footswitchable volume boost?

[iknowjohnny]

With my previous store bought amps i always had a outboard pot i'd patch into the effects loop and it was footswitchable via a relay. I have no loop in this build, tho i could simply put it in the amp. but before i do that, does anyone have a better simple solution? i just want to be able to set a pot to a volume that will drop whatever volume the master is at by a few percent and be able to switch it in and out via relay. If anyone has a better solution please speak up. Also, putting it in the amp no matter how i do it, what would the best place to take a 5-12v tap for the relay coil from w/o adding buzz or any other noise issues to the amp circuit? heaters?

[selloutrr]

if you have an spl meter you could meter resistance at a given point and back it down 3db and measure again while running test tone threw the amp and solder that value in as part of your total volume and when taken away gives the volume drop or vise versa when inserted adds a gain. tap on to the heaters or run a new power transformer for the relay and filter it to the voltage you need as long as you properly ground and keep your wires as short as possible you shouldf be fine. you could also do this passive with a 3PDT and ground a 1M resister to the send / return legs. best luck

[Jana]

see this thread:
https://tubeamparchive.com/viewtopic.php?t=6751

[iknowjohnny]

thats what i was thinking and have done before...a pot to ground after the master and a relay. Guess i'll do the same thing.

[Structo]

Or you could install the Ironsounds FX buffered loop.

It has a 10db pad switch on it or you can install a pot there and have a variable adjustment.

I have one in my D'Lite and it works great. I did not install the pot on mine.

It also has a true bypass switch in case you don't want to run the loop.

http://www.ironsounds.com/

[iknowjohnny]

Thanks, but i just want it simple. I can add it in no time and it's free since i have the few parts i'd need. i don't need a loop either because i use a small second amp as a dedicated effects amp.

[rfgordon]

Here's the variable boost I've started putting in my amps. It's butt-simple, and works great.

Disconnect the cathode bypass cap on the amp's first gain stage from the ground point. On the back of the cab (or wherever you want to put the adjusting pot) mount a 1KL pot, a 1/4" jack and a mini toggle switch. Attach the ground end of that capacitor to the wiper of the pot. Connect the one other lug of the pot to the tip lug of the jack, and connect that lug to one side of the mini toggle. Wire the other side of the mini toggle to the ground lug of the jack.

Poof!! You now have an adjustable, footswitchable boost. The mini toggle allows the boost to be on if you have no footswitch.

Also, I've taken to making my foot switches in modular fashion. I get the smallest Hammond die cast aluminum box and mount the switch and a 1/4" jack in it. That way any old instrument cable can be a footswitch cable. Use a short one when you need a short one, a long one when you need a long one, etc. For two-button boxes (which I've made for some Fender owners) I make a stereo cable.

[iknowjohnny]

I'm trying to visualize this, but i'm not sure exactly what you are suggesting. What i am hearing is that you are suggesting is to use a foot switch to toggle a bypass cap in the preamp. But all that would do is 1)- give me boost in preamp distortion, and 2)-change the amp's tone between the 2 settings. This would not do what i'm wanting at all. It would change the distortion amount and tone, and all i want is the same tone and distortion level and to just change the overall volume, just as if i reached over and turned the master up a hair. But i a Maybe you misunderstood me and thought i wanted a foot switchable distortion boost?

[Andy Le Blanc]

a pot to ground from the volume or master is simplest...... a quarter inch
shorting jack and a standard footswitch... your shorting to ground
have either the vol. or the boost adjustment be a push-pull to use when
theres no footswitch...... I done this with non-master rigs to set two gain levels
it works .... and is very simple ...... but you need to plan ahead for it on layout...

[iknowjohnny]

Well, thats how i always did it in the past and plan on doing it this time. I just wondered if there is a better way because i always felt that way wasn't electronically right for lack of a better word. In the past however i always had the pot in a outboard rack i have used for years that just houses my boss effects, tuner, and wireless. in that rack i built in a relay with it's own PSU. So i'd plug the loop into the rack and the signal was just routed out and back into the loop. i used the effects without the loop....they would go from the DI into effects and to a second amp. So the loop was only used for the volume boost. So in the rack i'd have the pot and relay making it unnecassary to mod the amp and i could use it with any amp that has a loop. I may just use it with this amp the same way instead of using the amp's PSU to power the relay. i just have to put a jack in the amp and have the signal after the master go to the jack and to the rack is all.

[mhuss]

Another simple and flexible arrangement is to have two master volume controls and switch between them (using a SPDT relay). The only downside is you have to set both when setting an overall level.

You can also add a lower value pot between the bottom of the MV and ground, and short this out for boost. This solution tracks pretty well over a reasonable range of MV settings.

--mark