Just finished my amp and it works fine except that there is a slight hiss in the tweeter (you can hear it if you put your ear next to the speaker). This hiss is there independent of whether something is connected to the input of the PCBs or not. It occurs on both channels. Is there anything specific that can cause this or should i just randomly start to reroute cables?
Thanks
Thanks
Hi, thanks for the reply. However the noise is there without any input wires at all. I'll still try to reroute the output wiring though
I was not clear enough. My fault.
I meant to re route the input / output wires which are attached to the board and your amp's chassis, not the RCA cables. You should have ZERO RCA cables attached to your amp at this point.
I would like to hear others opinions about shorting the input RCA jacks for testing. Wait until someone with more experience advises testing with shorted inputs.
Ron
I meant to re route the input / output wires which are attached to the board and your amp's chassis, not the RCA cables. You should have ZERO RCA cables attached to your amp at this point.
I would like to hear others opinions about shorting the input RCA jacks for testing. Wait until someone with more experience advises testing with shorted inputs.
Ron
Try shorting the input signal to input ground and see if the noise goes away.
This helped a lot, it gets much quieter. However you can still hear a little bit of noise if you have your ear next to the tweeter.
OK! It is high frequency, it only appears in the tweeter as a hiss like sound.
Yes, or at leas sort of. I'm using the DIYaudio universal PSU, and have connected all the ground wires along the solder pads available, so they are all connected within 3-4 cm of each other. From the starground there is then one wire going to the chassis attached together with the safety earth
For testing, temporarily unhook the chassis from the star ground. You may need a loop breaker. Earthing (Grounding) Your Hi-Fi - Tricks and Techniques
Disregard, I missed the digikey reference on the BOM (I modified my BOM as I was ordering, and accidentally deleted that PN).
It does use the 250 series connectors.
I also have a high frequency hiss with my Honey Badger build that I've been trying to resolve, it sounds like white noise. I'm using the DIY universal PSU star grounded with an Antek 400VA trafo with shield (AS series). No ground loop hum at all, plays OK but with source paused I can hear a high frequency hiss from both speakers. It definitely impacts the low level detail. I reworked my internal wiring to minimize the input wiring length, all of the internal wiring is tightly twisted. All measurements are adjusted per the manual and the DC offset is good floats between +1 to -1 mV.
I have an Aleph J with a similar wiring and build technique that is dead silent. I have the speaker grounds coming from the PSU gnds to shorten the wiring, tried coming off of the board, made no difference. Next I'm planning to try bridging the input signal and grd with a high value resistor (~ 1M) to see if I can shunt some of the noise to gnd before the amplifier. I wonder if this design is sensitive to picking up PSU noise in the case ?
PJN
I have an Aleph J with a similar wiring and build technique that is dead silent. I have the speaker grounds coming from the PSU gnds to shorten the wiring, tried coming off of the board, made no difference. Next I'm planning to try bridging the input signal and grd with a high value resistor (~ 1M) to see if I can shunt some of the noise to gnd before the amplifier. I wonder if this design is sensitive to picking up PSU noise in the case ?
PJN
Badger/Wolverine should be dead silent. (-110 - 115db+)
List what transistors you use.
Show pix of amp.
No ebay semi's ???
Noise that occurs in BJT's is thermal noise, shot noise, partition noise, flicker noise ....
Usually occurs with excessive current , too little degeneration-too much gain.
Jacked my circuit like this to 40X global gain - could hear no noise with my
ear to the tweeter.
I have used 1845's and BCxxx as the input pair - the BC's are a bit quieter
... but the 1845's are not bad (very close).
First I've heard of this fault ???
OS
List what transistors you use.
Show pix of amp.
No ebay semi's ???
Noise that occurs in BJT's is thermal noise, shot noise, partition noise, flicker noise ....
Usually occurs with excessive current , too little degeneration-too much gain.
Jacked my circuit like this to 40X global gain - could hear no noise with my
ear to the tweeter.
I have used 1845's and BCxxx as the input pair - the BC's are a bit quieter
... but the 1845's are not bad (very close).
First I've heard of this fault ???
OS
Nice to know ,I can assure you are not alone , unrelevant I used the dale LVR low inductance 0.22R 5W too. Has anybody tried the NS series?. Can someone explain the driver 1K 1K 150R all looks balanced with mje15032/33 bias works symmetrical output 0V speaker but not with 68 + 68 or 75 + 75 no 150 in circuit goes to + rail at 0speaker output . Tried the 9411-mg 6331-R and njw 1302 3281 same + 5v output . Burned Mje 15033 . Lightbulb used 40w not bright . tested tmc and miller . .not tested since tried use tight tolerance per resistors 0.1% 25 ppm 0.6w and I do not own a presion dmm just a uni-t ut71d just measured same vbe with diode tester and hfe with another dmm let it sit 5 to 10 min . Panasonic fc 100v series 470uF 220uF 22uF . Did look for gaps in transistor mounting mica insulator used I have kapton not tried yet. Softstart also in use 80000uF 10000uF * 80V cheap united chemicon with power supply circuit v3 4*0.22R dale rs series 3w and twisted 2.5mm wires . Can't buy a good oscilloscope and signal generator there would go one accuphase amp in cash. I could get a a atlas dc pro75 but it does only to 12V , the bjt are in correct possision npn to pnp I have to look at my measurments values , Can someone help i did a mesurment similar to pjn per bjt and I have 50njw 0302 and 50 0281 from mouser if it does help . So help please
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