have "Low noise" mention in datasheet which other Zeners don't have in their datasheets, whatever that mean.