Amptweaker - BigRock/TightMetal Pro

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.

Re: Amptweaker - BigRock/TightMetal Pro

Postby bajaman » 25 Aug 2017, 05:07

Okay - boards arrived and I have built it - worked first time too :D , except for one small mistake on the pcb - I connected the effect output to the main output terminal instead of the footswitch pad. An easy fix though just involves cutting one trace and adding a small link wire. How does it sound - awesome! On my oscilloscope i observed asymmetrical clipping behaviour similar to my Baja Tube drive pedal - very dynamic, touch sensitive and cleans up nicely with the guitar volume pot wound back. I have a few spare boards available - pm me for details - cheers bajaman
be kind to all animals - especially human beings

For this message the author bajaman has received thanks: 2
nexion777 (25 Aug 2017, 18:13), snofla1900 (06 Sep 2017, 13:16)
User avatar
bajaman
Old Solderhand
 
Posts: 4102
Joined: 26 Jun 2007, 22:18
Location: New Brighton, Christchurch, NZ
Has thanked: 343 times
Have thanks: 810 times

Re: Amptweaker - BigRock/TightMetal Pro

Postby bajaman » 25 Aug 2017, 05:21

IMG_3246s.JPG
IMG_3245s.JPG
IMG_3243s.JPG
[attachment=3]IMG_3240s.JPG
You do not have the required permissions to view the files attached to this post.
be kind to all animals - especially human beings

For this message the author bajaman has received thanks: 6
287m (13 Sep 2017, 11:49), apollomusicservice (03 Sep 2017, 13:09), batak_man (25 Aug 2017, 14:25), Daza (03 Sep 2017, 22:53), nexion777 (25 Aug 2017, 18:48), snofla1900 (06 Sep 2017, 13:17)
User avatar
bajaman
Old Solderhand
 
Posts: 4102
Joined: 26 Jun 2007, 22:18
Location: New Brighton, Christchurch, NZ
Has thanked: 343 times
Have thanks: 810 times

Re: Amptweaker - BigRock/TightMetal Pro

Postby nexion777 » 25 Aug 2017, 18:18

Awesome build Bajaman! That pcb is... ultra-tight! :D

For this message the author nexion777 has received thanks:
bajaman (25 Aug 2017, 23:52)
nexion777
 
Posts: 27
Joined: 25 Apr 2009, 17:20
Has thanked: 41 times
Have thanks: 1 time

Re: Amptweaker - BigRock/TightMetal Pro

Postby DimebuGG » 26 Aug 2017, 10:24

I made a single side pcb yesterday with boost function minus loops and LED lights. It's done already but I need to do final touch. Once finalized, I'll post it herre immediately.

Oh BTW, what's the value of BOOST GAIN and BOOST MASTER pots?. And also I see from bajaman's pcb that R56 is 100K and C31 is 220pF. Is this right?.
Finch: A witty saying proves nothing - Voltaire
Stifler: Suck my dick - Ron Jeremy

For this message the author DimebuGG has received thanks: 2
Jan1966 (26 Aug 2017, 13:39), rcustoms (26 Aug 2017, 21:04)
User avatar
DimebuGG
Solder Soldier
 
Posts: 210
Joined: 02 Sep 2008, 12:37
Location: Doha, Qatar
Has thanked: 8 times
Have thanks: 159 times

Re: Amptweaker - BigRock/TightMetal Pro

Postby DimebuGG » 27 Aug 2017, 08:32

What's the purpose of the second 1M trimmer and 18K resistor in the noise gate section BTW?. If the gate switch is in OFF position, the 4.75K resistor will be in parallel with the 1M trim/18K resistor. That means less than 4.75K in total resistance, right?. Same thing also when the switch is in ON position(500K pot/4.75K in parallel to 1M trim/18K).
Finch: A witty saying proves nothing - Voltaire
Stifler: Suck my dick - Ron Jeremy
User avatar
DimebuGG
Solder Soldier
 
