I am devestated.... I just built today a loop breaker circuit to eliminate ground loop, and as I connected it to the circuit, the test speaker started to give out huge noise.. Both Left and Right V+ leds stopped working. I tought: Oh well, the fuses blew.
But then, when I watched the fuses, they had no problems at all. removed the fuse, started the amp, and the V+ is still glowing!
So maybe the R53 burned... I replaced it, but it still buzzes like hell and doesn't give out any sound... I don't know how to diagnostize the problem, I watched everyting, and everything seems to be normal from the outside.
Please help me!
UPDATE:
Pretty Noob thing from me: Found out that the output jack from my audio interface was halfway out, that caused the huge noise.... Sorry for the alert. Now I have sound. But still, I have hum, even with the loop breaker circuit.
But then, when I watched the fuses, they had no problems at all. removed the fuse, started the amp, and the V+ is still glowing!
So maybe the R53 burned... I replaced it, but it still buzzes like hell and doesn't give out any sound... I don't know how to diagnostize the problem, I watched everyting, and everything seems to be normal from the outside.
Please help me!
UPDATE:
Pretty Noob thing from me: Found out that the output jack from my audio interface was halfway out, that caused the huge noise.... Sorry for the alert. Now I have sound. But still, I have hum, even with the loop breaker circuit.
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I have wondered the same. I believe there were some older boards which did not have connecting traces and therefore the jumpers were necessary. But not on the newer boards. I built mine without these extra jumpers and all is well, as far as I can tell.
.Hi dear Diyaudio!
I haave problems once again. My amplifier is up and running nicely.... well, sort of nicely.
If anyone can help me what that could be that would be awesome!
Let's see what is happenning to better understand my problem: I have a Focusrite 18i8 Audio Interface connected to my computer. After that interface comes my beloved honey badger, then my ATC speakers.
I turn on the amplifier after the audio interface. No problems, no noise, works well.
I start to work on my speakers. Suddenly, a high level static noise comes in, sometimes goes away after 1 secs with a "poof" sound. But most of the times, it stays. It stays and gets louder and louder slowly... UNLESS!
Unless I turn up the volume knob on my Focusrite 18i8. The noise begins to be louder, louder, then, it stops for some time, then it starts again after some minutes of silence. I attached an audio clip of this event: Making speaker louder to stop noise.
Ground loop is eliminated through Loop breaker circuit, and for some strange reasons, if I disconnect the audio interface, and turn the amp back on, it remains silent.
Another strange thing is that if I touch the cables, moving the cables which interconnect the amp and the interface makes a "scratchy" sound, I have attached a sound sample of it too: These sounds come from the speakers if I move the cables.
So my Idea is that there might be something wrong with my audio interface. But what could go wrong? What is making my cables "sizzle"? It is a Klotz cable, with neutrik connectors, so it can't be low quality... Please help me!
I haave problems once again. My amplifier is up and running nicely.... well, sort of nicely.
If anyone can help me what that could be that would be awesome!
Let's see what is happenning to better understand my problem: I have a Focusrite 18i8 Audio Interface connected to my computer. After that interface comes my beloved honey badger, then my ATC speakers.
I turn on the amplifier after the audio interface. No problems, no noise, works well.
I start to work on my speakers. Suddenly, a high level static noise comes in, sometimes goes away after 1 secs with a "poof" sound. But most of the times, it stays. It stays and gets louder and louder slowly... UNLESS!
Unless I turn up the volume knob on my Focusrite 18i8. The noise begins to be louder, louder, then, it stops for some time, then it starts again after some minutes of silence. I attached an audio clip of this event: Making speaker louder to stop noise.
Ground loop is eliminated through Loop breaker circuit, and for some strange reasons, if I disconnect the audio interface, and turn the amp back on, it remains silent.
Another strange thing is that if I touch the cables, moving the cables which interconnect the amp and the interface makes a "scratchy" sound, I have attached a sound sample of it too: These sounds come from the speakers if I move the cables.
So my Idea is that there might be something wrong with my audio interface. But what could go wrong? What is making my cables "sizzle"? It is a Klotz cable, with neutrik connectors, so it can't be low quality... Please help me!
I couldn't download the first sound sample, but the second worked. Sounds like some static thingy (no hum or similar). Do you have a bad volume pot in the Focusrite?
Some tests and suggestions:
Some tests and suggestions:
- Does this happen only with a source connected to the amp? What if you leave the input of the amp unconnected? What if the input is connected to GND?
- Try different sources! A phone with a headphone out might do for testing purposes. Does the noise go away with different sources?
- Try a different amp with the Focusrite. Does the noise go away?
- Try different audio cables.
- Is this a laptop computer? Try running it off its battery, without any connection to the mains line. I once had issues with a poorly isolated USB interface that coupled some noise to ground.
I have talked to an electronic engineer today and he said, that you have to use this thermal bar with Q13 because if you place it direct on the big main heatsink Q13 wont be able get working temperature quick enough and will make mish match on Q14 and Q15 from the beginning and this will sound very bad.
Best regards,
Henrik
Q13 has to monitor the output stage.
