tfridgen":1xdgpfd8 said:
I've got an amp on the way here that has no line out or effects loop. I need a cheap, effective(good sounding) way to create a lineout from the speaker tap to run to my power amp. Dry cab is 4 ohms. Please suggest away.....
If you're good with a soldering iron and can drill a hole, I can show you how to turn a speaker out into an adjustable line out for $5 in parts that works great...
Here are are complete step by step instructions. But remember, your amps speaker out jacks may be wired differently than the ones in my amp. Anyway, here goes:
1) Obtain three 1W resistors (2.2K ohm, 470 ohm and 100 ohm)
2) Obtain a 5K linear taper mini potentiometer
3) Obtain a small marshall style knob
4) Find a good place between your two speaker jacks and drill a hole through the chassis that will accomodate the shaft of the mini pot. Make sure to clean out the debris from drilling...
5) My speaker jacks had the tips (and tip sw) connected to the hot speaker out and the sleeves (sleeve sw) connected to ground with straight bare wire. This means that the tip and tip sw are connected on each output jack as well as the sleeve and sleeve sw and both jacks are connected together via the same two wires. You want to use the second downstream output jack for your lineout, so clip out the wire connecting the tip sw of the first speaker jack to the tip of the second speaker jack (that jack will become your lineout).
6) Now, on the lineout jack, clip out the wire connecting the tip to the tip sw and the wire connecting the sleeve to the sleeve sw. Leave the wire connecting the sleeve of the lineout to the sleeve of the remaining speaker out. This is your ground.
7) Install your pot so that the 3 solder lugs are pointing up at you from the chassis (the amp should be upside down on the transformers with the circuit board facing you). Put the Marshall knob on.
8) From the center lug of the pot (the wiper), connect and solder the 100 ohm resistor to the tip of the lineout jack. Make sure you clip the resistor leads appropriately.
9) Connect one lead of the 2.2k ohm and 470 ohm to the right lug of the pot and then connect the other lead of the 2.2k ohm to the tip s/w of the remaining speaker out (not the lineout you are making). Connect the other lead of the 470ohm to the sleeve of the lineout. The sleeve of the lineout should still be connected to the sleeve sw of the remaining speaker out and thus to ground. Don't solder these yet!
10) Connect a plastic covered wire from the left lug of the pot to the sleeve (where the 470 ohm is connected).
11) Now solder all the connections
That is it... Make sure you understand the schematic of YOUR amp before attempting this - as it may be different. My amp is kinda like a Marshall 2204. Also, unplug your amp before working on it and drain the caps. If you don't do this you are exposing yourself to life threatening voltages.
DISCLAIMER: I take no responsibility for this mod in any way messing up your amp or you hurting or killing yourself with lethal voltages and am provding the info for informational/educational purposes only. Make sure you know what you are doing if you attempt it!
Best of luck!
Steve