Posts: 210
Joined: 02 Sep 2008, 12:37
Location: Doha, Qatar
Has thanked: 8 times
Have thanks: 159 times

Re: Amptweaker - BigRock/TightMetal Pro

Postby nexion777 » 28 Aug 2017, 04:05

DimebuGG wrote:What's the purpose of the second 1M trimmer and 18K resistor in the noise gate section BTW?. If the gate switch is in OFF position, the 4.75K resistor will be in parallel with the 1M trim/18K resistor. That means less than 4.75K in total resistance, right?. Same thing also when the switch is in ON position(500K pot/4.75K in parallel to 1M trim/18K).


I noted the same thing, in fact that arrangement is absent in the vanilla tight metal schematic, maybe something related to the FET actuator? :scratch:
nexion777
 
Posts: 27
Joined: 25 Apr 2009, 17:20
Has thanked: 41 times
Have thanks: 1 time

Re: Amptweaker - BigRock/TightMetal Pro

Postby J0K3RX » 01 Sep 2017, 17:40

DimebuGG wrote:What's the purpose of the second 1M trimmer and 18K resistor in the noise gate section BTW?. If the gate switch is in OFF position, the 4.75K resistor will be in parallel with the 1M trim/18K resistor. That means less than 4.75K in total resistance, right?. Same thing also when the switch is in ON position(500K pot/4.75K in parallel to 1M trim/18K).



On the standard tight rock or tight metal the gain and gate dual gang 500k are always at a fixed level.. The gate tracks the gain at a fixed level and if you are going to use the gate then you really have no control over it. I am guessing that was one of the complaints about it.. The 1M trim pot lets you adjust the gate to gain ratio basically by throwing parallel resistance across the lugs of the gate. So, when the gate is in the On position you can turn up the gain and at the same time have some control over how much gate comes along for the ride.. When the gate is in the On position the 4k75 resistor and 500k gate pot are connected in series to the other side of the diodes and in parallel with the 1M trim which is in series with the 18k resistor... So, when the gate is On you basically have a 504.75k pot in parallel with a 1.018M trimmer which is adjustable. When the gate is Off the 500k gate pot is taken out of the equation and you have only the 4k75 resistor in parallel with 1M trimmer that is in series with the 18k resistor. To keep it simple lets just say that it's a 4k75 resistor in parallel with a 1.018M trimmer. Now, in the Off position it doesn't matter what the trimmer is set to or the fact that it's in series with the 18k resistor making it 1.018M, it's always gonna be 4.75k or at the very least 3.75 if you have the trimmer dialed off.

For this message the author J0K3RX has received thanks: 4
287m (08 Sep 2017, 09:33), bajaman (02 Sep 2017, 01:03), bmxguitarsbmx (04 Sep 2017, 22:11), nexion777 (01 Sep 2017, 19:34)
User avatar
J0K3RX
Degoop Doctor
 
Posts: 961
Joined: 29 Jun 2011, 02:25
Location: US Florida
Has thanked: 289 times
Have thanks: 449 times

Re: Amptweaker - BigRock/TightMetal Pro

Postby DimebuGG » 03 Sep 2017, 10:29

Here you go. Thanks to bajaman for letting me attach his (simplified) schematic.
You do not have the required permissions to view the files attached to this post.
Finch: A witty saying proves nothing - Voltaire
Stifler: Suck my dick - Ron Jeremy

For this message the author DimebuGG has received thanks: 13
bajaman (03 Sep 2017, 13:17), batak_man (04 Sep 2017, 04:19), bmxguitarsbmx (05 Sep 2017, 20:46), brejna (03 Sep 2017, 18:17), J0K3RX (03 Sep 2017, 16:49), karul (03 Sep 2017, 21:42), Manfred (03 Sep 2017, 17:13), Mich P (04 Sep 2017, 12:07), nexion777 (04 Sep 2017, 23:21), rcustoms (04 Sep 2017, 02:11) and 3 more users
User avatar
DimebuGG
Solder Soldier
 
