Ceriatone Forum

I made an interesting observation. I have a regular OTS ad one of Erwins D-lators.
Used a Kleinulator before that.
I always felt the amp lacked some brightness when using a fx loop like the Klein or D-lator. Using the Bright swicth makes the whole sound thinner and it's not realy usable with the OD
I have learned (with help from Erwin) that the amp brightens up a lot when you add more Presence. I wasn't to keen on using a lot of presence cause it adds attack and I like a fairly mild attack, but it does wonders for the sound. It takes away that blanket over the speaker thing.
The thing I do notice is that this doesn't seem to be a gradual effect. It start to work on about 7. (we checked the presence pot is linear)

what are you views on this?
Steven

My presence know starts working at around '8' - and that where I think the sweet sound is.

Some amp builders like Henry Heisthl, Red plate amps, use a 'fixed' presence,  soldering in a resistor instead of the presence pot, with an ohmage value amounting to the presence pots ohm value at '8'.

I guess Dumble's accent switch, on his 70s amps, works in a similar fashion.

Steven, one of the first thing I noticed about the presence pot was that it did very little until it gets to 2 o'clock.

Something that Matt Schofield showed me when dialling in an unfamiliar amp. Take each tone control one at a time and very rapidly sweep from 0 to 10. Doing this you will find where the 'cusp' is, i.e. the point at which the rate of change of the effect is greatest. Using this knowledge you can then more easily work the interaction of the tone controls.

Do you guuys agree that is brightens up the sound? without adding treble. Just making it less dull sounding?

Yes it does ,but I would have liked more range from the control personally.

me 2

Making the LNFB resistor 8k instead of 4,7k does make a better finetuning range for the presence pot.

I often wondered if there's something else in all the dumbles that are documented.
Had the pleasure playing a exact #124 dumble copy a few times. Same story; you really have to crank the presence...

Hi Erwin. was that the mod you tried on my amp?

I that is the case:
It seemed to react a bit different altogether. Hard to explain without a real a/b test
I have the feeling with the mod we tried, there wasn't a real linear effect either. The sound seemd a bit different as well.

No the mod I did (and later reversed) was something else.

ah ok
srange, if you look at RF's Dumble. His Presence is mostly around noon I think.

I forgot to mention; speakers do matter a lot.
F.e. Celestion Gold is a very bright speaker. You don't have to turn your presence up like you have to do with a Celestion G12-65.

who knows what value his potmeter is or maybe his amp has a resistor put in series with the pot, which limit/zooms its range to the 'working' range of a standard amp. Hence, it starts at '7' (on your amp) and ends on '10'

Could be

true. I need to trust my ears not my eyes.
If you realise what kind of gasses I use that might be a better option anyway LOL 8)

Adding a resistor in series with the excisting pot is getting your range further away from the sweet spot.
Decreasing the value of the presence pot or increasing the LNFB resistor would be a option to have more control in the sweet spot IMO.

Steven don't be like that :-) you know what I mean.

OK, paralel the presence pot with a 470 ohm resistor and ad a 1,8 k resistor in series.
This will put the 8-10 on the old pot range across the whole pot range. In effect making 8='1' on the pot range  and  10='10' on the scale.

@blues.....  lol that would be Erwin

Bump

@erwin_ve

OK, paralel the presence pot with a 470 ohm resistor and ad a 1,8 k resistor in series.
This will put the 8-10 on the old pot range across the whole pot range. In effect making 8='1' on the pot range  and  10='10' on the scale. 

Bluesfenderman: maybe I misinterpret something; but adding a series resistor to your presence pot doesn't allow all ac voltage from the GNFB go to the presence cap(and therefore to ground) if you presence pot is at 10. That just doesn't make it happen.
If I understood you the wrong way; can you draw a schem?

I was wondering if any of you had more succes with improving the range of the Presence.