Again, I know you have been down this road, but putting shorting plugs in the inputs, no hum means something up stream. My case was same way. Having two power cords, I noticed one other anomaly. If I disconnected one side first, silence, then unplug other side, amp off both channels. But, If I unplugged the other side first, the remaining one hummed slightly until I unplugged it. That should have been a hint, but until I finally installed dual (one for each power cord ) CL-60 inrush pieces, and disassembled the powercons did I discover my mistake.
Russellc
Russellc
If you rebuild, take pics and document like you say. Building it out of chassis is good idea.
Build power supply first, and test it. Make sure to use drain resistors to drain power supply caps.
Measure power supply for proper function. Get your soldering skills tweaked and ready. If you haven't, buy a decent solder rig, hakko is my go to, lots of cheap clones. Tip on pad and wire at SAME time, wait until solder melts on pad, flow and leave going up wire. Leave nice shiny little volcano looking, no dull silver blobs. A good iron makes this simple.
Use a good power supply board, from store, or I like teabags board, very nice thick board. Something folks eyes are familiar with.
Build power supply first, and test it. Make sure to use drain resistors to drain power supply caps.
Measure power supply for proper function. Get your soldering skills tweaked and ready. If you haven't, buy a decent solder rig, hakko is my go to, lots of cheap clones. Tip on pad and wire at SAME time, wait until solder melts on pad, flow and leave going up wire. Leave nice shiny little volcano looking, no dull silver blobs. A good iron makes this simple.
Use a good power supply board, from store, or I like teabags board, very nice thick board. Something folks eyes are familiar with.
@Russellc ... dear Sir... i have two soldering irons no worries there 😁... also some skills... made couple of amps back in the days
... this one is making me crazy... also my buddies that also did couple of things themselves..... none of us could figure where the problem might be.....
Will get those psu boards just to reduce possible problems and do it and will take pic's as i assemble it.....
Sincenit did not work for three times - hopefully the 4th will be the lucky one 😁😁🤣
... this one is making me crazy... also my buddies that also did couple of things themselves..... none of us could figure where the problem might be.....
Will get those psu boards just to reduce possible problems and do it and will take pic's as i assemble it.....
Sincenit did not work for three times - hopefully the 4th will be the lucky one 😁😁🤣
Hi there, I know that buzz and hum can drive you up the wall. I had the same with my F5, which I bought as a finished build. I had a buzz when connecting both inputs, with one connected it was dead quiet. I tried everything as you do to no avail, until I stumbled upon a thread where this issue was discussed as a layout error in the PCB from Cviller, the ones you have as well.
For me cutting the trace between in ground and ground and connecting them with a 3.3R resistor did it. I had to cut one more trace iirc, but I can't remember which one. As I sold the amp some time ago, I can't look it up unfortunately.
Everything else stayed as it was.
Maybe it helps a bit, good luck!
For me cutting the trace between in ground and ground and connecting them with a 3.3R resistor did it. I had to cut one more trace iirc, but I can't remember which one. As I sold the amp some time ago, I can't look it up unfortunately.
Everything else stayed as it was.
Maybe it helps a bit, good luck!
@Jogi my friend... you cut in between the in gnd and power supply gnd trace and put 3R3.. i know exactly where that cut needs to be done..... maybe i need to return the R2, cut that trace and use smaller resistor that will be a different thing ti what i have now..... will for sure check that out before i do anything else on my amp...
One other trace... hmmmm?
Any chance to helo how to find that thread...?
Will also search myself too.... cheers mate
One other trace... hmmmm?
Any chance to helo how to find that thread...?
Will also search myself too.... cheers mate
Found the thread and the lucky guy who removed the buzz:
HBR Cviller boards
So it is cutting 2 traces and adding a wire and a resistor. I didn't use the reverse diodes, was quiet even with the one resistor.
I wish you good luck, it is such a relief when finally there is silence. Although 108 dB speakers are really sensitive...
