AMZ Splitter - Weak signal from 1 of the outputs

Started by egisseur, June 01, 2023, 09:20:45 AM

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egisseur

Dear friends and pedalbuilding family,

Yet again I've struck troubleshooting gold and found myself in the unfortunate position of bothering the experts with my (proberbly) simpelton issues...

I've been creating pcb based effects for a while now and thats going great. I thought it time to touch the veroboard's and wanted to start with something simple. As the title states, the AMZ 2 channel splitter.

The splitter seems to work as I do get proper sound from one of the outputs (top one on the image). However the 2nd one (bottem output) only passes veeeeeery little sound.

Something to consider is that I didn't have acces to the 2N5457 JFET as the build suggested. I used the 2N3819 and bended the pinout to match the layout from the veroboard drawing.

First I though it might be a grounding issue. Thats why all ground are now seperatly connected to the power supply.

Veroboard layout: http://tagboardeffects.blogspot.com/2014/08/amz-2-channel-splitter.html
Schematic (-1 output): http://www.muzique.com/images/split1.gif

Q1 readings
D:0.18
S: 2.80
G: 2.3

Q2 readings
D: 0.19
S: 2.71
G: 2.3

*fyi. I have to admit i'm unsure how to read transistor voltages. I use a multimeter with the red probe a the 9v input and use the black probe for the reading on the transistor pins. Please let me know if this is incorrect so I can rectify it in this post.

Again, thanks for all the fish!







antonis

Quote from: egisseur on June 01, 2023, 09:20:45 AM
*fyi. I have to admit i'm unsure how to read transistor voltages. I use a multimeter with the red probe a the 9v input and use the black probe for the reading on the transistor pins. Please let me know if this is incorrect so I can rectify it in this post.

As you used it, you get tha voltage difference between +9V and respective point of interest..
(meaning you have to subtrack those voltages from +9V to find the actual vokltage difference from Ground..) :icon_wink:

Or, much better, place the Black probe on GND and Red probe on the point to me measured..

P.S.
In case of your current measurements are correct, you should get:

Q1 readings
D: 8.80
S: 6.00
G: 6.5

Q2 readings
D: 8.80
S: 6.10
G: 6.5

for the new measurements, considering about 8.8V power supply..

I presume you've tangled JFTs pin-out 'cause correct voltage readings should point Source standing on voltage level higher than Gate one..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

antonis

Also, I'd try to clean any short-suspect points on board solder side.. :icon_wink:

"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

duck_arse




your cap leg at green should instead be at magenta.
I feel sick.

egisseur

Quote from: duck_arse on June 01, 2023, 12:26:41 PM



your cap leg at green should instead be at magenta.

You have a sharp eye!! Thanks for the assist.

We just welcomed our 3rd child yesterday :icon_biggrin:, so yey me but it really doesnt help with circuit focus ;)

Thanks again.

egisseur

Thanks for the tips Antonis! The potential crossovers are slightly upward bend leads, luckly they werent real bridges.

Bit I do now know how to properly read and provide pin values! Thanks for that.

ElectricDruid

Quote from: egisseur on June 01, 2023, 01:56:51 PM
We just welcomed our 3rd child yesterday :icon_biggrin:, so yey me but it really doesnt help with circuit focus ;)

Lol, "Congratulations!", and "No, I bet!" ;)

Just try and get some sleep?!

egisseur

Thanks! As soon as our little girl permits I'll definately do so.

antonis

Quote from: ElectricDruid on June 01, 2023, 02:41:35 PM
Just try and get some sleep?!

Usually, the 3rd child doesn't discommode a lot..
(from parents point of view..) :icon_wink:
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

egisseur

Quote from: antonis on June 01, 2023, 04:32:10 PM

Usually, the 3rd child doesn't discommode a lot..

Well we're definately prepared! However these broken nights will never become my favorite. And thus misplacing capacitor legs is an offer I'll have to make...  :icon_cool: