Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Tubes and Hybrids => Topic started by: GLUGSTER on January 09, 2009, 07:54:58 AM

Title: Fender Super Reverb FX loop conversion...is it possible?
Post by: GLUGSTER on January 09, 2009, 07:54:58 AM
I recently acquired a '66 Fender Super Reverb. The reverb tank is connected by two RCA connections (one in, one out). This to me looks a lot like an FX loop. I am wondering if it would be possible to use this in-out as an FX loop. Since this is a valuable amp and I don't want to screw it up, I am wondering if anybody has successfully done this and if some kind of impedance matching device needs to be instituted. Thanks again folks!
Title: Re: Fender Super Reverb FX loop conversion...is it possible?
Post by: phatt on January 09, 2009, 10:52:32 AM
Short answer is NO don't even think about it.
Long answer is yes but it's going to cost you so much as not to be worthwhile. :'(

On the subject of Efx loops I never found a use for them anyway,
maybe half useful on SState Amps but kinda stuffs the whole magic of tube Amps.
Cheers, Phil Nambour Australia.
Title: Re: Fender Super Reverb FX loop conversion...is it possible?
Post by: GLUGSTER on January 09, 2009, 07:18:15 PM
Quote from: phatt on January 09, 2009, 10:52:32 AM
Short answer is NO don't even think about it.
Long answer is yes but it's going to cost you so much as not to be worthwhile. :'(

On the subject of Efx loops I never found a use for them anyway,
maybe half useful on SState Amps but kinda stuffs the whole magic of tube Amps.
Cheers, Phil Nambour Australia.
I thank you for your response. However, "no don't even think about it" isn't working for me for 2 reasons: 1.Why not? Please explain why these the reverb loop CAN'T be used this way and 2. What would need to be done in some form of an out board conversion box to make this possible. Get technical and include Ohms and all that if possible. I guess I want the long answer.
Title: Re: Fender Super Reverb FX loop conversion...is it possible?
Post by: phatt on January 10, 2009, 09:21:58 AM
Hi glugster,
            Oh I see your not gonna give up but believe me you will eventually  :)
This is a bit like wanting a tow bar fitted on an F1 car so you can tow a boat.

The signal from the Rev Drive is designed to drive a transducer [not line level]
which is a coil of wire wrapped around a small chunk of steel.
Via magnetic transfer it then moves [vibrates] a suspended magnet connected to a long spring.
The principal is sorta reversed at the other end where the slightly delayed signal is picked up
and mixed into the original [Dry] signal.

The output at the Rev Driver socket is pumping maybe 5watts needed to drive the rev tank
and will kill most line level inputs connected directly without any serious
and probably expensive modification.

There's also a pile of complex impedence /inductance issues to deal
with both drive side and return side.
Obviously you don't want the reverb so just take it to a teck and rewire to a dedicated Effects loop, there should be enough space once you remove the reverb stuff.

There are already enough things that can go wrong just building a propper dedicated Effects loop,  Now add all these extra complexities,, and the odds of it working well are 20times worse.
This will likely end in tears for you and quite frankly,, IMHO
It's a darn easy way to stuff the resale value of a very good tube amp.

Hope you understand I'll have to go find a whole pile of complex equations for you and Having messed around with 100's if not more ways to wire things up inside and out side of Amplifiers I have learnt enough to know when Not to try certain things,, this is one of em.

Be warned Effx loops can easy bugga the whole magic of tube amps like yours.
They where never really designed for the modern efx junkies,, though some will agree.
If you want the bells and wistles  stuff buy an amp that has all that pleases you.

Cheers Phil.
Title: Re: Fender Super Reverb FX loop conversion...is it possible?
Post by: Enzo on January 12, 2009, 10:18:05 PM
Also, there is a reason most bass amps have no reverb.  Bottom end through a reverb makes not much but mud.  You will find a lot of reverb circuits limit the bottom end coming into the pan, so the send signal may be real tinny if you try this.
Title: Re: Fender Super Reverb FX loop conversion...is it possible?
Post by: monkeycabbage on August 29, 2009, 09:53:57 PM

I know that keeping an old post going isn't cool but I had a further question regarding using the reverb channel for effects.

http://www.studiosoundelectronics.com/ampkits.htm (http://www.studiosoundelectronics.com/ampkits.htm) sell a Fender® Gain Boost Cable
Stock No: GBC-1 for $9.95.

(http://www.studiosoundelectronics.com/gbc-1.gif)

Can/could this be used in a rock pro 700 (if I ever get it fixed that is). Would be great to use this as an extra punch for lead work as I barely ever use reverb.

Many thanks,
Ronnie
Title: Re: Fender Super Reverb FX loop conversion...is it possible?
Post by: J M Fahey on August 30, 2009, 07:50:35 AM
Hi Ronnie/monkeycab.
I know and used that trick, but it´s not for your amp or any modern Fender.
It´s nothing more than an rca to rca cable with an 8 ohm 2W resistor wired in parallel.
It absorbs the power supplied to the reverb drive coil and sends the remaining voltage into the reverb recovery preamp , overdriving it.
You get a fuzzy buzzy muddy distortion, controlled by the reverb pot, which although generally poor, was better than nothing in those old and clean blackface and silverface glories.
Of course you also lost Reverb.
You can get *much* better results by making your own DS1, Rat, Tube Screamer, or even a simple MXR Dist+ or a clean booster  MicroAmp.
Title: Re: Fender Super Reverb FX loop conversion...is it possible?
Post by: monkeycabbage on August 31, 2009, 07:57:08 PM
Thanks J M Fahey, I guess I should concentrate on just getting the amp working first eh?!??!