JHS - Morning Glory  [traced]

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irmcdermott
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Post by irmcdermott »

Got one of these in and traced it. Here you go!

Not sure what te yellow part is at the top. But there is continuity between both legs and the voltage is the same on both sides, so I left it off the schematic, if anyone has an idea, I'd love to know.
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JHS Morning Glory schematic
JHS Morning Glory schematic

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Post by Jack Deville »

I guess that's one way to track a board.
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Post by Seiche »

Multicolored yay! Analogguru does it this way too. Whats the other way?

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Post by Jack Deville »

Track. Not trace.
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Post by Bill_Mountain »

As someone who has mixed feelings on JHS and as a bass player I'm surprised how much I want to try this pedal.

When I thought about building my own MBB clone I was going to put a transistor boost on the end to fix the phase. Well...there goes another idea I thought I had...

I still want to try one of these.

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Post by phibes »

Default autoroute for the win!
GuitarlCarl - "TGP = The Gear Polishers"

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Post by grrrunge »

irmcdermott wrote:Not sure what the yellow part is at the top
My guess is a 100nF multilayer ceramic to help the electrolythic cap filter out high frequency noise in the supply voltage. Or a decoupling cap for V+
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Post by grrrunge »

irmcdermott wrote:I wish I had one to fully trace, but someone I know who has a double barrel (but lives states away from me) was kind enough to let me know that the opamp is a LM833N.
Apparently the LM833 is an opamp specifically for audio purposes http://www.ti.com/product/lm833 . I've used those for quite a few builds, and tend to prefer those and TL072's for buffer, amp and filter stages among all the different dual op-amps i've ome across so far
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irmcdermott
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Post by irmcdermott »

grrrunge wrote:
irmcdermott wrote:Not sure what the yellow part is at the top
My guess is a 100nF multilayer ceramic to help the electrolythic cap filter out high frequency noise in the supply voltage. Or a decoupling cap for V+
On the silkscreen it's labeled "F1" and the symbol there is for a thermistor, but it definitely looks like a MLCC

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Post by mozwell »

As it is in series with the DC input power, it is most likely a special type of PTC. These are used as "electronic fuses" and can be quite small, for "tripping" at low currents.
There is a reverse power supply protection diode D2, if the DC supply is reversed, the diode will effectively short out the DC supply, as soon as this happens, the PTC will go high resistance, limiting any "fault" current, so as to not damage D2 or anything else on the pedal. In normal operation, the PTC has a few ohms of resistance, so will provide some RC filtering into the cap C1.
I use the high current ones all the time on the outputs of SS amps of up to approx 150W, as speaker protection, or two in parallel for up to 300W amps.
Its an excellent idea to use small ones this way in pedals.

What is marked on the device.
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bourns mfr.pdf
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irmcdermott
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Post by irmcdermott »

I don't have the unit any more. But this is the only pic I got of that part and it unfortunately is blurry. The markings I could make out, and very well could be wrong were:

LF 30
BH3E

It was extremely difficult to read, so I have no idea if that is correct.

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Post by irmcdermott »

Also, I'm an idiot in the way I worded the, "there is continuity on both legs"... what I meant to say was:

Both legs are connected to +9v, one side is connected by a track, the other side is connected to the V+ plane

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Post by freq67 »

Is that much filtering necessary??

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Post by irmcdermott »

freq67 wrote:Is that much filtering necessary??
I agree. It's excessive.

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Post by bondieffects »

So what exactly did they improve? Adding an output buffer? Their website claims "4X more headroom, 2X the available gain, and a more useful tone control"

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Post by irmcdermott »

Build doc for anyone who wants it.

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Post by Bill_Mountain »

Anyone notice that it used to be called a "discrete" overdrive. I wonder how JHS justified that bit of marketing?

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Post by cdeschenes »

irmcdermott wrote:Build doc for anyone who wants it.
You just gave me something to etch this weekend. Thanks

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Post by irmcdermott »

Thanks for the direction on the PTC. I wonder if there were markings on the other side that I missed. It's definitely the Littelfuse series, and from the LF30 marking, it's the 30R series. Here is the datasheet. I just don't know which of these it is.

http://www.mouser.com/ds/2/240/Littelfuse_30R-19977.pdf

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Post by erichoh »

Anybody build this yet? I never learned how to etch my own boards so I made a perf layout for it based off the build doc. Got nothing. Wondering if anybody has the voltages for the IC?

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