Hi OmeEd,
Thanks for the reply. All of my projects are for personal use with 8 ohm speakers. I wasn't sure if a toroid with a 625 VA rating would be overtaxed by the current demands of the Honey Badger specifically. I appreciate the reassurance. Thanks again.
Dave M.
Thanks for the reply. All of my projects are for personal use with 8 ohm speakers. I wasn't sure if a toroid with a 625 VA rating would be overtaxed by the current demands of the Honey Badger specifically. I appreciate the reassurance. Thanks again.
Dave M.
Hello Forum Members,
I just ordered my boards for my Honey Badger project. I hope to liven this thread with occasional progress reports when the time comes. Cheers!
Dave M.
I just ordered my boards for my Honey Badger project. I hope to liven this thread with occasional progress reports when the time comes. Cheers!
Dave M.
Just finished building the boards , adjusted bias, ccs and offset.
Plays, but very very low sound,
I know i have good enough audio source.
Where to start looking?
Must be something in the input stage that does not amplify enough
Plays, but very very low sound,
I know i have good enough audio source.
Where to start looking?
Must be something in the input stage that does not amplify enough
Post the schematic with all the operating voltages. badger is a design that "just has to work".
Typical me to get a fault no one have experienced before me lol. here is a schematic with my measured voltages
Read the voltage across R14 ,R27 , want to establish operating currents.
Oh , BTW are you using a small or large input cap , I think there is a bridge
you have to jumper for cap size. ?
Does this happen on both channels ?
OS
Oh , BTW are you using a small or large input cap , I think there is a bridge
you have to jumper for cap size. ?
Does this happen on both channels ?
OS
Q15 emitter should be at about -550 to -600mV since its base is at -1.2V, the measured +600mV value is not correct,
indeed there s only 26mV at the ends of R36 wich amount to only 173uA while it should be something like 1.2-1.3V
and about 8-9mA, possibly that this transistor is not functional.
Are you sure that the 600mV at this transistor emitter is not a typo and that it s actualy -600mV ?
Because there s still 54mA flowing through R48 but it s impossible to draw a conclusion since there s
no mention of the output DC offset.
indeed there s only 26mV at the ends of R36 wich amount to only 173uA while it should be something like 1.2-1.3V
and about 8-9mA, possibly that this transistor is not functional.
Are you sure that the 600mV at this transistor emitter is not a typo and that it s actualy -600mV ?
Because there s still 54mA flowing through R48 but it s impossible to draw a conclusion since there s
no mention of the output DC offset.
I find it very helpful to measure output stage voltages with respect to the output. So negative of your meter to the output (L1, R39). Measure your voltages from that point. Your readings will be clear and accurate.
Measuring DC offset is normally your first measurement if you aren't drawing high current.
Measuring DC offset is normally your first measurement if you aren't drawing high current.
I tested one of the amplifier boards today and it played like a champion. The other one had a accident under previous testing for faults. My own mistake, one of the silpads got damaged after x amount of times taking the board off and on tothe heatsink, so i barbequed some of the output transistors and one of the drivers. But that is a easy fix. I have enough parts in stock to make 20 honey badgers so. So a reminder to myself, check every time if there is connection between the heatsink and the output transistors.
And Ostripper , thanks for a really fun project. Its the 3rd solid state amp i have built. And i im totally addicted. I have so much rare and cool parts i can use for builds, so after im finished with this build, im on the hunt for a new one. Rare and hard to get parts is no problem
And Ostripper , thanks for a really fun project. Its the 3rd solid state amp i have built. And i im totally addicted. I have so much rare and cool parts i can use for builds, so after im finished with this build, im on the hunt for a new one. Rare and hard to get parts is no problem
People must take care to the fact that 80-120V is just separated by thin mica or Sil-pads. ALWAYS check continuity between
collectors and HS/ground.
