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DIY Stompboxes => Building your own stompbox => Topic started by: jimladladlooklike on August 22, 2018, 05:21:32 PM

Title: Small Clone copy questions...
Post by: jimladladlooklike on August 22, 2018, 05:21:32 PM
Hey pals,

I've started building a copy of the EHX Small Clone from the layout below:

(https://s15.postimg.cc/w3knwxpkn/EHX_Small_Clone_by_Iv_Iark.png) (https://postimg.cc/image/w3knwxpkn/)

Currently soldering in the resistors and I'm missing a few: 12k, 20k, 39k, 120k, 180k. Could I replace these with the nearest value I can find or do they have to be exact?

Cheers!
Title: Re: Small Clone copy questions...
Post by: mth5044 on August 22, 2018, 09:54:36 PM
Could you post a schematic? How far away are your nearest values?
Title: Re: Small Clone copy questions...
Post by: jimladladlooklike on August 23, 2018, 07:54:29 AM
Hmm I could post a similar one. It is different in places but was the closest thing I could find. There was no schematic on tag board effects where I pulled the layout from.

I have 10k, 22k, 33k, 100k and 220k
Title: Re: Small Clone copy questions...
Post by: antonis on August 23, 2018, 11:36:55 AM
It's a rather complicated board for trace so better get right resistor values..

You probably didn't proceed to caps populating or it should be more than peculiar to have 2.7nF cap handy and not 12k/120k resistor..  :icon_wink:
Title: Re: Small Clone copy questions...
Post by: jimladladlooklike on August 23, 2018, 02:33:06 PM
Haha! Actually I began soldering what cap values I had, but you're right; I don't have 2u7 and quite a few of the other rarer values and will have to get them too I guess.

Thanks for the help and I will report back, hopefully with a working pedal!

Jim
Title: Re: Small Clone copy questions...
Post by: jimladladlooklike on September 25, 2018, 01:02:58 PM
Slowly making progress with this one. However, I've just noticed that I have DPDT switches and the layout includes an LED. Is there a way I can omit the LED from the build altogether as it's not something I'm particularly fussed about.

Thanks!
Title: Re: Small Clone copy questions...
Post by: antonis on September 26, 2018, 10:14:07 AM
Of course you can omit the LED, if you don't mind for status indication a lot..

Or you can build a smal daughterboard for Millenium by-pass of any version you like....
Title: Re: Small Clone copy questions...
Post by: jimladladlooklike on September 27, 2018, 07:39:20 AM
By that do you mean I could literally just not connect the LED?

Thanks!
Title: Re: Small Clone copy questions...
Post by: antonis on September 27, 2018, 08:54:39 AM
Yeappp..!!

As far as I can trace, you can also omit 2k2 current limiting resistor..
(the one with it's upper leg set between LED+ white wire and 2 holes left strip cut..)
Title: Re: Small Clone copy questions... (debugging)
Post by: jimladladlooklike on September 30, 2018, 09:39:57 AM
Awesome, thanks!

So I've finished building it with the LED omitted and a DPDT switch. However, when the effect is engaged I get a more treble but no chorus effect... time to debug!

All parts are the same as specified in the layout.

Voltages: (IC1 IC2 etc etc are listed in relation to the vero layout - not the schematic.)

Positive terminal on DC socket measuring at 9.1v

IC1
1: 4.4v
2: 4.4v
3: 3.5v
4: 0v
5: 4.3v
6: 4.4v
7: 4.4v
8: 9.1v

IC2
1: 7v
2: 3.4v
3: 0.2v
4: 0v
5: 0v
6: 0.6v
7: 0.5v
8: 0.5v

IC3
1: 7v
2: 0v
3: 5.9v
4: 7.1v
5: 7.1v
6: 7.1v
7: 0v
8: 0v
9: 0v
10: 0.8v
11: 3.5v
12: 0v
13: 7v
14: 0v

IC4
1: 7.8v
2: 2.1v
3: 1.2v
4: 0v
5: 3.8v
6: 4.1v
7: 6.1v
8: 9v

Q1
C: 0v
B: 4.3v
E: 4.8v

Q2
C: 9.1v
B: 0.4v
E: 0v

Q3
C: 9.1v
B: 7.8v
E: 7.1v

D1
A: 5.2v
K: 4.9v

D2
A: 0v
K: 3.7v  (weird?)
Title: Re: Small Clone copy questions...
Post by: ElectricDruid on September 30, 2018, 11:52:18 AM
Q1 looks weird. In the wrong way around, maybe?

Title: Re: Small Clone copy questions... (debugging)
Post by: antonis on October 02, 2018, 06:08:29 AM
Quote from: jimladladlooklike on September 30, 2018, 09:39:57 AM
D2
A: 0v
K: 3.7v  (weird?)
Indeed..!!

But weird also 300mV forward voltage drop on D1 1N4148 Si diode..
Title: Re: Small Clone copy questions...
Post by: ElectricDruid on October 02, 2018, 02:30:24 PM
Quote from: ElectricDruid on September 30, 2018, 11:52:18 AM
Q1 looks weird. In the wrong way around, maybe?

My mistake -it's a PNP of course. That's why it looks like it's back to front...doh  :icon_redface:
Title: Re: Small Clone copy questions... (debugging)
Post by: jimladladlooklike on October 15, 2018, 07:42:10 AM
Quote from: antonis on October 02, 2018, 06:08:29 AM
Quote from: jimladladlooklike on September 30, 2018, 09:39:57 AM
D2
A: 0v
K: 3.7v  (weird?)
Indeed..!!

But weird also 300mV forward voltage drop on D1 1N4148 Si diode..

Thanks for pointing that out. What does this mean though? I literally have no idea how to approach debugging this one!
Title: Re: Small Clone copy questions...
Post by: jimladladlooklike on October 19, 2018, 07:55:16 AM
Anyone care to take a look at this? Still have no clue where to start debugging.

Thanks in advance!