Posts: 210
Joined: 02 Sep 2008, 12:37
Location: Doha, Qatar
Has thanked: 8 times
Have thanks: 159 times

Re: Amptweaker - BigRock/TightMetal Pro

Postby J0K3RX » 03 Sep 2017, 16:52

DimebuGG - Dude, you got Madd Skillz!! :twisted:

For this message the author J0K3RX has received thanks:
DimebuGG (05 Sep 2017, 08:56)
User avatar
J0K3RX
Degoop Doctor
 
Posts: 961
Joined: 29 Jun 2011, 02:25
Location: US Florida
Has thanked: 289 times
Have thanks: 449 times

Re: Amptweaker - BigRock/TightMetal Pro

Postby J0K3RX » 05 Sep 2017, 06:24

DimebuGG wrote:I made a single side pcb yesterday with boost function minus loops and LED lights. It's done already but I need to do final touch. Once finalized, I'll post it herre immediately.

Oh BTW, what's the value of BOOST GAIN and BOOST MASTER pots?. And also I see from bajaman's pcb that R56 is 100K and C31 is 220pF. Is this right?.


Boost volume and boost gain are both B100k, R56 is 47k and C31 is 560pF.

For this message the author J0K3RX has received thanks: 2
bajaman (05 Sep 2017, 06:44), DimebuGG (05 Sep 2017, 08:54)
User avatar
J0K3RX
Degoop Doctor
 
Posts: 961
Joined: 29 Jun 2011, 02:25
Location: US Florida
Has thanked: 289 times
Have thanks: 449 times

Re: Amptweaker - BigRock/TightMetal Pro

Postby DimebuGG » 15 Sep 2017, 09:30

Oh fuck!. I apologize. There's a mistake on that layout. I built it today and was wondering why didn't I get any signal. Only to find out that "Va" is supplied to 3 opamp's pin 8. I'll revise the layout ASAP.
Finch: A witty saying proves nothing - Voltaire
Stifler: Suck my dick - Ron Jeremy
User avatar
DimebuGG
Solder Soldier
 
Posts: 210
Joined: 02 Sep 2008, 12:37
Location: Doha, Qatar
Has thanked: 8 times
Have thanks: 159 times

Re: Amptweaker - BigRock/TightMetal Pro

Postby agung » 15 Sep 2017, 15:17

already built this from dimebug layout..and yeaah, something wrong with this layout. im using flying jumper from 12v out to all pin 8 opamp , and this thing come alive :applause: . thanks to DImebuGG
http://oi65.tinypic.com/1g3kwm.jpg
agung
 
Posts: 16
Joined: 10 Aug 2010, 15:32
Has thanked: 5 times
Have thanks: 2 times

Re: Amptweaker - BigRock/TightMetal Pro

Postby DimebuGG » 15 Sep 2017, 20:42

This is how I did with mine. I kinda fucked up the drilling of the two boost control pots. :slap: And also I used slide switch that I took from a dead M-Audio interface( I actually ordered sub mini toggles from Futurlec and still waiting for it to be shipped..poor customer service :evil: ). I did flying jumpers too.. :lol: . I really dig the boost controls in this one, it adds a different character to the sound.
You do not have the required permissions to view the files attached to this post.
Finch: A witty saying proves nothing - Voltaire
Stifler: Suck my dick - Ron Jeremy

For this message the author DimebuGG has received thanks: 2
J0K3RX (16 Sep 2017, 00:56), nexion777 (22 Sep 2017, 00:10)
User avatar
DimebuGG
Solder Soldier
 
Posts: 210
Joined: 02 Sep 2008, 12:37
Location: Doha, Qatar
Has thanked: 8 times
Have thanks: 159 times

Previous

Return to Boutique Stompboxes dissected...

Who is online

Users browsing this forum: agung, Monje, zeromax and 4 guests