Night Train Footswitch Mod

[voxted]

Hi folks, I have not modded my Night Train, but I would like to replace the toggle switch which takes it to "Thick Mode" with a female 1/4 jack that would attach to a footswitch that would allow me to use the "Thick Mode" for lead or heavier rock. Has anyone done this or know what I would need to do?

Regards,

Ted

[Paragon]

According to the schematic
http://www.prowessamplifiers.com/schema ... 20NT15.pdf

That switch is a DPDT (6 connections) so a single 1/4 TRS jack would not be enough.

One possibility would be to change that switch to a DPDT ON-OFF-ON switch and use the off as the external footswitch setting. You would need to use a connection like a DIN or something of that sort with at least 6 conductors and have that go to the footswitch.

The only thing I am unsure of is the voltage or current that Thick switch has going through it. I wouldn't think it would be much since it is only after the first half of the first preamp tube but you wouldn't want to use a cheap cable for it. Not sure how much signal degradation we are talking either.

You may be better off with a relay or something.

I'm not sure how other amps handle channel switching or boosting but if you know of one that does what you want to do, you can find a schematic and see how that ones is done.

[retrobob]

I would like to replace the toggle switch which takes it to "Thick Mode" with a female 1/4 jack that would attach to a footswitch

Great idea! Thanks to Paragon with the schematic link, this would be relatively easy using a relay. I can draw a circuit solution for this a little later when I have more time.

WARNING!! Severe shock danger!!
This is a tube amp operating at high voltages! The filter caps must be drained of power before you work on anything inside. Most times this can be done by unplugging the amp from the house power source and leaving the speaker connected to the amp with the amp set in the on position (not standby) for at least an hour. Always make sure the A/C (house) power is disconnected and test using a volt meter set to the 600 volt scale at the el84 tube socket pin#7 (pinout shown only applies to el84) and ground to be sure the caps are drained completely before you work on the amp.

el84pin#7.jpg (24.56 KiB) Viewed 1137 times

[Paragon]

I think the relay option would be the best for sound quality.
I think you could use a latching relay with a flip flop circuit. I will check on it.

[Paragon]

It help if I think about things for a while. Simplest would be to use Two OFF-(ON) momentary (can be SPST) pushbutton switches (Carling brand switches look like nice ones) in the foot pod to control a the relay ( use the +-3V heater supply) when an additional switch is moved into position and the footswitch is plugged in (should be able to use a standard TRS connection)

Leave the thick switch as is, tap into pin 1, 3, 4, 6 of switch connections and go to a relay. Cut the 2 and 5 connections from teh switch. A DPDT switch will have the R35 pin1 connection and ground as center taps and switch between the relay and the current thick switch.

The relay dual or single coil but must be a latching type and coils need to work off 3 volts. The lower the coil current the better.

Single coil relay:
A TRS jack (must be isolated - use a plastic housing) and plug (standard 3-conn stereo plug) will go to the foot pod. The 3 connductors would be +3V, -3V (both taken from the heater DC parts of the amp) and signal. One switch would connect +3V to the signal, the other -3V. Signal is connected to the relay coil which is grounded.

Double coil relay:
A TRS jack and plug (standard 3-conn stereo plug) will go to the foot pod. The 3 connductors would be Coil#1, Coil#2, and Ground. One switch would connect Coil#1 to ground, the other Coil #2 to ground. The other side of coil #1 would be to +3V, Coil #2 would be -3V.

One foot switch will switch to Bright, the other will switch to Thick

Relay will be mounted in the amp.
The only thing in the footswitch would be the two switches.

[Paragon]

TRS jack must be isolated so I suggest using a plastic housing with thread and nut to attache to amp.
I would suggest having the footswitch inserted in jack only when power is OFF as well as flipping the added switch when power is OFF

You will have too see which coil control which way on the relays to see which button controls Bright and which controls Thick.

[Paragon]

BTW, if you wanted LEDs, it would be possible to add them using a circuit I am working on for the VFS5 footswitch. You would just need to use DPST or SPDT momentary pushbutton switches in the footpod. It could run off the same power so no need for a battery.

[voxted]

I have a foot switch for the AC15CC amp.. It has two switches in it. Could that be used to do this Night Train mod?

[Paragon]

I have a foot switch for the AC15CC amp.. It has two switches in it. Could that be used to do this Night Train mod?

It might be possible. I would need to know what kind of switches are in it and how they are connected to the plug. Might be able to adjust this schematic to accomodate that. Let me know if they are momentary switches or if they are clickers (latching type) like stompboxes and perhaps some photos of the insides of the switch.

If they are latching switches (I think tehy are since the control tremolo and reverb) then only one switch could be used, a non-latching relay would have to be used.

I think the VFS2 footswitch would work (I'm pretty sure it has momentary switches - non-latching type) but does not have any LEDs (could be added)

[voxted]

I tell you what, pick a footswitch that you know will work and I will buy that and then use the schematic that you think would be easiest to make the mod... That should make this easier.

Thanks,

Ted