OS
Another good tip is If you get frustrated after many hours of fault searching, put it away, get a good night's sleep and look at it with fresh eyes, and not just keep on and get more and more frustrated , thats when more misstakes easily happen, like it did to me
Member
Joined 2021
I have some questions about the power rating of the Honeybadger.
I recently upgraded my old HB with the MJL4281 and MJL4302 transistors (didn't make any other changes) and measured input and output.
Using an oscilloscope, I measured my input signal (1.0 kHz sine wave) and output across an 8R and a 4R load.
Into an 8R load, I got 32.0 dB gain all the way up to 795mV(RMS), where the output signal just started to clip, for 126 Watts.
Into an 4R load, I got 32.0 dB gain all the way up to 743mV(RMS), where the output signal just started to clip, for 215 Watts.
Power output was a bit low, but I'm using less than the recommended rail voltages, so OK.
But what is a mystery is that the standard line-level voltage for consumer audio gear is only 316mV. At 316mV IN I was getting 20 watts into 8R load (didn't measure into 4R load)
So the question is: what is the purpose of a 126 Watt amplifier (into 8R) if it will never deliver more than 20 watts? People say that the extra power is for "dynamic headroom", but doesn't the "dynamic headroom" still have to be limited to 316mV? When Google says the standard line voltage is 316mV, is that some kind of average for a musical track, and this it can have much higher spikes? Or is 316mV an absolute limit?
I recently upgraded my old HB with the MJL4281 and MJL4302 transistors (didn't make any other changes) and measured input and output.
Using an oscilloscope, I measured my input signal (1.0 kHz sine wave) and output across an 8R and a 4R load.
Into an 8R load, I got 32.0 dB gain all the way up to 795mV(RMS), where the output signal just started to clip, for 126 Watts.
Into an 4R load, I got 32.0 dB gain all the way up to 743mV(RMS), where the output signal just started to clip, for 215 Watts.
Power output was a bit low, but I'm using less than the recommended rail voltages, so OK.
But what is a mystery is that the standard line-level voltage for consumer audio gear is only 316mV. At 316mV IN I was getting 20 watts into 8R load (didn't measure into 4R load)
So the question is: what is the purpose of a 126 Watt amplifier (into 8R) if it will never deliver more than 20 watts? People say that the extra power is for "dynamic headroom", but doesn't the "dynamic headroom" still have to be limited to 316mV? When Google says the standard line voltage is 316mV, is that some kind of average for a musical track, and this it can have much higher spikes? Or is 316mV an absolute limit?
Hi Bryon,
"0" Vu in consumer land is 316 mV, that isn't even close to what you send an amplifier for maximum power. This is the expected line level out into a preamp level. Period. The levels seen at the amplifier vary between mV (cartridge output level) to volts. Most preamps have supplies of +/- 15 VDC, older ones can be +/- 35 VDC. The high voltages are for peaks of course.
Now, 20 watts continuous is extremely loud. Given a 10:1 to 15:1 peak to average ratio in music, that means 200 to 300 watts. I don't see a problem here. Just for giggles, send your amplifier a 1 KHz sine at 31.6 mV - please. A 1 watt level is probably what you want as a target power for this test, I'm just warning you. 1 watt will be loud. Figure out what input level that is.
"0" Vu in consumer land is 316 mV, that isn't even close to what you send an amplifier for maximum power. This is the expected line level out into a preamp level. Period. The levels seen at the amplifier vary between mV (cartridge output level) to volts. Most preamps have supplies of +/- 15 VDC, older ones can be +/- 35 VDC. The high voltages are for peaks of course.
Now, 20 watts continuous is extremely loud. Given a 10:1 to 15:1 peak to average ratio in music, that means 200 to 300 watts. I don't see a problem here. Just for giggles, send your amplifier a 1 KHz sine at 31.6 mV - please. A 1 watt level is probably what you want as a target power for this test, I'm just warning you. 1 watt will be loud. Figure out what input level that is.