Switching pop-noise solution?

  • Now that I finished the J5Mk1 everything works well. I followed close the wiring indications to reduce background noise and it is very low compared with other amps I heard. But switchg on/off Gain produces an audible pop-noise. Does anybody found a solution or at least a way to reduce such poping noises?


    Best regards.
    Alvaro

  • Re: Switching pop-noise solution?


    Did you already try the 1meg-resistor-across-the-switch approach?
    Just ageneric thought, as I don't have the schematic...

    "It's such a fine line between clever and...and..."
    "...stupid?"
    "Yeah, stupid, right."

  • Re: Switching pop-noise solution?


    Quote from J.Doe


    Did you already try the 1meg-resistor-across-the-switch approach?
    Just ageneric thought, as I don't have the schematic...


    I would try this if I was sure how it works. There are one input signal wire and two output wires. Do I have to solder one resistor for all three wires to ground?

  • Re: Switching pop-noise solution?


    Hi Alvaro,
    no, we don't necessarily want to pull anything to ground here. The popping noise is caused by different DC potentials which give a short spike when you connect them with your switch...
    If there is no DC biasing involved (0V DC on all 3 points), you could use the pulldowns you mentioned(on the other hand, I don't know any design that does not have resistors to ground around channel switches, so you may want to re-check your wiring in the first place). Otherwise you could use 2 resistors, 'bridging' both ways of your switch(your shorting one of them in each position of your switch).
    Maybe Martin himself chimes in to help us out here, as I strongly suspect a wiring problem to be the cause - I personally don't think it's a design flaw...

    "It's such a fine line between clever and...and..."
    "...stupid?"
    "Yeah, stupid, right."

  • Re: Switching pop-noise solution?


    Hi,


    perhaps this is the solution you are looking for:


    http://forum.musikding.de/yabb…tach;topic=8297.0;id=3552


    I worked out the muting circuit from the German ENGL Amps and it works perfect.


    Regards,
    Oli

    [size=1]DIY: Soldano X88R, Peavey 5150, Engl 530,Boss AC-2,BD-2,BF-2,CE-2,DM-2,DS-1,DS-2,EH-2,FT-2,HM-2,MD-2,MT-2,NF-1,NS-2,OC-2,OD-1,OD-2,OD-3,OS-2,PH-1, SD-1,SD-2,SG-1,SP-1,TW-1,XT-2,Rocktave Divider,Small Stone,Woody,STL,TS10,TS9,TS808,Obsidian 1+2,EasyVibe,Ultraflanger,Zombie Chorus,PT-80,MU-TRON, etc.[/size]

  • Re: Switching pop-noise solution?


    Yep,
    if everthing else fails, this will surely work. I never took a closer look at those Engls, but I'm quite surprised to see such a solution in a german amp - usually german engineers tend to even out problems at the source, such a solution looks a little 'japanese' to me.
    Does the amp we're talking about already have 12V DC supply?

    "It's such a fine line between clever and...and..."
    "...stupid?"
    "Yeah, stupid, right."

  • Re: Switching pop-noise solution?


    Hi,


    I don´t know if the J5MK1 has a 12V supply, because unfortunatelly I have no schematic.


    Why do you think it looks Japanese? I haven´t seen this circuit some where else. Or even another different popping suppression circuit.
    Sometimes it is really hard and sometimes impossible the solve a problem at the source - e.g. cap switching at the cathode of a tube. And sometimes it is a matter of money e.g. photomos relais vs. mechanical ones.
    An when the output pops why not mute the output?
    And be honest, who cares why the amp has no switching pops, it is much more important that it has none.


    But anyway, if the J5MK1 of other DIYers don´t pop, then there is an error in your wiring. And if it generally pops, nobody without a schematic can help.
    Perhaps you can draw the Gain switching part of the amp, so we can help you.


    Regards,
    Oli

    [size=1]DIY: Soldano X88R, Peavey 5150, Engl 530,Boss AC-2,BD-2,BF-2,CE-2,DM-2,DS-1,DS-2,EH-2,FT-2,HM-2,MD-2,MT-2,NF-1,NS-2,OC-2,OD-1,OD-2,OD-3,OS-2,PH-1, SD-1,SD-2,SG-1,SP-1,TW-1,XT-2,Rocktave Divider,Small Stone,Woody,STL,TS10,TS9,TS808,Obsidian 1+2,EasyVibe,Ultraflanger,Zombie Chorus,PT-80,MU-TRON, etc.[/size]

  • Re: Switching pop-noise solution?


    Sorry Oli,
    of course there is nothing wrong with that solution, whatever works is just fine...(Btw, in no way did I want to offend any japanese engineer, there's always several ways to fix a problem).

    A little OT geektalk: Another over-engineered solution for switching cathode caps would be to use FETs or optocupplers, but you'd hardly save anything compared to the mute-solution...

    "It's such a fine line between clever and...and..."
    "...stupid?"
    "Yeah, stupid, right."

