Simple remote Loop Switch

[Minty]

Ha!

Why had I not thought of that!!!!!

Yes, it works. I was expecting it to be "off" by default until the GT8 shorts to 0v. It is infact 'always on' until the GT8 shorts it. (the GT8 simply closes the circuit)

This is ok, because I can set the GT8 to suit.

Power...well, I'd still like to use one power source, so your recommendations on that would be appreciated. As mentioned before, the GT8 supply gave me 16.8 on the meter, so a V loss can be tolerated by adding a rectifier.

But, for now - I'm happy feeding it 9VDC, I have a supply ready and willing.

NOW, to test this 'in situ' and hope for no strange effects to the signal..


Stand by.....

[Minty]

Would you believe it. It works!!!!!   

Although, as I initially feared, there is a lot of buzz, not sure if it's ground loop (I'm using a 9V battery to power it).

Suggestions?

[duck_arse]

a buzz? not the relay buzzing I hope.

is there buzz when signal goes straight thru, and when sent to fx, or one or the other? and did you isolate the gt8 control from the signals ground?

nearly time for photos of the work (but it's bedtime for me now).

[Minty]

Yes, there is a lot of buzz (loud too).

I was careful use two seperate common grounds (one for power/relay, the other for guitar signal).

My soldering is atrocious (it's been many, many years. Pics below.

The buzz is there even if only this is plugged alone in to the amp - no RAT pedal attached. the relay position makes no difference. There is no buzz if I remove the power supply.

[duck_arse]

well, let me say, you need soldering practice.

it is best practice to stick a single wire through a single hole, and link all the pads of joined wires together with tinned copper wire. then you at least have a chance of removing a single incorrect wire withoutout destroying the board. stip the wire, give the bare ends a twist to keep the strays together, then tin with solder so they can't fray. then stick them through the hole and solder, you can bend them over to buss them together if they are stripped long enough.

and it might be easier to make those busses with bare tinned copper wire instead of insulated. there is no shortage of space on your board, so they shouldn't bump together anywhere.

as for the buzz, I think you answered the question. "no buzz if I remove the power supply." you can't be connecting your AC supply to this without the rectifier/smoothing you don't yet have. and the battery is DC, no buzzing there. and the circuit shows (well, we know) that there is NOTHING common between the audio and the power needing parts. the relay contacts are in a world of their own, that's why it's there.

something from the relay powering part is connected to the audio part. are those panels metal? your dc jack is wired .... ? backwards?

[Minty]

At the moment, it is only a 9V DC supply and those end panels are plastic.

Should I try a meter on the relay to see if I got voltage or continuity with the power circuit?

DC Jack (backwards?) Not following you 100% here. The socket is wired with positive centre (to match the supply I'm using).

If you think it's best I start this over, let me know - I'll try strip board instead.

[duck_arse]

well, you can meter it (everything, just about), or pull all the wires off carefully, then add the flyings through the top and the bussings on the bottom. it should then be a little easier to see. you need to find where the common between audio and switcher is.

if you are meter-demonstrated sure that the centre pin of your supplies plug is positive, and dc, ok. it is backwards to the general plug wiring, I believe, and will cause smoke on other brands of pedal. seeing your relay works, your box must be wired right.

get the lead that plugs to the next stage. unplugg everything else. power on, and plug that next stage plug into each of the audio sockets. do it buzz in all? when the relay switches to other, still in all?

I'm baffled.

[Minty]

This is likely to be just bad workmanship on my part.

I'll order some stripboard and rework it, at least with stripboard I don't have to bus anything. Sounds a lot easier.

[duck_arse]

no! no stripboard, you've got plenty space there to shift wire runs, the parts are in (and working, remember), just the wires the problems. in my opinion. perhaps if you restrict black wires to DC ground, red wires to DC +, and green wires to audio grounds.

I use vero, and it's no fun.

[Minty]

What is Vero - is that strip board?

I've already bought it (it's on the way). THIS is what I bought.....and I already did a new plan in DIY Layout Creator (before seeing your response). Is it really that bad? it looks far simpler to me, neater too.

You'da boss here so I'll go with your direction, I'll have to see if I can get more green wire.

Just FYI, I drew the stripboard layout including the power regulator, and then removed it, ready for when we are OK to add the recitifier and filters. The regulator would go on (what is below) the 9V rail, whiel we could add the rectifier and filter in the space above:

[duck_arse]

well, that is indeed vero/stripboard. you understand the track-cuttings priciple then? I suppose for a circuit like this it will be alright, but I hate all the wasted holes and space when doing larger than 1 transistor.

anyway, if it were me, I'd cut that sized vero in half, maybe thirds even. I'd place the relay, contacts outermost, either top or bottom of the board. this means there is nothing but audio connections above/below the coil connections, less chance of wiring trouble. then I'd re-arrange all the resta the stuff to fit, with maybe the red lines "upper" and the black lines "lower", as fits. (and those slanty caps!)

did you find anything w/ the meter, or did you pull all apart? there must be some audio connection not being made, or some non-audio section (can we agree on a name for all the stuff driving the relay coil?) connection that is being made.

