Has anyone played around with lower Rp values on a 12AX7?

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hans-jörg
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Re: Has anyone played around with lower Rp values on a 12AX7?

Post by hans-jörg »

JoeCon wrote: Wouldn't this let you set your amp for like a jazz gig or a country gig or a rock gig by changing that first stage?
Anyone????
Hi,
try the "Rock/Jazz" switch from the 124 OD (or similar) Dumble. You could try a On/off/on switch for rock/country/jazz.
But this has nothing to do with reducing the anode R, but hits your aim.

Hans-Jörg
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matt h
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Re: Has anyone played around with lower Rp values on a 12AX7?

Post by matt h »

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JoeCon
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Re: Has anyone played around with lower Rp values on a 12AX7?

Post by JoeCon »

Matt

Thanks, lots to digest there. But I do like the split plate load idea with the seperate coupling cap for each resistance. So you'd adjust the gain and freq responce at the same time. That makes more sense...
In theory, theory is the same as practice. In practice it's different.
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matt h
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Re: Has anyone played around with lower Rp values on a 12AX7?

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JoeCon
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Re: Has anyone played around with lower Rp values on a 12AX7?

Post by JoeCon »

Matt
While most love al these switches and dials, and boy it's fun to play with them alright, I really prefer the "less is more" approach to amp controls. Sure it goes against everything here but a simple gain and tone control in the right amp is all I need. I guess all those switches and dials are needed for getting all the parts right to make "the right" amp.
The amp is just a means to an end and that end is making music...
In theory, theory is the same as practice. In practice it's different.
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matt h
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Re: Has anyone played around with lower Rp values on a 12AX7?

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Ken Moon
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Re: Has anyone played around with lower Rp values on a 12AX7?

Post by Ken Moon »

Rather than use switches when I'm tuning a new amp, I just put in extra turrets for two anode resistors in series (I usually start with a 50k in series with a 100k), and the same for the cathode resistors (starting with two 820R resistors in series), along with 1uF and 22uF bypass caps that are left open at one end, so either one (or none)can be jumpered into the circuit.

Then I can quickly switch between several combinations using short Pomona jumper clips.

This keeps the wires short, and I don't have to drill extra holes in the chassis for switches.

When I get the sound I want, I just re-do the board without the extra components. You can even use this method to jump across entire gain stages or to switch global NFB in and out, among other things.

I've found this useful because in the time it takes to switch a component or two, my aging brain can't remember what it sounded like before I changed it :oops:
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