Relay problems in Tweed Overdrive Special

[daveyajd]

Hello all,
I recently completed a build on my second amp.


Original thread here: http://el34world.com/Forum/index.php?topic=19513.msg215999#msg215999


Everything went pretty smooth. My problem is that the Overdrive channel is not producing any sound. The clean channel plays perfectly. No noise or buzz, motor boating, weird sounds, etc. It plays beautifully! When I switch over to the OD there is no sound. It seems to me that maybe I have my relay wired incorrectly. I am using Doug's relay and PS. Attached are the schematic, a couple pictures and my voltages. Any help is greatly appreciated.


Aaron

[sluckey]

Do you have 5V across the relay diode when the relay is switched on and zero volts across the diode when the relay is switched off? Can you hear the relay click when you turn it on? You may need to put a long screwdriver blade on the relay and stick the handle in your ear to hear the click.

[daveyajd]

Yes I have voltage when switched and the relay sounds like it is switching.


Aaron

[sluckey]

Then the contacts are probably wired wrong. Study this pic...


I've attached the schematic with pin numbers to show the correct wiring for the relay contacts.

[tubenit]

I wire my amps up with normally closed being the OD channel engaged.   And normally open means the clean channel alone is engaged.

I may be incorrect in this, ............... but my understanding is with the OD engaged in the normally closed that the switching would be quieter?
I may have this backwards in my thinking, but my amps are pretty quiet at idle and when switching.

So, with my thinking,  this is how I label and wire up my amps with clean/OD relay switching.   

Note that Sluckey and I have simply labeled the (manual) mini-toggle switch poles of normally closed and normally open differently.  There is nothing incorrect in how he labeled it.  He simply has normally closed to be open where I choose to have normally closed be OD engaged.

With respect, Tubenit

[tubenit]

I've tried to draw the Hoffman relay into the TOS Hoffman style layout for you.  CHECK for ERRORS!   And please compare this carefully with
the schematic.

Note on the Level pot (usually called a pre-LTPI master volume) how the clean goes straight into the Overdrive & how the Level pot controls the clean volume going into the LTPI.  Look at the schematic for a better visual.

with respect, Tubenit

[daveyajd]

Thank you guys for the replies. I can see that I have a couple of wires on each side of the relay that need to be reversed. I will swap these this evening(hopefully) and report back. Tubenit, if I understand you correctly when your relay coil is energized you are on the clean channel right? Do you have an LED wired into your switching? If so how does that work? Mine is wired so energized powers the LED which lights up to signify OD. I understand what you say about quieter switching, just curious.


Aaron

[sluckey]

How would I wire the relay contacts? Should I wire the contacts so I'll be in clean mode when the relay coil is de-energized? Or should I wire the contacts so I'll be in OD mode when the relay coil is de-energized?

I would let the mode of playing determine the answer to those questions. I would not be concerned with noise (if any)that the relay may cause. If I will be playing mostly in clean mode and occasionally shift into overdrive then I would wire the contacts for clean mode whenever the relay coil is de-energized.

[tubenit]

Tubenit, if I understand you correctly when your relay coil is energized you are on the clean channel right? Do you have an LED wired into your switching? If so how does that work? Mine is wired so energized powers the LED which lights up to signify OD. I understand what you say about quieter switching, just curious.

As Sluckey alluded to,  I play mostly in the overdrive mode so this is my "normally closed" mode & my LED light on the foot switch lights up when in the OD mode.  When I switch to clean mode, then the LED light is off. 

With respect, Tubenit

[daveyajd]

Ok. I have moved a few wires around with mixed results. I wired it up according to Tubenits TOS insert above and all is working......but backwards. I knew this would happen but at least it both channels seem totally functional.


I tried switching pins 11 and 9 on the relay thinking that might do it but that gave me no sound. Do I need to swap a couple wires on the other side as well? Seems like a simple fix and I'm sure it will get resolved. This seems to be the only bug in this entire build but I need a few more days to run it through. I will post some sound bites when I can. Thanks all.


Aaron

[tubenit]

I wired it up according to Tubenits TOS insert above and all is working......but backwards

Hey, congrats on getting both channels to work!

