JHS Morning Glory V4  [traced]

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jhergonz
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Post by jhergonz »

Matlevo12 wrote: 02 Apr 2021, 14:41
jhergonz wrote: 01 Apr 2021, 19:17 Just finished building the first schematics of Morning Glory v4 with some changes,
Wow, that's cool, which schem did you base your mods on ?

I compared the two V4, but my v4 is REALLY noisy (like synth fuzz noisy) when I turn the knobs up in the red mode so...
The V4 rev 1.5 is dead silent on comparison, probably because off all the independent bias voltages, and probably with that negative feedback to ground.
I measured them, just in case that interests someone :
Power supply
8.86V

UC1
3 4.07
5 4.12

UC2
3 4.13
5 4.12

UC3
3 4.43
5 4.44

I'm going to try the two mods on my v4 rev 1 :
- negative feedback of the first opamp to ground instead of Vb
- 100nf cap between Vb and gnd close to the second opamp

EDIT : Just tested the two mods. The fuzz drone is STILL HERE. STILL. If anyone has an idea before I DETROY THIS CURSED PEDAL, I'm all ears :)
I think I found out the problem of the first v4 schematics in red mode.

I modified my build of V4 clone, I made the additional opamp have higher gain, and the problem happens.

it is like a drone noise, same with the synth players.

This is what I noticed, there is no resistor between the output of the opamp and the clipping diodes(LED). I put 1k resistor then the problem disappears.

Maybe that is the reason why in the V4's version 1.5, there is a 10k resistor between the opamp's output and the LEDs.

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Matlevo12
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Post by Matlevo12 »

jhergonz wrote: 18 Oct 2022, 06:40 This is what I noticed, there is no resistor between the output of the opamp and the clipping diodes(LED). I put 1k resistor then the problem disappears.

Maybe that is the reason why in the V4's version 1.5, there is a 10k resistor between the opamp's output and the LEDs.
Thanks a LOT !
FINALLY !

I put a 10k there (actually i just moved the led connection to the other side of the 10k numbered R24 on the v4 rev1 I have, by cutting a trace on the pot side... and it's almost entirely gone !
What really annoys me if that I traced both pedals and never even saw the damn difference. Shame on me... but :worship: to you sir !

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jhergonz
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Post by jhergonz »

Matlevo12 wrote: 07 Dec 2022, 16:36
jhergonz wrote: 18 Oct 2022, 06:40 This is what I noticed, there is no resistor between the output of the opamp and the clipping diodes(LED). I put 1k resistor then the problem disappears.

Maybe that is the reason why in the V4's version 1.5, there is a 10k resistor between the opamp's output and the LEDs.
Thanks a LOT !
FINALLY !

I put a 10k there (actually i just moved the led connection to the other side of the 10k numbered R24 on the v4 rev1 I have, by cutting a trace on the pot side... and it's almost entirely gone !
What really annoys me if that I traced both pedals and never even saw the damn difference. Shame on me... but :worship: to you sir !
You're welcome.

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lukatosh
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Post by lukatosh »

Hi everyone... Nice things here on V4 Rev 3.0

Bypass is achieved using a TLP291-4 and two TL072 that i assume are for buffering. The opto is controlled by a microcontroller. No more 3pdt's

There is a charge pump and three LM833. The Diodes ar 1N4148 and red leds.

i'm starting to desolder smd this week... is there a way that i can identify the SMD transistors?

By the way... Pretty dirty PCB. This things cost like hell..

Thanks.

Image
Last edited by lukatosh on 05 Mar 2023, 19:18, edited 1 time in total.

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karul
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Post by karul »

lukatosh wrote: 04 Mar 2023, 13:01is there a way that i can identify the SMD transistors?
https://www.sos.sk/pdf/SMD_Catalog.pdf
https://www.s-manuals.com/smd

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lukatosh
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Post by lukatosh »

So far... some differences from V4 rev 1.5

Image

+- 9V

Extra gin stage is switched by using MMBFJ112

Some resistors are not pupulated on the PCB.

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