Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: shortfuse on October 09, 2010, 10:45:39 pm

Title: Adding a Effects Loop to a Amp W/O one Question
Post by: shortfuse on October 09, 2010, 10:45:39 pm

I have a good friend who knows I have embarked into the world of amp building and asked me to post this as I can not answer nor understand the answers he received.  He has been looking at plexi type amps mass produced, hand wired, and custom built.  Almost all of them do not have effects loops on them as the originals didn't.  He inquired at several local and out of state repair shops and a few builders and they all told him it could not and should not be added.  One person told him it absolutely could not be added to any PCB type amp.
He ended up buying a Marshall 1959 SLP because he had to have the effects loop.

If these statements are true, why? 

Title: Re: Adding a Effects Loop to a Amp W/O one Question
Post by: 67polara on October 09, 2010, 11:29:18 pm

I would think an Xacto and a drill would get you pretty close to getting it accomplished.  Are you talking active or passive?

Tony

Title: Re: Adding a Effects Loop to a Amp W/O one Question
Post by: LooseChange on October 10, 2010, 05:36:05 am

I've added loops to many amps with and without PC boards. Usually you can lift the coupling cap going into the pase inverter and splice the loop there. The other issue is making it look professional when you drill the chassis to add the loop. Sometimes I use one of the speaker jacks and install only one jack. I'll use a stereo type jack and set it up like an insert on a mixing board.

Title: Re: Adding a Effects Loop to a Amp W/O one Question
Post by: Fresh_Start on October 10, 2010, 08:13:53 am

Quote from: LooseChange on October 10, 2010, 05:36:05 am

I've added loops to many amps with and without PC boards. Usually you can lift the coupling cap going into the pase inverter and splice the loop there. The other issue is making it look professional when you drill the chassis to add the loop. Sometimes I use one of the speaker jacks and install only one jack. I'll use a stereo type jack and set it up like an insert on a mixing board.

LC - cool idea to use a single, stereo jack for the effects loop!

Chip

Title: Re: Adding a Effects Loop to a Amp W/O one Question
Post by: LooseChange on October 10, 2010, 08:30:56 am

I think I'm leaking too many Amp Cave secrets.   :smiley:

Title: Re: Adding a Effects Loop to a Amp W/O one Question
Post by: shortfuse on October 10, 2010, 02:28:20 pm

So it can be done these guys just didn't want to mess with it, as I suspected.
LC I have a amp that came factory with the stereo jack type loop it think the tip is send and the ring is return.  Cost an arm and a leg for the cable, knowing what I know now I would have just made one for 10 bucks.
Thanks for the reply's.

Title: Re: Adding a Effects Loop to a Amp W/O one Question
Post by: G._Hoffman on October 11, 2010, 04:46:42 pm

Quote from: shortfuse on October 10, 2010, 02:28:20 pm

So it can be done these guys just didn't want to mess with it, as I suspected.
LC I have a amp that came factory with the stereo jack type loop it think the tip is send and the ring is return.  Cost an arm and a leg for the cable, knowing what I know now I would have just made one for 10 bucks.
Thanks for the reply's.

That is typically how such things are set up.


Gabriel