diyAB Amp The "Honey Badger" build thread

[bullittstang]

Considering building this amplifier and I know I saw a list of alternative parts somewhere on this forum but cannot find it now. Given how fast electronic parts become obsolete many parts are obsolete in the diyaudio store BOM. I hope someone knows where to find the alternative active parts list.

Go to the DIYaudio store and look at the build guide it’s a few pages down and has reasons and specifics for alternate parts.

edit - Page 7 - "ideas and alternative"

 

[wdecho]

Thanks. I thought I saw in this thread or the general discussion of the Honey Badger more info on different alternatives. Maybe not, get old and you cannot depend of memory being correct.

 

[Mark Whitney]

A question on the way you have bolted the transformer to the chassis in 3941. Does the chassis and bolt form a short?

 

[stuartmp]

A question on the way you have bolted the transformer to the chassis in 3941. Does the chassis and bolt form a short?

No, it's insulated.

Thanks for checking.

 

[Kay Pirinha]

Where did you get this big bushing from? Did you turn it yourselves?
Best regards!

 

[stuartmp]

Where did you get this big bushing from? Did you turn it yourselves?
Best regards!

Yes, I made all the parts for my amplifier myself. Luckily enough I have access to all that equipment at work.

 

[jwilhelm]

Spaenaur has those bushings here in Canada.

 

[Kay Pirinha]

They're very useful if you, like me, decide to mount a toroid vertically, using an U shaped profile.
Best regards!

 

[wdecho]

Toriod 45V or 40V. Opinions?

 

[bullittstang]

diyAB Amp The "Honey Badger" build thread

Toriod 45V or 40V. Opinions?

How much wattage do you need? I would go 45Vac dual secondary transformer, but I push limits constantly.


Edit - also depends on ohm load you will be running. Lower the load, lower the voltage to stay safe

 

[AudioSan]

I would go for 2x40Vac. That will be safer when the load dips below 8ohm.

 

[wdecho]

I am thinking 40V to be on the safe side. I have horns that are very efficient and do not need every bit of power the design is capable of. Another thing is my house voltage averages about 123V AC or more.

 

[AudioSan]

Then you could even go down to 2x35Vac.

 

[janusz]

You can calculate all you need in the attached Transistor Load Lines file. I wrote Transistor Load Lines long time ago so I remember that you place your data in BLUE fields. Attached is also 2sa1943 SOA file.

cheers,

 

[wdecho]

C2 in this amp is supposed to be a polystyrene 270pf 50-100 V. My searching has revealed no longer made. What is a good replacement or rather what have members used for C2 at digikey preferable?

 

[AudioSan]

if memory serves me right, i think i had to order from e-bay.

 

[wdecho]

Ebay has some 430pf that I have bought. I can just use one increasing the capacitance or 2 in series for 215pf. How is that going to effect the circuit or rather which way to go.

 

[sandrohv]

It changes the BW of the input network. The BW will depend on the C2 and R2+RS, where RS is the source impedance (output impedance of the pre-amplifier or whatever your source is).

For example, say RS=600 ohms, a standard in audio. Then R2+RS= 1.42K.
The cut-off frequency is then:
C2=270p -> Fc=420KHz
C2=215p -> Fc=530KHz
C2=430p -> FC=265KHz

Given this choices I would go with 215p in case your RS is higher.

I made a video on this here: YouTube

Enjoy!
- Sandro

 

[wdecho]

It changes the BW of the input network. The BW will depend on the C2 and R2+RS, where RS is the source impedance (output impedance of the pre-amplifier or whatever your source is).

For example, say RS=600 ohms, a standard in audio. Then R2+RS= 1.42K.
The cut-off frequency is then:
C2=270p -> Fc=420KHz
C2=215p -> Fc=530KHz
C2=430p -> FC=265KHz

Given this choices I would go with 215p in case your RS is higher.

I made a video on this here: YouTube

Enjoy!
- Sandro

Thanks, this is what I was hoping for. Good advice from someone more knowledgeable than myself. I only understand the basics of electronics.

 

[Harry3]

You can use a Wima polypropylene cap that fits the PCB from Digikey or Mouser. Just get the correct lead spacing.