The temperature changes of the driver stage are much lower than the output stage and there is much less need to monitor the driver temperature.
Attach Q13 to the main heatsink or on top of one of the outputs or best of all a sot23 on the middle lead out of one output device right next to the plastic package.
This leadout changes temperature more quickly with changes in Tj than any other external part of the output stage.
The temperature changes of the driver stage are much lower than the output stage and there is much less need to monitor the driver temperature.
Attach Q13 to the main heatsink or on top of one of the outputs or best of all a sot23 on the middle lead out of one output device right next to the plastic package.
This leadout changes temperature more quickly with changes in Tj than any other external part of the output stage.
The SOT23 sounds good in theory but how do you make a mechanically sound attachment and electrical connections?
In my builds I've never seen a huge lag in thermal compensation with the sensing transistor mounted on the heatsink itself. Never enough to warrant the decreased reliability of a more secure attachment.
I have done four like this and so far there have been no reliability issues.
From this little experience I have concluded that the fast reaction of the sot23 to Tj changes is better than any other Vbe multiplier. The integrated diodes in NJL may be faster and sense a higher portion of the Tj change, but I have no way of measuring/comparing.
I have experienced a lot of time lag. So much so in some examples that the Vbe tempco as proposed by the designer did not work.
I guess I've just been lucky. Ostripper's Slewmaster bias circuit was pretty much perfection and Vzaichenko's bias circuits are very good too. My choice of heat sinks might have helped too. How do you mount the SOT23 to the pin of the transistor? Do you use an adapter board to attach the wires?
I glue the sot23 upside down to the underside of the middle pin.
The first I did wire it directly with three strands from a 0.1mm stranded cable and insulated two strands with tubes cut from cat5. I was not confident of the wire to sot23 fixing.
For the next I cut a tiny single sided pcb with the three lands separated by knife cuts. Each land was soldered to the upside down chip leaving just enough sticking out to attach 0.15mm strands, again two insulated. These partially insulated close coupled wires were run to the three holes where the To126 should have been fitted.
The first I did wire it directly with three strands from a 0.1mm stranded cable and insulated two strands with tubes cut from cat5. I was not confident of the wire to sot23 fixing.
For the next I cut a tiny single sided pcb with the three lands separated by knife cuts. Each land was soldered to the upside down chip leaving just enough sticking out to attach 0.15mm strands, again two insulated. These partially insulated close coupled wires were run to the three holes where the To126 should have been fitted.
Hi all, sorry to interrupt the current conversation. but I just would like to confirm something.
So I finally built a power supply so I can test my Honey badger boards.
I left out R36 and installed the 68 ohm resistors and the 10 ohm 1w resistors as per the installation guide
The guide the says to
My problem is I am unable to get 0.55v on resistors R34 and 35. With R30 set to maximum resistance
I am getting 1.0v on resistors R34 and R35 and 2v across C20.
Just to be clear I am measuring from GND to the connection point between R34 and the Base Side of the transistor Q14.
Everything else seams fine. CCS is ok
8.25v across R14 and my DC offset is 0v.
I read on post #1093 from Mr Ostripper
diyAB Amp The "Honey Badger" build thread
So something is not quite right or clear as the build guide written by Mr Ostripper
Says
Please confirm that I am meant to take my 0.55v reading across each of the 68 ohm resistors not across R34 and R35.
These should be 1v..
Thanks…..
So I finally built a power supply so I can test my Honey badger boards.
I left out R36 and installed the 68 ohm resistors and the 10 ohm 1w resistors as per the installation guide
The guide the says to
My problem is I am unable to get 0.55v on resistors R34 and 35. With R30 set to maximum resistance
I am getting 1.0v on resistors R34 and R35 and 2v across C20.
Just to be clear I am measuring from GND to the connection point between R34 and the Base Side of the transistor Q14.
Everything else seams fine. CCS is ok
8.25v across R14 and my DC offset is 0v.
I read on post #1093 from Mr Ostripper
diyAB Amp The "Honey Badger" build thread
So something is not quite right or clear as the build guide written by Mr Ostripper
Says
Please confirm that I am meant to take my 0.55v reading across each of the 68 ohm resistors not across R34 and R35.
These should be 1v..
Thanks…..
Hi Stu,
the 2 x 68 ohm temporary test resistors, replacing R36, go between the emitters of Q14/Q15 to the output track. The 0.55V is measured between the 2 emitters and across the pair of test resistors.
The test simply allows the bias to be set to a safe starting point before the outputs are installed. Because each test resistor is connected to the output track the preceding stages have appropriate feedback and are behaving normally.
(not sure where you got the idea for R34/35, they are simply the base stoppers for the driver transistors)
Cheers
the 2 x 68 ohm temporary test resistors, replacing R36, go between the emitters of Q14/Q15 to the output track. The 0.55V is measured between the 2 emitters and across the pair of test resistors.
The test simply allows the bias to be set to a safe starting point before the outputs are installed. Because each test resistor is connected to the output track the preceding stages have appropriate feedback and are behaving normally.
(not sure where you got the idea for R34/35, they are simply the base stoppers for the driver transistors)
Cheers