trinityamps.com

I have now finished my Triwatt build and it sounds fantastic!
But I have problems with hum/buzz from V2 induced by the OD relay board.
Apart from this the amp is very quiet and the noise floor very low but the hum is louder than I think it have to be.

I have performed the following tests:
1. disconnected the 6.3 V AC heater cables from the OD PCB and powered the OD board from a 9V battery. Result same hum level as when powered from the heater supply.

2. When battery powered grounded the OD board. All hum disappears! A very low hum can be heard on full volume, same as with no OD board installed.

Conclusion:
The OD board needs some form of ground reference. But how to do this when it is powered from the heater supply?
When the OD board is not grounded the whole board acts as an antenna for hum and the cables to the front panel OD-switch are very sensitive. Whit the card grounded this is not a problem and you can touche all cables without inducing hum.

Any tips what to do? Is it verified that the new OD-board works without inducing hum?

/Bjorn

Give me a little time to test this. I am workng on one right now.
We do have a seperate transformer we can send if necessary. No charge.
This is a new design.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Beautiful job on the build too!!

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Riise, I’m in the process of building a Triwatt with the same board, does the hum exist at all times or just when the footswitch In engaged? I’m not too sure how I should proceed with my build. Does the pull switch function still work or does it still hum. Sorry about the stupid questions.

Give me a little time to test this. I am workng on a build right now. In a week or so There will be an answer.
We do have a seperate transformer we can send if necessary. No charge.
This is a new design.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

bbrodie, The hum appears when you turn up the master volume, regardless if the footswitch is connected or not. The hum is proportional to the volume setting and doubles when the overdrive gain stage is engaged and the overdrive volume is set to full.
The pull switch works when the footswitch is disconnected. There is no difference in hum level with or without the footswitch connected.
I've had no time to investigate this further. My plan is to exchange the voltage regulator and the relay for 3V versions and supply the card from only one side of the filament winding and the center tapp (grounded). I will order the components tomorrow and return with the result when tested.
I suggest that you wait for Stephens answer. I'm convinced that he will come up with a much more elegant solution.

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Bjorn

Thanks so much for the reply!

If we test and we have to send a small power transformer for this, it will be able to be grounded.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

So we did some testing and it seems we will need to send a small relay power trasnformer. We cant get a ground reference. Although we didnt put the new board iinto an amp yet, we know a seperate transformer will work. We will send detail out shortly. Anyone with this issue should let us know to make sure we cover you. We will also look through our sales records.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

All tested with the extra mini power transformer and ready to go. Will send out docs and parts this weekend to those who still need them.
Below is a picture of a current build with the new mini transformer installed at the powe end of the amp.



Riise also developed a working solution we will try when we can get the parts in.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Nice looking build. It looks very familiar . Wondering if you may have seen photos of my build on posts from some years ago?

Riise/Bjorn, I just wanted to say thanks for the great internals pic--I found it very useful in my just-completed Triwatt build. Your wiring is absurdly neat, and although I'm really not capable of that level of control, your pic did elevate my game when it came to keeping things clean and orderly! One thing I have to ask that puzzled me from your pic--the 2 red wires coming off the right side of the progressive power switch appear to have their downstream connections reversed compared with the layout diagram--is that something related to the OD footswitch, or was it done with some other intention, or does it just not matter which is which?

Riise, I just wanted you to know your build inspired me to make it look as good as you have done. Thanks for doing a fantastic job. You can check out my build at "Triwatt build from Texas"
Thanks
Mark

OK I'm almost there and ready to install OD Kit with little tranny.
I'd rather have the LED on the pedal switch rather than glowing inside the amp.
Is there a way to do this?

Thanks for the photo. Looks good so far.

Try wiring an LED in series with the switch on the foot controller. No resistor. Doesn't matter which side of the switch you put the LED on, as long as the cathode is towards 0-volts.

This works at 12 volts. Not sure if it will work at 5 volts. I don't have any 5-volt relays to test it. The LED drops the voltage by about 1.2 volts so a 5-volt relay may not pull in.

The footswitch is part of the relay's ground wiring. +5 volts doesn't run to the footswitch so there's no other way to install an LED.

By passing the LED on PCB should eliminate the voltage drop from there, compensating for the FS LED .

On my tramp P.A.B. footswitch, I use a 3PDT with battery cell for the LED. It works fine.

I don't have the schematic for the relay board, but the LED probably isn't in series with the relay, so no voltage drop there.

Yes, using an extra pole on a footswitch to light an LED is a fairly standard thing to do. In this case, as you said, that would need a battery and maybe a switch with more poles. Not as elegant a solution as using what's already there, but if putting an LED in series with the switch doesn't work, you could certainly do it.

Hi all! New to the forum but not to amp design and building.

I’m currently building a Trinity Amps TriWatt and have a question, most specifically for Riise, but anyone who can answer, please feel free to chime in.

My question relates to hookup of the relay board and how that changes wiring on the Overdrive pot. I’m trying to sort out whether the jumper wire (orange on the layout diagram) from the mixing resistors to the back tab of the switch on the Overdrive pot is still needed. Likewise, the coax from the middle tab on the switch to the grid. Looking at the schematic and tracing the connections on the relay board suggests not. Also the gut shot Riise posted seems to support that. However, the pic Steven posted shows those connections present.

Thanks for any input!


BTW. I’m posting videos of my build to my YouTube channel if any of you are interested in checking it out. You can find my channel here, https://youtube.com/user/TheJagJones.

Actually, I see now that Steven’s does not have the coax on the middle tab of the switch so, the orange connected to it does not do anything. Got it sorted out now. Thanks