  • Re: Switching pop-noise solution?


    Ok,
    after a quick shufti over the (unfortunately rather dull) schematic on Martin's page, I'm almost certain that a wiring problem is the cause for the popping, as there's a pulldown on all three sides of the switch.
    It would be interesting to hear about the experiences of other DIYers that have built this amp.

    "It's such a fine line between clever and...and..."
    "...stupid?"
    "Yeah, stupid, right."

  • Re: Switching pop-noise solution?


    Hi,


    Quote

    It would be interesting to hear about the experiences of other DIYers that have built this amp


    I've build this amp exactly as the plan shows and had no switching noise.


    But I've had a lot of work to get this little high gain monster quiet regarding hum, noise and oscillation (btw. I changed the original measures of the chassis to a smaller one - "little monster" ;D)


    Bernd

  • Re: Switching pop-noise solution?


    Thanks a lot, Bernd!
    Gosh, I just realised what an impollite person I am... my name is Thomas.
    Ok, so you just confirmed my suspicion - those three resistors should keep switching noise quite low...so there's two posibilities left:
    a) wiring
    b) a leaky capacitor (should be impossible with new parts, but it happens)
    Yeah, I can imagine that this 'little monster' is hard to tame...btw, how's the sound of that SE when you really hit it hard?

    "It's such a fine line between clever and...and..."
    "...stupid?"
    "Yeah, stupid, right."

  • Re: Switching pop-noise solution?


    Thanks for all these replies.





    If it is confirmed that other j5Mk1 does not have switching noises, it is clear that there must be something wrong in mine. And not only gain switch produces pop noises, but also all the other switchs. Perhaps this change a bit the possible cause of this.
    Wiring error? I thing that now all the connenctions are just like the schematic, so it is difficult, but I wll recheck.
    Leaky capacitor? May be. How can I check if there is a leaky capacitor? measuring its resistance to DC?



    Best Regards
    Alvaro

  • Re: Switching pop-noise solution?


    Hi,


    Quote

    How can I check if there is a leaky capacitor? measuring its resistance to DC?


    by simple means - like a DVM - you can't do this. Because a "leaky" cap can have still a DC resistance above tenths of megohms. And leakage may occur/increase just at the higher operation voltage (in tube amps several 100 volts).


    Bernd

  • Re: Switching pop-noise solution?


    Hi,


    but if all switching actions are popping (glad that we are in the English part of the forum...) I am quite shure, that the problem is not just one leaky cap, e.g. a leaky coupling cap after a triode can´t cause popps when you do some switching at the grid of the same triode.
    So you have to look at the schematic, where exactly the popps will happen. Perhaps there is a cold soldering in the ground wires or something else.


    Regards,
    Oli

    [size=1]DIY: Soldano X88R, Peavey 5150, Engl 530,Boss AC-2,BD-2,BF-2,CE-2,DM-2,DS-1,DS-2,EH-2,FT-2,HM-2,MD-2,MT-2,NF-1,NS-2,OC-2,OD-1,OD-2,OD-3,OS-2,PH-1, SD-1,SD-2,SG-1,SP-1,TW-1,XT-2,Rocktave Divider,Small Stone,Woody,STL,TS10,TS9,TS808,Obsidian 1+2,EasyVibe,Ultraflanger,Zombie Chorus,PT-80,MU-TRON, etc.[/size]

  • Re: Switching pop-noise solution?


    I replaced all big capacitors (100uF and 47uF) with other with better specifications and the same capacity. And the result is... the same poping noises. In fact, the Gain switch always pop, the Highs filter (at V3) never do it and the Fat (at V1 and V2) switch only pops the first time it is switched and if you switch again inmediatly it do not pops, but if you wait some time (15 seconds for example) the pop noise return again. It is just like the pop noise were "recharging" :D.


    Best regards.
    Alvaro

  • Re: Switching pop-noise solution?


    We're talking about two different things now:
    The 'thumping' of the FAT-switch, that's due to the cathodecap getting charged (the reason why it takes some time until it reoccurs), and there's no easy way (e.g., one that doesn't need an extra DC-supply) around this (no way I would know of, that is). Oli mentioned it a few posts above.
    The poppin' gainswitch (I heard 'poppen' is a common german term for 'coger') is something different, the suspects here are the caps at the anodes of the first two triodes, if one is leaky there may be some DC-offset at the switch. Also take a look at the solderjoints of the corresponding resistors to ground. If this doesn't help, the last possibility I can think of would be the wiring itself, you could move the resitors straight to the switch, thus killing any offset caught up on the way.
    If you happen to own (or know someone who does) an accurate DC-mvmeter (e.g. an old tube-voltmeter), you could check the DC-offset at the gainswitch and trace it back from there.
    I hope this helps...


    Cheers, Thomas

    "It's such a fine line between clever and...and..."
    "...stupid?"
    "Yeah, stupid, right."

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