Adding outboard FX Circuit to RM22 Head Complete!!

[pettymusic]

Hello all,

I put together a BBE Sonic Stomp-ish circuit. Since completion, I have no reason to turn it off. (Sounds amazing!)

I am thinking of ways to add it internally. I have plenty of room for the 2 Pots in the rear (See Photo). Which is fine because I do not adjust them often.

There is also plenty of room under the hood. The PCB itself is only 2" square.

Anyone have any thoughts on where to integrate the input/ output?

I was thinking the FX loop. May have too add extra input or output jack?

What about the 9v?

Looking at the schematics, with my limited brain power, that I got from Randall I cannot locate 9v any where for tap.

I could install the power connector next to the pots though.


Thanks!

 

[mikegyver]

I've never opened up an RM22, but it looks like you will be able to accomplish this just fine. I wouldn't go through fx loop because it switches on and off with a jack inserted.

Don't look for a 9V tap on the board because I think it will require too much current and will cause problems, just hook up a 9V adapter directly in the mains or install a 9V battery compartment that is accessible to the outside.

If you want it on all the time, just wire it up to the existing input jack as if it were one continuous chain, Input jack-> BBE stomp unit->input signal to preamp. Any adjustment pots can be extended or drilled through the chassis on the front or back panel (or wherever there is room).

If you need to turn it on off, and it's true-bypass, then just wire a toggle to interrupt the 9V power source to the pedal circuit. If it's not true bypass, then you might have to deal with a degraded signal, use switching jacks or just have the pedal on all the time.

Another idea is that you might want to just wire it into your guitar instead. It's a lot easier and safer to drill a pickguard and install a 9V battery in your guitar than deal with amp guts.

Be careful!

 

[pettymusic]

Thanks for the great ideas mikegyver!

Interesting. I haven't thought about wiring to the input.

It sounds best when between preamp and power : input>FX Send>effects>Bloviator/ BBE>FX Return>

It is a serial FX loop. I think I could wire it to the FX Return, I would just have to install 1 extra 1/4" jack. Therefore, it would have FX Send, FX Return, FX Return w/ the desired FX Circuit in the signal path.

This way, if I want to bypass the circuit, I simply plug the end of FX chain to the original FX Return Jack. When I want the FX circuit, I plug the end of my FX chain to the newly installed 1/4" jack.

So, to sum up

Drill 4 holes total to the back of the chassis

1 x for 1/4" Jack
2 x for 16mm pots
1 x for incoming 9v power supply

I will have to play around with it tonight and make sure this is the best place in the signal for it. If my memory serves me, it did not sound as good before the input.

 

[mikegyver]

I think I see what you are talking about now. You are trying to build this pedal into your RM22?

http://www.madbeanpedals.com/projects/Bloviator/docs/Bloviator.pdf

The serial FX loop on the RM22 I'm guessing has switching 1/4" jacks to where they bypass the normal guitar signal when a cable is inserted into either jack. You can take advantage of this by putting it permanently into the NC (normally closed) intact standard guitar signal path. If you want to switch it on/off, install the 3PDT switch and just follow the diagram and use the FX loop out as the "input" and FX loop in as the "output" signal. Make sure to ground both "sleeves" that would normally be grounded from having a cable inserted.

This way, you can turn the pedal on/off like normal using the stomp switch (or use a toggle instead). You can also bypass it completely (so it doesn't color your tone, even in the "off" position) with a jumper cable. AND you keep the stock FX loop feature so you can use other effects, tho this couldn't be used at the same time as the bloviator.

So, this is what I would do. Drill 3 or 4 holes: 2 tone pots, 1 switch and one LED (optional). Be sure to keep power sources away from signals to minimize noise. You don't need to install another input jack.

To wire the power, get the 9V wall wart, tie that into the normal 111/120V AC from the wall that the amp uses. Splice the wall wart wires directly to the new PCB or attach a battery compartment on the back and wire it that way.

OR, this might save you lots of trouble (an external solution):

Just build the pedal like normal with the stomp box case and everything. Wire the power like I said, but keep the end of the wall wart power supply with the jack attached. Wire the supply directly into the 110/120v internal wall power that the amp uses, keep the 9V jack adapter attachment and feed that out the amp somewhere. Bolt the pedal to the head box (through the pedal itself or use a bracket) somewhere on the backside under the transformers or tubes. Run two normal cables from the in/out of the FX.