[Minty]

I haven't had the chance to  test any connections on the existing unit yet. I will tonight.

I suppose we can call the connections driving the relay coil the "Power Section" and the Audio connections "Audio Section"?

...and, is there anything wrong with slanty caps? 

[duck_arse]

"well if you don't know, I'm certainly not going to tell you" I think is a quote from becker, or women in general. ocd affects us all differently, I'm finding. for me, things go north-south or east-west.

power section it is. what will we call the voltage regulator part?

[Minty]

The Regulation Section I suppose., and then the rectification section.

Ah, yes, OCD. I have it in some ways but not all. I understand your concern.


OK, I've run the meter across all relay terminals, and jack socket tabs. I have continuity only where I should. There is no power bleeding in and there is nothing grounding to earth where it shouldn't.

Step by step:

• Amp on - no noise
• plug in guitar lead to amp - standard hiss (as - no guitar connected)
• plug lead into "to next stage" - hiss increases
• touch lead jack shroud - hiss decreases but still apparent
• plug in 9VDC but wall switch OFF (no power) - buzz begins
• switch on power - buzz hugely amplified
• switch off power - buzz returns to quieter state, squelchy noises as caps discharge

Sound like a grounding issue? Should I try running the negative terminal off the relay direct to 0v to eliminate the "quietening" part of the power section?

...and here's a condensed version of the strip diagram:



Better?

[duck_arse]

I'm completely baffled now. do the plugging in test again, WITH NO POWER. just plug the lead to the amp into each of the 4 jacks, I know it won't make any humming, but ....

can you hack up a battery to the dc in socket, instead of wart power? it looks very much like your supply is the problem, but when it's off as well?? try wiring an electro, 22 or 47 or 100 or 10uF, whatever you have, cap (+) to board V+ and cap (-) to power ground. see if that improves the humm w/ wart.

that's a much nicer layout. how come C1 is so small now? all those tracks below the Q and left the relay are spare, you can run those scrunched parts up and then link back if you like.

[Minty]

Before I try adding the electrocap, here's a vid of the issue.

The unit (I'm calling it the Rat Trap, by the way) fully connected with the exception of the rat itself, I've run a patch lead from "FX out" to FX Return". Before connecting the power, the unit doesn't add any hiss to the standard 'amp noise, but a quick swap shows that it does change the pitch of the hiss slightly.

Anyway, at the start it's all connected for audio signal only (no power, no GT8 switch cable). With the GT8 off, it's 'normalish'
Power on GT8, noise gets worse (still no amp control or any other connection from GT8)

@0:12 - I connect a 9V BATTERY
@0:20 - I connect the GT8 switching cable
@0:24 - I cycle the amp control button on the GT8 to illustrate the difference in noise between 'on' and 'off'.

I'm thinking this is a grounding issue, the amp and the GT8 are both fed from the same power extension. even before I connect the GT8 amp control lead, the noise is greater when I simply switch the GT8 on. Ground Loop?

None of this is representative of the racket that happened when I connected 9VDC from a transformer. That was insane!



Regarding that condensed circuit, C1 is smaller so it'll fit across 2 tracks (no more slanty caps!)

[duck_arse]

hughes&kettner? you're not the bloke that was going to bring his floorbox around to get fixxed, and has never shown up are you? what model is that? his was a triamp mkII.

my connection does not lend itself to the watchings of utubes, I'm happy to say, but yours was so funny instructive I watched it twice.

the problem, as I see from your circuit diagram (not your real life rat trap, excelllent name, full points there), is that there is NO connection between the audio section and anything else to cause a loop. so, it seems the loop, if that's what it is, is being generated by the other stuff. and it all starts with the gt8, from all your sequence postings.

so. put the gt8 in another room for a minute. make it so you can CAREFULLY short across the rat trap gt8 jack to un-switch the relay, open to switch. a push-button switch, or a patch-lead and paperclip, like that. and the 9V battery to power the relay. add the fx patch as before and an in something and an out something. what happens? humm?

and did you add the electro? I'm off to look for a gt8 schem.

[Minty]

No, not added the electro yet, won't have a chance now until Saturday.

I'm not the other H&K Guy, mine's a Tubemeister 36.

Forgot to mention, without adding the GT8, even without the GT8 on, I've already did the shorting exercise. lots of humm/buzz, different pitches when open/closed. But I did that with the Rat Trap sitting on top of the amp. I'll try it with 6 metre leads and see if it makes a difference.

Thanks again for your constant attention here, glad my video amused

[duck_arse]

how to do perfboard:


!!. after some many years, maybe.

I went looking for a circuit, saw a picture of a gt8. bloody hell! and then started swearing at the innernets connection, because I couldn't get the .pdf to download (don't even know how big it is) before my patience expired.

interesting results from your shortings.

[Minty]

I placed a 47uF electro across V+ and 0v. Not much, if any difference.

longer audio leads, no difference.

I did note one thing though, even with wart power, when turning the volume knob on the guitar down the noise changed (kinda like a wah or tone control), and when the guitar volume knob was in the 'completely off' position, no noise.....no noise at all.