diyAB Amp The "Honey Badger" build thread

[ncg2013]

Any transformer I have not bought one yet...

[AndrewT]

transformer voltages 22, 25, 28, 30, 35 & 40Vac are generally available, although few if any manufacturers offer any more than three voltage options from that range.

[ncg2013]

You mentioned that I could get between 120w and 160W, if I use a 40Vac transformer what else can I do to make sure it produces 150W into a 4R load? If anything!

[AndrewT]

40Vdc is not the same as 40Vac.
40Vac+40Vac can achieve 170W into 8r0 and over 300W into 4r0.
I have reported these results some 5 or more years ago in the Leach Thread.

[ncg2013]

Thanks Andrew, that’s cleared that up. Wires crossed!

But if I wanted to work out the power from a transformer is it something like this:

40 Vac x 1.414 = 56.56

V squared over R gives 800 watts! not right I think, where have I gone wrong?

[ncg2013]

Beginner question...
I am going through the BOM and ordering transistors on mouser and a few of the parts have more than one option. take Q5 it is specified as KSA992, but on mouser there are a few different types. Some with a suffix of FBU and some FTA and FBTA and FATA. The KSA992FTA has Gain Bandwidth Product of 100MHz, is that needed or do they all have this? They do look mostly the same!

A conclusive answer to this would be appreciated.

[danielwritesbac]

Question:
For a Honey Badger monobloc with 3xMJL3281, 3XMJL1302, and a load of 2.6DCR, then what what is the maximum transformer (in amperes) that will safety throttle before the outputs could be harmed?

Specifically, I'm looking for the "maximized power" figure, such as 45+45vac in case of 8 ohm speakers, but need an answer in amperes to hold back the power in the case of 4 ohm speakers so that output device SOA cannot be exceeded. Assume worst case, music production use (digital organ, 32' stop, young caffeinated organist). How many amperes transformer is safe in these conditions?

[tsip]

Originally Posted by ncg2013

Beginner question...
I am going through the BOM and ordering transistors on mouser and a few of the parts have more than one option. take Q5 it is specified as KSA992, but on mouser there are a few different types. Some with a suffix of FBU and some FTA and FBTA and FATA. The KSA992FTA has Gain Bandwidth Product of 100MHz, is that needed or do they all have this? They do look mostly the same!

A conclusive answer to this would be appreciated.

Althoung i am not that more experienced than you, i think this project might be to complicated for you at the moment. I would suggest you leave this aside for a while, build something more simple like a gainclone and then take this up. This project has several pitfalls, i dont think that it is intended for a complete beginner and if something goes wrong, except from the components cost, it might put you off from the hobby altogether.
Just a friendly suggestion.

[mattmcl]

It is my understanding that the intention of this amp was to provide something a beginner could easily complete. As a beginner myself (though with a few projects under my belt) it has been confusing to match the BOM to Mouser parts. I believe someone is working on a BOM with Mouser part numbers, or in fact a parts kit to sell here. Either of these would solve the issue.

Personally I'm waiting for one of these two to happen before moving forward.

[ostripper]

Dan -The fuses "throttle" the outputs.

TSIP - My first projects were an ampslab project and quasi's Nmos amp. I acknowledge this amp is a little more complicated , but it can be done by a beginner.

If this is built right up to the drivers(don't put the expensive outputs in yet) and Q14/15's emitters are tied to the output (L1) with 68R resistors (temporarily omit r36) , you will not blow anything -hopefully.

Adjust R30 (Vbias) for 1.2V between the emitters of Q14-15 and this amp is ready for the outputs. I use this for OEM repairs and all my builds (frugalamp , etc) ... only fried a couple of devices with probe slips and other stupid mistakes .


OS