Lower mid pot frequency

[59model]

Anyone know how to lower the frequency level of the mid pot on a Ceriatone kit? It seems to work on the high mids and I`d like it to adjust the lower mids. Any mods for this?

[gearhead]

I believe if you raise the value of the mid tone cap, it will lower the mid point.

[rhinson]

the "mid" pot in any fender/marshall tone stack is not really a mid control/boost---it boosts all frequencies. it simply separates the tone stack from losing signal to ground---the bigger the pot the less signal loss and the bigger the boost---this gives more distortion and sounds like a mid boost. a true mid boost is not available using this kind of tone stack. rh

[Darkbluemurder]

I believe if you raise the value of the mid tone cap, it will lower the mid point.

My experience is that it is exactly the opposite - a smaller mid cap gives you more low midrange since less of the lower midrange frequencies are bled to ground. The scooped Fender sound comes by a large part from the 0.047 mid cap. I replaced this in my Deluxe Reverb II with a 0.022 which made it a lot fuller sounding.

[gearhead]

I had discussed this before with someone (Scott Lerner), and couldn't remember which it was.

Used Duncan Amps Tone Stack Calculator with the Express values (Marshall Tonestack). Based on it, the mid operating point is lower in frequency for higher value caps. But (and a big one at that), the overall attenuation is quite a bit higher for higher value caps. So if you use a lower cap, you will see an increase in volume for sure.

[tictac]

Think of it this way, a .047 mid cap (Fender Blackface) will bleed more mid frequencies to ground with the pot turned to zero than a .01 (Dumble Skyliner TS) So you get a bigger mid dip with the .047 which translates to a more glassy mid range tone which the BF Fenders are famous for.

Using a .01 mid cap gives you a bit of a mid boost since less mid frequencies are going to ground. Players of guitars with single coil pickups may like this effect but you do lose that Fender glassiness.

My midrange control is a pull pot that switches between either a .01 or .047 value mid cap to get both tones which are very usable.

A nice good sounding alternative is using a .02 cap. You get a decient mid dip like a .047 but it still gives you a good mid boost too. Check it out with the Duncan TSC and you'll see what I mean.

[gearhead]

That's kinda ironic; I have that same .01/.047 pullpot option on my Fuchs ODS30.

[59model]

Thanks for the help guys. Gearhead, I too have a Fuchs ODS30 and love that fat sound with the midboost. It seems to boost the lower mids in the 200-500hz range, and thats what I`d like to do with my Ceriatone Express. I know on my Fuchs the mid boost is on the treble pot, and looking at the Express layout there is a .022uf cap connected to the treble pot, and the wiper of the mid pot is connected to the 1st lug of the bass pot and then goes to another .022uf cap. Which cap would I change and any idea of what value I should use to start with? I wish someone would make a variable cap so I could tweak it to where I like it, but I could use a switch or push pull pot if I found a value I liked for boosted mids and then switch it back to stock, or better yet make it footswitchable so when I crank my guitar volume and hit the mid boost.......hold on, LOL!

[Mark]

The tone controls caps in the Express/Liverpool are 0.022uF as was originally mentioned as a mod to Fender amps by Ken Fischer in his section in the Groove Tubes book.

I can't say that I have experimented in any way with this mod in any Fender or Fender clone that I've owned.

I believe that Dave Funk is also a big fan of replacing the 0.1uF and the 0.047uF cap with two 0.022uF caps.

Has anyone had any experience with this sort of thing?

P.S. Sorry to highjack the thread, though this sort of thing has been of some interest to me for a while.

P.P.S. In an attempt to offer some assistance to 59model, I could suggest that you try the Zinky tone control cap values of 0.047uF for the bass cap, and 0.022uF for the mid cap value. That may deliver the sort of lower mid/bass response you are after. From my own experimentation with the Express, if you omit the third stage of the amplifier, you'll be surprised that it still has quite a bit of gain though the tone controls are (from memory) more effective. There are a few ways around increasing the mids. Sorry to ramble, but I hope that helps?

[Darkbluemurder]

I can't say that I have experimented in any way with this mod in any Fender or Fender clone that I've owned. I believe that Dave Funk is also a big fan of replacing the 0.1uF and the 0.047uF cap with two 0.022uF caps. Has anyone had any experience with this sort of thing?

Mark,

I have. The two 0.022s sound a bit warmer than 0.1 and 0.047. For a really full clean sound I like a 0.1 bass cap and a 0.022 mid cap. Great for filling up those low powered single 12" combos.

Here's a rundown of my experiences with tone stacks (regardless of Fender, Marshall or *umble):

1.) Increasing the bass cap increases bass. Typical values range from 0.022uF to 0.1uF.
2.) Increasing the mid cap DECREASES mids. Typical values: 0.01uF - 0.047uF.
3.) Increasing the treble cap increases mids as well but it's more the high mids are increased. Typical values: 50pf - 500pf.
4.) Increasing the slope resistor decreases bass and increases high mids. Typical values: 33k - 150k.

Have fun
Stephan

[59model]

Thanks again for all the help, especially the note about the Duncan tone stack calculator. Please keep in mind I am modding this amp for my own use and not to get the exact TW specks. For the tone I like I did the following:
Removed the bright switch
Changed out the bass and mid caps from .022 to .01
Removed the presence control
That`s it, now that`s the tone I was looking for! A little fatter in the low mids, and it doesn`t mush out really at high volume. Pinch harmonics fly out easily and the treble pickup is middy as heck on leads just the way I like it. Almost Tube Screamer`ish, but no pedals on the floor, just my trusty volume pot.
Has anyone tried an audio taper pot on the volume control? This will be next as it dirties up real quick, and it would be nice to have a little more control. Personally I like it dirty, but I`m thinking of selling a LOT of other amps as this one`s got THE tone, so a little clean from the amp wouldn`t hurt. I like the clean when turning down the guitar volume, but it just sustains too much, LOL! I can`t believe I said that!