freestompboxes.org

zamguitar wrote:

VH4 PEDAL.png

is 100% ok or there something so so in the final schematics

D3,D4 looks like D1,D2,D5,D6 to me.
Did you measure the Diodes?

rcustoms wrote:

zamguitar wrote:

VH4 PEDAL.png

is 100% ok or there something so so in the final schematics

Didn't build yet. But I'm pretty sure that the schem will give close results.

Just need to figure out the D3 and D4 zener values.

Manfred wrote:D3,D4 looks like D1,D2,D5,D6 to me.
Did you measure the Diodes?

Just drew from the pictures, D3 and D4 are indeed 500mW zener diodes with the 1n5XX code.

awesome work zamguitar,i design the pcb layout ,in this days

zamguitar wrote:

Manfred wrote:D3,D4 looks like D1,D2,D5,D6 to me.
Did you measure the Diodes?

Just drew from the pictures, D3 and D4 are indeed 500mW zener diodes with the 1n5XX code.

Thanks!

Who can check the clipping voltages of both polarities with an oscilloscope?

Why does the edit function sometimes not work?

I meant the pointed out position.

A simple way to check what the zener is without removing it.
POWER OFF the unit
Get a 9V battery, connect battery negative to the anode of the zener, connect the cathode of the zener to the 9V battery positive THROUGH A 1k RESISTOR.
Using a multimeter, measure the voltage across the zener

I would guess these are 3.3V zeners, or maybe even as low as 2.4V

Manfred wrote:Why does the edit function sometimes not work?

I meant the pointed out position.

CheckPoint.png

You are right, that is the easiest way to measure the zener voltages.

A simple way to check what the zener is without removing it.
POWER OFF the unit
Get a 9V battery, connect battery negative to the anode of the zener, connect the cathode of the zener to the 9V battery positive THROUGH A 1k RESISTOR.
Using a multimeter, measure the voltage across the zener

I would guess these are 3.3V zeners, or maybe even as low as 2.4V

Here again, I quote my self in the last post .

You are right, that is the easiest way to measure the zener voltages.

Hi. anyone build a VH4 klone, based on a this schematic?

Hi, thanks for the schematic! I was waiting for this

I've build it and it looks like there is some kind of problem around IC1.
It generates a high pitch noise and seems to have something like a grounding issue or some kind of connection missing.
The gain pot reacts more like and gain on/off switch then gradually changing gain level.
After IC1 it seems to be working ok (EQ, pres, deep). The mistake might be in my build but I have checked it pretty thoroughly.

Anybody else who has build this?
Any thoughts? Different results?

Hi together,

The diodes are 1N5232. Could read 1N5 on one of them and 232 on the other one.
Measured both with app. 5.6V.

Regards

Apparently the voltages of the D3 & D4 zeners are labelled on their respective silksreen layouts, under the diodes, they could be read as "5V6" for instance. Please try to bend the leads carefully to verify my guess, make us that favor.
Thanks in advance.

Dave

kh602 wrote:

J0K3RX wrote:kh602, excelent pics! Hate to bother you further but, do those pots have any values on them that you can see without lifting them? I have a few pots like that so I am fairly sure the values are on the bottom facing the board.. We can probably guestimate what they should be in the tonestack since it looks like your average marshall type stack with standard values judging from the cap and resistor values.

Measured values of the pots (most are in rheostat config, i assume master and treb are potential dividers at a glance).

Gain pot = 159.7k
Bass pot = 566k
Mid pot = 24.82k
Treb Pot = 262.3k
Master Pot = 10.93k
Pres Pot = 21.07k
Deep pot = 25.35k

Hope this helps

Did you measure those with a multimeter while they were still wired into the circuit?

I've always heard that you can't measure resistance when the resistor in question is still hooked up to the rest of a circuit. Is there any reason that it would work in this case?

R26 and R34 are 1k not 110R

guess what I am doing with all the nice gut shot pictures

bajaman wrote:guess what I am doing with all the nice gut shot pictures

Making magic happen?

I'd like to breadboard this. I realize these are 400V caps, but could C11 really be only 4n7? Seems a bit small for that late in the gain stages...