Mesa Boogie - Throttle Box  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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Nikifena
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Post by Nikifena »

There is something strange (or not complete) in the schematics around C19

First leaving one of the C19 pins unconnected this will makes some pops, so a high value resistor to ground must be added.
Second Mesa adds SW1B switch there to decrease the the gain (drive) from stage around IC1A. With this trick they makes the drive quiet in bypass. Connecting C19 to ground will increase the gain in the low frequencies and this is not the original mesa idea. I'm sure. And yes, the effect will works with this schematics, but there is some schematics mistake.

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56335130
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Post by 56335130 »

Image

one yats plus one 5band eq and boom you got your self a mesa,fuzz ish ,mark 1 and 2 kind of sound :horsey:

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56335130
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Post by 56335130 »

56335130 wrote:[ Image ]

one yats plus one 5band eq and boom you got your self a mesa,fuzz ish ,mark 1 and 2 kind of sound :horsey:
oops image too large.it was a 78' ic huge muff pie

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kaya112
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Post by kaya112 »

R19 =0 ? :scratch:

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tasteless
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Post by tasteless »

Zero Ohm resistor - Yes , There is such a thing ! - Just don't ask Me why.
It looks like a resistor with a single black band.
I think they are sometimes used for test points - Where it's easier to quickly see a blank resistor than a wire link.

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Nocentelli
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Post by Nocentelli »

Also, for automated board-stuffing - The same machine can place resistors or zero ohm resistors in place of a jumper.
Plus, they look cool.
modman wrote: Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...

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kaya112
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Post by kaya112 »

There is something strange (or not complete) in the schematics around C19
Black lines and red line ?

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kaya112
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Post by kaya112 »

C10=0u22 220nF ? :scratch:

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apollomusicservice
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Post by apollomusicservice »

kaya112 wrote:C10=0u22 220nF ? :scratch:
yes

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kaya112
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Post by kaya112 »

thank apollomusicservice :D

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kaya112
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Post by kaya112 »

Image new pcb :D

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kaya112
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Post by kaya112 »

kaya112 wrote:[ Image ] new pcb :D

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kaya112
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Post by kaya112 »

Image :D

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Lord Metal
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Post by Lord Metal »

apollomusicservice wrote:OK here is pcb done in through-hole technology, like original. There are two pcb's,
first with almost all components and second with jacks, pots and few components.
Pedal has very originally sounds and I change my prejudice about Mesa pedals. 8)

What are SV1 and SV2?

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apollomusicservice
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Post by apollomusicservice »

Throttle Box has two Pcb's, SV1, SV2, SV3 and SV4 are connectors for
flat cables that connects these boards. SV1 with SV3 and SV2 with SV4.

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andregarcia57
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Post by andregarcia57 »

kaya112 wrote:
kaya112 wrote:[ Image ] new pcb :D
?

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gregilmejo
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Post by gregilmejo »

Hello guys.
Firts of all, what a wonderful work!
I am building this mesa boogie throttle box and i wish the sound will be as same as possible as the MB.
Second, if anyone has a audio test, please post it.(Obviously of the mesa boogie throttle DIY)
So, i have a little question, it's : how many switch has this pedal? I can't understand what are the switches. Please give me help..
And, what op-amp can replace jrc4558? And Tl?
Thanks!!

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giacu92
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Post by giacu92 »

gregilmejo wrote: So, i have a little question, it's : how many switch has this pedal? I can't understand what are the switches. Please give me help..
And, what op-amp can replace jrc4558? And Tl?
Thanks!!
Hello!
To reply your answer.. The pedal has two switches. One is the outer "LO/HI" DPDT, the other is internal and provides signal equalization through the three active filter made on IC3 (the second TL074).

The JCR4558 can be replaced by any double opamp such as TL072, TL082, NE5532, OPA2604 etc..

I'm upping this thread because i made a panelized version of the pcbs that can be ordered on pcbs maker sites such as "Oshpark" or "itead studio".

If anybody want to share pcbs realization with me, i can order them on dirtypcbs.com and then re-ship. A batch of 10 for the price of 25$, shipping included. It makes the "pcb kit" for the project costs 2.5$ each, plus shipping.

This is the oshpark render, just as idea:
Image

I have to adjust silkscreen graphics. This is just a render..

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AAntonio
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Post by AAntonio »

giacu92 wrote:
gregilmejo wrote: So, i have a little question, it's : how many switch has this pedal? I can't understand what are the switches. Please give me help..
And, what op-amp can replace jrc4558? And Tl?
Thanks!!
Hello!
To reply your answer.. The pedal has two switches. One is the outer "LO/HI" DPDT, the other is internal and provides signal equalization through the three active filter made on IC3 (the second TL074).

The JCR4558 can be replaced by any double opamp such as TL072, TL082, NE5532, OPA2604 etc..

I'm upping this thread because i made a panelized version of the pcbs that can be ordered on pcbs maker sites such as "Oshpark" or "itead studio".

If anybody want to share pcbs realization with me, i can order them on dirtypcbs.com and then re-ship. A batch of 10 for the price of 25$, shipping included. It makes the "pcb kit" for the project costs 2.5$ each, plus shipping.

This is the oshpark render, just as idea:
[ Image ]

I have to adjust silkscreen graphics. This is just a render..


i'm interested

could you give me the file eagle?

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wkhoury
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Post by wkhoury »

Hello everyone,
Was anyone successful in building this from the original posted schematic? It's not the easiest pedal to build so it'd be nice to know if it's been verified to work before I get started on it :)

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