Hey guys, another trouble here, I feel a bit unfortunated in these last months.
I'm building a Multiplexer Octave, veroboard layout is here: http://tagboardeffects.blogspot.it/2016/09/electro-harmonix-octave-multiplexer.html
Three version verified. Vintage, Vintage with boost and Modern with boost.
I opted for the Modern with boost.
- I replaced the 2N5459 with a 2N5457.
- The bypass switch is a toggle DPDT, just for trying.
- In the 9v I inserted a CLR 1.2k with a led.
As usually everything seems ok, I got the effect but I got even a big bump when I engage and disengage the circuit. The led turns on, the sound seems good enough, but even adjusting the tirmmer I can't go over the unitary volume, and this is suspect. The boost is in the output of the circuit right to boost the signal.
Schematic's here: http://topopiccione.atspace.com/pjimages/EHOctaveMultiplexer.sch.gif
And another's here:
Layout's here: https://2.bp.blogspot.com/-EvNbNYEORfM/V_JeiaVWFnI/AAAAAAAABAE/snGaHjXarCQmskQUuCGFN_tdeqJoV6cGQCLcB/s1600/Multiplexer%2528Modern%2529.png
Suggestion?
Thank you!
Update:
Voltage of the 2N5457 (left transistor).
G: 0,00v
S: 0,06v
D: 5,76v
And the led doesn't turn on fully, the intensity oscillate for a bit, it need a moment to turn on well.
If I'm not wrong, by the Jfet voltages, seems to be a bit missbiased
And by the led: any shortcut?
I guess the led is ok, at least about the connection. A resistor in the 9v stripe goes in the positive of the led. The negative is wired to the switch lug following the instruction of the layout.
Anyway al that problem there was when the led there's no there, too. I inserted the led to see if them fixed with the led. But not
Maybe is something about the power.
I didn't find the "right" voltage of the JFET booster. Anybody know them?
Quote from: Elijah-Baley on November 28, 2017, 10:11:19 AM
I guess the led is ok, at least about the connection. A resistor in the 9v stripe goes in the positive of the led. The negative is wired to the switch lug following the instruction of the layout.
Anyway al that problem there was when the led there's no there, too. I inserted the led to see if them fixed with the led. But not
Maybe is something about the power.
I didn't find the "right" voltage of the JFET booster. Anybody know them?
Sure..thats what I mean: some cap and power shortcut.
For the jfet I would try to get 4,5 or 5v at D.
I don't have anymore the led issue. Myany was meaningless.
Don't forget the trimmer. But though it is set fully counterclockwise I still get 4,80v at D.
What about S and G voltage?
QuoteSchematic's here: http://topopiccione.atspace.com/pjimages/EHOctaveMultiplexer.sch.gif
hey E-B, that "page not found". can you point me/us another schem?
Oops, I did it again. :P
Topopiccione is a great resource but there's some problem with the links.
(http://i61.tinypic.com/4pxs15.gif)
>> Schematic's here: http://topopiccione.atspace.com/pjimages/EHOctaveMultiplexer.sch.gif
> hey E-B, that "page not found".
It is there; but topopiccione's free web-host does not serve links from other sites.
Copy the URL to clipboard. Open new tab. Paste the link into the address bar. Boom, you got it. (This way it can not tell you came from here.)
"Boom". thanks Paul. I don't think I've ever seen that circuit before [which is of no help or interest to E-B].
The JFET boost in the output is missing in the original schematic, and that should be pretty regular, I guess. Can someone tell me something about the voltages? I didn't fine anything.
I am a bit busy, but I'll try check the other voltages sooner than possible.
Here's the layout I used:
(https://2.bp.blogspot.com/-EvNbNYEORfM/V_JeiaVWFnI/AAAAAAAABAE/snGaHjXarCQmskQUuCGFN_tdeqJoV6cGQCLcB/s1600/Multiplexer%2528Modern%2529.png)
I found the voltage published from someone who sais: «
With these voltages works perfectly». But in this vintage version there's a LM324 instead the two 4558, and there's none JFET booster in the output. So could be useful this layout, too:
(https://3.bp.blogspot.com/-0drONHMlLhI/WHzhBTv0idI/AAAAAAAABNg/52XoVLIki4oRUkA4CbtRE8o5Ivw65bmPgCLcB/s1600/Multi%2BPlex%2B1.png)
On the left the right voltages. On the right my measurements.
(Seems a J201 replaced the 2N5459).
**When there are two voltages: no hitting the strings - hitting the strings. At least with my measurements.
J FET 201
D - 4.19
S - 4.20
G - 2.60
LM324 (upper one)
1. 4.20
2. 4.20
3. 4.17
4. 8.39
5. 4.17
6. 4.21
7. 4.20
8. 4.20
9. 4.20
10. 4.13
11. 0
12. 4.15
13. 4.20
14. 4.20
LM324 (parallel with 4013)
1. 7.11
2. 4.13
3. 4.20
4. 8.39
5. 4.20
6. 4.20
7. 0.02
8. 0.015
9. 4.20
10. 0.02
11. 0
12. 4.20
13. 7.11
14. 0.03
4013
1. 1.70-2.50
2. 3.20-4.10
3. 0
4. 0.03
5. 0
6. 0.015
7. 0
8. 0
9. 4.90
10. 0
11. 3.40
12. 4.90
13. 2.50
14. 8.39
|
|
JFET 2N5457 (replaced the 2N5459)
D - 3.98
S - 4.20
G - 0.00-2.20
LM324 (upper one)
1. 4.15
2. 4.15
3. 3.81
4. 8.31
5. 3.81
6. 4.25
7. 4.16
8. 4.15
9. 4.16
10. 3.52
11. 0
12. 3.70
13. 4.15
14. 4.14
4558 (upper one)
1. 6.98
2. 3.54
3. 4.11
4. 0
5. 4.12
6. 4.15
7. 1.60-1.25**
8. 8.31
4558 (down one)
1. 1.60-2.35
2. 4.15
3. 4.11
4. 0
5. 3.54
6. 4.11
7. 2.14-7.65
8. 8.31
4013
1. 8.31-4.10
2. 0.00-4.45
3. 0
4. 1.61-2.47
5. 0
6. 7.65-2.07
7. 0
8. 0
9. 8.28-4.07
10. 0
11. 0.00-4.29
12. 8.28-4.10
13. 8.28-4.10
14. 8.31
|
My JFET booster 2N5457:
G - 0.00
S - 0.06
D - 5.19 (with the trimmer counterclockwise) - 6.64 (with the trimmer at half)
I can see some difference, but I don't know what that means.
Necropost alert.
So I've got this modern version all soldered up, but nothing's going right. I've put it away for the time being and will attack it again maybe next weekend.
Elijah-Baley, did you manage to find a schematic for this version?
I don't think you can find this version schematic, but some schematic of the Multiplexer Octave yes.
My built is abandoned, now. I just solved the pop noise using the bypass switch. I used to bypass completely the circuit, the original isn't like that, tut it worked.
The effect works, but there's too hum, and the volume is still too low.
Cheers for the quick reply.
Yeah, I'm already thinking of just killing this build. Annoying, but a learning experience.