diyAB Amp The "Honey Badger" build thread

Re : Feed Back Capacitor

Question for James :

I currently have 6 Nichicon Muse BP 100uF 25V, I can start with 3 for each channel.

But, I first use only one Nichicon BP per channel, the high is little bit brittle. So I switched. Is that the sound signature for Muse BP ?

Question for Daniel :

The reason that you suggest 2X of 220uF for cleaner bass is because
a) higher capacitance ?
b) lower ESR ?

Thanks for all the suggestion and reply
 
Final attempt for feed back capacitor

O.K.

I found additional 4 Nichicon Muse 50V 220uF BP in my stock.
However, they come with elephant feet and can not go though the PCB.

So I start trying 2X 100uF 25V Nichicon BP per channel. The bass is clean. However, it is too cold for my taste.

Then I go back to 2X Panasonic FC 220uF 63V per channel, I like this sound better. I know there could be distortion due to capacitor leakage. I could not detect it yet.

The feedback capacitor copper trace on my PCB all lift up now and can not do more experiment. I really hate this PCB. I will live with Panasonic for now until DC servo installed. This is how to get rid of feedback capacitor. No component is smoother than a copper wire.

I do have one regret for this project. I was too greedy and bought a 800VA transformer. Nothing wrong with 800VA. It just occupy huge space that I could not find room for the DC Servo power supply. Still in the creativity mode to find space at this moment.

Thanks everyone again.
Lou
 
C
Source devices, which are all theoretically perfect, are not actually perfect in practice, so you can try a good discrete buffer just to find out if your source needed it. All of the sources that I have, will do much better bass when given a buffer. I'm always astonished at the low pitched cleaner bass. But I think it is a great deal more fun to amplify that.

buffer before, or after the cable connecting source to amp ?
buffer before, or after the passive volume control ?
 
dedicated bass ?

by DWB-I'm always astonished at the low pitched cleaner bass.

If it is the bass you are after , go for a dedicated bass driver. Trying to colour the amps sound (while possible.. ) to have a so called "cleaner bass" run on a
full range speaker system is problematic at best.

A dedicated bass amp , (bridged badger - working on it !!) is the only way.

My original badgers are now set to do only 80hz - 20khz.
An isobaric sub with the above bridge will handle all below 80hz.
I also have a cheap DAC kit hooked to my amps (spdif-digital) , an WOW ! ... now I hear just my source (asus card).
As far as a buffer , I have a choice of the stock 5532 op amp on the DAC or (opa2134). In full range mode (no sub) , I can't hear any difference between them ?? The big differences are in the dsp settings of the sound card , MP3 or FLAC as source ...and the mindset of the listener (I realize as a human that my listening experience is VERY subjective.)

So , my latest "approach" .. is to eliminate all things analog , except for the op-amp and the badger. I must say , to hear "just the amp"(or just the sound card) is pretty awesome.

Using esoteric capacitors is NOT a bad thing. Black gates have
lower ESR which will actually change with time (carbon in the electrolyte) , this will alter the sound over time ... cause and effect. The great debate is whether this is truly audible outside of the subjective.
Using quality caps will just make the amp more stable over time (MTBF).
The badger board was physically modeled after the adcom 535 ADCOM GFA-535 II Review . Even as this amp is a classic , the badger has it beat in components , circuit , and specs (especially noise) .

Output transistor + speaker choices will affect sound more than subtle component changes , so will using Keen's suggestion of an "ideal" current mirror
(BCxxx or Ksa1015),matching input pairs , and the ideal current source settings (hint - 2ma - ksc1845 LTP).
I can not stress enough that this amp was chosen to give the "best for the least". Using scrap-yard parts - mje340/350 vas, recycled japanese 2sa/c output devices from street receivers , you would still have to listen VERY carefully to hear any difference. The "buffer factor" could just be from not having the amp loading the output of the source. BTW , I did notice a VERY subtle change in bass definition with the DAC's integrated buffer.

OS
 
buffer before, or after the cable connecting source to amp? buffer before, or after the passive volume control ?
What I've been doing is: PC > 50k pot > buffer > cable > power amp
The buffer is not "for the power amp" and not because of the power amp, but rather the buffer is "for the source" so the buffer is located close to the source. The source is driving the pot, the pot is mounted on the buffer board (the pot isn't driving a significant length of cable, just a 1cm trace), and the buffer is driving the RCA cable that goes to the power amp. I don't use chip buffers--too difficult. I like discrete or tube with a variable resistors for adjustable voltage regulated power and variable resistor for adjustable bias current.
 
Last edited:
If it is the bass you are after , go for a dedicated bass driver. Trying to colour the amps sound (while possible.. ) to have a so called "cleaner bass" run on a full range speaker system is problematic at best. A dedicated bass amp, (bridged badger - working on it !!) is the only way.

My original badgers are now set to do only 80hz - 20khz.
An isobaric sub with the above bridge will handle all below 80hz.

I also have a cheap DAC kit hooked to my amps (spdif-digital), an WOW ! ... now I hear just my source (asus card).
As far as a buffer, I have a choice of the stock 5532 op amp on the DAC or (opa2134). In full range mode (no sub) , I can't hear any difference between them?? The big differences are in the dsp settings of the sound card, MP3 or FLAC as source ...and the mindset of the listener (I realize as a human that my listening experience is VERY subjective.)

So, my latest "approach" .. is to eliminate all things analog , except for the op-amp and the badger. I must say, to hear "just the amp" (or just the sound card) is pretty awesome.

. . .BTW , I did notice a VERY subtle change in bass definition with the DAC's integrated buffer.

Bass Badger!!! :D
I like it! So, the bridged setup is helping to keep the power supply voltage down in the favorable range for the output devices SOA? That's cool!

Question: Assuming Honey Badger monoblocs for the main channels, the small signal ground has already met at the source and shall not meet again for a ground loop, it is needful to avoid shorting out the stereo separation enhancement of monoblocs, and then how does one arrange the input for the monophonic Bass Badger?

I didn't get very far trying to imagine this.
One place the grounds could meet is at the source (where they have already met, so no harm done) and therefore a head unit or control amp located near the source could work.
As far as I got was inverting buffers pushing an inverting bridging adapter and located very close to the source and an XLR balanced line cable run to the Bass Badger.
This deal could be turned into a full head unit or control amp by adding a couple of nice main channels non-inverting buffers (with bypass), a 3 source selector like 3p3t and a volume control that isn't driving cables.

That could be quite the dandy accessory and make it fairly easy to use the Honey Badger boards currently in the store for power amps. Thinking ahead a bit, if all three channels have stereo buffers, there would be extraneous taps for main stereo outputs to which one could plug in delay and rear channel amplifiers. It is also possible flip a switch for stereo subwoofer output to really satisfy the bass-heads.

Of course it might be easier to use the sound card's multi-channel outputs; however, that is made for movies, and I'd rather do something more suited and easy to use for music production and replay, without requiring a specifically surround-oriented source.

For comparison, here's a radio from 1937 with 6 speaker sound plus an on-board 18" subwoofer: Crosley Model 634
With those specs on a radio, I'm assuming that it wasn't impossible to rock the house in concert realistic surround (widecast) sound with big band music from a monophonic source, but it was merely very expensive to do so. Perhaps the surround sound prospect would have been somewhat easier with a stereo source?
 
Last edited:
Alternative Honey Badger DIY Chassis

Although I really like the HIFI2000 Chassis I fancy something a little different, and cheaper. I found a design which seems simple to put together and fairly cheap. See design here. But what I was wondering was if I put the heatsinks on the inside, and drill approriate vents will it be enough to cool the Honeybadger, with a 45+45Vac? The heatsinks I had in mind were these, With a length of 100mm.

I will adjust the size of the chassis seen in the link to the same as the "Jack of all Chassis" size.

Also anyone else copied this design?
 
For that shorter height enclosure I'd be looking for heatsinks with BIG fins like these:
Heatsinks: Search results
9540HS Width:750.00mm x Height: 83.50mm
9740HS Width:600.00mm x Height: 85.00mm
9530HS Width:600.00mm x Height: 83.50mm
9730HS Width:500.00mm x Height: 85.00mm
9520HS Width:500.00mm x Height: 83.50mm
9720HS Width:400.00mm x Height: 85.00mm
9630HS Width:400.00mm x Height: 84.00mm
9510HS Width:400.00mm x Height: 83.50mm
1633HS Width:300.00mm x Height: 84.00mm
9710HS Width:300.00mm x Height: 84.00mm
9620HS Width:300.00mm x Height: 84.00mm
9500HS Width:300.00mm x Height: 83.50mm
1630HS Width:300.00mm x Height: 83.00mm
. . . and some creative ventilation.
 
45vac with 4ohm load

Hello,

I am gathering supplies to build this amp, and am now looking at the power supply portion.

The build guide recommends the AN-8445 transformer, which is 45-0-45, but earlier in this thread it states 45vac is not suitable for 4ohm loads.

If this is true, i would likely go with a 35+35vac transformer, in order to suite my 4ohm load.

possibly the AN-8435, this is going to be a dual monoblock, so that would give plenty of overhead in the transformer department (also as a bonus thats one of the transformers they will be producing first after antek's fire).

Next would be caps for the psu. The build guide recommends 4x 10,000uf caps for each rail. I have yet to find 30mm diameter 10k uf caps anywhere.

Since this is a dual monoblock, could I get away with less capacitance on each rail?

4x 4.7k uf caps on each rail would be acceptable? but give less protection against fluctuation on the mains?

Thanks in advance,
Juvenal
 
My Mouser BOM...

Hi Everyone, I have eventually managed to complete (more or less) a Mouser BOM. Any suggestions, alternatives, sharp intakes of breath welcome. I have tried to follow suggestions for alternative components and have tended towards higher voltage/tolerances where cost allows. No idea what the total of this lot is.

I would like to know if I am going in the right direction.

Published on google docs, hopefully this will work. CLICK HERE
 
Re : My Mouser BOM

0) I am assuming you are using the PCB supplied by the store. Otherwise, ignore all of my comment.
1) For D3, I had trouble fitting 1W diode through the PCB hole. I ended up with using resistor approach.
2) For 0.22R resistor, it is not the same package type as build guide shows. It will work if you don't mind unstable resistor mounting. I did the same thing as you, later on, switch all 12 to the smaller kind.
3) Those 220uF and 470uF Nichicon KW series capacitors are audio grade. You may or may not need 0.1uF capacitor. Also check whether the hole is large enough for those audio grade cap. Their leg maybe very thick in diameter. If I were you and prefer Nichicon, I will also purchase inexpensive Nichicon VR as a back up. They will fit although only for general purpose.