Morning Glory V4

[tveen323]

Howdy,

Did anyone already figured out the new Morning Glory 4? I like to build on with the additional mod (gain switch).
I like the way the gain switch can also be operated by an external foodswitch!
As I understand from the description on JHS website there is a extra gain stage / booster build in, operated by the external switch or the toggle.

Can someone give me a push in the right direction?

Cheers!

[Kevin Mitchell]

I like to build on with the additional mod (gain switch).

As I understand from the description on JHS website there is a extra gain stage / booster build in, operated by the external switch or the toggle.

Wow that was quick!

[tveen323]

That' a smart one, Kevin.

Now I just need to know what kind of booster, the gain of the booster etc.

So I was asking, did somebody already figure this thing out?

[GGBB]

I have no idea what's actually in the v4, but they describe it as a "gain toggle" not a booster. A "gain toggle" is nothing unusual. Here's an example from my own take on the Bluesbreaker circuit that I call the Notorious OD. The gain switch S3 toggles between the two common gain resistor pairs - 27k and 33k (King of Tone) or 4.7k and 3.3k (Morning Glory) - by adding/removing parallel resistors to 27k and 33k:

[Kevin Mitchell]

That' a smart one, Kevin.

Sorry, bud Your question was unclear so I was sarcastically hinting for you to elaborate. I read it as "I want to mod in a boost, also I read it has a booster switch already". But really it could be that I don't know a thing about the pedal

[sominka]

Howdy,

Did anyone already figured out the new Morning Glory 4? I like to build on with the additional mod (gain switch).
I like the way the gain switch can also be operated by an external foodswitch!
As I understand from the description on JHS website there is a extra gain stage / booster build in, operated by the external switch or the toggle.

Not new. Why?

[matlevo12]

Hi,

since I had a faulty unit sent to me I traced the extra part.
It's connected to a non lathing dpdt relay that's piloted with the switch or the external footswitch system.
Here it is :



It looks weird, I know, but it seems to be like that, I checked a few times... The second half of the extra opamp is there to stabilize the 4.5v.

There are a few minor differences as well in the v4, including a 47pf cap between pins 1 and 2 of the opamp, meaning between the non-inverting input and the output of the second stage of the circuit (like in the first part, but instead of being a SMD cap it's a normal through-hole ceramic cap that's been added afterwards, but it's not just on mine, it's there on pisctures of the v4 pcb you can find online.
Parts numbers are different as well than in the v3 schem we have.

I still have a problem with this pedal, in case someone would like to help, by the way.

[GGBB]

It looks weird, I know, but it seems to be like that, I checked a few times...

The connection to VB via R25 is definitely weird if correct. That part of the circuit is already at VB from the output of the second gain stage through to the series RC just before the JFET. The whole tone section is referenced to VB (see http://music.codydeschenes.com/wp-content/uploads/2013/05/JHS-Morning-Glory-Schematic.png). Is it possible that you left some other v4 mods out?

[Steben]

The leds are wired like that??? 

[matlevo12]

Hi.
Thanks for your answers.

I know, it's weird... here's a picture of the circuit, and the same pictures with indications : voltages, ground and traces that are on the other side of the pcb (A, B and C).
I might be wrong, I spent way too much time looking at this [...] pedal that I might be missing something but I did test quite a few times, and again just now when noting the annotations on the picture.





The leds are all in the same orientation.

Apart from the values that I didn't check (SMD caps...) the only other differences that I noted from the V3 schematic are :
- R16 is bridged : 0ohm smd resistor on the V4, still named R16
- C15 is a smd cap on the V4, named C14

[matlevo12]

Oh and by the way, you might have guessed it seeing the pictures I took), I have aproblem with this pedal.
Is was noisy, and not the good drive-hum type of noise.
I tried powering it with a lot of different power supplies, it changed a bit but didn't solve anything... but powering it with a battery did.

I tried changing the opamp to see how it would go, I tried a TL072 and it wasn't noisy, just a lot quieter... I don't remember using the red/more gain mode with the TL072.
I decided to put new LM833 inthere and the problem is still the same : the pedal is not noisy but a lot quieter (unity volume with gain at 10 and volume at 3/4) and the red/more gain mode is very unstable :  it starts fuzzing when gain is at 12, and it gets hissy after that.
Extra bonus point : the hiss is event there when in bypass mode if I turn up the gain. I know.

I hadn't had time to work on it much more, but if anyone's got a tip or clue that's be great !

Thanks folks !

[GGBB]

the hiss is event there when in bypass mode if I turn up the gain. I know.

That suggests a bad bypass switch, or some other leak of circuit output to jack. Check resistance between circuit output on switch and jack when in bypass mode.

[matlevo12]

the hiss is event there when in bypass mode if I turn up the gain. I know.

That suggests a bad bypass switch, or some other leak of circuit output to jack. Check resistance between circuit output on switch and jack when in bypass mode.

After struggling for quite some time with the pedal but getting a lot of help from people. You could even hear the problem when lsound probing the 9V and ground... but it was solved by ading a capacitor in the "red mode" opamp loop. 10n did the trick. since part of that opamp is directly connected to the 4.5V that does make sense in a very strange way.

I investigated a lot and found out that there are different versions of the V4 morning glory, they changed ths circuit and pcb around or before 2018.

I didn't manage to find some clear pictures of the new pcb though, and I'm asking you wonderful people on this forum : does anyone has a morning glory v4, preferably "recent" and could take some pictures ?

Thanks !

[matlevo12]

Hi.

Two things : I finally solved my v4 rev1 problem.

First here's the "new" v4 (rev1.5 on the pcb) schematic :


and then, here's how I managed to fix the drone in my red mode (thanks to the awesome dude who pointed this differenve between the two v4 schematics) :
- add a resistor between the red mode opamp output and the leds. He said 1k's enough, what I did (since he was making his own clone and I'm just fixing my existing v4 rev 1 jhs pcb) is moving the led connection to the other side of the R24 (10k). Works perfectly.

Have a good day everyone !