"Presonance" Control Mod

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EtherealWidow
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Re: "Presonance" Control Mod

Post by EtherealWidow »

Awesome. Thanks so much for the quick response. So both C1 and C2 are going to be .1uf? Not .05+.05 in order to equal .1?
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martin manning
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Re: "Presonance" Control Mod

Post by martin manning »

No, 0.1uF total goes with a ~5k tail. Together these set the low frequency break point on the presence end.
EtherealWidow
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Re: "Presonance" Control Mod

Post by EtherealWidow »

Terrific! Thanks!
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Meat&Beer
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Re: "Presonance" Control Mod

Post by Meat&Beer »

I may or may not have a silly question about the "Martinizer"... I'm wondering if it could be integrated into a "Hi-Fi" application? Attached is a schematic for an amp I'm trying to optimize for listening. Integrated amp? Line level power amp?

As is, it sounds rather sweet and nice. But, trying to include this circuit may prove difficult, or even impossible. Possibly, not even playing the right ball game here... See, this amp has the paraphase inverter, and the NFB loop connects to the cathode of the gain stage, not the PI (PPI) like we normally see. The secondary on the OT has a wire I just discovered, it went to the "umbilical" to the tone generator/oscillator tubes. I'll have to research that...

No joy on finding this schematic anywhere. Conn Caprice Model 430.

Reasoning behind wanting to use this circuit in the amp, is in leu of a tone control, necessitating another gain stage to push it through. Any thoughts? As always, thanks!

Ps, feel free to comment on the overall schematic as well as far as making it "better" for listening to devices such as CD player, MP3 player *gasp!*, a phono preamplifier, etc.
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C Moore
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Re: "Presonance" Control Mod

Post by C Moore »

I have a question about this.
I built the Xits 10 (sure looks like an AC15) from the TAG schem.
The amp sounded OK...but I added NFB on a switch. Values are 1k FB resistor and a 47 Ohm from the PI to ground.....like a BF Fender I guess.
There is no Presence Control on this amp of course.
Would I just use Martins schem as is, and insert R2 in place of the 100 Ohm resistor that is part of the PI/NFB in this AA864.?
I am wondering about the ratios to use.
My AC15 has a 1k NFB resistor, and a 47 Ohm to ground.
I am wondering about (getting rid of the 47) and then the 1k and 4k7 (takes place of the 5k presence pot that I do not have) to ground.

Thank You
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Baddog01
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Presence mod

Post by Baddog01 »

meow...
gsb
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Re: "Presonance" Control Mod

Post by gsb »

Hi ,
I,m building jtm45 now.Is Presonance controlMod useful on this amp ?
thanks
gsb
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martin manning
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Re: "Presonance" Control Mod

Post by martin manning »

It has worked very well on Marshall circuits, so I assume so. Beware of possible oscillations though.
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roberto
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Re: "Presonance" Control Mod

Post by roberto »

Hi Martin,

thanks for sharing this schematic, is it an evolution of the presence control of the Kitty Hawk Quattro preamp?
It is from that one that the idea started?

Thanks!
Roberto
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martin manning
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Re: "Presonance" Control Mod

Post by martin manning »

Hi Roberto, this was my own idea, which came from combining presence and resonance circuits.
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roberto
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Re: "Presonance" Control Mod

Post by roberto »

Thanks Martin,

they are both great controls.
You had a very good idea and thanks for sharing it!
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ViperDoc
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Re: "Presonance" Control Mod

Post by ViperDoc »

Hi Martin,

I was looking at this Presonance mod wrt the SDM-version of a 2550 Silver Jubilee I'm looking at.

SDM 2550 SCHEMATIC:
TL 2550 schem R10.jpg
The SDM Jube PI schematic does not show a R-tail resistor in addition to the 10K because it implements the more classic 5KL/.1uF presence control instead of the 4K7/22KL/.1uF control. I saw the formula you presented based on that tail resistor value. If there isn't one, how would you approach this mod? Thanks as always.
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Just plug it in, man.
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martin manning
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Re: "Presonance" Control Mod

Post by martin manning »

I would try the configuration shown on pg. 2 of the .pdf, first post.
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