Thanks ostripper,
That's what I thought. One should set voltage drop across these resistors soldered temporarily between emitters of the drivers and the output track and not on R34-35.
I have soldered two 68 ohm resistors between the emitters of Q14-15 and the output track so I should set R30 to get 1-1.1V drop between emitters of the drivers across 2x68 ohm resistors. I'll do it when I get home.
cheers,
That's what I thought. One should set voltage drop across these resistors soldered temporarily between emitters of the drivers and the output track and not on R34-35.
I have soldered two 68 ohm resistors between the emitters of Q14-15 and the output track so I should set R30 to get 1-1.1V drop between emitters of the drivers across 2x68 ohm resistors. I'll do it when I get home.
cheers,
You have the Semelab's?? If you do ... you are the "icebreaker".
I await with baited breath , so I can recommend them as a High (I)
alternative.
OS
I am building 3 honey badgers right now. I ended up with some 3watt resistors, instead of 5watt for the 0.22 ohm R43-R48. I'm going to drive them off of a 30-0-30 VAC transformer, so I'll should have rails around 41 watts. Can I get by with using the 3 W resistors or do I really need 5 W ones? I don't want to sacrifice on THD or noise.
I think I'm ready to solder in MG power transistors. Temporary 2x68ohm resistors removed, R36 and C20 are in.
One question:
when powered on just without power transistors, offset is now over 700mV and there is also AC - a few hundred mV at the output. Is it OK or is it too high?
With temporary resistors to the output in and R36/C20 out AC and DC at the output were almost zero (some uV).
Globe goes completely black after 20 sec, light diodes are on straight away and PS rails are +/-64.3V within 100mV.
May I solder in power transistors or there is something wrong?
My nfb is 27k to 1k.
cheers,
One question:
when powered on just without power transistors, offset is now over 700mV and there is also AC - a few hundred mV at the output. Is it OK or is it too high?
With temporary resistors to the output in and R36/C20 out AC and DC at the output were almost zero (some uV).
Globe goes completely black after 20 sec, light diodes are on straight away and PS rails are +/-64.3V within 100mV.
May I solder in power transistors or there is something wrong?
My nfb is 27k to 1k.
cheers,
if your are just listening to music and not doing sine wave power testing, then those 3 watters will do, just make sure they are off the boards by at least 3mm
for air circulation...
R30 bias adjustment
I'm sorry for posing such a beginner's question but in setting R30 to maximum (from the HB builder's guide biasing procedure) which two pins on a Bourns pot are measured?
Looking at the top so that the writing can be read, the brass adjustment screw is in the top left corner. The central pin is under this "top" edge. Does one want the (in this orientation) left pin to center pin at maximum resistance?
I'm sorry for posing such a beginner's question but in setting R30 to maximum (from the HB builder's guide biasing procedure) which two pins on a Bourns pot are measured?
Looking at the top so that the writing can be read, the brass adjustment screw is in the top left corner. The central pin is under this "top" edge. Does one want the (in this orientation) left pin to center pin at maximum resistance?
Look at the tracks. If you install the trimpot according to the pcb component side drawing GAP is between the wiper and the right pin looking at the trimpot from the top. This is the pin above, which there is the turning screw. Practically, solder in the trimpot and then set the maximum resistance across the gap: wiper connected pin and the other pin.
cheers,
cheers,
I like clockwise to increase the effect being read/measured/heard
eg.
clockwise to increase the gain and the volume.
clockwise to increase the output bias voltage/current.
clockwise to increase the output offset, (in the positive direction).
Most multi-turn trimmers are not laid out in a PCB to achieve my preference consistently.
Some PCB layouts even manage to get trimmers to do the opposite on the same PCB !
eg.
clockwise to increase the gain and the volume.
clockwise to increase the output bias voltage/current.
clockwise to increase the output offset, (in the positive direction).
Most multi-turn trimmers are not laid out in a PCB to achieve my preference consistently.
