Search found 183 matches

by Zokk
19 May 2020, 21:15
Forum: Pimp-My-Cheap-Pedal
Topic: can I build an effects pedal with side jacks and top jacks
Replies: 6
Views: 707

Re: can I build an effects pedal with side jacks and top jacks

I've often wondered why nobody offers this sort of layout as it would be super versatile? I'm about to build my very first pedal (a Tube screamer type clone from a kit) but I'd certainly like to have input/output jacks at the side AND the top...how would I wire them in parallel? Nobody offers this ...
by Zokk
26 Jan 2020, 21:52
Forum: Amplifiers
Topic: Sunn Beta Bass preamp schematic
Replies: 82
Views: 55262

Re: Sunn Beta Bass preamp schematic

Hello I've built a Beta Lead aswell, I used the "common" schematic. It sounds awesome! But the Level pot is quite scratchy at the beginning of the sweep, like if it passes DC signal (kind of a SHO behaviour). I don't understand the output stage of this preamp: usually the potentiometer is in the fee...
by Zokk
20 Jan 2020, 10:44
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Marlboro - Quadra Sound Blender QBS [schematic]
Replies: 32
Views: 25124

Re: Marlboro - Quadra Sound Blender QBS [schematic]

Hello the general rule with old electronics is to change first all the electrolytics capacitors, so you can have a steady power supply and make measures of the rest of the circuit clearly. Those "tropical fishes" capacitors are prone to cracking, if you want to avoid further problems I'd suggest to ...
by Zokk
17 Jan 2020, 16:54
Forum: Pedal Debugging & Troubleshooting Support
Topic: Big pedal board project 20 odd effects inside
Replies: 6
Views: 466

Re: Big pedal board project 20 odd effects inside

Modman is right, I also love your build, it's very impressive outside 8) However you should take really care of the psu, a bad choice and it will ruin the whole build with ground loops, noise, etc. As I said many cheap psus are sold as "isolated", but their are not galvanically isolated. The "right"...
by Zokk
15 Jan 2020, 20:45
Forum: Pedal Debugging & Troubleshooting Support
Topic: Big pedal board project 20 odd effects inside
Replies: 6
Views: 466

Re: Big project help needed.

Hello Are you sure the HB power supply is really isolated? I've opened other cheap power supplies and very few are effectively isolated; I mean all the regulators are fed by only one secondary from the transformer. You can check it easily: unplug the power supply and all your pedals insert some DC j...
by Zokk
24 Sep 2019, 07:13
Forum: Software Room
Topic: LushProjects online simulator
Replies: 0
Views: 4672

LushProjects online simulator

Hi
I've recentely discovered this very nice simulator, very good for small circuits and learning.
http://lushprojects.com/circuitjs/circuitjs.html

JFETs and OTAs are in the "Misc. Devices" list 8)
by Zokk
23 Sep 2019, 08:29
Forum: Pedal Debugging & Troubleshooting Support
Topic: audio probing a steel string stinger from pedalpcb
Replies: 11
Views: 778

Re: audio probing a steel string stinger from pedalpcb

Hi it does not seem normal to me to see +9.21VDC on the gate of Q2. will need the help of a more skilled person to explain that. If you have a PF5102, it is more like a J111, a chopper/fast switch. Not sure how it will behave in this circuit. You may try with 2SK117, 2N5457... N-Channel small signal...
by Zokk
22 Sep 2019, 20:05
Forum: Pedal Debugging & Troubleshooting Support
Topic: audio probing a steel string stinger from pedalpcb
Replies: 11
Views: 778

Re: audio probing a steel string stinger from pedalpcb

Hi
what is your power supply voltage? it runs at 18VDC?
What is the level of your input signal? you may try with 500mVpp or even 1Vpp.

Have you checked on C6's negative lug?
Can you swap Q2 with another J201?
by Zokk
21 Sep 2019, 19:27
Forum: Pedal Debugging & Troubleshooting Support
Topic: audio probing a steel string stinger from pedalpcb
Replies: 11
Views: 778

Re: audio probing a steel string stinger from pedalpcb

Hi yes it is normal that not all the resistors are in the audio path. first you may want to check the power supply voltage in the circuit. Feed the pedal with a steady signal (sinewave is nice ), then check the signal path with something. Here your signal path is: C3 R7 Q2 C6 C8 R12 "GAIN" Q4 C10 "t...
by Zokk
20 Sep 2019, 08:15
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

Sorry I forgot about C3, it's just a small buffer/filter on the +9V rail for the transistor power.
I'm used to always put a small cap on power lines.
You can use a ceramic, or anything cheap 8)
by Zokk
20 Sep 2019, 08:11
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

Hi yes it could be interesting to have a multipurpose vactrol board, to hack existing circuits! Let me know if you need the tracks only to make small pcbs. Your vero seems ok. The idea with the LED resistor is that when the CV input is at minimum the LED should just be at the right current to be nea...
by Zokk
19 Sep 2019, 19:50
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

Nice!
I've drawn a quick perfboard layout with its schematic/parts:
Systech exp pedal3perf.png
Systech exp pedal2.png
Let us know if it works :D
by Zokk
19 Sep 2019, 14:03
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

Hi it seems you've forgotten the LED and the LDR 8) Also the 1K resistor in the bottom right corner should be adjusted to suit the LED (but here it's connected to nothing). The LED should be connected to the emitter, by the way here's a standard pinout: https://protosupplies.com/wp-content/uploads/2...
by Zokk
23 Jun 2019, 15:07
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

One thing which is holding me down of digging deeper with this circuit, is that it is not true bypass, and i noticed that when bypassed, moving the expression pedal was chaing the dry sound... I guess this is because the audio is actually going through the filter pot, even when bypassed, so the exp...
by Zokk
20 Jun 2019, 08:00
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

Here is an example with the correct pin numbers, use an isolated jack socket:
systech exp.jpg
by Zokk
20 Jun 2019, 07:28
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

Sorry still no edit: I've messed the pin numbers in my previous message. So to be clear here is what I take as standard wiring for an expression pedal: http://www.freestompboxes.org/download/file.php?id=33071&mode=view To correct myself: try to hook (Tip and RIng) + Sleeve or (Ring and Sleeve) + Tip...
by Zokk
20 Jun 2019, 07:24
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

Have you disconnected the onboard pot when trying your TRS jack? This won't work if the expression pedal is in parallel with the pot, it should totaly replace the pot in circuit. If you have tried with an isolated socket you should be fine, the Sleeve is one end of the pot. So you can try to use the...
by Zokk
16 Jun 2019, 13:06
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

:roll: well maybe they have simply used a switched jack to connect the expression pedal in place of the pot like you tried before. You need an isolated stereo switched jack socket, so you can swap the Sleeve and Ring on the expression pedal to change the sweep direction. Remember the Tip is the curs...
by Zokk
14 Jun 2019, 12:45
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

No the vactrol and its driver are not shown. A vactrol is a LED + an light dependant resistor (more light=less resistance), so you have to know what resistance values you need, here it's around 50Kohm, so you'll add a limit resistor in parallel with the LDR to avoid huge values when in the dark (ie ...
by Zokk
14 Jun 2019, 07:25
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Systech - Harmonic Energizer [schematic]
Replies: 177
Views: 87277

Re: Systech - Harmonic Energizer [schematic]

Sorry no "edit".
By the way the pot1 is the expression pedal's pot which is more or less the standard value, 20K/25K it's ok.