Diezel VH4 Pedal  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
User avatar
caspercody
Resistor Ronker
Information
Posts: 388
Joined: 15 Jul 2009, 14:34
Has thanked: 34 times
Been thanked: 48 times

Post by caspercody »

What do you use to attach the voltage regulator to the board? To help heat sink it.

User avatar
bmxguitarsbmx
Cap Cooler
Information
Posts: 510
Joined: 25 Mar 2010, 21:15
Has thanked: 700 times
Been thanked: 216 times

Post by bmxguitarsbmx »

caspercody wrote:What do you use to attach the voltage regulator to the board? To help heat sink it.
To sink what heat? Not being snotty, but the TO-220 package could easily be dropped to a TO-92 package and use only air cooling:

https://www.mouser.com/ProductDetail/ON ... %2fRhHA%3d

^100mA TO-92 12V linear regulator

User avatar
caspercody
Resistor Ronker
Information
Posts: 388
Joined: 15 Jul 2009, 14:34
Has thanked: 34 times
Been thanked: 48 times

Post by caspercody »

I ordered a kit, and it came with the LM2940CT-12.

User avatar
Svullgo
Information
Posts: 6
Joined: 01 Nov 2016, 17:29
Has thanked: 1 time
Been thanked: 5 times

Post by Svullgo »

First I wanna say thanks to all you heroes who put down a lot of time in this community and sharing your results and knowledge!
You have helped me a lot in learning and understanding the electronics of pedals!

I have built this after Alex Vero at tagboardeffects and everything works. (I needed to up the the 47p capacitor to 560p as reichi suggested to get rid of the oscillation/feedback on higher gain levels)
I wonder if the presence and resonance works as the original (which I never have tested)
The presence lowers the the perceived volume a lot when turned down and resonance feels like its to much in the lower midrange. (but thats what Bajaman on page 4 says that they should do but have anyone have had the opportunity to A/B-test it with an original?)

User avatar
Daza
Information
Posts: 7
Joined: 15 Jan 2010, 13:26
Has thanked: 2 times
Been thanked: 1 time

Post by Daza »

I set the bass version, and I also have oscillation with high gain (around 12 o'clock) I'll see if it goes down changing the 47p

User avatar
Daza
Information
Posts: 7
Joined: 15 Jan 2010, 13:26
Has thanked: 2 times
Been thanked: 1 time

Post by Daza »

Daza wrote:I set the bass version, and I also have oscillation with high gain (around 12 o'clock) I'll see if it goes down changing the 47p

I set the bajaman version, and I also have oscillation with high gain (around 12 o'clock) I'll see if it goes down changing the 47p

User avatar
brejna
Breadboard Brother
Information
Posts: 118
Joined: 25 Nov 2012, 17:14
Has thanked: 68 times
Been thanked: 62 times

Post by brejna »

It does, but pedal sound muddier...

User avatar
bmxguitarsbmx
Cap Cooler
Information
Posts: 510
Joined: 25 Mar 2010, 21:15
Has thanked: 700 times
Been thanked: 216 times

Post by bmxguitarsbmx »

The real way to tame oscillation is to examine the layout. IMO

User avatar
Daza
Information
Posts: 7
Joined: 15 Jan 2010, 13:26
Has thanked: 2 times
Been thanked: 1 time

Post by Daza »

It would not be good muddy sound.
I put shielded cable and it improved a bit. Increasing the depth increases the oscillation considerably

User avatar
Daza
Information
Posts: 7
Joined: 15 Jan 2010, 13:26
Has thanked: 2 times
Been thanked: 1 time

Post by Daza »

Will you have a problem with the input impedance the scheme?
I put a buffer before the pedal as recommended by Brejna and the oscillations disappeared!

User avatar
J0K3RX
Degoop Doctor
Information
Posts: 1057
Joined: 29 Jun 2011, 01:25
Location: US Florida
Has thanked: 315 times
Been thanked: 556 times

Post by J0K3RX »

I wouldn't bother with shielding the output... I would shield the input and definitly the gain pot! Poke around with an audio probe and it should lead you right to the source of the oscillation...

User avatar
bmxguitarsbmx
Cap Cooler
Information
Posts: 510
Joined: 25 Mar 2010, 21:15
Has thanked: 700 times
Been thanked: 216 times

Post by bmxguitarsbmx »

I wish I could attribute this quote pertaining to pcb layout:

"rarely will stray capacitance to ground cause the problems that stray capacitance between any other traces have".

Shield it up! Proximity/phase is also worth considering.

User avatar
sego91
Information
Posts: 11
Joined: 02 Oct 2013, 17:10
Location: Prague, Czech Republic
Has thanked: 13 times
Been thanked: 15 times
Contact:

Post by sego91 »

Im gonna try to replace the 7660s with another IC to eliminate the oscilation and squeel, maybe a 1054 im gonna check it out .

User avatar
RockKenny
Information
Posts: 5
Joined: 16 Nov 2017, 13:05
Been thanked: 4 times

Post by RockKenny »

sego91 wrote:Im gonna try to replace the 7660s with another IC to eliminate the oscilation and squeel, maybe a 1054 im gonna check it out .
Hi! Any good news after changing 7660? I'm also have oscillation problem & no ideas how to fix...

User avatar
temol
Solder Soldier
Information
Posts: 200
Joined: 25 Feb 2017, 20:58
Has thanked: 23 times
Been thanked: 213 times

Post by temol »

I've completed my VH4 build. Worked on first try, no oscillation. Because I did not have 25kC potentiometers, I used 25kB with an additional resistor, which was supposed to change the pot characteristics from LIN to ANTI-LOG. Unfortunately, it does not work as it should. In my opinion it still works as a linear potentiometer. It worked on a breadboard - I connected battery to the potentiometer, measured voltage, plotted a curve - definitely C characteristics. Maybe I should try with a lower resistor value. Now it's a 5k1 across leg 2 and 3.

T.

User avatar
Silverhair
Information
Posts: 3
Joined: 11 Oct 2017, 23:44
Has thanked: 1 time

Post by Silverhair »

Maybe the TC1044SCPA, in this version they use it: http://www.pedalpcb.com/product/valhalla/

User avatar
temol
Solder Soldier
Information
Posts: 200
Joined: 25 Feb 2017, 20:58
Has thanked: 23 times
Been thanked: 213 times

Post by temol »

I have 7660SCPAZ in my build and no oscillation.

Image

T.

User avatar
bajaman
Old Solderhand
Information
Posts: 4544
Joined: 26 Jun 2007, 21:18
Location: New Brighton, Christchurch, NZ
Has thanked: 593 times
Been thanked: 2048 times

Post by bajaman »

nice build :D
be kind to all animals - especially human beings

User avatar
RockKenny
Information
Posts: 5
Joined: 16 Nov 2017, 13:05
Been thanked: 4 times

Post by RockKenny »

temol wrote:I have 7660SCPAZ in my build and no oscillation.
T.
What kind of 7660 do you use? I mean firs letters.
I have oscillation with ICL7660SCPA.

User avatar
bajaman
Old Solderhand
Information
Posts: 4544
Joined: 26 Jun 2007, 21:18
Location: New Brighton, Christchurch, NZ
Has thanked: 593 times
Been thanked: 2048 times

Post by bajaman »

No problem with any oscillation my board layout as Temol has found :roll:
be kind to all animals - especially human beings

Post Reply