Triangulum & Integral Preamp - omit unnecessary parts, save some time & $

[Chuck D. Bones]

If you look at the schematics for the Integral Preamp & Triangulum, it becomes pretty obvious that Fortin "borrowed" the TCE Integrated Preamp design, hardwired the tone controls and retuned them slightly. Begs the question: "Why build a Triangulum when you can build an Integral?" I'll leave that for the group to sort out.
There are 6 parts on the Integral that do absolutely nothing:
R2, R3, D1, D2, Q1, and C101. They have absolutely no effect on circuit operation. None, zilch, nada, bupkess. The 1st 5 parts are leftovers from an earlier generation of the TCE Integrated preamp. As wired in this design, the current in those 5 parts is always zero. C101 only does something if IC100 is use to make -9V. It isn't, so C101 is superfluous.
There are 12 parts on the Triangulum that do absolutely, or virtually nothing.
R9, R10, D1, D2 & Q2. Same as the Integral.
Then there's the tone shaping network with resistors in series and parts in parallel that don't do anything within the range of human hearing.
Replace R13 & R18 with jumpers. Use 2.7K for R12. If you're A-R and must hit the resistor value as close as possible, get a 2.87K. But you will not hear the difference.
Replace R16 with a jumper, use either 20K or 22K for R6. Makes no difference.
Replace R11 with a jumper, change R4 to 16.5K or 16.9K. Or 16K, makes no difference.
Replace C15 with a jumper, remove R2 & R15. This network takes effect above 20KHz. Way beyond the hearing range of anyone who has spent time standing in front of a 4 x 12 cabinet.

No need to mod a pedal that is already built, but something to think about if you plan on building one.

 

[Robert]

C101 was my fault and has been removed from the current revision of the PCB.

 

[ErickPulido]

Could this frequencies be used in the tyrian distortion?

 

[Chuck D. Bones]

¿Que?

The Triangulum and Tyrian are completely different circuits. I don't understand the question.

 

[David]

Hi Chuck D. Bones,
Thank you for these informations.

Do you know which value component to change to have a little more bass on the Triangulum ?

 

[Chuck D. Bones]

The best option is to build the Isoceles instead of the Triangulum. It's the same circuit, only with BASS & TREBLE controls.

 

[David]

Thanks for the reply.
As i already built the Triangulum, i just wondered if i could change a particular value to extend the lowpass filter and keep it fixed.
Isosceles is probably the next on my build list.

 

[Chuck D. Bones]

For more Bass, make R12 bigger, Make R16 smaller. Try changing them both to 10K. If that's too much Bass, then try 4.7K and 15K. Keep the sum of two resistors around 20K. Alternatively, take out R2 & R16, temp install a 20K or 25K pot in their place, adjust until you get the amount of Bass you want, then remove and measure the pot. Replace R2 & R16 with the measured values (or as close as you can get). I'm assuming you can read a schematic.

 

[David]

That's ok for the schematic.
Thank you for your help, will try this asap.

 

[ErickPulido]

¿Que?

The Triangulum and Tyrian are completely different circuits. I don't understand the question.

I mean the Tyrian has some values for each position of the switch, what would be a way to get the same frequencies cut ala Triagulum instead of the upper position of the switch

 

[Chuck D. Bones]

There's more to the Tyrian tone shaping than just the switch. It's not clear if the Triangulum is even capable of the same freq cut you're hearing in the Tyrian. I'm going to suggest the same thing to you that I did for David. Build the Isoceles, see if you can get the frequency response you want from that. If you can, great. If you can't, then modding the Triangulum would probably not get you there either.

 

[ErickPulido]

There's more to the Tyrian tone shaping than just the switch. It's not clear if the Triangulum is even capable of the same freq cut you're hearing in the Tyrian. I'm going to suggest the same thing to you that I did for David. Build the Isoceles, see if you can get the frequency response you want from that. If you can, great. If you can't, then modding the Triangulum would probably not get you there either.

Thanks for the help, but what I wanted is the opposite, now it is clear I won't be able to do it

 

[Chuck D. Bones]

Sorry, I completely misunderstood. This thread was about Triangulum mods, so I thought you were asking for a different Triangulum mod. Let me think about a Tyrian mod and get back to you.

 

[ErickPulido]

Sorry, I completely misunderstood. This thread was about Triangulum mods, so I thought you were asking for a different Triangulum mod. Let me think about a Tyrian mod and get back to you.

Thanks again, you are awesome

 

[evilarsen]

For more Bass, make R12 bigger, Make R16 smaller. Try changing them both to 10K. If that's too much Bass, then try 4.7K and 15K. Keep the sum of two resistors around 20K. Alternatively, take out R2 & R16, temp install a 20K or 25K pot in their place, adjust until you get the amount of Bass you want, then remove and measure the pot. Replace R2 & R16 with the measured values (or as close as you can get). I'm assuming you can read a schematic.

Thank you Chuck, i do this mod, R12 R16 10k both. Works fine with my gear.

 

[Moltenmetalburn]

In the integral can C3 4u7 be an NP film cap? I have a bunch.

I know C6 can be NP as it is in the Isosceles.

Ok to use 2n5089 in Q1 and Q2?

 

[Chuck D. Bones]

Yes, NP film caps are always ok in place of electrolytics. 2N5089 is a good choice for Q2. Don't bother installing Q1 on the Integral, it doesn't do anything.

 

[Moltenmetalburn]

Yes, NP film caps are always ok in place of electrolytics. 2N5089 is a good choice for Q2. Don't bother installing Q1 on the Integral, it doesn't do anything.

Thank you for your help.

Is “always” true for any electrolytic in these pedal builds? Do we just use them to save money?

I am now planning to omit the leftover switching crap in my integral/triangulum builds. ??

How about the 6M8? Can I just swap to fortins’ 1M?

 

[Chuck D. Bones]

The original pedal designers and builders used what was available and inexpensive. Boutique pedal builds use whatever they think brings the correct amount of Mojo. Electrolytics are more compact that film for large values. You'd have a hard time fitting a 100uF film cap into a pedal.

Feel free to swap the 6.8M for a 1M. It will load your guitar's pickups a tiny bit more, but I doubt you will hear much of a difference.

 

[Moltenmetalburn]

thanks!