# New Guy here with Tyrian build questions for tone tweaking



## ScottVA (Sep 2, 2020)

Hey folks!

I just built a Tyrian using a Hammond 1590B3 enclosure. First kit I've built from Pedal PCB and have nothing but praise for the products and the community here. The reason I went with the 1590B3 was to get a slightly lower height profile at the expense of increased width.  I think I'll probably cave and put it in a 125B as I'm not sure if I'm a fan of the enclosure size as it is?

Very satisfied with this guy for the most part, but I'd like to tweak the tone controls more to my "lower end" side of tonal preference. If anyone can share some advice to tame the Treble a bit and give the Bass and Mids more range I'd appreciate it! Thanks!


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## Chuck D. Bones (Sep 2, 2020)

Looks good!

More Bass before the distortion: increase C7.  This mod increases Bass when the toggle switch is in the up or down position; middle is no change.

More Bass after the distortion: reduce R23, R24 and C18.  Start by cutting each in half, see if that gets you there.  If not, cut them in half again.

If you want to cut Treble across the board, increase C17.  Each time you cut R23 in half, you have to double C17 just to break even.  Get the Bass dialed in, then increase C17 some more from there.  C16 is another place to cut Treble.

The Mid control is cut only, not sure what you're looking for there.

I don't own a Tyrian, I have not tried any of these mods, but they should work.


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## ScottVA (Sep 3, 2020)

Thanks Chuck D.

I made the below changes.

I replaced R22 with a 10K which moved the Freq. cutoff of R22&C16 low pass from 3.3kHz to 1.5kHz.  This produced a noticeable reduction in overall highs.  Why such a high cut off freq there?

I replaced R23 with a 22K which moved the Freq. cutoff of R23&C17 low pass from 604Hz to 1.5kHz.  Why such a low cut off there?  Later I thought removing R23&C17 all together would be smarter?  Not sure how much difference in tone TBH, I didn't test after that specific change. ? Anywho..

I also replaced R24 with a 22K.  I found some common audio passive Op Amp tone ckt on the intergoogle that supported a 10 to 1 ratio of resistors in the bass leg, made up of R24 and R25. This makes more sense to me.  I also replaced the 50K treble POT with a A100K, which also jives with same common passive tone ckt I found, (attached). I suspect these changes made the Bass and Treble controls more balanced. I left the Mid alone.

With these changes the highs were reduced to a more usable range to suit my taste, and the ckt is just a little more transparent tonally. I also replaced the Gain POT with a B500K to take a little of the hair off if this guy. I'm more of a geezer, "classic rock" type.  In retrospect I probably should have built the Malachite or Sanguine.  I might try to wire up a IC2.2 bypass switch? It's really tough to mod these damn things post build. 

Anyway, thanks so much for your help!

Scott


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## Chuck D. Bones (Sep 3, 2020)

You're welcome.  Good to hear that the mods are working for you.  The "balanced" James tone controls are desirable for HiFi applications, where one can achieve a flat setting with the controls at or near noon.  Guitar amps and pedals are a different beast altogether.  Since our pedals and amps are supposed to color the sound, a flat freq response isn't all that useful.  There are amps and pedals with balanced tone controls out there, but they are in the minority.  At the end of the day, all that matters is whether we like the sound we get.

IC2.2 has about 9dB gain. You can change it to unity (0dB) by removing R6, just leave that spot on the board empty. I think a better place to lower the gain is IC2.3. Try increasing R20.


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## ScottVA (Sep 3, 2020)

Yeah I lean towards medium gain transparent overdrives. I go and build a high gain chugg-ah beast and then immediately try to change it?!? 
Good thing I have time to waste huh?



Chuck D. Bones said:


> IC2.2 has about 9dB gain.  You can change it to unity (0dB) by removing R6, just leave that spot on the board empty.  I think a better place to lower the gain is IC2.3.  Try increasing R20.



You looking at the Tyrian schematic? The resistor #s don't look right.


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## Chuck D. Bones (Sep 3, 2020)

You know what?  I was looking at the V1 Build Docs and you built V2.  My bad.  I went back and edited my previous message.  IC2.2 doesn't have that much gain and you might want to keep the soft clipping.  So maybe try lowering IC2.1 gain, increase R20.


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