Naylor Presence expertise needed - Fusionbear? Anyone?

[Gainzilla]

I'm working on an 15 or so watt Superdrive type circuit, but am not sure I've got the presence working right. Currently it's wired like this:

16 ohm tap --> .0015 cap --> tail/cap junction//to presence pot. Presence pot lug 1 has the 10k and .0047 cap to ground, pin 3 has the 20uf cap to ground.

Does this sound right? It seems to really darken things up, but I'm not really hearing much of a change from low to high settings on the pot. I can feel things tighten up a tiny bit, though.

Attached is my schem and a pretty sad pic. Any help is greatly appreciated!

Cheers[/list]

[Littlewyan]

I think you've posted this in the wrong section as this section is for Marshall amps and I've not heard of a Marshall Superdrive?

Anyway I've never seen that NFB circuit but a quick google brought up another topic on this forum which might help.

http://ampgarage.com/forum/viewtopic.ph ... eb3badd17d

Hope this helps

[Gainzilla]

Thanks for the reply Littlewyan,

Guilty as charged, my apologies. In my defense, there is no "other" amps section. javascript:emoticon('8)') Maybe under the technical section would've been more appropriate? If one of the mods wants to move this to a more appropriate area, that would be great!

Anyway, thanks for the link. It's a pretty strange arrangement. I'm going to give it another go tonight, but it only took me about 5 minutes to successfully wire up a more traditional presence circuit. I'm just wondering if there's something obvious I'm missing.

Cheers

[Gainzilla]

Small update:

I've rewired the circuit and it does work, it can be a pretty subtle effect in terms of the sweep of the pot. However, this circuit really darkens your tone (which is perfect for the Naylor circuit).

The Superdrive circuit cuts a lot of bass early, especially with the bite switch engaged. With a standard presence circuit it's just too bright. However, the Naylor presence does something really cool in that it allows a very bright, lively circuit allowing effortless pinch harmonic, ringing chords, and easy playability, butthen manages the overall brightness at the power stage. Probably not unlike a Vox cut control (which I've also used in a high gain circuit with nice results).

For some amps this might not be great, but on other bright amps (#36 maybe) this is a nice option.

Cheers!

[passfan]

The 20uf goes through its pin to the wiper as well. There are super clear pics on this at the gear page. When you get it right there is a huge range of adjustment on this setup. More than you could possibly ever use.

[JazzGuitarGimp]

Yes, I noticed the same thing. The wiper of the pot is the center terminal. It's unconnected, and as such, you'll hear absolutely no difference when turning the pot. Whatever subtle difference you thought you were hearing is probably just because you expected to hear it.

[mhartman]

Here you go. This is from my early (Michigan made) SD60.

[Gainzilla]

Thanks for the info guys, and for the super-clear pic!

Funny, but I wondered if I was really hearing anything or just thinking I was. I have pretty fine tuned ears, even with a little tinnitus, and can usually hear subleties in tones that others can't. Now at least I know I'm not crazy. lol

If I had more room on my board I'd move the other two components, but I suppose I can keep those where they are and just rewire the eCap.

[arcturus]

Hi!

Gainzilla, can you tell me the specs you're using for the OT?

[fusionbear]

Here is how I did it:

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/IMG_0471_zps3b807128.jpg[/img]

[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/IMG_0479_zpsbfdb1331.jpg[/img]


This is the only way I was able to get to be stable. It sounded and worked really well in the SD circuit.

The 20uf is the only one hooked up to the wiper of the pot. The rest of the components attach to the ground buss. The .001 is on the board.