The most important Blackface Mod for Silverface Gender Amps

The most important Blackface Mod for Silverface Gender Amps

Hello fellow guitar tone aficionados! If you know me, then you know that I am a total Fender amp geek; my desert island amp is a blackface Super Reverb, and the blackface Bassman, Pro Reverb, Vibrolux Reverb, and Deluxe Reverb probably round-out my top-5 list.  Yep, I'm crazy about vintage Fender amps, and, like most folks, I feel the blackface era amps are among the finest amps ever, period.  The tweed Fender amps (and browns, too) tend to not have as much solid bottom as I need, and the latter silverface amps just sound a little too sterile and clinical.  There are a couple of notable exceptions, see here: Drip Edge Fender Amps , and 1967 Silverface Deluxe Reverb;  but for let's assume we are NOT talking about the few rare 1967 drip-edge silverface amps that actually still sport blackface circuitry inside.  Right here and now I want to point out the one single most important mod for "blackfacing" a silverface Fender Amp.  Ready, let's go!

First I must credit the source of my photos, another fine blog on this same subject from Blueglow.de.  If you want to do the work yourself, there is a very good walk-through there.  However, the scope of this blog is simply to make you aware of the importance of the mod.  WARNING: if you are not well-versed in tube-amp repair, thoroughly educate yourself before sticking your hands in a tube-amp chassis, there IS available current inside to KILL you!  Nuff said, that's why I'm going to recommend you take your amp to a qualified tech to do this mod.  Here's what you request:

Remove my "balance" pot and give me blackface bias specs, pretty please.

In the silverface era  Fender changed the bias supply from a level to a balance control. The balance control allows the tech to match the tubes, but not set the bias level which is very much something that determines tone!  I generally change the bias supply to blackface specs because we generally use matched tubes these days!

Here are examples of the bias balance pot in different silverface amps and eras:

Now, this last thought:  Like I said, I snagged my pics from Blueglow.de, and he recommends actually KEEPING the bias balance pot but ADDING a bias adjustment pot for sorta a best of both worlds arrangement where you CAN set bias for the desired tone but can ALSO use unbalanced output tubes.  I'd be a little wary of using output tubes that are too terribly unbalanced as I'd be concerned they are of poor quality and/or one is worn out and on its last legs, but if you are a cheapskate always looking t save a few bucks on output tubes, it might be wort at least considering, so check out Blueglow.de  and also https://robrobinette.com/Silverface_Amp_Mods.htm  

See ya next week!