HBR Cviller boards
So it is cutting 2 traces and adding a wire and a resistor. I didn't use the reverse diodes, was quiet even with the one resistor.
I wish you good luck, it is such a relief when finally there is silence. Although 108 dB speakers are really sensitive...
That is interesting. Originally I proposed the same HBR scheme in my post #39, modifying the Ground at the input and at the JFETs. Then I simulated it in LTSpice and it increased the gain of the input JFETs substantially (is the LTSpice simulation trustworthy?). So I changed the HBR scheme to only modify the Ground at the input only.
It would be interesting to see a progression of changes and their results. The input HBR is already in place. Make the PS board and ground changes leaving the existing input HBR in place and check the result. Then if necessary, add the HBR modification to the JFET ground and see if it makes a difference.
It would be interesting to see a progression of changes and their results. The input HBR is already in place. Make the PS board and ground changes leaving the existing input HBR in place and check the result. Then if necessary, add the HBR modification to the JFET ground and see if it makes a difference.
Last edited:
Could you have a noise source in your residence that is injecting this noise?
Light dimmer, LED strips, digital component, etc?
I've even had a NE-2 neon bulb pilot light inject buzzing into the audio.
Try turning off a bunch of your electronic stuff and see.
Last edited:
Dear @Bonsai , i am very grateful for your amount of time and effort invested in trying to help my issue....
thank you...
that psu board will be removed...
i bought yesterday the psu board from diyaudio store... to remove possible issues i might have on my psu board. that one is designed properly and should work....
My toroid is separated from the rest of the circuit - in between that toroid and amplifier pcb's i have a plate of iron that is grounded... so it will act as a shield - also i tried to cover the toroid completely with iron cap - it did not do nothing to reduce the hum - so i suspect toroid as it is does not affect buzzing much - most probably it is wirring the psu board and other issues pointed ....
indeed 22R i used as HDR seems like made a problem bigger actually....
will try to implement your suggestions when assembling the amplifier next time - for now, i am waiting psu board and additional set of amplifier boards just in case.....
... will dismantle everything and start all over again....
thank you...
that psu board will be removed...
i bought yesterday the psu board from diyaudio store... to remove possible issues i might have on my psu board. that one is designed properly and should work....
My toroid is separated from the rest of the circuit - in between that toroid and amplifier pcb's i have a plate of iron that is grounded... so it will act as a shield - also i tried to cover the toroid completely with iron cap - it did not do nothing to reduce the hum - so i suspect toroid as it is does not affect buzzing much - most probably it is wirring the psu board and other issues pointed ....
indeed 22R i used as HDR seems like made a problem bigger actually....
will try to implement your suggestions when assembling the amplifier next time - for now, i am waiting psu board and additional set of amplifier boards just in case.....
... will dismantle everything and start all over again....
Well, i really hoped 0R47/5w resistors will arrive today... they did not so i am kind of stuck for now with what i did shown bellow... with this hot weather, i have an excuse to actually rest...
....
Can't move forward because i need to install those 4 pieces of 0R47 missing.... the small cap's at the end are 100uF caps (i bypassed R12 and R11 and installed them in place of C17 and C18).....
....
Can't move forward because i need to install those 4 pieces of 0R47 missing.... the small cap's at the end are 100uF caps (i bypassed R12 and R11 and installed them in place of C17 and C18).....
Attachments
Hello girls abd boys....
..
Constructive question - universal power supply board for F5 - in my box, the edges of the psu board will come close to the amplifier boards on 4cm..... will that be a problem?
...
My box is as big as it is.... hopefully, it will not be a problem...... thank you for your time.. cheers
..
Constructive question - universal power supply board for F5 - in my box, the edges of the psu board will come close to the amplifier boards on 4cm..... will that be a problem?
...
My box is as big as it is.... hopefully, it will not be a problem...... thank you for your time.. cheers
Will tra to do it today and send.......
Being as crazy as i am now with working on this amp for months now i am jumping on everything.. 😁😁
Being as crazy as i am now with working on this amp for months now i am jumping on everything.. 😁😁