Tonepad Ross Compressor - Problem with my build

Started by Flareless, September 25, 2015, 04:15:02 PM

Previous topic - Next topic

Flareless

Hello.  I've just completed a Ross Compressor from Tonepad.com.  Very cool company!

Anyway, I've got it all wired up, however, while the bypass works ok and the guitar can be heard through the amp, activating the pedal makes everything go silent.  The LED becomes active but that's about it.  I've tried adjusting the trim pot and the potentiometers but no go.

I should mention I've very new to building electronics  :-[ .  I've take my multimeter to the board and found voltages where they seem they should be although I'm really not sure what I'm looking for.

The build went pretty well.  My soldering skills are semi-decent.  I used Tonepad's BOM to get the part numbers from Small Bear Electronics but some look different from build essays on Tonepad's site.  I'm including some photos in this post.  The orange radial capacitors are 1uf 50v and the blue are 10f 35v.  I noticed that the trim pot I'm using has only 3 leads and that there are 4 extra holes on the PCB that aren't filled.  I don't know if that's an issue.

Any help would be greatly appreciated!  Thanks.

Images;









mcknib

#1
Check you don't have your IN and OUT mixed up might sound daft but something as simple as plugging your guitar lead into the pedal OUT jack and your amp lead into the pedal IN jack would have the effect (or lack of it) you are describing i.e bypass / no effect and it's very easily done when the pedals not boxed up.

If it's not that check your IN and OUT wires from the PCB to the 3PDT switch have continuity looking at your 3PDT image it looks like you have all the wires going to the right place but just make sure you have good solder contact on the switch lugs by re flowing the solder.

Hopefully you don't have any heat damage to the transistors but checking your voltages with those below should give you an indication if that's the case.

Those extra holes around the trimpot should be empty and looking at the build docs you have the trimpot soldered to the correct pads albeit one looks like it needs re soldered there's not a lot of solder on it, the top one as you look at your solder side image.

Here's some voltages for comparison from a working Ross Compressor build although not the tonepad one but with the same layout using 2N5088's for all of the transistors

Power supply 9.12

all 2N5088

Q1
E 2.06
B 2.39
C 7.06

Q2
E 2.73
B 3.24
C 6.42

Q3
C 8.98
B 0.06
E 0

Q4
C 8.85
B 0.07
E 0

Q5
E 2.89
B 8.68
C 9.12

CA3080
1. 0
2. 4.66
3. 4.66
4. 0
5. 0.65
6. 3.27
7. 9.12
8. 0




Flareless

Thank you tons for the tips!  I'll check out your suggestions tomorrow and let you know how it goes.

Flareless

I've checked all my solder connections, double checked that the correct parts are in the correct places and the compressor sort of works.   I get a clean bypass with the switch off.  When I activate the pedal I get sound, however, I have to turn the sustain and level potentiometers most of the way up.  The volume level out of the amp is significantly lower than when the pedal is off.  About 20 decibels according to a sound level meter I have on my iPhone (SPL).

If I turn either pot down from about 3/4 the sound from the amp is gone.  I'm also getting a bit of noise.  Sometimes.  The readings I'm getting from the CA3080AE are not the same as the ones posted.  I'll measure them tomorrow and post them.

I'm obviously doing something wrong.  I'm just not sure what it is.

mth5044