diyAB Amp The "Honey Badger" build thread

[danielwritesbac]

You now see the use (actually primary) for the blue/red leds.

LED glows - DO NOT touch. (told that to my kids) .
PS - shocked myself once , all my amps are now "christmas trees" .
My New amps actually combine LED function (voltage/CCS references) with the safety factor and "looks" (UV ,blue,green).

I just LOVE led's .

OS

I do too!
Hey, if you use a bunch of the orange ones, it makes an interesting tube-like glow outta the vents.

 

[jdg123]

Aaaarg

I was about to begin pinning up the last of the details on my Honeybadger and discovered that my R36 (150R) are rated at only 1/2W not 1W.

I have 2W at 120R and at 180R are either of these an OK substitute?

 

[TonyTecson]

i'd go for the 120 ohms....although either will work just fine...

 

[jdg123]

Thanks AJT! Should C20 be adjusted at all because I am switching to 120R for R36? OS gave quite a range on C20 and I have quite a few possibilities (what I have in place is Mullard Tropical Fish 0.68uF)...

 

[TonyTecson]

i used 1uf in that spot..

 

[jdg123]

Thanks again!

 

[TonyTecson]

i change some values here and there as what i have in my parts bin,
i stuffed a pair of boards and will post my as-built scheme showing changes i made...

 

[Freecrowder]

How do i get to the mouser badger BOM again. Tried in the past but forgot how. help please

 

[TonyTecson]

How do i get to the mouser badger BOM again. Tried in the past but forgot how. help please

https://docs.google.com/spreadsheet/ccc?key=0Amrcm2tjU-ZfdGZqTGhhbUQyNzQ1TU5vSUNoeHZlMXc#gid=0

 

[janusz]

Three pictures of my first HB unit. There will be at least one more like this one.
It's a terribly compact case. Speaker protection is bolted to the upper cover above and between PS caps.

cheers,

 

[Freecrowder]

Does a BOM already exist at one of the electronic suppliers that I can use. Trying to import but running into issues!! If so what is it titled and how to access?

 

[rohot01]

I'm finish it. The sound is good.
I have a question.
The R4 value is 5 ohm in circuit.
But it is 4.7ohm in BOM.
Which one is right?

 

[AndrewT]

R4 is the Signal Ground to Power Ground reference connection.
The tolerance is unimportant.

Use can use a 4r7 +-20%, or a 5r +-20% part here.
You may well find that any value from 2r2 to 10r will not change the performance of the amplifier in any measurable way.

 

[danielwritesbac]

Another option, especially applicable if larger resistor values are used. . .

Is it okay to put a little cap in parallel with the 10R groundlift, say about 100n for treble bypass?

yes , that is a good idea. I used a bypass across the 10R to mitigate PC power supply noise in an earlier amp project . A .1uf multilayer ceramic was used.
OS

 

[Freecrowder]

Ok I have finished boards and am testing now. should I be concerned with unequal currents through outputs without any heatsinking at all? I'm assuming not but one board looks very balanced under same conditions. only running output at 10ma bias.

 

[TonyTecson]

yes, better install the heatsinks first...

 

[still4given]

Ok I have finished boards and am testing now. should I be concerned with unequal currents through outputs without any heatsinking at all? I'm assuming not but one board looks very balanced under same conditions. only running output at 10ma bias.

You can blow an output is seconds without a heatsink attached. Don't do it.

 

[Freecrowder]

OK I'll install sink before doing anything more. what is the purpose of R53and 54, the 22 ohm resistors to each rail. looks like they would only come into play if fuses go out.

 

[still4given]

OK I'll install sink before doing anything more. what is the purpose of R53and 54, the 22 ohm resistors to each rail. looks like they would only come into play if fuses go out.

Yes, OS calls them safety resistors. I call them board burners. I would leave a space between them and the board is you use them. If the fuse blows, they will probably burn as well, mine did.

 

[AndrewT]

They act as very slow fuses, that allow the rest of the circuit to blow up when another fault occurs and/or one abuses the amplifier.