# 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.


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## Robert

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


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## ErickPulido

Could this frequencies be used in the tyrian distortion?


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## Chuck D. Bones

¿Que?   

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


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## 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 ?


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## 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.


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## 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.


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## 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.


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## David

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


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## ErickPulido

Chuck D. Bones said:


> ¿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


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## 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.


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## ErickPulido

Chuck D. Bones said:


> 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


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## 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.


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## ErickPulido

Chuck D. Bones said:


> 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


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## evilarsen

Chuck D. Bones said:


> 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.


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## 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?


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## 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.


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## Moltenmetalburn

Chuck D. Bones said:


> 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?


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## 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.


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## Moltenmetalburn

thanks!


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## dlazzarini

Moltenmetalburn said:


> 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?


I was just browsing through these older threads and just saw this. Can you clarify what you mean by “Fortin’s 1m”.  Is it simply Fortin uses a 1m resistor instead of the 6.8m on the Triangulum?  If so do you know why?  Hoping maybe somebody could fill me in. I see Chuck said it would perhaps load the pickup more. What effect would that have?


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## Chuck D. Bones

dlazzarini said:


> I was just browsing through these older threads and just saw this. Can you clarify what you mean by “Fortin’s 1m”.  Is it simply Fortin uses a 1m resistor instead of the 6.8m on the Triangulum?  If so do you know why?  Hoping maybe somebody could fill me in. I see Chuck said it would perhaps load the pickup more. What effect would that have?



Yes.  
No.  If I had to guess, it would be that Fortin didn't have any 6.8M resistors.  
At 1M the loading will probably not be audible.


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## Moltenmetalburn

dlazzarini said:


> I was just browsing through these older threads and just saw this. Can you clarify what you mean by “Fortin’s 1m”.  Is it simply Fortin uses a 1m resistor instead of the 6.8m on the Triangulum?  If so do you know why?  Hoping maybe somebody could fill me in. I see Chuck said it would perhaps load the pickup more. What effect would that have?


I did use that 1M value and felt I could discern no difference as chuck has already said.


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## dlazzarini

Chuck D. Bones said:


> Yes.
> No.  If I had to guess, it would be that Fortin didn't have any 6.8M resistors.
> At 1M the loading will probably not be audible.


Thanks guys


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## digitalsea

Hey @Chuck D. Bones - Firstly, thanks for your work here. Learn something new each time.
I'm working through your notes / comments above and got a couple of queries.

You've noted:
_Replace R16 with a jumper, use either 20K or 22K for R6. Makes no difference._​Then clarified in a later comment:
_For more Bass, make R12 bigger, Make R16 smaller. Try changing them both to 10K_​
I'm assuming that we just make the R6 / R16 combo resistor 10k as well as R12 10k? Sorry, seems obvious but just want to make sure.

You've also noted that Q1 and Q2 are functionally useless and can be removed. I understand that Q1 can just be omitted, but do we need to jumper Q2s pins? I assume just omitting Q2 from the PCB means the audio path is broken?

Thanks again Chuck. Learnt alot reading through your posts.


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## Chuck D. Bones

digitalsea said:


> You've noted:
> _Replace R16 with a jumper, use either 20K or 22K for R6. Makes no difference._​Then clarified in a later comment:
> _For more Bass, make R12 bigger, Make R16 smaller. Try changing them both to 10K_​
> I'm assuming that we just make the R6 / R16 combo resistor 10k as well as R12 10k? Sorry, seems obvious but just want to make sure.


In the 2nd sentence, I was answering a question about an unmodified Triangulum.  

If you perform the mods and want more bass, then leave C15 in.  Jumper R15 & R6.  Make R2 22K. Make R16 2.7K.  These are not magic values, just a recommended first try.  Since I don't know how much more bass you want, you would be better off temporarily installing an A25K pot in place of R2 and R16.  Dial-in the amount of bass you want, then remove the pot, measure it and install the nearest standard resistors for R2 and R16.



digitalsea said:


> You've also noted that Q1 and Q2 are functionally useless and can be removed. I understand that Q1 can just be omitted, but do we need to jumper Q2s pins? I assume just omitting Q2 from the PCB means the audio path is broken?


Things get a little muddy because the Integral & Trianglulum ref designators don't match.  At the beginning of this thread, I was talking about both pedals.  For the purpose of this discussion, let's focus on the Triangulum.  

Q2, R9, R10, D1 and D2 get removed and nothing goes in their place.  You could reconfigure R10 as an anti-pop resistor, but it's not really necessary since the stomp switch grounds the board input in bypass mode.

Q1 can be removed, but we need to add jumpers, lift an IC lead and change some resistors.  A lot of effort to save one transistor.  Make your build easy, leave Q1 alone.



digitalsea said:


> Thanks again Chuck. Learnt a lot reading through your posts.



You're very welcome.


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## digitalsea

Chuck D. Bones said:


> In the 2nd sentence, I was answering a question about an unmodified Triangulum.
> 
> If you perform the mods and want more bass, then leave C15 in.  Jumper R15 & R6.  Make R2 22K. Make R16 2.7K.  These are not magic values, just a recommended first try.  Since I don't know how much more bass you want, you would be better off temporarily installing an A25K pot in place of R2 and R16.  Dial-in the amount of bass you want, then remove the pot, measure it and install the nearest standard resistors for R2 and R16.
> 
> 
> Things get a little muddy because the Integral & Trianglulum ref designators don't match.  At the beginning of this thread, I was talking about both pedals.  For the purpose of this discussion, let's focus on the Triangulum.
> 
> Q2, R9, R10, D1 and D2 get removed and nothing goes in their place.  You could reconfigure R10 as an anti-pop resistor, but it's not really necessary since the stomp switch grounds the board input in bypass mode.
> 
> Q1 can be removed, but we need to add jumpers, lift an IC lead and change some resistors.  A lot of effort to save one transistor.  Make your build easy, leave Q1 alone.
> 
> 
> 
> You're very welcome.


Perfect. Answers everything.

A legend. Appreciate your time.

Thanks again


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