Gain Box for FX loop

[jeroen_verbeeck]

Hi,

About a year ago I found this thing that was named "Gain Box".
You connect it to the FX loop of your amp.
It allows you to cranck up your amp to saturate your power tubes, but still keeps the volume low so you won't go deaf.

Since I'm going to buy a decent tube amp suitable for gigging really soon,
I wanted to have this so I can use this amp at home to without getting in to trouble with my neighbours.

The problem is I can't find it anymore.
Can you guy's help me please

[Ps: I think I found it on ebay for 20$ last year, and it stated that you could really easily build one yourself... ]

[crywolf]

Hi,
It is called the volume box. See the link
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=38074&item=3763023594&rd=1&ssPageName=WDVW

[gtech]

Here is the schematic of the last version with an effect loop added.

The original one had only the volume pot.

http://www.diystompboxes.com/cgi-bin/webbbs_scripts/webbbs_config.pl?read=281

[jjs]

It allows you to cranck up your amp to saturate your power tubes, but still keeps the volume low so you won't go deaf.

I don't think that it works this way. It's more like an (additional) master volume for the amp, because it just attenuates the signal coming from the "effect send"-jack and then sends the lower signal to the "effect return". This lower signal won't push the power tubes into distortion.

It more seems like you needed an attenuator for plugging in between the speaker output of the amp and the box. Like a Marshall Power Break.

[jeroen_verbeeck]

It allows you to cranck up your amp to saturate your power tubes, but still keeps the volume low so you won't go deaf.

I don't think that it works this way. It's more like an (additional) master volume for the amp, because it just attenuates the signal coming from the "effect send"-jack and then sends the lower signal to the "effect return". This lower signal won't push the power tubes into distortion.

I was thinking that to,
so I conclude that I won't drive my power tubes, but the preamp tubes will get hotter won't they ?
How will this affect the sound ?

[jjs]

Well, I think the main advantage of such a box is, that you can switch between two different volume levels with it.
As the seller in the ebay auction (see above) says on the article page, you can also reduce the volume, if the volume pot of the amp is too sensitive. Par example, volume 1 is already too much, when the preamp gain is maxed out. Then you can reduce the volume using the "gain box" without the need to reduce preamp distortion.

Btw, this is just what I think, I never used one of these devices.