Gil Ayan tone cut control for non HRM amps.

[Mark]

I had a go at this tone control today. I find the control isn't necessary for guitars like Les Paul's, however some PRS', Strat's, Tele's, Danelectro's will probably require this control.

The cut control is a 1000pF cap in series with a 250K pot. You'll notice the difference in tone straight away. I put a switch in series with the tone control, to tell the difference in a way I'd find meaningful.

I found it removed some upper frequencies as well as lower the level of the signal from the second overdrive stage.

The effect of the tone control doesn't change the tone like a guitars tone control would. In fact I tried a 2200pF cap instead of the 1000pF, I found I had greater control over the high frequencies, but the tone was bland and no longer exciting.

Stick with Gil's circuit values, or go with the HRM.

[tubedogsmith]

That filter doesnt seem to work as well in that position on an HRM. Try something like a 100pf tp 300pf on the OD master, hot lug to ground. Also, a cap and resistor to ground right at the V2b plate can work well.

[dogears]

Guys, hate to be a broken record but a 250K pot is too small. This is not open for discussion as with the pot set for full bright, you still have a ton of "bleed". You could use a 100K resistor to lift ground so that you better better range.

However, my choice is a 500K or 1M pot. No change on max bleed, but you get to take the treble bleed more out of circuit. My amp has a switch pot where I can click it out of circuit. There is a very noticeable difference when I am out of circuit versus the 1 Meg max resistance of the pot! Proves the point......

It is silly to not use at least a 500K. No change to the tone control except you can take it more out of circuit.

I had a go at this tone control today. I find the control isn't necessary for guitars like Les Paul's, however some PRS', Strat's, Tele's, Danelectro's will probably require this control.

The cut control is a 1000pF cap in series with a 250K pot. You'll notice the difference in tone straight away. I put a switch in series with the tone control, to tell the difference in a way I'd find meaningful.

I found it removed some upper frequencies as well as lower the level of the signal from the second overdrive stage.

The effect of the tone control doesn't change the tone like a guitars tone control would. In fact I tried a 2200pF cap instead of the 1000pF, I found I had greater control over the high frequencies, but the tone was bland and no longer exciting.

Stick with Gil's circuit values, or go with the HRM.

[butwhatif]

500k pot, .002 cap

[Mark]

I can sub a 1Meg pot in and try that, though experience tells me the 0.002uF was pretty savage. The higher value pot may make all the difference?

[dogears]

Exactly. Maybe the 2000pf and a bigger pot would be the ticket. 250K is way too small!

I can sub a 1Meg pot in and try that, though experience tells me the 0.002uF was pretty savage. The higher value pot may make all the difference?

[glasman]

Exactly. Maybe the 2000pf and a bigger pot would be the ticket. 250K is way too small!

I can sub a 1Meg pot in and try that, though experience tells me the 0.002uF was pretty savage. The higher value pot may make all the difference?

You may find the .002uf a tad big even with a 1Meg control. I tried this a long time ago and settled on a .001 and 1Meg.

Gary

[Mark]

I'll try the 1 meg pot with both cap values and report back. Naturally it will have to be when the wife is out of the house.

[ericlee]

I’ve published a better solution while ago on the Ceriatone forum where some members used and loved it. This circuit does not cut the high mids and overall tone characteristics of the amp as RC filter does. It affects only high frequencies without any volume change.
[img:749:569]http://www.drika.biz/hicut.JPG[/img]

and here is a pic by Bryan aka Sonicmojo
[img:764:671]http://www.suthard.com/ceriatone/highcut1.JPG[/img]

Try it! You will LOVE it!

[martin manning]

ericlee, if I understand your diagram correctly, you have placed a cap to ground from the top of the ratio pot, where the value of the cap is variable from 200-2200p, right?

If so, this makes a low-pass filter/divider with the series R and the ratio pot, where the knee ranges from 1.1kHz to 12kHz. The other network is a shelving filter where the LF break is more or less fixed at something like 2.4 kHz, and the upper one moves up as the treble cut increases.

Do you find that you like a particular setting most of the time?

[ericlee]

"martin manning"ericlee, if I understand your diagram correctly, you have placed a cap to ground from the top of the ratio pot, where the value of the cap is variable from 200-2200p, right?

Hi Martin,
Actually from 0 to 2200pf. First step on the rotary is no capacitor to keep amp’s tone intact.
On the 100k ratio pot X leg, drive signal level is always constant (maximum) so is resistance to the ground. In this scenario I prefer to use 220pf – 330pf.
But I also have third channel on the drive when relay bypasses post drive trimmer 220k (hi gain) and same time second part of the relay activates 420pf or 550pf on the filter to cut more highs.

In live situation I never used a cap higher than 420pf.

[dogears]

I think you may be mistaken. The traditional bleed is very similar except it has additional adjustable resistance to ground with only one cap size. Your solution will have more volume cut IMO. I like the idea but I'd like to see the switch connected to a pot to ground to dial out the effect if need be. You are just bleeding right to ground.

Fwiw, I have never experience a volume cut using the traditional bleed. Just the loss of high end gain as a result of the bleed.

I’ve published a better solution while ago on the Ceriatone forum where some members used and loved it. This circuit does not cut the high mids and overall tone characteristics of the amp as RC filter does. It affects only high frequencies without any volume change.
[img:749:569]http://www.drika.biz/hicut.JPG[/img]

and here is a pic by Bryan aka Sonicmojo
[img:764:671]http://www.suthard.com/ceriatone/highcut1.JPG[/img]

Try it! You will LOVE it!

[martin manning]

Hi Martin,
Actually from 0 to 2200pf. First step on the rotary is no capacitor to keep amp’s tone intact.
On the 100k ratio pot X leg, drive signal level is always constant (maximum) so is resistance to the ground. In this scenario I prefer to use 220pf – 330pf.
But I also have third channel on the drive when relay bypasses post drive trimmer 220k (hi gain) and same time second part of the relay activates 420pf or 550pf on the filter to cut more highs.

In live situation I never used a cap higher than 420pf.

Thanks, very good info. Interesting idea for the third channel. Where is the "post drive" trimmer? Is this an additional trimmer after the second OD stage, with the relay effectively turning up the ratio/level control?

[martin manning]

I think you may be mistaken. The traditional bleed is very similar except it has additional adjustable resistance to ground with only one cap size. Your solution will have more volume cut IMO. I like the idea but I'd like to see the switch connected to a pot to ground to dial out the effect if need be. You are just bleeding right to ground.

Yea, that would enable both a variable LF break point and a variable shelf... or no shelf. The way it is there is no shelf, but below the knee the volume loss is minimal.

[butwhatif]

It doesn't have to be that difficult---a 500k trimmer and a cap is all u need. .002 is a good starting point, try a couple cap values. it's set and forget, and play-- quality of speaker will determine