Volume Box for effects loop

[vanhansen]

This may seem like an amp question, but the main interest is this little box:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=38075&item=7305008935&rd=1

Can you really do this without hurting the amp?  My Marshall has an effects loop and I'd love to have something like this.  Aside from a pot, 2 1/4 inch jacks and an enclosure, what else would be involved?   Any additional caps or resistors?

Seems like this could be a simple thing to make and use rather than spending  $300 on a power attenuator.

[petemoore]

Probably a pot and two jacks in a box.
 Maybe a little cap across the SP lugs of the pot.
 ...[    ] ... RIght sized tube amp is hard to beat.

[vanhansen]

Thanks, pete.  What value pot?  500K, 1M?  I thought about the cap too, treble bleed.

Now, to wire the sucker, you'd go jack sleeve to jack sleeve (easy), in jack tip to pot lug 3, wiper to out jack tip.  Now, how about the pot ground, just ground it to the back of the pot?  I know you'd do that for the guitar but in stompboxes, I see it going to circuit ground but since there is no circuit board, I'm assuming it would just go to the back of the pot.  Correct?

[bwanasonic]

This would not be a replacement for a power attenuator as your power tubes are still not being pushed at low volumes. What a gadget like this can help with is give you some room between 0 and *too damn loud* on your amps volume control. The THD Hot Plate goes for around $250 and is what you would need if you really want to get power tube distortion at lower volumes. That or a smaller amp :wink:

Kerry M

[bigjonny]

If you're going to do this, I'm a fan of DIYguitarist's "Solo-Pro" design.

[vanhansen]

I know it's not a replacement for an attenuator, I just don't have the money to get one, plus I just got an Epi Les Paul so the wife has restricted me from buying anymore music equipment for a while.  Good thing I can DIY.    I just can't stop using my Marshall.  It may be 100 Watts, but I love it.  I haven't been able to find a lower wattage amp that comes even close to it.

I've looked at the Solo Pro but that isn't what I'm going to use the volume box for.  From some reviews I've read about the volume box, it works well.  It's simple enough that I'll build it and see what it does on my rig.

I'm going to use a 1M pot to control the volume level.  If I need to, then I'll add a small cap on to it.

[petemoore]

With a big pot the Cap will do more'.
 The rising resistance in signal path a large pot induces, as it is turned down, attenuates highs a bit more than lows, the cap allows a lower resistance path past the S.P. portion [wiper and input] of the pot.

[vanhansen]

With a big pot the Cap will do more'.
 The rising resistance in signal path a large pot induces, as it is turned down, attenuates highs a bit more than lows, the cap allows a lower resistance path past the S.P. portion [wiper and input] of the pot.

Makes sense.  Thanks.  I'll post updates in this thread once I build it and test it out.  Won't be today though, daughter's birthday part going on at 3.  We're entering the terrible 2's.  Although, she's still my angel.

[vanhansen]

After a battle with being sick, getting over it, and all sorts of other unexpected crap, I finally have been able to make this thing.  Works great.  Does exactly what it should.  I can turn the master vol of my Marshall up to 5 , which is TOO DAMN LOUD for this area    and then use this little volume box to keep it down.  I can hear a much fuller sound out of the amp.

I think the 1Meg pot is too big.  Not much happens until the last 1/4 turn.  May have to try a 250K.  That may do the trick.

[al3151]

I used my MiniBooster in the effects loop before and found it worked great for lowering the volume.

MiniBooster,is there any thing you can't do :wink: .

[Gilles C]

This is the original wiring for this kind of box, except that the first version only had the volume pot.

http://www.diystompboxes.com/pedals/schems/volbox_mkii.gif

Gilles

[vanhansen]

Hmm, I never saw that one.  Interesting.  I think my 1meg pot is log rather than linear.  I'm going to try a few different pot values and find what works best for me.  Won't get to that until next week though.  Going out of town for the weekend.

One thing that I didn't mention in my last post is all the ground connections go to the back of the volume pot, both wires from the jack sleeve lug, and lug 1 of the volume pot.

[casey]

if you want an EASY attenuator, there is one on my site....link at the bottom of this message...  good luck...