What does "backwards" mean ?????

Does that mean the LED light is off when the OD is on?   .............. OR ............... does that mean normally closed is clean and engaged is OD?

IF the OD is normally closed, then change the LED light and not the relay,  IF you are wanting the LED light on when the OD is normally closed .

with respect, Tubenit

[daveyajd]

Sorry. Backwards for me means that NC on the relay is the OD with no LED light. When I flip/step on the switch the relay switches to NO and clean but the LED energizes and lights up.


Aaron

[sluckey]

I tried switching pins 11 and 9 on the relay thinking that might do it but that gave me no sound. Do I need to swap a couple wires on the other side as well?

You need to swap pins 8 and 6 also.

[daveyajd]

Thanks. In response to Tubenits post: how would I power my LED without the relay diode energized? I will poke around on it tonight.
According to my wiring notes for this relay it seems I have had it wired like sluckey suggests (swap pins 9 and 11, and pins 6 and 8) and I got no sound at all. I'll work on it and report back.


Aaron

[tubenit]

Maybe Steve will confirm or correct my response here .............. ?

 

how would I power my LED without the relay diode energized?

I think you simply change the "ground" on the footswitch to the other side pole?  (See illustration I posted Reply #10)   It would just take a couple of minutes to try that.

I am thinking the voltage to power the LED is there and controlled or directed by the foot switch NOT controlled by the relay being engaged  (if that makes sense?). 

With respect, Tubenit

[tubenit]

I think you need to answer two questions for us:

1)  Do you want the OD "normally closed" or the clean "normally closed".

2)  Do you want the LED on with normally closed?    (vs. LED light on with normally open).


With respect, Tubenit

[sluckey]

I thought you wanted the relay to select clean mode when DE-ENERGIZED. If so, wire it like the schematic I posted. Then connect the LED (observe polarity) and series current limiting resistor across the relay coil. The LED will illuminate when the relay is ENERGIZED to select OD mode. If you want the relay to select OD mode when DE-ENERGIZED, then don't wire it as I showed you.

I'm gonna drop out of this discussion because Tubenit is showing you how to wire the relay one way and I'm showing you how to wire it exactly opposite. Either way is fine. It's your choice, but  ♫stay with the one, let the other one ride♫. Too much room for confusion with both of us talking.

[tubenit]

Hey guys,  please accept my apology.  I was not trying to confuse things but maybe I was confused in what daveyajd was wanting?

I think you need to answer two questions for us:

1)  Do you want the OD "normally closed" or the clean "normally closed".

2)  Do you want the LED on with normally closed?    (vs. LED light on with normally open).

Give us some clarity please. 

with respect, Tubenit

[daveyajd]

Ha! Sorry this seems to have gotten so confusing. I appreciate everyone's input. I believe when I first connected the relay I imagined it working so NC was the clean channel( not energized) and switching to overdrive flipped the relay to NO and energized the LED.


I'm not set in my views on that so now that I have it wired the way I do I just want the easiest path to having the LED light up for the OD channel. Sounds like reversing the connections at the LED is the way to go?


Aaron

[shooter]

I just want the easiest path

sounds like if you don't have 99 problems, than this ain't one

[daveyajd]

So it seems that the toggle that I used is only a SPST with two poles so your diagram for changing LED wiring doesn't work. I will swap the pins on the relay tonight and see how that goes.


Aaron

[tubenit]

When you say a toggle,  are you also using a footswitch for the relay or only a manual toggle switch? 

When you get it fixed, please update us on what the solution was.

With respect, Tubenit

[daveyajd]

I have both a footswitch and a front panel mini toggle. I am going to mess with it tonight to get it figured out.


Aaron.

[daveyajd]

Alright I got it set. I swapped my relay wires 6 and 8,  9 and 11 and everything is working great. This amp is so fun to play! I think it sounds better than my first build and is really loud even though I was a hoping for a bit lower wattage amp. :) I will post some sound clips and more pics soon. Thanks.


Aaron

[tubenit]

Congrats on getting it worked out!  Glad you like the town of the Tweed Overdrive Special.

Yes, please share soundclips!  Would love to hear them.

with respect, Tubenit