Some PCB layouts even manage to get trimmers to do the opposite on the same PCB !
Pictures help SO much
Oh and janusz...if you can post pictures of your process I am (among many others I assume) tracking all the efforts of those building the HB trying to "get it right the first time".
I am still in the checking parts stage and on my third read of the manual, second of this thread series
Oh and janusz...if you can post pictures of your process I am (among many others I assume) tracking all the efforts of those building the HB trying to "get it right the first time".
I am still in the checking parts stage and on my third read of the manual, second of this thread series
Honeybadger problems
Hi everyone,
I built a stereo pair of badgers based on the latest revision of the boards from the store. I have adjusted everything based on the build guide and the CCS current, offset and bias are all where they should be. I am powering the board from a dual tracking supply (+-35 volts, that's as high as the supplies go) with current limited to 750mA. The board is drawing about 220 mA when idle and the heatsink is at 35 deg Celcius.
The problem is that when I connect a source (mp3 Player) I hear nothing, and see very little on the scope (besides about 40mvP-P noise). When I turn the volume all the way up, I barely hear a bit of music from the connected 8 ohm speaker (I am guessing I'd hear about as much if the board was just a pair of wires!)...Any ideas why?
BTW I am not using the D-BC optional diode. Do I need a jumper there, or should it be left open?
Thanks in advance for you help.
Hi everyone,
I built a stereo pair of badgers based on the latest revision of the boards from the store. I have adjusted everything based on the build guide and the CCS current, offset and bias are all where they should be. I am powering the board from a dual tracking supply (+-35 volts, that's as high as the supplies go) with current limited to 750mA. The board is drawing about 220 mA when idle and the heatsink is at 35 deg Celcius.
The problem is that when I connect a source (mp3 Player) I hear nothing, and see very little on the scope (besides about 40mvP-P noise). When I turn the volume all the way up, I barely hear a bit of music from the connected 8 ohm speaker (I am guessing I'd hear about as much if the board was just a pair of wires!)...Any ideas why?
BTW I am not using the D-BC optional diode. Do I need a jumper there, or should it be left open?
Thanks in advance for you help.
An externally hosted image should be here but it was not working when we last tested it.
I'm getting close to powering up my 3 honey badgers. For convenience reasons, I'd like to power them up initially using a smaller 33-0-33 VAC transformer, but plan on eventually using a larger 30-0-30 VAC transformer. Would this cause a problem? Would I need to readjust the bias, ccs, and offset adjustments upon changing power supplies, or are these settings independent of this change in rail voltages?
If it matters, I'm doing the 12V zener referenced cascode option.
If it matters, I'm doing the 12V zener referenced cascode option.
Bridge the jumper next to C1 - you have no input. Also , some say "LC" creates peaking (worse sound) .... remove.
Only a 3.5mm cap does not require the jumper - you have 5mm or 7.5mm
PS - do not jumper D-bc !!! Boom !
OS
Last edited:
Being CCS based , the badger is "rail tolerant" . All will be the same
from 30 - 70V.
OS
Thanks Ostripper,
-I jumpered the input and the amp works
-Removed the LC cap though I can't hear any difference with my crappy homemade speakers I'll try to get a good tone generator and do some testing on the scope with and without the LC cap (was a 3+-0.25 mica)
-I figured about the clamp diode after having another look at the circuit. A jumper there would have indeed made a loud noise
Can't wait to hear these puppies on good speakers, so far they look great and sound very nice. Once again, thanks for the design (I learned a lot from you and others here) and the troubleshooting help.
-I jumpered the input and the amp works
-Removed the LC cap though I can't hear any difference with my crappy homemade speakers
I'll try to get a good tone generator and do some testing on the scope with and without the LC cap (was a 3+-0.25 mica)-I figured about the clamp diode after having another look at the circuit. A jumper there would have indeed made a loud noise
Can't wait to hear these puppies on good speakers, so far they look great and sound very nice. Once again, thanks for the design (I learned a lot from you and others here) and the troubleshooting help.