Effects Loop...

[Bob M.]

My current client has requested an effects loop be installed on his/my latest homebrew build amp. I tried the most basic KO'C loop from TUT1 but with not great results. I need cheap, cheerful and basic, not a full-featured loop which could be either tube or solid state. Any helpful suggestions?

Thanks,

Bob M.

[Wilder Amplification]

You should consider ordering up the Zero Loss FX Loop kit from MetroAmp. They're 100% tonally transparent and they're as simple as they get. Just a simple send/return jack and a one time adjust trimpot on the board for setting it for unity gain plus an optional bypass toggle switch to bypass the loop.

[DIY_Guy]

My current client has requested an effects loop be installed on his/my latest homebrew build amp. I tried the most basic KO'C loop from TUT1 but with not great results. I need cheap, cheerful and basic, not a full-featured loop which could be either tube or solid state. Any helpful suggestions?

Thanks,

Bob M.

I copied the loop out of the 2203 Reissue amp. It's SS, and very easy to implement. I just use a different opamp in place of the TL072.

[Bob M.]

What's the 2203 reissue amp? Is that a Marshall?

[defaced]

The metroamp loop is based off of the LND150 high voltage, depletion mode, MOSFET. I've played with these and they are very nice devices, To-92 package, easily attainable, and inexpensive. The metroamp loop is by no means complicated, you could actually just take a basic tube loop, make a few small tweaks, install the LND150 MOSFETs, and probably be pretty close to it. You'll want to half the typical cathode resistors for this approach though, the LND-150 biases at a different point than typical preamp tubes.

[DIY_Guy]

What's the 2203 reissue amp? Is that a Marshall?

Yes. A company copied it as well, and sells kits if you are interested- IRONSOUNDS.COM

It's a bit cheaper than the Metro loop, but the Metro loop looks nicer.

[Bob M.]

Thanks, all for the suggestions!

Bob M.

[KevinOConnor]

Hi Guys

The simple loops shown in TUT are there to show you _what not to do_. The more sophisticated loops are transparent and do exactly what Bob and others desire. You do not have to install every switch or pot in the circuit, but you may regret that choice later. Fortunately, such things are easily retrofitted.

Our BFX loop kit is easy to install and is all-tube.

The cascode loops used in newer Marshalls are a copy of those shown in the Effects loops chapter of TUT.

Have fun
Kevin O'Connor