Split Plate Load Resistor SWitching

[sliberty]

I was reading Paul Ruby's wonderful description of the split plate load resistor approach to lower output levels in an Express ( http://ampgarage.com/forum/viewtopic.ph ... z&start=15 ), and wondered if it would work in a switchable arrangement. Here is the layout I came up with.

Is there any reason (like noise, etc.) not to move the resistors to a switch? Is there a better way?

Thanks,
Steve

[Normster]

Not to talk you out of it, but I think it's easier to add a resistor to the board and relocate your B+. Then the switch is pretty simple, much like the Komet pics...

[sliberty]

Yes, of course you are right - this is more elegant. I was trying to avoid making any changes to my turret board, mainly because I didn't make it myself. I bought it with turrets already installed, and have no spares

But, I have flea clips - Yea!!! So, I will simply use a single flea clip to enable me to place the 2nd resistor on the board as your diagram shows. And the switch will be much simpler as you stated.

Did you build this way? How were your results?

Thanks,
Steve

[Normster]

If you don't want to modify the board, you could drop the 100k to an 82k and put just the 22k on the switch.

I tried the split load using a 100k trimmer instead of the 82k/22k pair. I found that I prefer the breakup at a full 100k so I didn't bother with the mod.

I did however replace the 1M PI input resistor with a 1MA pot as a master volume. There's still nothing like power tube saturation but at least it's a decent practice volume when I need it.

[Allynmey]

Not to talk you out of it, but I think it's easier to add a resistor to the board and relocate your B+. Then the switch is pretty simple, much like the Komet pics...

This is exactly the same as the Komet Fast/Gradual switch.

Allyn

[Normster]

Not to talk you out of it, but I think it's easier to add a resistor to the board and relocate your B+. Then the switch is pretty simple, much like the Komet pics...

This is exactly the same as the Komet Fast/Gradual switch.

Allyn

[roknroll]

Not to talk you out of it, but I think it's easier to add a resistor to the board and relocate your B+. Then the switch is pretty simple, much like the Komet pics...

Hi Guys
I think? you have the 22k and the 82k backwards? 22k goes to B+, 82k to plate and and throw. (ala Komet)
Regards

[bluefireamps]

roknroll,
You're right. The 22K goes to B+, 82K to the plate.
Dave

[RockinLocken]

I have decided to rename this configuration, "Attack". Don't wan't the clone police to confiscate this thing. I followed a scheme someone was kind enough to shoot my way. It does show the 22k closer to the B+. Anyway's, thanks to all of you this thing is coming along and soon the whole neighborhood will be pissed not just my old lady.

[Vince]

Having B+ on switch isn't good idea - I use two 0,1uF caps instead one,
each cap go to switch.

regards.
V.

[sliberty]

Interesting point. How does Komet do this?

[tictac]

I never believe it's a good idea to put high voltage DC in a mini toggle switch, I don't think it's a good safety practice. I like to do my switching after the coupling cap. But that's just me.

TT

[sliberty]

I assume that using a full sized switch (which I did) is no safer???

[rhinson]

the couple hundred volts dc on these toggle switches is no big deal. most of these halfway decent mini toggles are rated 6a/125v, the better ones can even be rated at 10a/125v. if you're scared of the metal bat handle, just put one of those colorful slipover covers on it. but the switches can handle the relatively low dc voltage and very low current just fine. rh

[tictac]

Here's how I do my split load switching. Not only is it safer to switch after the caps, with this arrangment you can use the unused triode in V2 and really tune the gain and tone of the stage with the .1 cap[/img]