Split load plop

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hans-jörg
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Split load plop

Post by hans-jörg »

Hi,
I have the split load on my 2nd stage. With separate coupling res. (0,1µF/82k, 2n2/100k).
As long the caps are not fully loaded, there´s a huge plop when switched (depeds of the frequency of switching 8) ).
How can I solve that problem? With 2x100n caps over the switch lugs? Or with 1M res to ground?
Probably the best would be a relay and 2m2 to ground at the unused side, I guess. But this would need another small iron for the 5 or 12 VDC. Not shure that my heather wireing could stand this additional circuit. Its now at 6,2 V!

Any suggestions?

Best
Hans-Jörg
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Richie
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Re: Split load plop

Post by Richie »

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pablogt
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Re: Split load plop

Post by pablogt »

my footswitched split load k50 does not pop...
https://tubeamparchive.com/viewtopic.ph ... hlight=k50

Pablo
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cbass
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Re: Split load plop

Post by cbass »

Hi Pablo what part is the relay you are using.
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pablogt
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Re: Split load plop

Post by pablogt »

Lately I tend to use mosfet relays like Mouser Part No: 769-AQW654 . No moving parts and you can operate the led side with virtually anything between 2 and 5v

The one switching my K50's split load is a traditional 5v relay ( Mouser Part No: 653-G5V-2-H1-DC5). I used it because I wanted a dpdt relay for switching in an out a cathode bypass cap when changing plate load and because the mosfet relays I had left were 300v rated, while plate voltage was 390v ( I fried a few before I realized what was going on)

By the way, for those changing plate load with a tiny switch, be careful with the switch's voltage rating...

Pablo
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roberto
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Re: Split load plop

Post by roberto »

You have two coupling caps, both of them with one side connected to high voltage. Simply connect the other two sides of the caps with a 2M2 resistor (anything above 1M is ok).

This will keep the ground voltage avoiding any pop.
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hans-jörg
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Re: Split load plop

Post by hans-jörg »

roberto wrote:You have two coupling caps, both of them with one side connected to high voltage. Simply connect the other two sides of the caps with a 2M2 resistor (anything above 1M is ok).

This will keep the ground voltage avoiding any pop.
Hello Roberto:
you mean BETWEEN the two AC sides one 2m2 res, or with 2m2 from each cap to ground? And iF - at the sitch or direct at the caps? For the moment I use a normal switch.

@ Pablo: this AQW switching parts are really cool! No moving parts means no plopping! I have to organize some of them. Although for this (meantime a K50 variation like yours) I would need a separate 6V iron.
About the tiny switch: there is no DC voltage more, I use on both sides a coupling cap.

Hans-Jörg
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roberto
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Re: Split load plop

Post by roberto »

Both caps have one side connected to the plate of the previous stage.
Put a 2M2 resistor to connect the other side of the two caps. This will keep that side of both caps references to gnd.

I suggested 2M2 because it won't affect the sound, but you can decide to lower that value to something around 220-470k to obtain a frequency shape.
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hans-jörg
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Re: Split load plop

Post by hans-jörg »

roberto wrote:Put a 2M2 resistor to connect the other side of the two caps.
Roberto, you can think I´m an idiot - but still no clue where to put this resistor.

Between the two AC sides of the caps (bridged)? Cap-2m2-cap ?

Sorry for my misunderstanding.

EDIT: oh, yes, shure, with the 330k to ground its like a voltage devider. Thanks, I got it.

Hans-Jörg
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M Fowler
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Re: Split load plop

Post by M Fowler »

Bnwitt drew this up for me years ago showing the 1m resistors from switch to ground.

Mark
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Colossal
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Re: Split load plop

Post by Colossal »

That's a good way of doing the fast/gradual mode because you are not switching DC (switch is downstream of the caps) and you can change the coupling caps to suit your taste.
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hans-jörg
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Re: Split load plop

Post by hans-jörg »

M Fowler wrote:Bnwitt drew this up for me years ago showing the 1m resistors from switch to ground.

Mark
Hi Mark,
I have it this way (2 caps) So I could put this resistors direkt at the switch to ground.

But - I understand Roberto so, that he would connect the 2 caps with a 2m2 R.
Kinda shorting.
Hans-Jörg
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M Fowler
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Re: Split load plop

Post by M Fowler »

I could be wrong but I think Roberto is wiring it just as I show in the schematic.

The caps go to the out side terminals of the switch with a 1M resistor to ground on each end.

The center of the switch goes to pin 7 of next tube.

Mark
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roberto
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Re: Split load plop

Post by roberto »

This is what I mean.
Well, this time should really be what I mean. :lol:


This way you can adjust a little bit of shelving effect on sound, that sometimes is useful.
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Last edited by roberto on Fri Nov 02, 2012 7:22 pm, edited 2 times in total.
markr14850
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Re: Split load plop

Post by markr14850 »

roberto wrote:This is what I mean.
Not sure, but shouldn't your capacitors be connected one position closer to the plate? The way you have it, I think that the upper one is just listening to B+.
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