This way it is completely removable. You can unbolt and remove the pedal, it will have a permanent power supply (no batteries), it's one unit, you can unplug it from the signal, everything stays 99% stock and it's less of a hassle and less dangerous

 

[fuzzboat]

and when it comes time to sell them "it"


you'll be kicking yourself in the head , believe me BEEN THERE DONE THAT !

mount the pedal in the head (silicone ?) - run it off the battery

make an external fx loop (out of male/female jacks and perf board) and hardwire the external fx loop males to the pedal instead - (NOTE space the males so they can plug into randall's fx loop jack's
(that way all the wiring stays outside of the randall )

for ON/Off, add a switch

you wire the male jacks leads and females jack leads to a DPDT switch so you can switch the BBE in/out

the "hardwire" to the pedal is easier to do & remove
:roll:

for appearance & durability silcone the board and find an appropriate
enclosure

mount the pedal in the head with a removable adhesive & run the BBE off the battery

sounds like alot of work but its easier and safer than operating on the amp

 

[pettymusic]

and when it comes time to sell them "it"


you'll be kicking yourself in the head , believe me BEEN THERE DONE THAT !

mount the pedal in the head (silicone ?) - run it off the battery

make an external fx loop (out of male/female jacks and perf board) and hardwire the external fx loop males to the pedal instead - (NOTE space the males so they can plug into randall's fx loop jack's
(that way all the wiring stays outside of the randall )

for ON/Off, add a switch

you wire the male jacks leads and females jack leads to a DPDT switch so you can switch the BBE in/out

the "hardwire" to the pedal is easier to do & remove
:roll:

for appearance & durability silcone the board and find an appropriate
enclosure

mount the pedal in the head with a removable adhesive & run the BBE off the battery

sounds like alot of work but its easier and safer than operating on the amp

Good ideas!

I have a small enclosure on order from Mouser. Silicone is possible. I'm thinking maybe the adhesive style velcro. You know the kind used to mount pedals to pedal boards.

I'm thinking I will build the enclosure with the usual 1/4" in/out. Since it sounds best at the end of the FX Loop it will work mounting (with the velcro?) just under chassis.
Maybe mount it so that the 2 pots are accessible in the rear.

Sure am glad to be getting some input on this idea!

I just ordered the enclosure yesterday. I'll keep everyone posted on the progress. It may take some time. My 3 mos old and 3 year old girls keep me pretty busy lately.

 

[mikegyver]

I personally wouldn't use silicone because it will leave a leave a residue and/or be obvious when removed or it would be too soft and not hold well.

I've used the industrial-style velcro stuff and it works really well. The only way it will fail is from excessive heat where the adhesive gives out, so if you play a lot of outdoor shows in the sunshine in death valley then I would drill holes and mount it with a bracket.

 

[pettymusic]

Well, finally finished this little project.

Thanks mikegyver and fuzzboat for the advice! Going external was far better than my original plan.

I ended up using those little 3M Picture Hangers.

Maybe I'll paint it black one day. No matter. No one will see it anyway.

 

[GtrGeorge!]

cool stuff...I always thought the rm22 was under appreciatted...it was as if Randall finally was going to really meet the market..
and then...it was over.
I have wanted a deluxe version of the rm22...with room for 3 modules etc... AND Midi..which somehow used to show up in product descriptions of the rm22.
but its obvious thats to much to ask.

GtrGeorge

 

[pettymusic]

cool stuff...I always thought the rm22 was under appreciatted...it was as if Randall finally was going to really meet the market..
and then...it was over.
I have wanted a deluxe version of the rm22...with room for 3 modules etc... AND Midi..which somehow used to show up in product descriptions of the rm22.
but its obvious thats to much to ask.

GtrGeorge

I hear ya. I just keep doing different things to my tone and it just keeps getting better. My only complaint is while it sounds amazing for home recording, especially since I can beef it up with IRs, it is on the thin side when playing live. I will eventually get this problem resolved.......or blow it up trying!! :twisted:

 

[Jacksauce]

cool project! tried either of the MDA board upgrade offerings? may get you clearer and less thin 8)

 

[pettymusic]

cool project! tried either of the MDA board upgrade offerings? may get you clearer and less thin 8)

Actually would love to. Rob, told me it won't work for the RM22 and now that I think about it, I never heard back from Anthony about it. I just dropped the idea once Rob broke it down for me.

I made it sound less thin by getting a 7 string anyway! \m/