Blues Jr. IV Headphones and FX Mods

[LadderFromMGS3]

Hi all,

I found this page about a headphone and FX loop mod for a Super Reverb. It looks like a simple mod (in reality this is more of an accessory than a mod, they are circuits inline with the amplifier/reverb tank), but I’m wondering if this is specific to the Super Reverb in any way. The page mentions the input resistor for the headphone mod to be rated at least double your amp’s wattage, so I assume this can be done on other amplifiers. What about the FX loop mod? Are Fender reverb tanks different from each other?

I figured I should double check before I start buying parts. Thanks!

https://www.premierguitar.com/gear/revi ... fects-loop

[Stevem]

The effects mod will not work right in your BJ.

Your BJs reverb tank is driven by a solid state device, the tank in the SR is driven by a tube and as such the input side of both reverb tanks are of a different impedance.

[pdf64]

Hi all,

I found this page about a headphone and FX loop mod for a Super Reverb.

Wow, that tech section feature has taken a downturn since RG’s immortal amp mods.

My view is that neither of the ideas on that page have any merit.

I assume this can be done on other amplifiers.

Yes, but it will sound bad. Now that cheap, decent sounding alternatives are available, I really doubt anyone actually uses such an arrangement by choice in a regular basis.
A reasonable emulation of a guitar speaker requires a more complex circuit than the simple single pole low pass filter presented in the article.

What about the FX loop mod? Are Fender reverb tanks different from each other?

Yes but more importantly, as noted, a variety of circuits are used to power signal into the tank. Almost all have significant high pass filtering, the send signal has no bottom end.
And with previous versions of the BJ, the sleeve circuit of the send is floating, not referenced to circuit common. If connected to circuit common, the circuit will malfunction, the signal will become very distorted.
The BJ IV schematic is not yet in the public domain, so dunno if that applies to your amp.

[LadderFromMGS3]

That’s unfortunate :/ it’s more complex than I thought! Thanks for the replies!!